support go vet

Gopkg.lock

@@ -46,6 +46,17 @@
   revision = "1adfc126b41513cc696b209667c8656ea7aac67c"
   version = "v1.0.0"
 
+[[projects]]
+  branch = "master"
+  name = "github.com/golang/go"
+  packages = [
+    ".",
+    "lib/cfg",
+    "lib/whitelist"
+  ]
+  revision = "c5b798e3c473354ef919e8fe4e0a11b4a9e36d18"
+  source = "github.com/golangci/govet"
+
 [[projects]]
   name = "github.com/golang/mock"
   packages = ["gomock"]
@@ -201,6 +212,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "51ff4a5cc3ccf4539cdef62ac5a53cf5c57180d76d7ac9179380922d45b618c1"
+  inputs-digest = "6d7156f4c2a3467b6a312e9ddb07dc6f07385f9637c29e42a386afded9bb6ef3"
   solver-name = "gps-cdcl"
   solver-version = 1

Gopkg.toml

@@ -50,6 +50,11 @@
   branch = "master"
   source = "github.com/golangci/errcheck"
 
+[[constraint]]
+  name = "github.com/golang/go"
+  branch = "master"
+  source = "github.com/golangci/govet"
+
 [prune]
   go-tests = true
   unused-packages = true

internal/commands/run.go

@@ -37,6 +37,8 @@ func (e *Executor) initRun() {
 	runCmd.Flags().BoolVar(&rc.Errcheck.CheckClose, "errcheck.check-close", false, "Check missed error checks on .Close() calls")
 	runCmd.Flags().BoolVar(&rc.Errcheck.CheckTypeAssertions, "errcheck.check-type-assertions", false, "Check for ignored type assertion results")
 	runCmd.Flags().BoolVar(&rc.Errcheck.CheckAssignToBlank, "errcheck.check-blank", false, "Check for errors assigned to blank identifier: _ = errFunc()")
+
+	runCmd.Flags().BoolVar(&rc.Govet.CheckShadowing, "govet.check-shadowing", true, "Check for shadowed variables")
 }
 
 func (e Executor) executeRun(cmd *cobra.Command, args []string) {
@@ -76,7 +78,7 @@ func (e Executor) executeRun(cmd *cobra.Command, args []string) {
 		runner := pkg.SimpleRunner{
 			Processors: []processors.Processor{
 				processors.MaxLinterIssuesPerFile{},
-				processors.UniqByLineProcessor{},
+				//processors.UniqByLineProcessor{},
 				processors.NewPathPrettifier(),
 			},
 		}

pkg/config/config.go

@@ -27,6 +27,9 @@ type Run struct {
 		CheckTypeAssertions bool
 		CheckAssignToBlank  bool
 	}
+	Govet struct {
+		CheckShadowing bool
+	}
 }
 
 type Config struct {

pkg/golinters/govet.go

@@ -0,0 +1,34 @@
+package golinters
+
+import (
+	"context"
+
+	govetAPI "github.com/golang/go"
+	"github.com/golangci/golangci-lint/pkg/config"
+	"github.com/golangci/golangci-lint/pkg/result"
+	"github.com/golangci/golangci-shared/pkg/executors"
+)
+
+type govet struct{}
+
+func (govet) Name() string {
+	return "govet"
+}
+
+func (g govet) Run(ctx context.Context, exec executors.Executor, cfg *config.Run) (*result.Result, error) {
+	issues, err := govetAPI.Run(cfg.Paths, cfg.BuildTags, cfg.Govet.CheckShadowing)
+	if err != nil {
+		return nil, err
+	}
+
+	res := &result.Result{}
+	for _, i := range issues {
+		res.Issues = append(res.Issues, result.Issue{
+			File:       i.Pos.Filename,
+			LineNumber: i.Pos.Line,
+			Text:       i.Message,
+			FromLinter: g.Name(),
+		})
+	}
+	return res, nil
+}

pkg/golinters/govet_test.go

@@ -1,22 +0,0 @@
-package golinters
-
-import (
-	"testing"
-
-	"github.com/golangci/golangci-lint/pkg/result"
-)
-
-func TestGovetSimple(t *testing.T) {
-	const source = `package p
-
-import "os"
-
-func f() error {
-  return &os.PathError{"first", "path", os.ErrNotExist}
-}
-`
-
-	ExpectIssues(t, govet, source, []result.Issue{
-		NewIssue("govet", "os.PathError composite literal uses unkeyed fields", 6),
-	})
-}

pkg/golinters/supported_linters.go

@@ -6,8 +6,7 @@ const pathLineColMessage = `^(?P<path>.*?\.go):(?P<line>\d+):(?P<col>\d+):\s*(?P
 const pathLineMessage = `^(?P<path>.*?\.go):(?P<line>\d+):\s*(?P<message>.*)$`
 
 var golint = newLinter("golint", newLinterConfig("", pathLineColMessage, ""))
-var govet = newLinter("govet", newLinterConfig("", pathLineMessage, "", "--no-recurse"))
 
 func GetSupportedLinters() []pkg.Linter {
-	return []pkg.Linter{errcheck{}}
+	return []pkg.Linter{govet{}, errcheck{}}
 }

pkg/golinters/testdata/errcheck.go

@@ -1,4 +1,4 @@
-package p
+package testdata
 
 import (
 	"net/http"

pkg/golinters/testdata/govet.go

@@ -0,0 +1,19 @@
+package testdata
+
+import "os"
+
+func govet() error {
+	return &os.PathError{"first", "path", os.ErrNotExist} // ERROR "os.PathError composite literal uses unkeyed fields"
+}
+
+func govetShadow(f *os.File, buf []byte) (err error) {
+	if f != nil {
+		_, err := f.Read(buf) // ERROR "declaration of .err. shadows declaration at testdata/govet.go:9"
+		if err != nil {
+			return err
+		}
+	}
+	// Use variable to trigger shadowing error
+	_ = err
+	return
+}

pkg/runner.go

@@ -3,6 +3,7 @@ package pkg
 import (
 	"context"
 	"fmt"
+	"os"
 
 	"github.com/golangci/golangci-lint/pkg/config"
 	"github.com/golangci/golangci-lint/pkg/result"
@@ -21,8 +22,16 @@ type SimpleRunner struct {
 
 func (r SimpleRunner) Run(ctx context.Context, linters []Linter, exec executors.Executor, cfg *config.Run) ([]result.Issue, error) {
 	results := []result.Result{}
+	savedStdout, savedStderr := os.Stdout, os.Stderr
+	devNull, err := os.Open(os.DevNull)
+	if err != nil {
+		return nil, fmt.Errorf("can't open null device %q: %s", os.DevNull, err)
+	}
+
 	for _, linter := range linters {
+		os.Stdout, os.Stderr = devNull, devNull
 		res, err := linter.Run(ctx, exec, cfg)
+		os.Stdout, os.Stderr = savedStdout, savedStderr
 		if err != nil {
 			analytics.Log(ctx).Warnf("Can't run linter %+v: %s", linter, err)
 			continue
@@ -35,7 +44,7 @@ func (r SimpleRunner) Run(ctx context.Context, linters []Linter, exec executors.
 		results = append(results, *res)
 	}
 
-	results, err := r.processResults(results)
+	results, err = r.processResults(results)
 	if err != nil {
 		return nil, fmt.Errorf("can't process results: %s", err)
 	}

vendor/github.com/golang/go/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/golang/go/README

@@ -0,0 +1,33 @@
+Vet is a tool that checks correctness of Go programs. It runs a suite of tests,
+each tailored to check for a particular class of errors. Examples include incorrect
+Printf format verbs and malformed build tags.
+
+Over time many checks have been added to vet's suite, but many more have been
+rejected as not appropriate for the tool. The criteria applied when selecting which
+checks to add are:
+
+Correctness:
+
+Vet's checks are about correctness, not style. A vet check must identify real or
+potential bugs that could cause incorrect compilation or execution. A check that
+only identifies stylistic points or alternative correct approaches to a situation
+is not acceptable.
+
+Frequency:
+
+Vet is run every day by many programmers, often as part of every compilation or
+submission. The cost in execution time is considerable, especially in aggregate,
+so checks must be likely enough to find real problems that they are worth the
+overhead of the added check. A new check that finds only a handful of problems
+across all existing programs, even if the problem is significant, is not worth
+adding to the suite everyone runs daily.
+
+Precision:
+
+Most of vet's checks are heuristic and can generate both false positives (flagging
+correct programs) and false negatives (not flagging incorrect ones). The rate of
+both these failures must be very small. A check that is too noisy will be ignored
+by the programmer overwhelmed by the output; a check that misses too many of the
+cases it's looking for will give a false sense of security. Neither is acceptable.
+A vet check must be accurate enough that everything it reports is worth examining,
+and complete enough to encourage real confidence.

vendor/github.com/golang/go/asmdecl.go

@@ -0,0 +1,730 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Identify mismatches between assembly files and Go func declarations.
+
+package govet
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/build"
+	"go/token"
+	"go/types"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// 'kind' is a kind of assembly variable.
+// The kinds 1, 2, 4, 8 stand for values of that size.
+type asmKind int
+
+// These special kinds are not valid sizes.
+const (
+	asmString asmKind = 100 + iota
+	asmSlice
+	asmArray
+	asmInterface
+	asmEmptyInterface
+	asmStruct
+	asmComplex
+)
+
+// An asmArch describes assembly parameters for an architecture
+type asmArch struct {
+	name      string
+	bigEndian bool
+	stack     string
+	lr        bool
+	// calculated during initialization
+	sizes    types.Sizes
+	intSize  int
+	ptrSize  int
+	maxAlign int
+}
+
+// An asmFunc describes the expected variables for a function on a given architecture.
+type asmFunc struct {
+	arch        *asmArch
+	size        int // size of all arguments
+	vars        map[string]*asmVar
+	varByOffset map[int]*asmVar
+}
+
+// An asmVar describes a single assembly variable.
+type asmVar struct {
+	name  string
+	kind  asmKind
+	typ   string
+	off   int
+	size  int
+	inner []*asmVar
+}
+
+var (
+	asmArch386      = asmArch{name: "386", bigEndian: false, stack: "SP", lr: false}
+	asmArchArm      = asmArch{name: "arm", bigEndian: false, stack: "R13", lr: true}
+	asmArchArm64    = asmArch{name: "arm64", bigEndian: false, stack: "RSP", lr: true}
+	asmArchAmd64    = asmArch{name: "amd64", bigEndian: false, stack: "SP", lr: false}
+	asmArchAmd64p32 = asmArch{name: "amd64p32", bigEndian: false, stack: "SP", lr: false}
+	asmArchMips     = asmArch{name: "mips", bigEndian: true, stack: "R29", lr: true}
+	asmArchMipsLE   = asmArch{name: "mipsle", bigEndian: false, stack: "R29", lr: true}
+	asmArchMips64   = asmArch{name: "mips64", bigEndian: true, stack: "R29", lr: true}
+	asmArchMips64LE = asmArch{name: "mips64le", bigEndian: false, stack: "R29", lr: true}
+	asmArchPpc64    = asmArch{name: "ppc64", bigEndian: true, stack: "R1", lr: true}
+	asmArchPpc64LE  = asmArch{name: "ppc64le", bigEndian: false, stack: "R1", lr: true}
+	asmArchS390X    = asmArch{name: "s390x", bigEndian: true, stack: "R15", lr: true}
+
+	arches = []*asmArch{
+		&asmArch386,
+		&asmArchArm,
+		&asmArchArm64,
+		&asmArchAmd64,
+		&asmArchAmd64p32,
+		&asmArchMips,
+		&asmArchMipsLE,
+		&asmArchMips64,
+		&asmArchMips64LE,
+		&asmArchPpc64,
+		&asmArchPpc64LE,
+		&asmArchS390X,
+	}
+)
+
+func init() {
+	for _, arch := range arches {
+		arch.sizes = types.SizesFor("gc", arch.name)
+		if arch.sizes == nil {
+			panic("missing SizesFor for gc/" + arch.name)
+		}
+		arch.intSize = int(arch.sizes.Sizeof(types.Typ[types.Int]))
+		arch.ptrSize = int(arch.sizes.Sizeof(types.Typ[types.UnsafePointer]))
+		arch.maxAlign = int(arch.sizes.Alignof(types.Typ[types.Int64]))
+	}
+}
+
+var (
+	re           = regexp.MustCompile
+	asmPlusBuild = re(`//\s+\+build\s+([^\n]+)`)
+	asmTEXT      = re(`\bTEXT\b(.*)·([^\(]+)\(SB\)(?:\s*,\s*([0-9A-Z|+()]+))?(?:\s*,\s*\$(-?[0-9]+)(?:-([0-9]+))?)?`)
+	asmDATA      = re(`\b(DATA|GLOBL)\b`)
+	asmNamedFP   = re(`([a-zA-Z0-9_\xFF-\x{10FFFF}]+)(?:\+([0-9]+))\(FP\)`)
+	asmUnnamedFP = re(`[^+\-0-9](([0-9]+)\(FP\))`)
+	asmSP        = re(`[^+\-0-9](([0-9]+)\(([A-Z0-9]+)\))`)
+	asmOpcode    = re(`^\s*(?:[A-Z0-9a-z_]+:)?\s*([A-Z]+)\s*([^,]*)(?:,\s*(.*))?`)
+	ppc64Suff    = re(`([BHWD])(ZU|Z|U|BR)?$`)
+)
+
+func asmCheck(pkg *Package) {
+	if !vet("asmdecl") {
+		return
+	}
+
+	// No work if no assembly files.
+	if !pkg.hasFileWithSuffix(".s") {
+		return
+	}
+
+	// Gather declarations. knownFunc[name][arch] is func description.
+	knownFunc := make(map[string]map[string]*asmFunc)
+
+	for _, f := range pkg.files {
+		if f.file != nil {
+			for _, decl := range f.file.Decls {
+				if decl, ok := decl.(*ast.FuncDecl); ok && decl.Body == nil {
+					knownFunc[decl.Name.Name] = f.asmParseDecl(decl)
+				}
+			}
+		}
+	}
+
+Files:
+	for _, f := range pkg.files {
+		if !strings.HasSuffix(f.name, ".s") {
+			continue
+		}
+		Println("Checking file", f.name)
+
+		// Determine architecture from file name if possible.
+		var arch string
+		var archDef *asmArch
+		for _, a := range arches {
+			if strings.HasSuffix(f.name, "_"+a.name+".s") {
+				arch = a.name
+				archDef = a
+				break
+			}
+		}
+
+		lines := strings.SplitAfter(string(f.content), "\n")
+		var (
+			fn                 *asmFunc
+			fnName             string
+			localSize, argSize int
+			wroteSP            bool
+			haveRetArg         bool
+			retLine            []int
+		)
+
+		flushRet := func() {
+			if fn != nil && fn.vars["ret"] != nil && !haveRetArg && len(retLine) > 0 {
+				v := fn.vars["ret"]
+				for _, line := range retLine {
+					f.Badf(token.NoPos, "%s:%d: [%s] %s: RET without writing to %d-byte ret+%d(FP)", f.name, line, arch, fnName, v.size, v.off)
+				}
+			}
+			retLine = nil
+		}
+		for lineno, line := range lines {
+			lineno++
+
+			badf := func(format string, args ...interface{}) {
+				f.Badf(token.NoPos, "%s:%d: [%s] %s: %s", f.name, lineno, arch, fnName, fmt.Sprintf(format, args...))
+			}
+
+			if arch == "" {
+				// Determine architecture from +build line if possible.
+				if m := asmPlusBuild.FindStringSubmatch(line); m != nil {
+					// There can be multiple architectures in a single +build line,
+					// so accumulate them all and then prefer the one that
+					// matches build.Default.GOARCH.
+					var archCandidates []*asmArch
+					for _, fld := range strings.Fields(m[1]) {
+						for _, a := range arches {
+							if a.name == fld {
+								archCandidates = append(archCandidates, a)
+							}
+						}
+					}
+					for _, a := range archCandidates {
+						if a.name == build.Default.GOARCH {
+							archCandidates = []*asmArch{a}
+							break
+						}
+					}
+					if len(archCandidates) > 0 {
+						arch = archCandidates[0].name
+						archDef = archCandidates[0]
+					}
+				}
+			}
+
+			if m := asmTEXT.FindStringSubmatch(line); m != nil {
+				flushRet()
+				if arch == "" {
+					// Arch not specified by filename or build tags.
+					// Fall back to build.Default.GOARCH.
+					for _, a := range arches {
+						if a.name == build.Default.GOARCH {
+							arch = a.name
+							archDef = a
+							break
+						}
+					}
+					if arch == "" {
+						f.Warnf(token.NoPos, "%s: cannot determine architecture for assembly file", f.name)
+						continue Files
+					}
+				}
+				fnName = m[2]
+				if pkgName := strings.TrimSpace(m[1]); pkgName != "" {
+					pathParts := strings.Split(pkgName, "∕")
+					pkgName = pathParts[len(pathParts)-1]
+					if pkgName != f.pkg.path {
+						f.Warnf(token.NoPos, "%s:%d: [%s] cannot check cross-package assembly function: %s is in package %s", f.name, lineno, arch, fnName, pkgName)
+						fn = nil
+						fnName = ""
+						continue
+					}
+				}
+				flag := m[3]
+				fn = knownFunc[fnName][arch]
+				if fn != nil {
+					size, _ := strconv.Atoi(m[5])
+					if size != fn.size && (flag != "7" && !strings.Contains(flag, "NOSPLIT") || size != 0) {
+						badf("wrong argument size %d; expected $...-%d", size, fn.size)
+					}
+				}
+				localSize, _ = strconv.Atoi(m[4])
+				localSize += archDef.intSize
+				if archDef.lr && !strings.Contains(flag, "NOFRAME") {
+					// Account for caller's saved LR
+					localSize += archDef.intSize
+				}
+				argSize, _ = strconv.Atoi(m[5])
+				if fn == nil && !strings.Contains(fnName, "<>") {
+					badf("function %s missing Go declaration", fnName)
+				}
+				wroteSP = false
+				haveRetArg = false
+				continue
+			} else if strings.Contains(line, "TEXT") && strings.Contains(line, "SB") {
+				// function, but not visible from Go (didn't match asmTEXT), so stop checking
+				flushRet()
+				fn = nil
+				fnName = ""
+				continue
+			}
+
+			if strings.Contains(line, "RET") {
+				retLine = append(retLine, lineno)
+			}
+
+			if fnName == "" {
+				continue
+			}
+
+			if asmDATA.FindStringSubmatch(line) != nil {
+				fn = nil
+			}
+
+			if archDef == nil {
+				continue
+			}
+
+			if strings.Contains(line, ", "+archDef.stack) || strings.Contains(line, ",\t"+archDef.stack) {
+				wroteSP = true
+				continue
+			}
+
+			for _, m := range asmSP.FindAllStringSubmatch(line, -1) {
+				if m[3] != archDef.stack || wroteSP {
+					continue
+				}
+				off := 0
+				if m[1] != "" {
+					off, _ = strconv.Atoi(m[2])
+				}
+				if off >= localSize {
+					if fn != nil {
+						v := fn.varByOffset[off-localSize]
+						if v != nil {
+							badf("%s should be %s+%d(FP)", m[1], v.name, off-localSize)
+							continue
+						}
+					}
+					if off >= localSize+argSize {
+						badf("use of %s points beyond argument frame", m[1])
+						continue
+					}
+					badf("use of %s to access argument frame", m[1])
+				}
+			}
+
+			if fn == nil {
+				continue
+			}
+
+			for _, m := range asmUnnamedFP.FindAllStringSubmatch(line, -1) {
+				off, _ := strconv.Atoi(m[2])
+				v := fn.varByOffset[off]
+				if v != nil {
+					badf("use of unnamed argument %s; offset %d is %s+%d(FP)", m[1], off, v.name, v.off)
+				} else {
+					badf("use of unnamed argument %s", m[1])
+				}
+			}
+
+			for _, m := range asmNamedFP.FindAllStringSubmatch(line, -1) {
+				name := m[1]
+				off := 0
+				if m[2] != "" {
+					off, _ = strconv.Atoi(m[2])
+				}
+				if name == "ret" || strings.HasPrefix(name, "ret_") {
+					haveRetArg = true
+				}
+				v := fn.vars[name]
+				if v == nil {
+					// Allow argframe+0(FP).
+					if name == "argframe" && off == 0 {
+						continue
+					}
+					v = fn.varByOffset[off]
+					if v != nil {
+						badf("unknown variable %s; offset %d is %s+%d(FP)", name, off, v.name, v.off)
+					} else {
+						badf("unknown variable %s", name)
+					}
+					continue
+				}
+				asmCheckVar(badf, fn, line, m[0], off, v)
+			}
+		}
+		flushRet()
+	}
+}
+
+func asmKindForType(t types.Type, size int) asmKind {
+	switch t := t.Underlying().(type) {
+	case *types.Basic:
+		switch t.Kind() {
+		case types.String:
+			return asmString
+		case types.Complex64, types.Complex128:
+			return asmComplex
+		}
+		return asmKind(size)
+	case *types.Pointer, *types.Chan, *types.Map, *types.Signature:
+		return asmKind(size)
+	case *types.Struct:
+		return asmStruct
+	case *types.Interface:
+		if t.Empty() {
+			return asmEmptyInterface
+		}
+		return asmInterface
+	case *types.Array:
+		return asmArray
+	case *types.Slice:
+		return asmSlice
+	}
+	panic("unreachable")
+}
+
+// A component is an assembly-addressable component of a composite type,
+// or a composite type itself.
+type component struct {
+	size   int
+	offset int
+	kind   asmKind
+	typ    string
+	suffix string // Such as _base for string base, _0_lo for lo half of first element of [1]uint64 on 32 bit machine.
+	outer  string // The suffix for immediately containing composite type.
+}
+
+func newComponent(suffix string, kind asmKind, typ string, offset, size int, outer string) component {
+	return component{suffix: suffix, kind: kind, typ: typ, offset: offset, size: size, outer: outer}
+}
+
+// componentsOfType generates a list of components of type t.
+// For example, given string, the components are the string itself, the base, and the length.
+func componentsOfType(arch *asmArch, t types.Type) []component {
+	return appendComponentsRecursive(arch, t, nil, "", 0)
+}
+
+// appendComponentsRecursive implements componentsOfType.
+// Recursion is required to correct handle structs and arrays,
+// which can contain arbitrary other types.
+func appendComponentsRecursive(arch *asmArch, t types.Type, cc []component, suffix string, off int) []component {
+	s := t.String()
+	size := int(arch.sizes.Sizeof(t))
+	kind := asmKindForType(t, size)
+	cc = append(cc, newComponent(suffix, kind, s, off, size, suffix))
+
+	switch kind {
+	case 8:
+		if arch.ptrSize == 4 {
+			w1, w2 := "lo", "hi"
+			if arch.bigEndian {
+				w1, w2 = w2, w1
+			}
+			cc = append(cc, newComponent(suffix+"_"+w1, 4, "half "+s, off, 4, suffix))
+			cc = append(cc, newComponent(suffix+"_"+w2, 4, "half "+s, off+4, 4, suffix))
+		}
+
+	case asmEmptyInterface:
+		cc = append(cc, newComponent(suffix+"_type", asmKind(arch.ptrSize), "interface type", off, arch.ptrSize, suffix))
+		cc = append(cc, newComponent(suffix+"_data", asmKind(arch.ptrSize), "interface data", off+arch.ptrSize, arch.ptrSize, suffix))
+
+	case asmInterface:
+		cc = append(cc, newComponent(suffix+"_itable", asmKind(arch.ptrSize), "interface itable", off, arch.ptrSize, suffix))
+		cc = append(cc, newComponent(suffix+"_data", asmKind(arch.ptrSize), "interface data", off+arch.ptrSize, arch.ptrSize, suffix))
+
+	case asmSlice:
+		cc = append(cc, newComponent(suffix+"_base", asmKind(arch.ptrSize), "slice base", off, arch.ptrSize, suffix))
+		cc = append(cc, newComponent(suffix+"_len", asmKind(arch.intSize), "slice len", off+arch.ptrSize, arch.intSize, suffix))
+		cc = append(cc, newComponent(suffix+"_cap", asmKind(arch.intSize), "slice cap", off+arch.ptrSize+arch.intSize, arch.intSize, suffix))
+
+	case asmString:
+		cc = append(cc, newComponent(suffix+"_base", asmKind(arch.ptrSize), "string base", off, arch.ptrSize, suffix))
+		cc = append(cc, newComponent(suffix+"_len", asmKind(arch.intSize), "string len", off+arch.ptrSize, arch.intSize, suffix))
+
+	case asmComplex:
+		fsize := size / 2
+		cc = append(cc, newComponent(suffix+"_real", asmKind(fsize), fmt.Sprintf("real(complex%d)", size*8), off, fsize, suffix))
+		cc = append(cc, newComponent(suffix+"_imag", asmKind(fsize), fmt.Sprintf("imag(complex%d)", size*8), off+fsize, fsize, suffix))
+
+	case asmStruct:
+		tu := t.Underlying().(*types.Struct)
+		fields := make([]*types.Var, tu.NumFields())
+		for i := 0; i < tu.NumFields(); i++ {
+			fields[i] = tu.Field(i)
+		}
+		offsets := arch.sizes.Offsetsof(fields)
+		for i, f := range fields {
+			cc = appendComponentsRecursive(arch, f.Type(), cc, suffix+"_"+f.Name(), off+int(offsets[i]))
+		}
+
+	case asmArray:
+		tu := t.Underlying().(*types.Array)
+		elem := tu.Elem()
+		// Calculate offset of each element array.
+		fields := []*types.Var{
+			types.NewVar(token.NoPos, nil, "fake0", elem),
+			types.NewVar(token.NoPos, nil, "fake1", elem),
+		}
+		offsets := arch.sizes.Offsetsof(fields)
+		elemoff := int(offsets[1])
+		for i := 0; i < int(tu.Len()); i++ {
+			cc = appendComponentsRecursive(arch, elem, cc, suffix+"_"+strconv.Itoa(i), i*elemoff)
+		}
+	}
+
+	return cc
+}
+
+// asmParseDecl parses a function decl for expected assembly variables.
+func (f *File) asmParseDecl(decl *ast.FuncDecl) map[string]*asmFunc {
+	var (
+		arch   *asmArch
+		fn     *asmFunc
+		offset int
+	)
+
+	// addParams adds asmVars for each of the parameters in list.
+	// isret indicates whether the list are the arguments or the return values.
+	addParams := func(list []*ast.Field, isret bool) {
+		argnum := 0
+		for _, fld := range list {
+			t := f.pkg.types[fld.Type].Type
+			align := int(arch.sizes.Alignof(t))
+			size := int(arch.sizes.Sizeof(t))
+			offset += -offset & (align - 1)
+			cc := componentsOfType(arch, t)
+
+			// names is the list of names with this type.
+			names := fld.Names
+			if len(names) == 0 {
+				// Anonymous args will be called arg, arg1, arg2, ...
+				// Similarly so for return values: ret, ret1, ret2, ...
+				name := "arg"
+				if isret {
+					name = "ret"
+				}
+				if argnum > 0 {
+					name += strconv.Itoa(argnum)
+				}
+				names = []*ast.Ident{ast.NewIdent(name)}
+			}
+			argnum += len(names)
+
+			// Create variable for each name.
+			for _, id := range names {
+				name := id.Name
+				for _, c := range cc {
+					outer := name + c.outer
+					v := asmVar{
+						name: name + c.suffix,
+						kind: c.kind,
+						typ:  c.typ,
+						off:  offset + c.offset,
+						size: c.size,
+					}
+					if vo := fn.vars[outer]; vo != nil {
+						vo.inner = append(vo.inner, &v)
+					}
+					fn.vars[v.name] = &v
+					for i := 0; i < v.size; i++ {
+						fn.varByOffset[v.off+i] = &v
+					}
+				}
+				offset += size
+			}
+		}
+	}
+
+	m := make(map[string]*asmFunc)
+	for _, arch = range arches {
+		fn = &asmFunc{
+			arch:        arch,
+			vars:        make(map[string]*asmVar),
+			varByOffset: make(map[int]*asmVar),
+		}
+		offset = 0
+		addParams(decl.Type.Params.List, false)
+		if decl.Type.Results != nil && len(decl.Type.Results.List) > 0 {
+			offset += -offset & (arch.maxAlign - 1)
+			addParams(decl.Type.Results.List, true)
+		}
+		fn.size = offset
+		m[arch.name] = fn
+	}
+
+	return m
+}
+
+// asmCheckVar checks a single variable reference.
+func asmCheckVar(badf func(string, ...interface{}), fn *asmFunc, line, expr string, off int, v *asmVar) {
+	m := asmOpcode.FindStringSubmatch(line)
+	if m == nil {
+		if !strings.HasPrefix(strings.TrimSpace(line), "//") {
+			badf("cannot find assembly opcode")
+		}
+		return
+	}
+
+	// Determine operand sizes from instruction.
+	// Typically the suffix suffices, but there are exceptions.
+	var src, dst, kind asmKind
+	op := m[1]
+	switch fn.arch.name + "." + op {
+	case "386.FMOVLP":
+		src, dst = 8, 4
+	case "arm.MOVD":
+		src = 8
+	case "arm.MOVW":
+		src = 4
+	case "arm.MOVH", "arm.MOVHU":
+		src = 2
+	case "arm.MOVB", "arm.MOVBU":
+		src = 1
+	// LEA* opcodes don't really read the second arg.
+	// They just take the address of it.
+	case "386.LEAL":
+		dst = 4
+	case "amd64.LEAQ":
+		dst = 8
+	case "amd64p32.LEAL":
+		dst = 4
+	default:
+		switch fn.arch.name {
+		case "386", "amd64":
+			if strings.HasPrefix(op, "F") && (strings.HasSuffix(op, "D") || strings.HasSuffix(op, "DP")) {
+				// FMOVDP, FXCHD, etc
+				src = 8
+				break
+			}
+			if strings.HasPrefix(op, "P") && strings.HasSuffix(op, "RD") {
+				// PINSRD, PEXTRD, etc
+				src = 4
+				break
+			}
+			if strings.HasPrefix(op, "F") && (strings.HasSuffix(op, "F") || strings.HasSuffix(op, "FP")) {
+				// FMOVFP, FXCHF, etc
+				src = 4
+				break
+			}
+			if strings.HasSuffix(op, "SD") {
+				// MOVSD, SQRTSD, etc
+				src = 8
+				break
+			}
+			if strings.HasSuffix(op, "SS") {
+				// MOVSS, SQRTSS, etc
+				src = 4
+				break
+			}
+			if strings.HasPrefix(op, "SET") {
+				// SETEQ, etc
+				src = 1
+				break
+			}
+			switch op[len(op)-1] {
+			case 'B':
+				src = 1
+			case 'W':
+				src = 2
+			case 'L':
+				src = 4
+			case 'D', 'Q':
+				src = 8
+			}
+		case "ppc64", "ppc64le":
+			// Strip standard suffixes to reveal size letter.
+			m := ppc64Suff.FindStringSubmatch(op)
+			if m != nil {
+				switch m[1][0] {
+				case 'B':
+					src = 1
+				case 'H':
+					src = 2
+				case 'W':
+					src = 4
+				case 'D':
+					src = 8
+				}
+			}
+		case "mips", "mipsle", "mips64", "mips64le":
+			switch op {
+			case "MOVB", "MOVBU":
+				src = 1
+			case "MOVH", "MOVHU":
+				src = 2
+			case "MOVW", "MOVWU", "MOVF":
+				src = 4
+			case "MOVV", "MOVD":
+				src = 8
+			}
+		case "s390x":
+			switch op {
+			case "MOVB", "MOVBZ":
+				src = 1
+			case "MOVH", "MOVHZ":
+				src = 2
+			case "MOVW", "MOVWZ", "FMOVS":
+				src = 4
+			case "MOVD", "FMOVD":
+				src = 8
+			}
+		}
+	}
+	if dst == 0 {
+		dst = src
+	}
+
+	// Determine whether the match we're holding
+	// is the first or second argument.
+	if strings.Index(line, expr) > strings.Index(line, ",") {
+		kind = dst
+	} else {
+		kind = src
+	}
+
+	vk := v.kind
+	vs := v.size
+	vt := v.typ
+	switch vk {
+	case asmInterface, asmEmptyInterface, asmString, asmSlice:
+		// allow reference to first word (pointer)
+		vk = v.inner[0].kind
+		vs = v.inner[0].size
+		vt = v.inner[0].typ
+	}
+
+	if off != v.off {
+		var inner bytes.Buffer
+		for i, vi := range v.inner {
+			if len(v.inner) > 1 {
+				fmt.Fprintf(&inner, ",")
+			}
+			fmt.Fprintf(&inner, " ")
+			if i == len(v.inner)-1 {
+				fmt.Fprintf(&inner, "or ")
+			}
+			fmt.Fprintf(&inner, "%s+%d(FP)", vi.name, vi.off)
+		}
+		badf("invalid offset %s; expected %s+%d(FP)%s", expr, v.name, v.off, inner.String())
+		return
+	}
+	if kind != 0 && kind != vk {
+		var inner bytes.Buffer
+		if len(v.inner) > 0 {
+			fmt.Fprintf(&inner, " containing")
+			for i, vi := range v.inner {
+				if i > 0 && len(v.inner) > 2 {
+					fmt.Fprintf(&inner, ",")
+				}
+				fmt.Fprintf(&inner, " ")
+				if i > 0 && i == len(v.inner)-1 {
+					fmt.Fprintf(&inner, "and ")
+				}
+				fmt.Fprintf(&inner, "%s+%d(FP)", vi.name, vi.off)
+			}
+		}
+		badf("invalid %s of %s; %s is %d-byte value%s", op, expr, vt, vs, inner.String())
+	}
+}

vendor/github.com/golang/go/assign.go

@@ -0,0 +1,52 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+This file contains the code to check for useless assignments.
+*/
+
+package govet
+
+import (
+	"go/ast"
+	"go/token"
+	"reflect"
+)
+
+func init() {
+	register("assign",
+		"check for useless assignments",
+		checkAssignStmt,
+		assignStmt)
+}
+
+// TODO: should also check for assignments to struct fields inside methods
+// that are on T instead of *T.
+
+// checkAssignStmt checks for assignments of the form "<expr> = <expr>".
+// These are almost always useless, and even when they aren't they are usually a mistake.
+func checkAssignStmt(f *File, node ast.Node) {
+	stmt := node.(*ast.AssignStmt)
+	if stmt.Tok != token.ASSIGN {
+		return // ignore :=
+	}
+	if len(stmt.Lhs) != len(stmt.Rhs) {
+		// If LHS and RHS have different cardinality, they can't be the same.
+		return
+	}
+	for i, lhs := range stmt.Lhs {
+		rhs := stmt.Rhs[i]
+		if hasSideEffects(f, lhs) || hasSideEffects(f, rhs) {
+			continue // expressions may not be equal
+		}
+		if reflect.TypeOf(lhs) != reflect.TypeOf(rhs) {
+			continue // short-circuit the heavy-weight gofmt check
+		}
+		le := f.gofmt(lhs)
+		re := f.gofmt(rhs)
+		if le == re {
+			f.Badf(stmt.Pos(), "self-assignment of %s to %s", re, le)
+		}
+	}
+}

vendor/github.com/golang/go/atomic.go

@@ -0,0 +1,71 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package govet
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+func init() {
+	register("atomic",
+		"check for common mistaken usages of the sync/atomic package",
+		checkAtomicAssignment,
+		assignStmt)
+}
+
+// checkAtomicAssignment walks the assignment statement checking for common
+// mistaken usage of atomic package, such as: x = atomic.AddUint64(&x, 1)
+func checkAtomicAssignment(f *File, node ast.Node) {
+	n := node.(*ast.AssignStmt)
+	if len(n.Lhs) != len(n.Rhs) {
+		return
+	}
+	if len(n.Lhs) == 1 && n.Tok == token.DEFINE {
+		return
+	}
+
+	for i, right := range n.Rhs {
+		call, ok := right.(*ast.CallExpr)
+		if !ok {
+			continue
+		}
+		sel, ok := call.Fun.(*ast.SelectorExpr)
+		if !ok {
+			continue
+		}
+		pkgIdent, _ := sel.X.(*ast.Ident)
+		pkgName, ok := f.pkg.uses[pkgIdent].(*types.PkgName)
+		if !ok || pkgName.Imported().Path() != "sync/atomic" {
+			continue
+		}
+
+		switch sel.Sel.Name {
+		case "AddInt32", "AddInt64", "AddUint32", "AddUint64", "AddUintptr":
+			f.checkAtomicAddAssignment(n.Lhs[i], call)
+		}
+	}
+}
+
+// checkAtomicAddAssignment walks the atomic.Add* method calls checking for assigning the return value
+// to the same variable being used in the operation
+func (f *File) checkAtomicAddAssignment(left ast.Expr, call *ast.CallExpr) {
+	if len(call.Args) != 2 {
+		return
+	}
+	arg := call.Args[0]
+	broken := false
+
+	if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND {
+		broken = f.gofmt(left) == f.gofmt(uarg.X)
+	} else if star, ok := left.(*ast.StarExpr); ok {
+		broken = f.gofmt(star.X) == f.gofmt(arg)
+	}
+
+	if broken {
+		f.Bad(left.Pos(), "direct assignment to atomic value")
+	}
+}

vendor/github.com/golang/go/bool.go

@@ -0,0 +1,197 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains boolean condition tests.
+
+package govet
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+func init() {
+	register("bool",
+		"check for mistakes involving boolean operators",
+		checkBool,
+		binaryExpr)
+}
+
+func checkBool(f *File, n ast.Node) {
+	e := n.(*ast.BinaryExpr)
+
+	var op boolOp
+	switch e.Op {
+	case token.LOR:
+		op = or
+	case token.LAND:
+		op = and
+	default:
+		return
+	}
+
+	comm := op.commutativeSets(f, e)
+	for _, exprs := range comm {
+		op.checkRedundant(f, exprs)
+		op.checkSuspect(f, exprs)
+	}
+}
+
+type boolOp struct {
+	name  string
+	tok   token.Token // token corresponding to this operator
+	badEq token.Token // token corresponding to the equality test that should not be used with this operator
+}
+
+var (
+	or  = boolOp{"or", token.LOR, token.NEQ}
+	and = boolOp{"and", token.LAND, token.EQL}
+)
+
+// commutativeSets returns all side effect free sets of
+// expressions in e that are connected by op.
+// For example, given 'a || b || f() || c || d' with the or op,
+// commutativeSets returns {{b, a}, {d, c}}.
+func (op boolOp) commutativeSets(f *File, e *ast.BinaryExpr) [][]ast.Expr {
+	exprs := op.split(e)
+
+	// Partition the slice of expressions into commutative sets.
+	i := 0
+	var sets [][]ast.Expr
+	for j := 0; j <= len(exprs); j++ {
+		if j == len(exprs) || hasSideEffects(f, exprs[j]) {
+			if i < j {
+				sets = append(sets, exprs[i:j])
+			}
+			i = j + 1
+		}
+	}
+
+	return sets
+}
+
+// checkRedundant checks for expressions of the form
+//   e && e
+//   e || e
+// Exprs must contain only side effect free expressions.
+func (op boolOp) checkRedundant(f *File, exprs []ast.Expr) {
+	seen := make(map[string]bool)
+	for _, e := range exprs {
+		efmt := f.gofmt(e)
+		if seen[efmt] {
+			f.Badf(e.Pos(), "redundant %s: %s %s %s", op.name, efmt, op.tok, efmt)
+		} else {
+			seen[efmt] = true
+		}
+	}
+}
+
+// checkSuspect checks for expressions of the form
+//   x != c1 || x != c2
+//   x == c1 && x == c2
+// where c1 and c2 are constant expressions.
+// If c1 and c2 are the same then it's redundant;
+// if c1 and c2 are different then it's always true or always false.
+// Exprs must contain only side effect free expressions.
+func (op boolOp) checkSuspect(f *File, exprs []ast.Expr) {
+	// seen maps from expressions 'x' to equality expressions 'x != c'.
+	seen := make(map[string]string)
+
+	for _, e := range exprs {
+		bin, ok := e.(*ast.BinaryExpr)
+		if !ok || bin.Op != op.badEq {
+			continue
+		}
+
+		// In order to avoid false positives, restrict to cases
+		// in which one of the operands is constant. We're then
+		// interested in the other operand.
+		// In the rare case in which both operands are constant
+		// (e.g. runtime.GOOS and "windows"), we'll only catch
+		// mistakes if the LHS is repeated, which is how most
+		// code is written.
+		var x ast.Expr
+		switch {
+		case f.pkg.types[bin.Y].Value != nil:
+			x = bin.X
+		case f.pkg.types[bin.X].Value != nil:
+			x = bin.Y
+		default:
+			continue
+		}
+
+		// e is of the form 'x != c' or 'x == c'.
+		xfmt := f.gofmt(x)
+		efmt := f.gofmt(e)
+		if prev, found := seen[xfmt]; found {
+			// checkRedundant handles the case in which efmt == prev.
+			if efmt != prev {
+				f.Badf(e.Pos(), "suspect %s: %s %s %s", op.name, efmt, op.tok, prev)
+			}
+		} else {
+			seen[xfmt] = efmt
+		}
+	}
+}
+
+// hasSideEffects reports whether evaluation of e has side effects.
+func hasSideEffects(f *File, e ast.Expr) bool {
+	safe := true
+	ast.Inspect(e, func(node ast.Node) bool {
+		switch n := node.(type) {
+		case *ast.CallExpr:
+			// Don't call Type.Underlying(), since its lack
+			// lets us see the NamedFuncType(x) type
+			// conversion as a *types.Named.
+			_, ok := f.pkg.types[n.Fun].Type.(*types.Signature)
+			if ok {
+				// Conservatively assume that all function and
+				// method calls have side effects for
+				// now. This will include func type
+				// conversions, but it's ok given that
+				// this is the conservative side.
+				safe = false
+				return false
+			}
+			// It's a type conversion, which cannot
+			// have side effects.
+		case *ast.UnaryExpr:
+			if n.Op == token.ARROW {
+				safe = false
+				return false
+			}
+		}
+		return true
+	})
+	return !safe
+}
+
+// split returns a slice of all subexpressions in e that are connected by op.
+// For example, given 'a || (b || c) || d' with the or op,
+// split returns []{d, c, b, a}.
+func (op boolOp) split(e ast.Expr) (exprs []ast.Expr) {
+	for {
+		e = unparen(e)
+		if b, ok := e.(*ast.BinaryExpr); ok && b.Op == op.tok {
+			exprs = append(exprs, op.split(b.Y)...)
+			e = b.X
+		} else {
+			exprs = append(exprs, e)
+			break
+		}
+	}
+	return
+}
+
+// unparen returns e with any enclosing parentheses stripped.
+func unparen(e ast.Expr) ast.Expr {
+	for {
+		p, ok := e.(*ast.ParenExpr)
+		if !ok {
+			return e
+		}
+		e = p.X
+	}
+}

vendor/github.com/golang/go/buildtag.go

@@ -0,0 +1,91 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package govet
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"strings"
+	"unicode"
+)
+
+var (
+	nl         = []byte("\n")
+	slashSlash = []byte("//")
+	plusBuild  = []byte("+build")
+)
+
+// checkBuildTag checks that build tags are in the correct location and well-formed.
+func checkBuildTag(name string, data []byte) {
+	if !vet("buildtags") {
+		return
+	}
+	lines := bytes.SplitAfter(data, nl)
+
+	// Determine cutpoint where +build comments are no longer valid.
+	// They are valid in leading // comments in the file followed by
+	// a blank line.
+	var cutoff int
+	for i, line := range lines {
+		line = bytes.TrimSpace(line)
+		if len(line) == 0 {
+			cutoff = i
+			continue
+		}
+		if bytes.HasPrefix(line, slashSlash) {
+			continue
+		}
+		break
+	}
+
+	for i, line := range lines {
+		line = bytes.TrimSpace(line)
+		if !bytes.HasPrefix(line, slashSlash) {
+			continue
+		}
+		text := bytes.TrimSpace(line[2:])
+		if bytes.HasPrefix(text, plusBuild) {
+			fields := bytes.Fields(text)
+			if !bytes.Equal(fields[0], plusBuild) {
+				// Comment is something like +buildasdf not +build.
+				fmt.Fprintf(os.Stderr, "%s:%d: possible malformed +build comment\n", name, i+1)
+				setExit(1)
+				continue
+			}
+			if i >= cutoff {
+				fmt.Fprintf(os.Stderr, "%s:%d: +build comment must appear before package clause and be followed by a blank line\n", name, i+1)
+				setExit(1)
+				continue
+			}
+			// Check arguments.
+		Args:
+			for _, arg := range fields[1:] {
+				for _, elem := range strings.Split(string(arg), ",") {
+					if strings.HasPrefix(elem, "!!") {
+						fmt.Fprintf(os.Stderr, "%s:%d: invalid double negative in build constraint: %s\n", name, i+1, arg)
+						setExit(1)
+						break Args
+					}
+					elem = strings.TrimPrefix(elem, "!")
+					for _, c := range elem {
+						if !unicode.IsLetter(c) && !unicode.IsDigit(c) && c != '_' && c != '.' {
+							fmt.Fprintf(os.Stderr, "%s:%d: invalid non-alphanumeric build constraint: %s\n", name, i+1, arg)
+							setExit(1)
+							break Args
+						}
+					}
+				}
+			}
+			continue
+		}
+		// Comment with +build but not at beginning.
+		if bytes.Contains(line, plusBuild) && i < cutoff {
+			fmt.Fprintf(os.Stderr, "%s:%d: possible malformed +build comment\n", name, i+1)
+			setExit(1)
+			continue
+		}
+	}
+}

vendor/github.com/golang/go/cgo.go

@@ -0,0 +1,141 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Check for invalid cgo pointer passing.
+// This looks for code that uses cgo to call C code passing values
+// whose types are almost always invalid according to the cgo pointer
+// sharing rules.
+// Specifically, it warns about attempts to pass a Go chan, map, func,
+// or slice to C, either directly, or via a pointer, array, or struct.
+
+package govet
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+func init() {
+	register("cgocall",
+		"check for types that may not be passed to cgo calls",
+		checkCgoCall,
+		callExpr)
+}
+
+func checkCgoCall(f *File, node ast.Node) {
+	x := node.(*ast.CallExpr)
+
+	// We are only looking for calls to functions imported from
+	// the "C" package.
+	sel, ok := x.Fun.(*ast.SelectorExpr)
+	if !ok {
+		return
+	}
+	id, ok := sel.X.(*ast.Ident)
+	if !ok {
+		return
+	}
+
+	pkgname, ok := f.pkg.uses[id].(*types.PkgName)
+	if !ok || pkgname.Imported().Path() != "C" {
+		return
+	}
+
+	// A call to C.CBytes passes a pointer but is always safe.
+	if sel.Sel.Name == "CBytes" {
+		return
+	}
+
+	for _, arg := range x.Args {
+		if !typeOKForCgoCall(cgoBaseType(f, arg), make(map[types.Type]bool)) {
+			f.Badf(arg.Pos(), "possibly passing Go type with embedded pointer to C")
+		}
+
+		// Check for passing the address of a bad type.
+		if conv, ok := arg.(*ast.CallExpr); ok && len(conv.Args) == 1 && f.hasBasicType(conv.Fun, types.UnsafePointer) {
+			arg = conv.Args[0]
+		}
+		if u, ok := arg.(*ast.UnaryExpr); ok && u.Op == token.AND {
+			if !typeOKForCgoCall(cgoBaseType(f, u.X), make(map[types.Type]bool)) {
+				f.Badf(arg.Pos(), "possibly passing Go type with embedded pointer to C")
+			}
+		}
+	}
+}
+
+// cgoBaseType tries to look through type conversions involving
+// unsafe.Pointer to find the real type. It converts:
+//   unsafe.Pointer(x) => x
+//   *(*unsafe.Pointer)(unsafe.Pointer(&x)) => x
+func cgoBaseType(f *File, arg ast.Expr) types.Type {
+	switch arg := arg.(type) {
+	case *ast.CallExpr:
+		if len(arg.Args) == 1 && f.hasBasicType(arg.Fun, types.UnsafePointer) {
+			return cgoBaseType(f, arg.Args[0])
+		}
+	case *ast.StarExpr:
+		call, ok := arg.X.(*ast.CallExpr)
+		if !ok || len(call.Args) != 1 {
+			break
+		}
+		// Here arg is *f(v).
+		t := f.pkg.types[call.Fun].Type
+		if t == nil {
+			break
+		}
+		ptr, ok := t.Underlying().(*types.Pointer)
+		if !ok {
+			break
+		}
+		// Here arg is *(*p)(v)
+		elem, ok := ptr.Elem().Underlying().(*types.Basic)
+		if !ok || elem.Kind() != types.UnsafePointer {
+			break
+		}
+		// Here arg is *(*unsafe.Pointer)(v)
+		call, ok = call.Args[0].(*ast.CallExpr)
+		if !ok || len(call.Args) != 1 {
+			break
+		}
+		// Here arg is *(*unsafe.Pointer)(f(v))
+		if !f.hasBasicType(call.Fun, types.UnsafePointer) {
+			break
+		}
+		// Here arg is *(*unsafe.Pointer)(unsafe.Pointer(v))
+		u, ok := call.Args[0].(*ast.UnaryExpr)
+		if !ok || u.Op != token.AND {
+			break
+		}
+		// Here arg is *(*unsafe.Pointer)(unsafe.Pointer(&v))
+		return cgoBaseType(f, u.X)
+	}
+
+	return f.pkg.types[arg].Type
+}
+
+// typeOKForCgoCall reports whether the type of arg is OK to pass to a
+// C function using cgo. This is not true for Go types with embedded
+// pointers. m is used to avoid infinite recursion on recursive types.
+func typeOKForCgoCall(t types.Type, m map[types.Type]bool) bool {
+	if t == nil || m[t] {
+		return true
+	}
+	m[t] = true
+	switch t := t.Underlying().(type) {
+	case *types.Chan, *types.Map, *types.Signature, *types.Slice:
+		return false
+	case *types.Pointer:
+		return typeOKForCgoCall(t.Elem(), m)
+	case *types.Array:
+		return typeOKForCgoCall(t.Elem(), m)
+	case *types.Struct:
+		for i := 0; i < t.NumFields(); i++ {
+			if !typeOKForCgoCall(t.Field(i).Type(), m) {
+				return false
+			}
+		}
+	}
+	return true
+}

vendor/github.com/golang/go/composite.go

@@ -0,0 +1,87 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains the test for unkeyed struct literals.
+
+package govet
+
+import (
+	"flag"
+	"go/ast"
+	"go/types"
+	"strings"
+
+	"github.com/golang/go/lib/whitelist"
+)
+
+var compositeWhiteList = flag.Bool("compositewhitelist", true, "use composite white list; for testing only")
+
+func init() {
+	register("composites",
+		"check that composite literals used field-keyed elements",
+		checkUnkeyedLiteral,
+		compositeLit)
+}
+
+// checkUnkeyedLiteral checks if a composite literal is a struct literal with
+// unkeyed fields.
+func checkUnkeyedLiteral(f *File, node ast.Node) {
+	cl := node.(*ast.CompositeLit)
+
+	typ := f.pkg.types[cl].Type
+	if typ == nil {
+		// cannot determine composite literals' type, skip it
+		return
+	}
+	typeName := typ.String()
+	if *compositeWhiteList && whitelist.UnkeyedLiteral[typeName] {
+		// skip whitelisted types
+		return
+	}
+	under := typ.Underlying()
+	for {
+		ptr, ok := under.(*types.Pointer)
+		if !ok {
+			break
+		}
+		under = ptr.Elem().Underlying()
+	}
+	if _, ok := under.(*types.Struct); !ok {
+		// skip non-struct composite literals
+		return
+	}
+	if isLocalType(f, typ) {
+		// allow unkeyed locally defined composite literal
+		return
+	}
+
+	// check if the CompositeLit contains an unkeyed field
+	allKeyValue := true
+	for _, e := range cl.Elts {
+		if _, ok := e.(*ast.KeyValueExpr); !ok {
+			allKeyValue = false
+			break
+		}
+	}
+	if allKeyValue {
+		// all the composite literal fields are keyed
+		return
+	}
+
+	f.Badf(cl.Pos(), "%s composite literal uses unkeyed fields", typeName)
+}
+
+func isLocalType(f *File, typ types.Type) bool {
+	switch x := typ.(type) {
+	case *types.Struct:
+		// struct literals are local types
+		return true
+	case *types.Pointer:
+		return isLocalType(f, x.Elem())
+	case *types.Named:
+		// names in package foo are local to foo_test too
+		return strings.TrimSuffix(x.Obj().Pkg().Path(), "_test") == strings.TrimSuffix(f.pkg.path, "_test")
+	}
+	return false
+}

vendor/github.com/golang/go/copylock.go

@@ -0,0 +1,256 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains the code to check that locks are not passed by value.
+
+package govet
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+func init() {
+	register("copylocks",
+		"check that locks are not passed by value",
+		checkCopyLocks,
+		funcDecl, rangeStmt, funcLit, callExpr, assignStmt, genDecl, compositeLit, returnStmt)
+}
+
+// checkCopyLocks checks whether node might
+// inadvertently copy a lock.
+func checkCopyLocks(f *File, node ast.Node) {
+	switch node := node.(type) {
+	case *ast.RangeStmt:
+		checkCopyLocksRange(f, node)
+	case *ast.FuncDecl:
+		checkCopyLocksFunc(f, node.Name.Name, node.Recv, node.Type)
+	case *ast.FuncLit:
+		checkCopyLocksFunc(f, "func", nil, node.Type)
+	case *ast.CallExpr:
+		checkCopyLocksCallExpr(f, node)
+	case *ast.AssignStmt:
+		checkCopyLocksAssign(f, node)
+	case *ast.GenDecl:
+		checkCopyLocksGenDecl(f, node)
+	case *ast.CompositeLit:
+		checkCopyLocksCompositeLit(f, node)
+	case *ast.ReturnStmt:
+		checkCopyLocksReturnStmt(f, node)
+	}
+}
+
+// checkCopyLocksAssign checks whether an assignment
+// copies a lock.
+func checkCopyLocksAssign(f *File, as *ast.AssignStmt) {
+	for i, x := range as.Rhs {
+		if path := lockPathRhs(f, x); path != nil {
+			f.Badf(x.Pos(), "assignment copies lock value to %v: %v", f.gofmt(as.Lhs[i]), path)
+		}
+	}
+}
+
+// checkCopyLocksGenDecl checks whether lock is copied
+// in variable declaration.
+func checkCopyLocksGenDecl(f *File, gd *ast.GenDecl) {
+	if gd.Tok != token.VAR {
+		return
+	}
+	for _, spec := range gd.Specs {
+		valueSpec := spec.(*ast.ValueSpec)
+		for i, x := range valueSpec.Values {
+			if path := lockPathRhs(f, x); path != nil {
+				f.Badf(x.Pos(), "variable declaration copies lock value to %v: %v", valueSpec.Names[i].Name, path)
+			}
+		}
+	}
+}
+
+// checkCopyLocksCompositeLit detects lock copy inside a composite literal
+func checkCopyLocksCompositeLit(f *File, cl *ast.CompositeLit) {
+	for _, x := range cl.Elts {
+		if node, ok := x.(*ast.KeyValueExpr); ok {
+			x = node.Value
+		}
+		if path := lockPathRhs(f, x); path != nil {
+			f.Badf(x.Pos(), "literal copies lock value from %v: %v", f.gofmt(x), path)
+		}
+	}
+}
+
+// checkCopyLocksReturnStmt detects lock copy in return statement
+func checkCopyLocksReturnStmt(f *File, rs *ast.ReturnStmt) {
+	for _, x := range rs.Results {
+		if path := lockPathRhs(f, x); path != nil {
+			f.Badf(x.Pos(), "return copies lock value: %v", path)
+		}
+	}
+}
+
+// checkCopyLocksCallExpr detects lock copy in the arguments to a function call
+func checkCopyLocksCallExpr(f *File, ce *ast.CallExpr) {
+	var id *ast.Ident
+	switch fun := ce.Fun.(type) {
+	case *ast.Ident:
+		id = fun
+	case *ast.SelectorExpr:
+		id = fun.Sel
+	}
+	if fun, ok := f.pkg.uses[id].(*types.Builtin); ok {
+		switch fun.Name() {
+		case "new", "len", "cap", "Sizeof":
+			return
+		}
+	}
+	for _, x := range ce.Args {
+		if path := lockPathRhs(f, x); path != nil {
+			f.Badf(x.Pos(), "call of %s copies lock value: %v", f.gofmt(ce.Fun), path)
+		}
+	}
+}
+
+// checkCopyLocksFunc checks whether a function might
+// inadvertently copy a lock, by checking whether
+// its receiver, parameters, or return values
+// are locks.
+func checkCopyLocksFunc(f *File, name string, recv *ast.FieldList, typ *ast.FuncType) {
+	if recv != nil && len(recv.List) > 0 {
+		expr := recv.List[0].Type
+		if path := lockPath(f.pkg.typesPkg, f.pkg.types[expr].Type); path != nil {
+			f.Badf(expr.Pos(), "%s passes lock by value: %v", name, path)
+		}
+	}
+
+	if typ.Params != nil {
+		for _, field := range typ.Params.List {
+			expr := field.Type
+			if path := lockPath(f.pkg.typesPkg, f.pkg.types[expr].Type); path != nil {
+				f.Badf(expr.Pos(), "%s passes lock by value: %v", name, path)
+			}
+		}
+	}
+
+	// Don't check typ.Results. If T has a Lock field it's OK to write
+	//     return T{}
+	// because that is returning the zero value. Leave result checking
+	// to the return statement.
+}
+
+// checkCopyLocksRange checks whether a range statement
+// might inadvertently copy a lock by checking whether
+// any of the range variables are locks.
+func checkCopyLocksRange(f *File, r *ast.RangeStmt) {
+	checkCopyLocksRangeVar(f, r.Tok, r.Key)
+	checkCopyLocksRangeVar(f, r.Tok, r.Value)
+}
+
+func checkCopyLocksRangeVar(f *File, rtok token.Token, e ast.Expr) {
+	if e == nil {
+		return
+	}
+	id, isId := e.(*ast.Ident)
+	if isId && id.Name == "_" {
+		return
+	}
+
+	var typ types.Type
+	if rtok == token.DEFINE {
+		if !isId {
+			return
+		}
+		obj := f.pkg.defs[id]
+		if obj == nil {
+			return
+		}
+		typ = obj.Type()
+	} else {
+		typ = f.pkg.types[e].Type
+	}
+
+	if typ == nil {
+		return
+	}
+	if path := lockPath(f.pkg.typesPkg, typ); path != nil {
+		f.Badf(e.Pos(), "range var %s copies lock: %v", f.gofmt(e), path)
+	}
+}
+
+type typePath []types.Type
+
+// String pretty-prints a typePath.
+func (path typePath) String() string {
+	n := len(path)
+	var buf bytes.Buffer
+	for i := range path {
+		if i > 0 {
+			fmt.Fprint(&buf, " contains ")
+		}
+		// The human-readable path is in reverse order, outermost to innermost.
+		fmt.Fprint(&buf, path[n-i-1].String())
+	}
+	return buf.String()
+}
+
+func lockPathRhs(f *File, x ast.Expr) typePath {
+	if _, ok := x.(*ast.CompositeLit); ok {
+		return nil
+	}
+	if _, ok := x.(*ast.CallExpr); ok {
+		// A call may return a zero value.
+		return nil
+	}
+	if star, ok := x.(*ast.StarExpr); ok {
+		if _, ok := star.X.(*ast.CallExpr); ok {
+			// A call may return a pointer to a zero value.
+			return nil
+		}
+	}
+	return lockPath(f.pkg.typesPkg, f.pkg.types[x].Type)
+}
+
+// lockPath returns a typePath describing the location of a lock value
+// contained in typ. If there is no contained lock, it returns nil.
+func lockPath(tpkg *types.Package, typ types.Type) typePath {
+	if typ == nil {
+		return nil
+	}
+
+	for {
+		atyp, ok := typ.Underlying().(*types.Array)
+		if !ok {
+			break
+		}
+		typ = atyp.Elem()
+	}
+
+	// We're only interested in the case in which the underlying
+	// type is a struct. (Interfaces and pointers are safe to copy.)
+	styp, ok := typ.Underlying().(*types.Struct)
+	if !ok {
+		return nil
+	}
+
+	// We're looking for cases in which a reference to this type
+	// can be locked, but a value cannot. This differentiates
+	// embedded interfaces from embedded values.
+	if plock := types.NewMethodSet(types.NewPointer(typ)).Lookup(tpkg, "Lock"); plock != nil {
+		if lock := types.NewMethodSet(typ).Lookup(tpkg, "Lock"); lock == nil {
+			return []types.Type{typ}
+		}
+	}
+
+	nfields := styp.NumFields()
+	for i := 0; i < nfields; i++ {
+		ftyp := styp.Field(i).Type()
+		subpath := lockPath(tpkg, ftyp)
+		if subpath != nil {
+			return append(subpath, typ)
+		}
+	}
+
+	return nil
+}

vendor/github.com/golang/go/dead.go

@@ -0,0 +1,108 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+// Simplified dead code detector. Used for skipping certain checks
+// on unreachable code (for instance, shift checks on arch-specific code).
+
+package govet
+
+import (
+	"go/ast"
+	"go/constant"
+)
+
+// updateDead puts unreachable "if" and "case" nodes into f.dead.
+func (f *File) updateDead(node ast.Node) {
+	if f.dead[node] {
+		// The node is already marked as dead.
+		return
+	}
+
+	switch stmt := node.(type) {
+	case *ast.IfStmt:
+		// "if" branch is dead if its condition evaluates
+		// to constant false.
+		v := f.pkg.types[stmt.Cond].Value
+		if v == nil {
+			return
+		}
+		if !constant.BoolVal(v) {
+			f.setDead(stmt.Body)
+			return
+		}
+		f.setDead(stmt.Else)
+	case *ast.SwitchStmt:
+		// Case clause with empty switch tag is dead if it evaluates
+		// to constant false.
+		if stmt.Tag == nil {
+		BodyLoopBool:
+			for _, stmt := range stmt.Body.List {
+				cc := stmt.(*ast.CaseClause)
+				if cc.List == nil {
+					// Skip default case.
+					continue
+				}
+				for _, expr := range cc.List {
+					v := f.pkg.types[expr].Value
+					if v == nil || v.Kind() != constant.Bool || constant.BoolVal(v) {
+						continue BodyLoopBool
+					}
+				}
+				f.setDead(cc)
+			}
+			return
+		}
+
+		// Case clause is dead if its constant value doesn't match
+		// the constant value from the switch tag.
+		// TODO: This handles integer comparisons only.
+		v := f.pkg.types[stmt.Tag].Value
+		if v == nil || v.Kind() != constant.Int {
+			return
+		}
+		tagN, ok := constant.Uint64Val(v)
+		if !ok {
+			return
+		}
+	BodyLoopInt:
+		for _, x := range stmt.Body.List {
+			cc := x.(*ast.CaseClause)
+			if cc.List == nil {
+				// Skip default case.
+				continue
+			}
+			for _, expr := range cc.List {
+				v := f.pkg.types[expr].Value
+				if v == nil {
+					continue BodyLoopInt
+				}
+				n, ok := constant.Uint64Val(v)
+				if !ok || tagN == n {
+					continue BodyLoopInt
+				}
+			}
+			f.setDead(cc)
+		}
+	}
+}
+
+// setDead marks the node and all the children as dead.
+func (f *File) setDead(node ast.Node) {
+	dv := deadVisitor{
+		f: f,
+	}
+	ast.Walk(dv, node)
+}
+
+type deadVisitor struct {
+	f *File
+}
+
+func (dv deadVisitor) Visit(node ast.Node) ast.Visitor {
+	if node == nil {
+		return nil
+	}
+	dv.f.dead[node] = true
+	return dv
+}

vendor/github.com/golang/go/deadcode.go

@@ -0,0 +1,298 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Check for syntactically unreachable code.
+
+package govet
+
+import (
+	"go/ast"
+	"go/token"
+)
+
+func init() {
+	register("unreachable",
+		"check for unreachable code",
+		checkUnreachable,
+		funcDecl, funcLit)
+}
+
+type deadState struct {
+	f           *File
+	hasBreak    map[ast.Stmt]bool
+	hasGoto     map[string]bool
+	labels      map[string]ast.Stmt
+	breakTarget ast.Stmt
+
+	reachable bool
+}
+
+// checkUnreachable checks a function body for dead code.
+//
+// TODO(adonovan): use the new cfg package, which is more precise.
+func checkUnreachable(f *File, node ast.Node) {
+	var body *ast.BlockStmt
+	switch n := node.(type) {
+	case *ast.FuncDecl:
+		body = n.Body
+	case *ast.FuncLit:
+		body = n.Body
+	}
+	if body == nil {
+		return
+	}
+
+	d := &deadState{
+		f:        f,
+		hasBreak: make(map[ast.Stmt]bool),
+		hasGoto:  make(map[string]bool),
+		labels:   make(map[string]ast.Stmt),
+	}
+
+	d.findLabels(body)
+
+	d.reachable = true
+	d.findDead(body)
+}
+
+// findLabels gathers information about the labels defined and used by stmt
+// and about which statements break, whether a label is involved or not.
+func (d *deadState) findLabels(stmt ast.Stmt) {
+	switch x := stmt.(type) {
+	default:
+		d.f.Warnf(x.Pos(), "internal error in findLabels: unexpected statement %T", x)
+
+	case *ast.AssignStmt,
+		*ast.BadStmt,
+		*ast.DeclStmt,
+		*ast.DeferStmt,
+		*ast.EmptyStmt,
+		*ast.ExprStmt,
+		*ast.GoStmt,
+		*ast.IncDecStmt,
+		*ast.ReturnStmt,
+		*ast.SendStmt:
+		// no statements inside
+
+	case *ast.BlockStmt:
+		for _, stmt := range x.List {
+			d.findLabels(stmt)
+		}
+
+	case *ast.BranchStmt:
+		switch x.Tok {
+		case token.GOTO:
+			if x.Label != nil {
+				d.hasGoto[x.Label.Name] = true
+			}
+
+		case token.BREAK:
+			stmt := d.breakTarget
+			if x.Label != nil {
+				stmt = d.labels[x.Label.Name]
+			}
+			if stmt != nil {
+				d.hasBreak[stmt] = true
+			}
+		}
+
+	case *ast.IfStmt:
+		d.findLabels(x.Body)
+		if x.Else != nil {
+			d.findLabels(x.Else)
+		}
+
+	case *ast.LabeledStmt:
+		d.labels[x.Label.Name] = x.Stmt
+		d.findLabels(x.Stmt)
+
+	// These cases are all the same, but the x.Body only works
+	// when the specific type of x is known, so the cases cannot
+	// be merged.
+	case *ast.ForStmt:
+		outer := d.breakTarget
+		d.breakTarget = x
+		d.findLabels(x.Body)
+		d.breakTarget = outer
+
+	case *ast.RangeStmt:
+		outer := d.breakTarget
+		d.breakTarget = x
+		d.findLabels(x.Body)
+		d.breakTarget = outer
+
+	case *ast.SelectStmt:
+		outer := d.breakTarget
+		d.breakTarget = x
+		d.findLabels(x.Body)
+		d.breakTarget = outer
+
+	case *ast.SwitchStmt:
+		outer := d.breakTarget
+		d.breakTarget = x
+		d.findLabels(x.Body)
+		d.breakTarget = outer
+
+	case *ast.TypeSwitchStmt:
+		outer := d.breakTarget
+		d.breakTarget = x
+		d.findLabels(x.Body)
+		d.breakTarget = outer
+
+	case *ast.CommClause:
+		for _, stmt := range x.Body {
+			d.findLabels(stmt)
+		}
+
+	case *ast.CaseClause:
+		for _, stmt := range x.Body {
+			d.findLabels(stmt)
+		}
+	}
+}
+
+// findDead walks the statement looking for dead code.
+// If d.reachable is false on entry, stmt itself is dead.
+// When findDead returns, d.reachable tells whether the
+// statement following stmt is reachable.
+func (d *deadState) findDead(stmt ast.Stmt) {
+	// Is this a labeled goto target?
+	// If so, assume it is reachable due to the goto.
+	// This is slightly conservative, in that we don't
+	// check that the goto is reachable, so
+	//	L: goto L
+	// will not provoke a warning.
+	// But it's good enough.
+	if x, isLabel := stmt.(*ast.LabeledStmt); isLabel && d.hasGoto[x.Label.Name] {
+		d.reachable = true
+	}
+
+	if !d.reachable {
+		switch stmt.(type) {
+		case *ast.EmptyStmt:
+			// do not warn about unreachable empty statements
+		default:
+			d.f.Bad(stmt.Pos(), "unreachable code")
+			d.reachable = true // silence error about next statement
+		}
+	}
+
+	switch x := stmt.(type) {
+	default:
+		d.f.Warnf(x.Pos(), "internal error in findDead: unexpected statement %T", x)
+
+	case *ast.AssignStmt,
+		*ast.BadStmt,
+		*ast.DeclStmt,
+		*ast.DeferStmt,
+		*ast.EmptyStmt,
+		*ast.GoStmt,
+		*ast.IncDecStmt,
+		*ast.SendStmt:
+		// no control flow
+
+	case *ast.BlockStmt:
+		for _, stmt := range x.List {
+			d.findDead(stmt)
+		}
+
+	case *ast.BranchStmt:
+		switch x.Tok {
+		case token.BREAK, token.GOTO, token.FALLTHROUGH:
+			d.reachable = false
+		case token.CONTINUE:
+			// NOTE: We accept "continue" statements as terminating.
+			// They are not necessary in the spec definition of terminating,
+			// because a continue statement cannot be the final statement
+			// before a return. But for the more general problem of syntactically
+			// identifying dead code, continue redirects control flow just
+			// like the other terminating statements.
+			d.reachable = false
+		}
+
+	case *ast.ExprStmt:
+		// Call to panic?
+		call, ok := x.X.(*ast.CallExpr)
+		if ok {
+			name, ok := call.Fun.(*ast.Ident)
+			if ok && name.Name == "panic" && name.Obj == nil {
+				d.reachable = false
+			}
+		}
+
+	case *ast.ForStmt:
+		d.findDead(x.Body)
+		d.reachable = x.Cond != nil || d.hasBreak[x]
+
+	case *ast.IfStmt:
+		d.findDead(x.Body)
+		if x.Else != nil {
+			r := d.reachable
+			d.reachable = true
+			d.findDead(x.Else)
+			d.reachable = d.reachable || r
+		} else {
+			// might not have executed if statement
+			d.reachable = true
+		}
+
+	case *ast.LabeledStmt:
+		d.findDead(x.Stmt)
+
+	case *ast.RangeStmt:
+		d.findDead(x.Body)
+		d.reachable = true
+
+	case *ast.ReturnStmt:
+		d.reachable = false
+
+	case *ast.SelectStmt:
+		// NOTE: Unlike switch and type switch below, we don't care
+		// whether a select has a default, because a select without a
+		// default blocks until one of the cases can run. That's different
+		// from a switch without a default, which behaves like it has
+		// a default with an empty body.
+		anyReachable := false
+		for _, comm := range x.Body.List {
+			d.reachable = true
+			for _, stmt := range comm.(*ast.CommClause).Body {
+				d.findDead(stmt)
+			}
+			anyReachable = anyReachable || d.reachable
+		}
+		d.reachable = anyReachable || d.hasBreak[x]
+
+	case *ast.SwitchStmt:
+		anyReachable := false
+		hasDefault := false
+		for _, cas := range x.Body.List {
+			cc := cas.(*ast.CaseClause)
+			if cc.List == nil {
+				hasDefault = true
+			}
+			d.reachable = true
+			for _, stmt := range cc.Body {
+				d.findDead(stmt)
+			}
+			anyReachable = anyReachable || d.reachable
+		}
+		d.reachable = anyReachable || d.hasBreak[x] || !hasDefault
+
+	case *ast.TypeSwitchStmt:
+		anyReachable := false
+		hasDefault := false
+		for _, cas := range x.Body.List {
+			cc := cas.(*ast.CaseClause)
+			if cc.List == nil {
+				hasDefault = true
+			}
+			d.reachable = true
+			for _, stmt := range cc.Body {
+				d.findDead(stmt)
+			}
+			anyReachable = anyReachable || d.reachable
+		}
+		d.reachable = anyReachable || d.hasBreak[x] || !hasDefault
+	}
+}

vendor/github.com/golang/go/doc.go

@@ -0,0 +1,224 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+
+Vet examines Go source code and reports suspicious constructs, such as Printf
+calls whose arguments do not align with the format string. Vet uses heuristics
+that do not guarantee all reports are genuine problems, but it can find errors
+not caught by the compilers.
+
+Vet is normally invoked using the go command by running "go vet":
+
+	go vet
+vets the package in the current directory.
+
+	go vet package/path/name
+vets the package whose path is provided.
+
+Use "go help packages" to see other ways of specifying which packages to vet.
+
+Vet's exit code is 2 for erroneous invocation of the tool, 1 if a
+problem was reported, and 0 otherwise. Note that the tool does not
+check every possible problem and depends on unreliable heuristics
+so it should be used as guidance only, not as a firm indicator of
+program correctness.
+
+By default the -all flag is set so all checks are performed.
+If any flags are explicitly set to true, only those tests are run. Conversely, if
+any flag is explicitly set to false, only those tests are disabled.  Thus -printf=true
+runs the printf check, -printf=false runs all checks except the printf check.
+
+By default vet uses the object files generated by 'go install some/pkg' to typecheck the code.
+If the -source flag is provided, vet uses only source code.
+
+Available checks:
+
+Assembly declarations
+
+Flag: -asmdecl
+
+Mismatches between assembly files and Go function declarations.
+
+Useless assignments
+
+Flag: -assign
+
+Check for useless assignments.
+
+Atomic mistakes
+
+Flag: -atomic
+
+Common mistaken usages of the sync/atomic package.
+
+Boolean conditions
+
+Flag: -bool
+
+Mistakes involving boolean operators.
+
+Build tags
+
+Flag: -buildtags
+
+Badly formed or misplaced +build tags.
+
+Invalid uses of cgo
+
+Flag: -cgocall
+
+Detect some violations of the cgo pointer passing rules.
+
+Unkeyed composite literals
+
+Flag: -composites
+
+Composite struct literals that do not use the field-keyed syntax.
+
+Copying locks
+
+Flag: -copylocks
+
+Locks that are erroneously passed by value.
+
+HTTP responses used incorrectly
+
+Flag: -httpresponse
+
+Mistakes deferring a function call on an HTTP response before
+checking whether the error returned with the response was nil.
+
+Failure to call the cancelation function returned by WithCancel
+
+Flag: -lostcancel
+
+The cancelation function returned by context.WithCancel, WithTimeout,
+and WithDeadline must be called or the new context will remain live
+until its parent context is cancelled.
+(The background context is never cancelled.)
+
+Methods
+
+Flag: -methods
+
+Non-standard signatures for methods with familiar names, including:
+	Format GobEncode GobDecode MarshalJSON MarshalXML
+	Peek ReadByte ReadFrom ReadRune Scan Seek
+	UnmarshalJSON UnreadByte UnreadRune WriteByte
+	WriteTo
+
+Nil function comparison
+
+Flag: -nilfunc
+
+Comparisons between functions and nil.
+
+Printf family
+
+Flag: -printf
+
+Suspicious calls to functions in the Printf family, including any functions
+with these names, disregarding case:
+	Print Printf Println
+	Fprint Fprintf Fprintln
+	Sprint Sprintf Sprintln
+	Error Errorf
+	Fatal Fatalf
+	Log Logf
+	Panic Panicf Panicln
+The -printfuncs flag can be used to redefine this list.
+If the function name ends with an 'f', the function is assumed to take
+a format descriptor string in the manner of fmt.Printf. If not, vet
+complains about arguments that look like format descriptor strings.
+
+It also checks for errors such as using a Writer as the first argument of
+Printf.
+
+Range loop variables
+
+Flag: -rangeloops
+
+Incorrect uses of range loop variables in closures.
+
+Shadowed variables
+
+Flag: -shadow=false (experimental; must be set explicitly)
+
+Variables that may have been unintentionally shadowed.
+
+Shifts
+
+Flag: -shift
+
+Shifts equal to or longer than the variable's length.
+
+Struct tags
+
+Flag: -structtags
+
+Struct tags that do not follow the format understood by reflect.StructTag.Get.
+Well-known encoding struct tags (json, xml) used with unexported fields.
+
+Tests and documentation examples
+
+Flag: -tests
+
+Mistakes involving tests including functions with incorrect names or signatures
+and example tests that document identifiers not in the package.
+
+Unreachable code
+
+Flag: -unreachable
+
+Unreachable code.
+
+Misuse of unsafe Pointers
+
+Flag: -unsafeptr
+
+Likely incorrect uses of unsafe.Pointer to convert integers to pointers.
+A conversion from uintptr to unsafe.Pointer is invalid if it implies that
+there is a uintptr-typed word in memory that holds a pointer value,
+because that word will be invisible to stack copying and to the garbage
+collector.
+
+Unused result of certain function calls
+
+Flag: -unusedresult
+
+Calls to well-known functions and methods that return a value that is
+discarded.  By default, this includes functions like fmt.Errorf and
+fmt.Sprintf and methods like String and Error. The flags -unusedfuncs
+and -unusedstringmethods control the set.
+
+Other flags
+
+These flags configure the behavior of vet:
+
+	-all (default true)
+		Enable all non-experimental checks.
+	-v
+		Verbose mode
+	-printfuncs
+		A comma-separated list of print-like function names
+		to supplement the standard list.
+		For more information, see the discussion of the -printf flag.
+	-shadowstrict
+		Whether to be strict about shadowing; can be noisy.
+
+Using vet directly
+
+For testing and debugging vet can be run directly by invoking
+"go tool vet" or just running the binary. Run this way, vet might not
+have up to date information for imported packages.
+
+	go tool vet source/directory/*.go
+vets the files named, all of which must be in the same package.
+
+	go tool vet source/directory
+recursively descends the directory, vetting each package it finds.
+
+*/
+package govet

vendor/github.com/golang/go/golangci.go

@@ -0,0 +1,64 @@
+package govet
+
+import (
+	"fmt"
+	"go/token"
+	"os"
+	"strings"
+)
+
+type Issue struct {
+	Pos     token.Position
+	Message string
+}
+
+var foundIssues []Issue
+
+func Run(paths, buildTags []string, checkShadowing bool) ([]Issue, error) {
+	foundIssues = nil
+
+	if checkShadowing {
+		experimental["shadow"] = false
+	}
+	for name, setting := range report {
+		if *setting == unset && !experimental[name] {
+			*setting = setTrue
+		}
+	}
+
+	tagList = buildTags
+
+	initPrintFlags()
+	initUnusedFlags()
+
+	for _, name := range paths {
+		// Is it a directory?
+		fi, err := os.Stat(name)
+		if err != nil {
+			warnf("error walking tree: %s", err)
+			continue
+		}
+		if fi.IsDir() {
+			dirsRun = true
+		} else {
+			filesRun = true
+			if !strings.HasSuffix(name, "_test.go") {
+				includesNonTest = true
+			}
+		}
+	}
+	if dirsRun && filesRun {
+		return nil, fmt.Errorf("can't mix dirs and files")
+	}
+	if dirsRun {
+		for _, name := range paths {
+			walkDir(name)
+		}
+		return foundIssues, nil
+	}
+	if doPackage(paths, nil) == nil {
+		return nil, nil
+	}
+
+	return foundIssues, nil
+}

vendor/github.com/golang/go/httpresponse.go

@@ -0,0 +1,137 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains the check for http.Response values being used before
+// checking for errors.
+
+package govet
+
+import (
+	"go/ast"
+	"go/types"
+)
+
+func init() {
+	register("httpresponse",
+		"check errors are checked before using an http Response",
+		checkHTTPResponse, callExpr)
+}
+
+func checkHTTPResponse(f *File, node ast.Node) {
+	call := node.(*ast.CallExpr)
+	if !isHTTPFuncOrMethodOnClient(f, call) {
+		return // the function call is not related to this check.
+	}
+
+	finder := &blockStmtFinder{node: call}
+	ast.Walk(finder, f.file)
+	stmts := finder.stmts()
+	if len(stmts) < 2 {
+		return // the call to the http function is the last statement of the block.
+	}
+
+	asg, ok := stmts[0].(*ast.AssignStmt)
+	if !ok {
+		return // the first statement is not assignment.
+	}
+	resp := rootIdent(asg.Lhs[0])
+	if resp == nil {
+		return // could not find the http.Response in the assignment.
+	}
+
+	def, ok := stmts[1].(*ast.DeferStmt)
+	if !ok {
+		return // the following statement is not a defer.
+	}
+	root := rootIdent(def.Call.Fun)
+	if root == nil {
+		return // could not find the receiver of the defer call.
+	}
+
+	if resp.Obj == root.Obj {
+		f.Badf(root.Pos(), "using %s before checking for errors", resp.Name)
+	}
+}
+
+// isHTTPFuncOrMethodOnClient checks whether the given call expression is on
+// either a function of the net/http package or a method of http.Client that
+// returns (*http.Response, error).
+func isHTTPFuncOrMethodOnClient(f *File, expr *ast.CallExpr) bool {
+	fun, _ := expr.Fun.(*ast.SelectorExpr)
+	sig, _ := f.pkg.types[fun].Type.(*types.Signature)
+	if sig == nil {
+		return false // the call is not on of the form x.f()
+	}
+
+	res := sig.Results()
+	if res.Len() != 2 {
+		return false // the function called does not return two values.
+	}
+	if ptr, ok := res.At(0).Type().(*types.Pointer); !ok || !isNamedType(ptr.Elem(), "net/http", "Response") {
+		return false // the first return type is not *http.Response.
+	}
+	if !types.Identical(res.At(1).Type().Underlying(), errorType) {
+		return false // the second return type is not error
+	}
+
+	typ := f.pkg.types[fun.X].Type
+	if typ == nil {
+		id, ok := fun.X.(*ast.Ident)
+		return ok && id.Name == "http" // function in net/http package.
+	}
+
+	if isNamedType(typ, "net/http", "Client") {
+		return true // method on http.Client.
+	}
+	ptr, ok := typ.(*types.Pointer)
+	return ok && isNamedType(ptr.Elem(), "net/http", "Client") // method on *http.Client.
+}
+
+// blockStmtFinder is an ast.Visitor that given any ast node can find the
+// statement containing it and its succeeding statements in the same block.
+type blockStmtFinder struct {
+	node  ast.Node       // target of search
+	stmt  ast.Stmt       // innermost statement enclosing argument to Visit
+	block *ast.BlockStmt // innermost block enclosing argument to Visit.
+}
+
+// Visit finds f.node performing a search down the ast tree.
+// It keeps the last block statement and statement seen for later use.
+func (f *blockStmtFinder) Visit(node ast.Node) ast.Visitor {
+	if node == nil || f.node.Pos() < node.Pos() || f.node.End() > node.End() {
+		return nil // not here
+	}
+	switch n := node.(type) {
+	case *ast.BlockStmt:
+		f.block = n
+	case ast.Stmt:
+		f.stmt = n
+	}
+	if f.node.Pos() == node.Pos() && f.node.End() == node.End() {
+		return nil // found
+	}
+	return f // keep looking
+}
+
+// stmts returns the statements of f.block starting from the one including f.node.
+func (f *blockStmtFinder) stmts() []ast.Stmt {
+	for i, v := range f.block.List {
+		if f.stmt == v {
+			return f.block.List[i:]
+		}
+	}
+	return nil
+}
+
+// rootIdent finds the root identifier x in a chain of selections x.y.z, or nil if not found.
+func rootIdent(n ast.Node) *ast.Ident {
+	switch n := n.(type) {
+	case *ast.SelectorExpr:
+		return rootIdent(n.X)
+	case *ast.Ident:
+		return n
+	default:
+		return nil
+	}
+}

vendor/github.com/golang/go/lib/cfg/builder.go

@@ -0,0 +1,512 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cfg
+
+// This file implements the CFG construction pass.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+)
+
+type builder struct {
+	cfg       *CFG
+	mayReturn func(*ast.CallExpr) bool
+	current   *Block
+	lblocks   map[*ast.Object]*lblock // labeled blocks
+	targets   *targets                // linked stack of branch targets
+}
+
+func (b *builder) stmt(_s ast.Stmt) {
+	// The label of the current statement.  If non-nil, its _goto
+	// target is always set; its _break and _continue are set only
+	// within the body of switch/typeswitch/select/for/range.
+	// It is effectively an additional default-nil parameter of stmt().
+	var label *lblock
+start:
+	switch s := _s.(type) {
+	case *ast.BadStmt,
+		*ast.SendStmt,
+		*ast.IncDecStmt,
+		*ast.GoStmt,
+		*ast.DeferStmt,
+		*ast.EmptyStmt,
+		*ast.AssignStmt:
+		// No effect on control flow.
+		b.add(s)
+
+	case *ast.ExprStmt:
+		b.add(s)
+		if call, ok := s.X.(*ast.CallExpr); ok && !b.mayReturn(call) {
+			// Calls to panic, os.Exit, etc, never return.
+			b.current = b.newUnreachableBlock("unreachable.call")
+		}
+
+	case *ast.DeclStmt:
+		// Treat each var ValueSpec as a separate statement.
+		d := s.Decl.(*ast.GenDecl)
+		if d.Tok == token.VAR {
+			for _, spec := range d.Specs {
+				if spec, ok := spec.(*ast.ValueSpec); ok {
+					b.add(spec)
+				}
+			}
+		}
+
+	case *ast.LabeledStmt:
+		label = b.labeledBlock(s.Label)
+		b.jump(label._goto)
+		b.current = label._goto
+		_s = s.Stmt
+		goto start // effectively: tailcall stmt(g, s.Stmt, label)
+
+	case *ast.ReturnStmt:
+		b.add(s)
+		b.current = b.newUnreachableBlock("unreachable.return")
+
+	case *ast.BranchStmt:
+		var block *Block
+		switch s.Tok {
+		case token.BREAK:
+			if s.Label != nil {
+				if lb := b.labeledBlock(s.Label); lb != nil {
+					block = lb._break
+				}
+			} else {
+				for t := b.targets; t != nil && block == nil; t = t.tail {
+					block = t._break
+				}
+			}
+
+		case token.CONTINUE:
+			if s.Label != nil {
+				if lb := b.labeledBlock(s.Label); lb != nil {
+					block = lb._continue
+				}
+			} else {
+				for t := b.targets; t != nil && block == nil; t = t.tail {
+					block = t._continue
+				}
+			}
+
+		case token.FALLTHROUGH:
+			for t := b.targets; t != nil; t = t.tail {
+				block = t._fallthrough
+			}
+
+		case token.GOTO:
+			if s.Label != nil {
+				block = b.labeledBlock(s.Label)._goto
+			}
+		}
+		if block == nil {
+			block = b.newBlock("undefined.branch")
+		}
+		b.jump(block)
+		b.current = b.newUnreachableBlock("unreachable.branch")
+
+	case *ast.BlockStmt:
+		b.stmtList(s.List)
+
+	case *ast.IfStmt:
+		if s.Init != nil {
+			b.stmt(s.Init)
+		}
+		then := b.newBlock("if.then")
+		done := b.newBlock("if.done")
+		_else := done
+		if s.Else != nil {
+			_else = b.newBlock("if.else")
+		}
+		b.add(s.Cond)
+		b.ifelse(then, _else)
+		b.current = then
+		b.stmt(s.Body)
+		b.jump(done)
+
+		if s.Else != nil {
+			b.current = _else
+			b.stmt(s.Else)
+			b.jump(done)
+		}
+
+		b.current = done
+
+	case *ast.SwitchStmt:
+		b.switchStmt(s, label)
+
+	case *ast.TypeSwitchStmt:
+		b.typeSwitchStmt(s, label)
+
+	case *ast.SelectStmt:
+		b.selectStmt(s, label)
+
+	case *ast.ForStmt:
+		b.forStmt(s, label)
+
+	case *ast.RangeStmt:
+		b.rangeStmt(s, label)
+
+	default:
+		panic(fmt.Sprintf("unexpected statement kind: %T", s))
+	}
+}
+
+func (b *builder) stmtList(list []ast.Stmt) {
+	for _, s := range list {
+		b.stmt(s)
+	}
+}
+
+func (b *builder) switchStmt(s *ast.SwitchStmt, label *lblock) {
+	if s.Init != nil {
+		b.stmt(s.Init)
+	}
+	if s.Tag != nil {
+		b.add(s.Tag)
+	}
+	done := b.newBlock("switch.done")
+	if label != nil {
+		label._break = done
+	}
+	// We pull the default case (if present) down to the end.
+	// But each fallthrough label must point to the next
+	// body block in source order, so we preallocate a
+	// body block (fallthru) for the next case.
+	// Unfortunately this makes for a confusing block order.
+	var defaultBody *[]ast.Stmt
+	var defaultFallthrough *Block
+	var fallthru, defaultBlock *Block
+	ncases := len(s.Body.List)
+	for i, clause := range s.Body.List {
+		body := fallthru
+		if body == nil {
+			body = b.newBlock("switch.body") // first case only
+		}
+
+		// Preallocate body block for the next case.
+		fallthru = done
+		if i+1 < ncases {
+			fallthru = b.newBlock("switch.body")
+		}
+
+		cc := clause.(*ast.CaseClause)
+		if cc.List == nil {
+			// Default case.
+			defaultBody = &cc.Body
+			defaultFallthrough = fallthru
+			defaultBlock = body
+			continue
+		}
+
+		var nextCond *Block
+		for _, cond := range cc.List {
+			nextCond = b.newBlock("switch.next")
+			b.add(cond) // one half of the tag==cond condition
+			b.ifelse(body, nextCond)
+			b.current = nextCond
+		}
+		b.current = body
+		b.targets = &targets{
+			tail:         b.targets,
+			_break:       done,
+			_fallthrough: fallthru,
+		}
+		b.stmtList(cc.Body)
+		b.targets = b.targets.tail
+		b.jump(done)
+		b.current = nextCond
+	}
+	if defaultBlock != nil {
+		b.jump(defaultBlock)
+		b.current = defaultBlock
+		b.targets = &targets{
+			tail:         b.targets,
+			_break:       done,
+			_fallthrough: defaultFallthrough,
+		}
+		b.stmtList(*defaultBody)
+		b.targets = b.targets.tail
+	}
+	b.jump(done)
+	b.current = done
+}
+
+func (b *builder) typeSwitchStmt(s *ast.TypeSwitchStmt, label *lblock) {
+	if s.Init != nil {
+		b.stmt(s.Init)
+	}
+	if s.Assign != nil {
+		b.add(s.Assign)
+	}
+
+	done := b.newBlock("typeswitch.done")
+	if label != nil {
+		label._break = done
+	}
+	var default_ *ast.CaseClause
+	for _, clause := range s.Body.List {
+		cc := clause.(*ast.CaseClause)
+		if cc.List == nil {
+			default_ = cc
+			continue
+		}
+		body := b.newBlock("typeswitch.body")
+		var next *Block
+		for _, casetype := range cc.List {
+			next = b.newBlock("typeswitch.next")
+			// casetype is a type, so don't call b.add(casetype).
+			// This block logically contains a type assertion,
+			// x.(casetype), but it's unclear how to represent x.
+			_ = casetype
+			b.ifelse(body, next)
+			b.current = next
+		}
+		b.current = body
+		b.typeCaseBody(cc, done)
+		b.current = next
+	}
+	if default_ != nil {
+		b.typeCaseBody(default_, done)
+	} else {
+		b.jump(done)
+	}
+	b.current = done
+}
+
+func (b *builder) typeCaseBody(cc *ast.CaseClause, done *Block) {
+	b.targets = &targets{
+		tail:   b.targets,
+		_break: done,
+	}
+	b.stmtList(cc.Body)
+	b.targets = b.targets.tail
+	b.jump(done)
+}
+
+func (b *builder) selectStmt(s *ast.SelectStmt, label *lblock) {
+	// First evaluate channel expressions.
+	// TODO(adonovan): fix: evaluate only channel exprs here.
+	for _, clause := range s.Body.List {
+		if comm := clause.(*ast.CommClause).Comm; comm != nil {
+			b.stmt(comm)
+		}
+	}
+
+	done := b.newBlock("select.done")
+	if label != nil {
+		label._break = done
+	}
+
+	var defaultBody *[]ast.Stmt
+	for _, cc := range s.Body.List {
+		clause := cc.(*ast.CommClause)
+		if clause.Comm == nil {
+			defaultBody = &clause.Body
+			continue
+		}
+		body := b.newBlock("select.body")
+		next := b.newBlock("select.next")
+		b.ifelse(body, next)
+		b.current = body
+		b.targets = &targets{
+			tail:   b.targets,
+			_break: done,
+		}
+		switch comm := clause.Comm.(type) {
+		case *ast.ExprStmt: // <-ch
+			// nop
+		case *ast.AssignStmt: // x := <-states[state].Chan
+			b.add(comm.Lhs[0])
+		}
+		b.stmtList(clause.Body)
+		b.targets = b.targets.tail
+		b.jump(done)
+		b.current = next
+	}
+	if defaultBody != nil {
+		b.targets = &targets{
+			tail:   b.targets,
+			_break: done,
+		}
+		b.stmtList(*defaultBody)
+		b.targets = b.targets.tail
+		b.jump(done)
+	}
+	b.current = done
+}
+
+func (b *builder) forStmt(s *ast.ForStmt, label *lblock) {
+	//	...init...
+	//      jump loop
+	// loop:
+	//      if cond goto body else done
+	// body:
+	//      ...body...
+	//      jump post
+	// post:				 (target of continue)
+	//      ...post...
+	//      jump loop
+	// done:                                 (target of break)
+	if s.Init != nil {
+		b.stmt(s.Init)
+	}
+	body := b.newBlock("for.body")
+	done := b.newBlock("for.done") // target of 'break'
+	loop := body                   // target of back-edge
+	if s.Cond != nil {
+		loop = b.newBlock("for.loop")
+	}
+	cont := loop // target of 'continue'
+	if s.Post != nil {
+		cont = b.newBlock("for.post")
+	}
+	if label != nil {
+		label._break = done
+		label._continue = cont
+	}
+	b.jump(loop)
+	b.current = loop
+	if loop != body {
+		b.add(s.Cond)
+		b.ifelse(body, done)
+		b.current = body
+	}
+	b.targets = &targets{
+		tail:      b.targets,
+		_break:    done,
+		_continue: cont,
+	}
+	b.stmt(s.Body)
+	b.targets = b.targets.tail
+	b.jump(cont)
+
+	if s.Post != nil {
+		b.current = cont
+		b.stmt(s.Post)
+		b.jump(loop) // back-edge
+	}
+	b.current = done
+}
+
+func (b *builder) rangeStmt(s *ast.RangeStmt, label *lblock) {
+	b.add(s.X)
+
+	if s.Key != nil {
+		b.add(s.Key)
+	}
+	if s.Value != nil {
+		b.add(s.Value)
+	}
+
+	//      ...
+	// loop:                                   (target of continue)
+	// 	if ... goto body else done
+	// body:
+	//      ...
+	// 	jump loop
+	// done:                                   (target of break)
+
+	loop := b.newBlock("range.loop")
+	b.jump(loop)
+	b.current = loop
+
+	body := b.newBlock("range.body")
+	done := b.newBlock("range.done")
+	b.ifelse(body, done)
+	b.current = body
+
+	if label != nil {
+		label._break = done
+		label._continue = loop
+	}
+	b.targets = &targets{
+		tail:      b.targets,
+		_break:    done,
+		_continue: loop,
+	}
+	b.stmt(s.Body)
+	b.targets = b.targets.tail
+	b.jump(loop) // back-edge
+	b.current = done
+}
+
+// -------- helpers --------
+
+// Destinations associated with unlabeled for/switch/select stmts.
+// We push/pop one of these as we enter/leave each construct and for
+// each BranchStmt we scan for the innermost target of the right type.
+//
+type targets struct {
+	tail         *targets // rest of stack
+	_break       *Block
+	_continue    *Block
+	_fallthrough *Block
+}
+
+// Destinations associated with a labeled block.
+// We populate these as labels are encountered in forward gotos or
+// labeled statements.
+//
+type lblock struct {
+	_goto     *Block
+	_break    *Block
+	_continue *Block
+}
+
+// labeledBlock returns the branch target associated with the
+// specified label, creating it if needed.
+//
+func (b *builder) labeledBlock(label *ast.Ident) *lblock {
+	lb := b.lblocks[label.Obj]
+	if lb == nil {
+		lb = &lblock{_goto: b.newBlock(label.Name)}
+		if b.lblocks == nil {
+			b.lblocks = make(map[*ast.Object]*lblock)
+		}
+		b.lblocks[label.Obj] = lb
+	}
+	return lb
+}
+
+// newBlock appends a new unconnected basic block to b.cfg's block
+// slice and returns it.
+// It does not automatically become the current block.
+// comment is an optional string for more readable debugging output.
+func (b *builder) newBlock(comment string) *Block {
+	g := b.cfg
+	block := &Block{
+		index:   int32(len(g.Blocks)),
+		comment: comment,
+	}
+	block.Succs = block.succs2[:0]
+	g.Blocks = append(g.Blocks, block)
+	return block
+}
+
+func (b *builder) newUnreachableBlock(comment string) *Block {
+	block := b.newBlock(comment)
+	block.unreachable = true
+	return block
+}
+
+func (b *builder) add(n ast.Node) {
+	b.current.Nodes = append(b.current.Nodes, n)
+}
+
+// jump adds an edge from the current block to the target block,
+// and sets b.current to nil.
+func (b *builder) jump(target *Block) {
+	b.current.Succs = append(b.current.Succs, target)
+	b.current = nil
+}
+
+// ifelse emits edges from the current block to the t and f blocks,
+// and sets b.current to nil.
+func (b *builder) ifelse(t, f *Block) {
+	b.current.Succs = append(b.current.Succs, t, f)
+	b.current = nil
+}

vendor/github.com/golang/go/lib/cfg/cfg.go

@@ -0,0 +1,142 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This package constructs a simple control-flow graph (CFG) of the
+// statements and expressions within a single function.
+//
+// Use cfg.New to construct the CFG for a function body.
+//
+// The blocks of the CFG contain all the function's non-control
+// statements.  The CFG does not contain control statements such as If,
+// Switch, Select, and Branch, but does contain their subexpressions.
+// For example, this source code:
+//
+//	if x := f(); x != nil {
+//		T()
+//	} else {
+//		F()
+//	}
+//
+// produces this CFG:
+//
+//    1:  x := f()
+//        x != nil
+//        succs: 2, 3
+//    2:  T()
+//        succs: 4
+//    3:  F()
+//        succs: 4
+//    4:
+//
+// The CFG does contain Return statements; even implicit returns are
+// materialized (at the position of the function's closing brace).
+//
+// The CFG does not record conditions associated with conditional branch
+// edges, nor the short-circuit semantics of the && and || operators,
+// nor abnormal control flow caused by panic.  If you need this
+// information, use golang.org/x/tools/go/ssa instead.
+//
+package cfg
+
+// Although the vet tool has type information, it is often extremely
+// fragmentary, so for simplicity this package does not depend on
+// go/types.  Consequently control-flow conditions are ignored even
+// when constant, and "mayReturn" information must be provided by the
+// client.
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/format"
+	"go/token"
+)
+
+// A CFG represents the control-flow graph of a single function.
+//
+// The entry point is Blocks[0]; there may be multiple return blocks.
+type CFG struct {
+	Blocks []*Block // block[0] is entry; order otherwise undefined
+}
+
+// A Block represents a basic block: a list of statements and
+// expressions that are always evaluated sequentially.
+//
+// A block may have 0-2 successors: zero for a return block or a block
+// that calls a function such as panic that never returns; one for a
+// normal (jump) block; and two for a conditional (if) block.
+type Block struct {
+	Nodes []ast.Node // statements, expressions, and ValueSpecs
+	Succs []*Block   // successor nodes in the graph
+
+	comment     string    // for debugging
+	index       int32     // index within CFG.Blocks
+	unreachable bool      // is block of stmts following return/panic/for{}
+	succs2      [2]*Block // underlying array for Succs
+}
+
+// New returns a new control-flow graph for the specified function body,
+// which must be non-nil.
+//
+// The CFG builder calls mayReturn to determine whether a given function
+// call may return.  For example, calls to panic, os.Exit, and log.Fatal
+// do not return, so the builder can remove infeasible graph edges
+// following such calls.  The builder calls mayReturn only for a
+// CallExpr beneath an ExprStmt.
+func New(body *ast.BlockStmt, mayReturn func(*ast.CallExpr) bool) *CFG {
+	b := builder{
+		mayReturn: mayReturn,
+		cfg:       new(CFG),
+	}
+	b.current = b.newBlock("entry")
+	b.stmt(body)
+
+	// Does control fall off the end of the function's body?
+	// Make implicit return explicit.
+	if b.current != nil && !b.current.unreachable {
+		b.add(&ast.ReturnStmt{
+			Return: body.End() - 1,
+		})
+	}
+
+	return b.cfg
+}
+
+func (b *Block) String() string {
+	return fmt.Sprintf("block %d (%s)", b.index, b.comment)
+}
+
+// Return returns the return statement at the end of this block if present, nil otherwise.
+func (b *Block) Return() (ret *ast.ReturnStmt) {
+	if len(b.Nodes) > 0 {
+		ret, _ = b.Nodes[len(b.Nodes)-1].(*ast.ReturnStmt)
+	}
+	return
+}
+
+// Format formats the control-flow graph for ease of debugging.
+func (g *CFG) Format(fset *token.FileSet) string {
+	var buf bytes.Buffer
+	for _, b := range g.Blocks {
+		fmt.Fprintf(&buf, ".%d: # %s\n", b.index, b.comment)
+		for _, n := range b.Nodes {
+			fmt.Fprintf(&buf, "\t%s\n", formatNode(fset, n))
+		}
+		if len(b.Succs) > 0 {
+			fmt.Fprintf(&buf, "\tsuccs:")
+			for _, succ := range b.Succs {
+				fmt.Fprintf(&buf, " %d", succ.index)
+			}
+			buf.WriteByte('\n')
+		}
+		buf.WriteByte('\n')
+	}
+	return buf.String()
+}
+
+func formatNode(fset *token.FileSet, n ast.Node) string {
+	var buf bytes.Buffer
+	format.Node(&buf, fset, n)
+	// Indent secondary lines by a tab.
+	return string(bytes.Replace(buf.Bytes(), []byte("\n"), []byte("\n\t"), -1))
+}

vendor/github.com/golang/go/lib/whitelist/whitelist.go

@@ -0,0 +1,28 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package whitelist defines exceptions for the vet tool.
+package whitelist
+
+// UnkeyedLiteral is a white list of types in the standard packages
+// that are used with unkeyed literals we deem to be acceptable.
+var UnkeyedLiteral = map[string]bool{
+	// These image and image/color struct types are frozen. We will never add fields to them.
+	"image/color.Alpha16": true,
+	"image/color.Alpha":   true,
+	"image/color.CMYK":    true,
+	"image/color.Gray16":  true,
+	"image/color.Gray":    true,
+	"image/color.NRGBA64": true,
+	"image/color.NRGBA":   true,
+	"image/color.NYCbCrA": true,
+	"image/color.RGBA64":  true,
+	"image/color.RGBA":    true,
+	"image/color.YCbCr":   true,
+	"image.Point":         true,
+	"image.Rectangle":     true,
+	"image.Uniform":       true,
+
+	"unicode.Range16": true,
+}

vendor/github.com/golang/go/lostcancel.go

@@ -0,0 +1,323 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package govet
+
+import (
+	"fmt"
+	"go/ast"
+	"go/types"
+	"strconv"
+
+	"github.com/golang/go/lib/cfg"
+)
+
+func init() {
+	register("lostcancel",
+		"check for failure to call cancelation function returned by context.WithCancel",
+		checkLostCancel,
+		funcDecl, funcLit)
+}
+
+const debugLostCancel = false
+
+var contextPackage = "context"
+
+// checkLostCancel reports a failure to the call the cancel function
+// returned by context.WithCancel, either because the variable was
+// assigned to the blank identifier, or because there exists a
+// control-flow path from the call to a return statement and that path
+// does not "use" the cancel function.  Any reference to the variable
+// counts as a use, even within a nested function literal.
+//
+// checkLostCancel analyzes a single named or literal function.
+func checkLostCancel(f *File, node ast.Node) {
+	// Fast path: bypass check if file doesn't use context.WithCancel.
+	if !hasImport(f.file, contextPackage) {
+		return
+	}
+
+	// Maps each cancel variable to its defining ValueSpec/AssignStmt.
+	cancelvars := make(map[*types.Var]ast.Node)
+
+	// Find the set of cancel vars to analyze.
+	stack := make([]ast.Node, 0, 32)
+	ast.Inspect(node, func(n ast.Node) bool {
+		switch n.(type) {
+		case *ast.FuncLit:
+			if len(stack) > 0 {
+				return false // don't stray into nested functions
+			}
+		case nil:
+			stack = stack[:len(stack)-1] // pop
+			return true
+		}
+		stack = append(stack, n) // push
+
+		// Look for [{AssignStmt,ValueSpec} CallExpr SelectorExpr]:
+		//
+		//   ctx, cancel    := context.WithCancel(...)
+		//   ctx, cancel     = context.WithCancel(...)
+		//   var ctx, cancel = context.WithCancel(...)
+		//
+		if isContextWithCancel(f, n) && isCall(stack[len(stack)-2]) {
+			var id *ast.Ident // id of cancel var
+			stmt := stack[len(stack)-3]
+			switch stmt := stmt.(type) {
+			case *ast.ValueSpec:
+				if len(stmt.Names) > 1 {
+					id = stmt.Names[1]
+				}
+			case *ast.AssignStmt:
+				if len(stmt.Lhs) > 1 {
+					id, _ = stmt.Lhs[1].(*ast.Ident)
+				}
+			}
+			if id != nil {
+				if id.Name == "_" {
+					f.Badf(id.Pos(), "the cancel function returned by context.%s should be called, not discarded, to avoid a context leak",
+						n.(*ast.SelectorExpr).Sel.Name)
+				} else if v, ok := f.pkg.uses[id].(*types.Var); ok {
+					cancelvars[v] = stmt
+				} else if v, ok := f.pkg.defs[id].(*types.Var); ok {
+					cancelvars[v] = stmt
+				}
+			}
+		}
+
+		return true
+	})
+
+	if len(cancelvars) == 0 {
+		return // no need to build CFG
+	}
+
+	// Tell the CFG builder which functions never return.
+	info := &types.Info{Uses: f.pkg.uses, Selections: f.pkg.selectors}
+	mayReturn := func(call *ast.CallExpr) bool {
+		name := callName(info, call)
+		return !noReturnFuncs[name]
+	}
+
+	// Build the CFG.
+	var g *cfg.CFG
+	var sig *types.Signature
+	switch node := node.(type) {
+	case *ast.FuncDecl:
+		obj := f.pkg.defs[node.Name]
+		if obj == nil {
+			return // type error (e.g. duplicate function declaration)
+		}
+		sig, _ = obj.Type().(*types.Signature)
+		g = cfg.New(node.Body, mayReturn)
+	case *ast.FuncLit:
+		sig, _ = f.pkg.types[node.Type].Type.(*types.Signature)
+		g = cfg.New(node.Body, mayReturn)
+	}
+
+	// Print CFG.
+	if debugLostCancel {
+		fmt.Println(g.Format(f.fset))
+	}
+
+	// Examine the CFG for each variable in turn.
+	// (It would be more efficient to analyze all cancelvars in a
+	// single pass over the AST, but seldom is there more than one.)
+	for v, stmt := range cancelvars {
+		if ret := lostCancelPath(f, g, v, stmt, sig); ret != nil {
+			lineno := f.fset.Position(stmt.Pos()).Line
+			f.Badf(stmt.Pos(), "the %s function is not used on all paths (possible context leak)", v.Name())
+			f.Badf(ret.Pos(), "this return statement may be reached without using the %s var defined on line %d", v.Name(), lineno)
+		}
+	}
+}
+
+func isCall(n ast.Node) bool { _, ok := n.(*ast.CallExpr); return ok }
+
+func hasImport(f *ast.File, path string) bool {
+	for _, imp := range f.Imports {
+		v, _ := strconv.Unquote(imp.Path.Value)
+		if v == path {
+			return true
+		}
+	}
+	return false
+}
+
+// isContextWithCancel reports whether n is one of the qualified identifiers
+// context.With{Cancel,Timeout,Deadline}.
+func isContextWithCancel(f *File, n ast.Node) bool {
+	if sel, ok := n.(*ast.SelectorExpr); ok {
+		switch sel.Sel.Name {
+		case "WithCancel", "WithTimeout", "WithDeadline":
+			if x, ok := sel.X.(*ast.Ident); ok {
+				if pkgname, ok := f.pkg.uses[x].(*types.PkgName); ok {
+					return pkgname.Imported().Path() == contextPackage
+				}
+				// Import failed, so we can't check package path.
+				// Just check the local package name (heuristic).
+				return x.Name == "context"
+			}
+		}
+	}
+	return false
+}
+
+// lostCancelPath finds a path through the CFG, from stmt (which defines
+// the 'cancel' variable v) to a return statement, that doesn't "use" v.
+// If it finds one, it returns the return statement (which may be synthetic).
+// sig is the function's type, if known.
+func lostCancelPath(f *File, g *cfg.CFG, v *types.Var, stmt ast.Node, sig *types.Signature) *ast.ReturnStmt {
+	vIsNamedResult := sig != nil && tupleContains(sig.Results(), v)
+
+	// uses reports whether stmts contain a "use" of variable v.
+	uses := func(f *File, v *types.Var, stmts []ast.Node) bool {
+		found := false
+		for _, stmt := range stmts {
+			ast.Inspect(stmt, func(n ast.Node) bool {
+				switch n := n.(type) {
+				case *ast.Ident:
+					if f.pkg.uses[n] == v {
+						found = true
+					}
+				case *ast.ReturnStmt:
+					// A naked return statement counts as a use
+					// of the named result variables.
+					if n.Results == nil && vIsNamedResult {
+						found = true
+					}
+				}
+				return !found
+			})
+		}
+		return found
+	}
+
+	// blockUses computes "uses" for each block, caching the result.
+	memo := make(map[*cfg.Block]bool)
+	blockUses := func(f *File, v *types.Var, b *cfg.Block) bool {
+		res, ok := memo[b]
+		if !ok {
+			res = uses(f, v, b.Nodes)
+			memo[b] = res
+		}
+		return res
+	}
+
+	// Find the var's defining block in the CFG,
+	// plus the rest of the statements of that block.
+	var defblock *cfg.Block
+	var rest []ast.Node
+outer:
+	for _, b := range g.Blocks {
+		for i, n := range b.Nodes {
+			if n == stmt {
+				defblock = b
+				rest = b.Nodes[i+1:]
+				break outer
+			}
+		}
+	}
+	if defblock == nil {
+		panic("internal error: can't find defining block for cancel var")
+	}
+
+	// Is v "used" in the remainder of its defining block?
+	if uses(f, v, rest) {
+		return nil
+	}
+
+	// Does the defining block return without using v?
+	if ret := defblock.Return(); ret != nil {
+		return ret
+	}
+
+	// Search the CFG depth-first for a path, from defblock to a
+	// return block, in which v is never "used".
+	seen := make(map[*cfg.Block]bool)
+	var search func(blocks []*cfg.Block) *ast.ReturnStmt
+	search = func(blocks []*cfg.Block) *ast.ReturnStmt {
+		for _, b := range blocks {
+			if !seen[b] {
+				seen[b] = true
+
+				// Prune the search if the block uses v.
+				if blockUses(f, v, b) {
+					continue
+				}
+
+				// Found path to return statement?
+				if ret := b.Return(); ret != nil {
+					if debugLostCancel {
+						fmt.Printf("found path to return in block %s\n", b)
+					}
+					return ret // found
+				}
+
+				// Recur
+				if ret := search(b.Succs); ret != nil {
+					if debugLostCancel {
+						fmt.Printf(" from block %s\n", b)
+					}
+					return ret
+				}
+			}
+		}
+		return nil
+	}
+	return search(defblock.Succs)
+}
+
+func tupleContains(tuple *types.Tuple, v *types.Var) bool {
+	for i := 0; i < tuple.Len(); i++ {
+		if tuple.At(i) == v {
+			return true
+		}
+	}
+	return false
+}
+
+var noReturnFuncs = map[string]bool{
+	"(*testing.common).FailNow": true,
+	"(*testing.common).Fatal":   true,
+	"(*testing.common).Fatalf":  true,
+	"(*testing.common).Skip":    true,
+	"(*testing.common).SkipNow": true,
+	"(*testing.common).Skipf":   true,
+	"log.Fatal":                 true,
+	"log.Fatalf":                true,
+	"log.Fatalln":               true,
+	"os.Exit":                   true,
+	"panic":                     true,
+	"runtime.Goexit":            true,
+}
+
+// callName returns the canonical name of the builtin, method, or
+// function called by call, if known.
+func callName(info *types.Info, call *ast.CallExpr) string {
+	switch fun := call.Fun.(type) {
+	case *ast.Ident:
+		// builtin, e.g. "panic"
+		if obj, ok := info.Uses[fun].(*types.Builtin); ok {
+			return obj.Name()
+		}
+	case *ast.SelectorExpr:
+		if sel, ok := info.Selections[fun]; ok && sel.Kind() == types.MethodVal {
+			// method call, e.g. "(*testing.common).Fatal"
+			meth := sel.Obj()
+			return fmt.Sprintf("(%s).%s",
+				meth.Type().(*types.Signature).Recv().Type(),
+				meth.Name())
+		}
+		if obj, ok := info.Uses[fun.Sel]; ok {
+			// qualified identifier, e.g. "os.Exit"
+			return fmt.Sprintf("%s.%s",
+				obj.Pkg().Path(),
+				obj.Name())
+		}
+	}
+
+	// function with no name, or defined in missing imported package
+	return ""
+}

vendor/github.com/golang/go/main.go

@@ -0,0 +1,625 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Vet is a simple checker for static errors in Go source code.
+// See doc.go for more information.
+package govet
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/build"
+	"go/importer"
+	"go/parser"
+	"go/printer"
+	"go/token"
+	"go/types"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+// Important! If you add flags here, make sure to update cmd/go/internal/vet/vetflag.go.
+
+var (
+	verbose = flag.Bool("v", false, "verbose")
+	source  = flag.Bool("source", false, "import from source instead of compiled object files")
+	tags    = flag.String("tags", "", "space-separated list of build tags to apply when parsing")
+	tagList = []string{} // exploded version of tags flag; set in main
+
+	vcfg          vetConfig
+	mustTypecheck bool
+)
+
+var exitCode = 0
+
+// "-all" flag enables all non-experimental checks
+var all = triStateFlag("all", unset, "enable all non-experimental checks")
+
+// Flags to control which individual checks to perform.
+var report = map[string]*triState{
+	// Only unusual checks are written here.
+	// Most checks that operate during the AST walk are added by register.
+	"asmdecl":   triStateFlag("asmdecl", unset, "check assembly against Go declarations"),
+	"buildtags": triStateFlag("buildtags", unset, "check that +build tags are valid"),
+}
+
+// experimental records the flags enabling experimental features. These must be
+// requested explicitly; they are not enabled by -all.
+var experimental = map[string]bool{}
+
+// setTrueCount record how many flags are explicitly set to true.
+var setTrueCount int
+
+// dirsRun and filesRun indicate whether the vet is applied to directory or
+// file targets. The distinction affects which checks are run.
+var dirsRun, filesRun bool
+
+// includesNonTest indicates whether the vet is applied to non-test targets.
+// Certain checks are relevant only if they touch both test and non-test files.
+var includesNonTest bool
+
+// A triState is a boolean that knows whether it has been set to either true or false.
+// It is used to identify if a flag appears; the standard boolean flag cannot
+// distinguish missing from unset. It also satisfies flag.Value.
+type triState int
+
+const (
+	unset triState = iota
+	setTrue
+	setFalse
+)
+
+func triStateFlag(name string, value triState, usage string) *triState {
+	flag.Var(&value, name, usage)
+	return &value
+}
+
+// triState implements flag.Value, flag.Getter, and flag.boolFlag.
+// They work like boolean flags: we can say vet -printf as well as vet -printf=true
+func (ts *triState) Get() interface{} {
+	return *ts == setTrue
+}
+
+func (ts triState) isTrue() bool {
+	return ts == setTrue
+}
+
+func (ts *triState) Set(value string) error {
+	b, err := strconv.ParseBool(value)
+	if err != nil {
+		return err
+	}
+	if b {
+		*ts = setTrue
+		setTrueCount++
+	} else {
+		*ts = setFalse
+	}
+	return nil
+}
+
+func (ts *triState) String() string {
+	switch *ts {
+	case unset:
+		return "true" // An unset flag will be set by -all, so defaults to true.
+	case setTrue:
+		return "true"
+	case setFalse:
+		return "false"
+	}
+	panic("not reached")
+}
+
+func (ts triState) IsBoolFlag() bool {
+	return true
+}
+
+// vet tells whether to report errors for the named check, a flag name.
+func vet(name string) bool {
+	return report[name].isTrue()
+}
+
+// setExit sets the value for os.Exit when it is called, later. It
+// remembers the highest value.
+func setExit(err int) {
+	if err > exitCode {
+		exitCode = err
+	}
+}
+
+var (
+	// Each of these vars has a corresponding case in (*File).Visit.
+	assignStmt    *ast.AssignStmt
+	binaryExpr    *ast.BinaryExpr
+	callExpr      *ast.CallExpr
+	compositeLit  *ast.CompositeLit
+	exprStmt      *ast.ExprStmt
+	forStmt       *ast.ForStmt
+	funcDecl      *ast.FuncDecl
+	funcLit       *ast.FuncLit
+	genDecl       *ast.GenDecl
+	interfaceType *ast.InterfaceType
+	rangeStmt     *ast.RangeStmt
+	returnStmt    *ast.ReturnStmt
+	structType    *ast.StructType
+
+	// checkers is a two-level map.
+	// The outer level is keyed by a nil pointer, one of the AST vars above.
+	// The inner level is keyed by checker name.
+	checkers = make(map[ast.Node]map[string]func(*File, ast.Node))
+)
+
+func register(name, usage string, fn func(*File, ast.Node), types ...ast.Node) {
+	report[name] = triStateFlag(name, unset, usage)
+	for _, typ := range types {
+		m := checkers[typ]
+		if m == nil {
+			m = make(map[string]func(*File, ast.Node))
+			checkers[typ] = m
+		}
+		m[name] = fn
+	}
+}
+
+// Usage is a replacement usage function for the flags package.
+func Usage() {
+	fmt.Fprintf(os.Stderr, "Usage of vet:\n")
+	fmt.Fprintf(os.Stderr, "\tvet [flags] directory...\n")
+	fmt.Fprintf(os.Stderr, "\tvet [flags] files... # Must be a single package\n")
+	fmt.Fprintf(os.Stderr, "By default, -all is set and all non-experimental checks are run.\n")
+	fmt.Fprintf(os.Stderr, "For more information run\n")
+	fmt.Fprintf(os.Stderr, "\tgo doc cmd/vet\n\n")
+	fmt.Fprintf(os.Stderr, "Flags:\n")
+	flag.PrintDefaults()
+	os.Exit(2)
+}
+
+// File is a wrapper for the state of a file used in the parser.
+// The parse tree walkers are all methods of this type.
+type File struct {
+	pkg     *Package
+	fset    *token.FileSet
+	name    string
+	content []byte
+	file    *ast.File
+	b       bytes.Buffer // for use by methods
+
+	// Parsed package "foo" when checking package "foo_test"
+	basePkg *Package
+
+	// The keys are the objects that are receivers of a "String()
+	// string" method. The value reports whether the method has a
+	// pointer receiver.
+	// This is used by the recursiveStringer method in print.go.
+	stringerPtrs map[*ast.Object]bool
+
+	// Registered checkers to run.
+	checkers map[ast.Node][]func(*File, ast.Node)
+
+	// Unreachable nodes; can be ignored in shift check.
+	dead map[ast.Node]bool
+}
+
+func main() {
+	flag.Usage = Usage
+	flag.Parse()
+
+	// If any flag is set, we run only those checks requested.
+	// If all flag is set true or if no flags are set true, set all the non-experimental ones
+	// not explicitly set (in effect, set the "-all" flag).
+	if setTrueCount == 0 || *all == setTrue {
+		for name, setting := range report {
+			if *setting == unset && !experimental[name] {
+				*setting = setTrue
+			}
+		}
+	}
+
+	// Accept space-separated tags because that matches
+	// the go command's other subcommands.
+	// Accept commas because go tool vet traditionally has.
+	tagList = strings.Fields(strings.Replace(*tags, ",", " ", -1))
+
+	initPrintFlags()
+	initUnusedFlags()
+
+	if flag.NArg() == 0 {
+		Usage()
+	}
+
+	// Special case for "go vet" passing an explicit configuration:
+	// single argument ending in vet.cfg.
+	// Once we have a more general mechanism for obtaining this
+	// information from build tools like the go command,
+	// vet should be changed to use it. This vet.cfg hack is an
+	// experiment to learn about what form that information should take.
+	if flag.NArg() == 1 && strings.HasSuffix(flag.Arg(0), "vet.cfg") {
+		doPackageCfg(flag.Arg(0))
+		os.Exit(exitCode)
+	}
+
+	for _, name := range flag.Args() {
+		// Is it a directory?
+		fi, err := os.Stat(name)
+		if err != nil {
+			warnf("error walking tree: %s", err)
+			continue
+		}
+		if fi.IsDir() {
+			dirsRun = true
+		} else {
+			filesRun = true
+			if !strings.HasSuffix(name, "_test.go") {
+				includesNonTest = true
+			}
+		}
+	}
+	if dirsRun && filesRun {
+		Usage()
+	}
+	if dirsRun {
+		for _, name := range flag.Args() {
+			walkDir(name)
+		}
+		os.Exit(exitCode)
+	}
+	if doPackage(flag.Args(), nil) == nil {
+		warnf("no files checked")
+	}
+	os.Exit(exitCode)
+}
+
+// prefixDirectory places the directory name on the beginning of each name in the list.
+func prefixDirectory(directory string, names []string) {
+	if directory != "." {
+		for i, name := range names {
+			names[i] = filepath.Join(directory, name)
+		}
+	}
+}
+
+// vetConfig is the JSON config struct prepared by the Go command.
+type vetConfig struct {
+	Compiler    string
+	Dir         string
+	ImportPath  string
+	GoFiles     []string
+	ImportMap   map[string]string
+	PackageFile map[string]string
+
+	SucceedOnTypecheckFailure bool
+
+	imp types.Importer
+}
+
+func (v *vetConfig) Import(path string) (*types.Package, error) {
+	if v.imp == nil {
+		v.imp = importer.For(v.Compiler, v.openPackageFile)
+	}
+	if path == "unsafe" {
+		return v.imp.Import("unsafe")
+	}
+	p := v.ImportMap[path]
+	if p == "" {
+		return nil, fmt.Errorf("unknown import path %q", path)
+	}
+	if v.PackageFile[p] == "" {
+		return nil, fmt.Errorf("unknown package file for import %q", path)
+	}
+	return v.imp.Import(p)
+}
+
+func (v *vetConfig) openPackageFile(path string) (io.ReadCloser, error) {
+	file := v.PackageFile[path]
+	if file == "" {
+		// Note that path here has been translated via v.ImportMap,
+		// unlike in the error in Import above. We prefer the error in
+		// Import, but it's worth diagnosing this one too, just in case.
+		return nil, fmt.Errorf("unknown package file for %q", path)
+	}
+	f, err := os.Open(file)
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}
+
+// doPackageCfg analyzes a single package described in a config file.
+func doPackageCfg(cfgFile string) {
+	js, err := ioutil.ReadFile(cfgFile)
+	if err != nil {
+		errorf("%v", err)
+	}
+	if err := json.Unmarshal(js, &vcfg); err != nil {
+		errorf("parsing vet config %s: %v", cfgFile, err)
+	}
+	stdImporter = &vcfg
+	inittypes()
+	mustTypecheck = true
+	doPackage(vcfg.GoFiles, nil)
+}
+
+// doPackageDir analyzes the single package found in the directory, if there is one,
+// plus a test package, if there is one.
+func doPackageDir(directory string) {
+	context := build.Default
+	if len(context.BuildTags) != 0 {
+		warnf("build tags %s previously set", context.BuildTags)
+	}
+	context.BuildTags = append(tagList, context.BuildTags...)
+
+	pkg, err := context.ImportDir(directory, 0)
+	if err != nil {
+		// If it's just that there are no go source files, that's fine.
+		if _, nogo := err.(*build.NoGoError); nogo {
+			return
+		}
+		// Non-fatal: we are doing a recursive walk and there may be other directories.
+		warnf("cannot process directory %s: %s", directory, err)
+		return
+	}
+	var names []string
+	names = append(names, pkg.GoFiles...)
+	names = append(names, pkg.CgoFiles...)
+	names = append(names, pkg.TestGoFiles...) // These are also in the "foo" package.
+	names = append(names, pkg.SFiles...)
+	prefixDirectory(directory, names)
+	basePkg := doPackage(names, nil)
+	// Is there also a "foo_test" package? If so, do that one as well.
+	if len(pkg.XTestGoFiles) > 0 {
+		names = pkg.XTestGoFiles
+		prefixDirectory(directory, names)
+		doPackage(names, basePkg)
+	}
+}
+
+type Package struct {
+	path      string
+	defs      map[*ast.Ident]types.Object
+	uses      map[*ast.Ident]types.Object
+	selectors map[*ast.SelectorExpr]*types.Selection
+	types     map[ast.Expr]types.TypeAndValue
+	spans     map[types.Object]Span
+	files     []*File
+	typesPkg  *types.Package
+}
+
+// doPackage analyzes the single package constructed from the named files.
+// It returns the parsed Package or nil if none of the files have been checked.
+func doPackage(names []string, basePkg *Package) *Package {
+	var files []*File
+	var astFiles []*ast.File
+	fs := token.NewFileSet()
+	for _, name := range names {
+		data, err := ioutil.ReadFile(name)
+		if err != nil {
+			// Warn but continue to next package.
+			warnf("%s: %s", name, err)
+			return nil
+		}
+		checkBuildTag(name, data)
+		var parsedFile *ast.File
+		if strings.HasSuffix(name, ".go") {
+			parsedFile, err = parser.ParseFile(fs, name, data, 0)
+			if err != nil {
+				warnf("%s: %s", name, err)
+				return nil
+			}
+			astFiles = append(astFiles, parsedFile)
+		}
+		files = append(files, &File{
+			fset:    fs,
+			content: data,
+			name:    name,
+			file:    parsedFile,
+			dead:    make(map[ast.Node]bool),
+		})
+	}
+	if len(astFiles) == 0 {
+		return nil
+	}
+	pkg := new(Package)
+	pkg.path = astFiles[0].Name.Name
+	pkg.files = files
+	// Type check the package.
+	errs := pkg.check(fs, astFiles)
+	if errs != nil {
+		if *verbose || mustTypecheck {
+			for _, err := range errs {
+				fmt.Fprintf(os.Stderr, "%v\n", err)
+			}
+			if mustTypecheck {
+				// This message could be silenced, and we could just exit,
+				// but it might be helpful at least at first to make clear that the
+				// above errors are coming from vet and not the compiler
+				// (they often look like compiler errors, such as "declared but not used").
+				errorf("typecheck failures")
+			}
+		}
+	}
+
+	// Check.
+	chk := make(map[ast.Node][]func(*File, ast.Node))
+	for typ, set := range checkers {
+		for name, fn := range set {
+			if vet(name) {
+				chk[typ] = append(chk[typ], fn)
+			}
+		}
+	}
+	for _, file := range files {
+		file.pkg = pkg
+		file.basePkg = basePkg
+		file.checkers = chk
+		if file.file != nil {
+			file.walkFile(file.name, file.file)
+		}
+	}
+	asmCheck(pkg)
+	return pkg
+}
+
+func visit(path string, f os.FileInfo, err error) error {
+	if err != nil {
+		warnf("walk error: %s", err)
+		return err
+	}
+	// One package per directory. Ignore the files themselves.
+	if !f.IsDir() {
+		return nil
+	}
+	doPackageDir(path)
+	return nil
+}
+
+func (pkg *Package) hasFileWithSuffix(suffix string) bool {
+	for _, f := range pkg.files {
+		if strings.HasSuffix(f.name, suffix) {
+			return true
+		}
+	}
+	return false
+}
+
+// walkDir recursively walks the tree looking for Go packages.
+func walkDir(root string) {
+	filepath.Walk(root, visit)
+}
+
+// errorf formats the error to standard error, adding program
+// identification and a newline, and exits.
+func errorf(format string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, "vet: "+format+"\n", args...)
+}
+
+// warnf formats the error to standard error, adding program
+// identification and a newline, but does not exit.
+func warnf(format string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, "vet: "+format+"\n", args...)
+	setExit(1)
+}
+
+// Println is fmt.Println guarded by -v.
+func Println(args ...interface{}) {
+	if !*verbose {
+		return
+	}
+	fmt.Println(args...)
+}
+
+// Printf is fmt.Printf guarded by -v.
+func Printf(format string, args ...interface{}) {
+	if !*verbose {
+		return
+	}
+	fmt.Printf(format+"\n", args...)
+}
+
+// Bad reports an error and sets the exit code..
+func (f *File) Bad(pos token.Pos, args ...interface{}) {
+	foundIssues = append(foundIssues, Issue{
+		Pos:     f.fset.Position(pos),
+		Message: fmt.Sprint(args...),
+	})
+	f.Warn(pos, args...)
+	setExit(1)
+}
+
+// Badf reports a formatted error and sets the exit code.
+func (f *File) Badf(pos token.Pos, format string, args ...interface{}) {
+	foundIssues = append(foundIssues, Issue{
+		Pos:     f.fset.Position(pos),
+		Message: fmt.Sprintf(format, args...),
+	})
+	f.Warnf(pos, format, args...)
+	setExit(1)
+}
+
+// loc returns a formatted representation of the position.
+func (f *File) loc(pos token.Pos) string {
+	if pos == token.NoPos {
+		return ""
+	}
+	// Do not print columns. Because the pos often points to the start of an
+	// expression instead of the inner part with the actual error, the
+	// precision can mislead.
+	posn := f.fset.Position(pos)
+	return fmt.Sprintf("%s:%d", posn.Filename, posn.Line)
+}
+
+// locPrefix returns a formatted representation of the position for use as a line prefix.
+func (f *File) locPrefix(pos token.Pos) string {
+	if pos == token.NoPos {
+		return ""
+	}
+	return fmt.Sprintf("%s: ", f.loc(pos))
+}
+
+// Warn reports an error but does not set the exit code.
+func (f *File) Warn(pos token.Pos, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, "%s%s", f.locPrefix(pos), fmt.Sprintln(args...))
+}
+
+// Warnf reports a formatted error but does not set the exit code.
+func (f *File) Warnf(pos token.Pos, format string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, "%s%s\n", f.locPrefix(pos), fmt.Sprintf(format, args...))
+}
+
+// walkFile walks the file's tree.
+func (f *File) walkFile(name string, file *ast.File) {
+	Println("Checking file", name)
+	ast.Walk(f, file)
+}
+
+// Visit implements the ast.Visitor interface.
+func (f *File) Visit(node ast.Node) ast.Visitor {
+	f.updateDead(node)
+	var key ast.Node
+	switch node.(type) {
+	case *ast.AssignStmt:
+		key = assignStmt
+	case *ast.BinaryExpr:
+		key = binaryExpr
+	case *ast.CallExpr:
+		key = callExpr
+	case *ast.CompositeLit:
+		key = compositeLit
+	case *ast.ExprStmt:
+		key = exprStmt
+	case *ast.ForStmt:
+		key = forStmt
+	case *ast.FuncDecl:
+		key = funcDecl
+	case *ast.FuncLit:
+		key = funcLit
+	case *ast.GenDecl:
+		key = genDecl
+	case *ast.InterfaceType:
+		key = interfaceType
+	case *ast.RangeStmt:
+		key = rangeStmt
+	case *ast.ReturnStmt:
+		key = returnStmt
+	case *ast.StructType:
+		key = structType
+	}
+	for _, fn := range f.checkers[key] {
+		fn(f, node)
+	}
+	return f
+}
+
+// gofmt returns a string representation of the expression.
+func (f *File) gofmt(x ast.Expr) string {
+	f.b.Reset()
+	printer.Fprint(&f.b, f.fset, x)
+	return f.b.String()
+}

vendor/github.com/golang/go/method.go

@@ -0,0 +1,179 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains the code to check canonical methods.
+
+package govet
+
+import (
+	"fmt"
+	"go/ast"
+	"go/printer"
+	"strings"
+)
+
+func init() {
+	register("methods",
+		"check that canonically named methods are canonically defined",
+		checkCanonicalMethod,
+		funcDecl, interfaceType)
+}
+
+type MethodSig struct {
+	args    []string
+	results []string
+}
+
+// canonicalMethods lists the input and output types for Go methods
+// that are checked using dynamic interface checks. Because the
+// checks are dynamic, such methods would not cause a compile error
+// if they have the wrong signature: instead the dynamic check would
+// fail, sometimes mysteriously. If a method is found with a name listed
+// here but not the input/output types listed here, vet complains.
+//
+// A few of the canonical methods have very common names.
+// For example, a type might implement a Scan method that
+// has nothing to do with fmt.Scanner, but we still want to check
+// the methods that are intended to implement fmt.Scanner.
+// To do that, the arguments that have a = prefix are treated as
+// signals that the canonical meaning is intended: if a Scan
+// method doesn't have a fmt.ScanState as its first argument,
+// we let it go. But if it does have a fmt.ScanState, then the
+// rest has to match.
+var canonicalMethods = map[string]MethodSig{
+	// "Flush": {{}, {"error"}}, // http.Flusher and jpeg.writer conflict
+	"Format":        {[]string{"=fmt.State", "rune"}, []string{}},                      // fmt.Formatter
+	"GobDecode":     {[]string{"[]byte"}, []string{"error"}},                           // gob.GobDecoder
+	"GobEncode":     {[]string{}, []string{"[]byte", "error"}},                         // gob.GobEncoder
+	"MarshalJSON":   {[]string{}, []string{"[]byte", "error"}},                         // json.Marshaler
+	"MarshalXML":    {[]string{"*xml.Encoder", "xml.StartElement"}, []string{"error"}}, // xml.Marshaler
+	"ReadByte":      {[]string{}, []string{"byte", "error"}},                           // io.ByteReader
+	"ReadFrom":      {[]string{"=io.Reader"}, []string{"int64", "error"}},              // io.ReaderFrom
+	"ReadRune":      {[]string{}, []string{"rune", "int", "error"}},                    // io.RuneReader
+	"Scan":          {[]string{"=fmt.ScanState", "rune"}, []string{"error"}},           // fmt.Scanner
+	"Seek":          {[]string{"=int64", "int"}, []string{"int64", "error"}},           // io.Seeker
+	"UnmarshalJSON": {[]string{"[]byte"}, []string{"error"}},                           // json.Unmarshaler
+	"UnmarshalXML":  {[]string{"*xml.Decoder", "xml.StartElement"}, []string{"error"}}, // xml.Unmarshaler
+	"UnreadByte":    {[]string{}, []string{"error"}},
+	"UnreadRune":    {[]string{}, []string{"error"}},
+	"WriteByte":     {[]string{"byte"}, []string{"error"}},                // jpeg.writer (matching bufio.Writer)
+	"WriteTo":       {[]string{"=io.Writer"}, []string{"int64", "error"}}, // io.WriterTo
+}
+
+func checkCanonicalMethod(f *File, node ast.Node) {
+	switch n := node.(type) {
+	case *ast.FuncDecl:
+		if n.Recv != nil {
+			canonicalMethod(f, n.Name, n.Type)
+		}
+	case *ast.InterfaceType:
+		for _, field := range n.Methods.List {
+			for _, id := range field.Names {
+				canonicalMethod(f, id, field.Type.(*ast.FuncType))
+			}
+		}
+	}
+}
+
+func canonicalMethod(f *File, id *ast.Ident, t *ast.FuncType) {
+	// Expected input/output.
+	expect, ok := canonicalMethods[id.Name]
+	if !ok {
+		return
+	}
+
+	// Actual input/output
+	args := typeFlatten(t.Params.List)
+	var results []ast.Expr
+	if t.Results != nil {
+		results = typeFlatten(t.Results.List)
+	}
+
+	// Do the =s (if any) all match?
+	if !f.matchParams(expect.args, args, "=") || !f.matchParams(expect.results, results, "=") {
+		return
+	}
+
+	// Everything must match.
+	if !f.matchParams(expect.args, args, "") || !f.matchParams(expect.results, results, "") {
+		expectFmt := id.Name + "(" + argjoin(expect.args) + ")"
+		if len(expect.results) == 1 {
+			expectFmt += " " + argjoin(expect.results)
+		} else if len(expect.results) > 1 {
+			expectFmt += " (" + argjoin(expect.results) + ")"
+		}
+
+		f.b.Reset()
+		if err := printer.Fprint(&f.b, f.fset, t); err != nil {
+			fmt.Fprintf(&f.b, "<%s>", err)
+		}
+		actual := f.b.String()
+		actual = strings.TrimPrefix(actual, "func")
+		actual = id.Name + actual
+
+		f.Badf(id.Pos(), "method %s should have signature %s", actual, expectFmt)
+	}
+}
+
+func argjoin(x []string) string {
+	y := make([]string, len(x))
+	for i, s := range x {
+		if s[0] == '=' {
+			s = s[1:]
+		}
+		y[i] = s
+	}
+	return strings.Join(y, ", ")
+}
+
+// Turn parameter list into slice of types
+// (in the ast, types are Exprs).
+// Have to handle f(int, bool) and f(x, y, z int)
+// so not a simple 1-to-1 conversion.
+func typeFlatten(l []*ast.Field) []ast.Expr {
+	var t []ast.Expr
+	for _, f := range l {
+		if len(f.Names) == 0 {
+			t = append(t, f.Type)
+			continue
+		}
+		for range f.Names {
+			t = append(t, f.Type)
+		}
+	}
+	return t
+}
+
+// Does each type in expect with the given prefix match the corresponding type in actual?
+func (f *File) matchParams(expect []string, actual []ast.Expr, prefix string) bool {
+	for i, x := range expect {
+		if !strings.HasPrefix(x, prefix) {
+			continue
+		}
+		if i >= len(actual) {
+			return false
+		}
+		if !f.matchParamType(x, actual[i]) {
+			return false
+		}
+	}
+	if prefix == "" && len(actual) > len(expect) {
+		return false
+	}
+	return true
+}
+
+// Does this one type match?
+func (f *File) matchParamType(expect string, actual ast.Expr) bool {
+	expect = strings.TrimPrefix(expect, "=")
+	// Strip package name if we're in that package.
+	if n := len(f.file.Name.Name); len(expect) > n && expect[:n] == f.file.Name.Name && expect[n] == '.' {
+		expect = expect[n+1:]
+	}
+
+	// Overkill but easy.
+	f.b.Reset()
+	printer.Fprint(&f.b, f.fset, actual)
+	return f.b.String() == expect
+}

vendor/github.com/golang/go/nilfunc.go

@@ -0,0 +1,67 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+This file contains the code to check for useless function comparisons.
+A useless comparison is one like f == nil as opposed to f() == nil.
+*/
+
+package govet
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+func init() {
+	register("nilfunc",
+		"check for comparisons between functions and nil",
+		checkNilFuncComparison,
+		binaryExpr)
+}
+
+func checkNilFuncComparison(f *File, node ast.Node) {
+	e := node.(*ast.BinaryExpr)
+
+	// Only want == or != comparisons.
+	if e.Op != token.EQL && e.Op != token.NEQ {
+		return
+	}
+
+	// Only want comparisons with a nil identifier on one side.
+	var e2 ast.Expr
+	switch {
+	case f.isNil(e.X):
+		e2 = e.Y
+	case f.isNil(e.Y):
+		e2 = e.X
+	default:
+		return
+	}
+
+	// Only want identifiers or selector expressions.
+	var obj types.Object
+	switch v := e2.(type) {
+	case *ast.Ident:
+		obj = f.pkg.uses[v]
+	case *ast.SelectorExpr:
+		obj = f.pkg.uses[v.Sel]
+	default:
+		return
+	}
+
+	// Only want functions.
+	if _, ok := obj.(*types.Func); !ok {
+		return
+	}
+
+	f.Badf(e.Pos(), "comparison of function %v %v nil is always %v", obj.Name(), e.Op, e.Op == token.NEQ)
+}
+
+// isNil reports whether the provided expression is the built-in nil
+// identifier.
+func (f *File) isNil(e ast.Expr) bool {
+	return f.pkg.types[e].Type == types.Typ[types.UntypedNil]
+}

vendor/github.com/golang/go/print.go

@@ -0,0 +1,807 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains the printf-checker.
+
+package govet
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/constant"
+	"go/token"
+	"go/types"
+	"regexp"
+	"strconv"
+	"strings"
+	"unicode/utf8"
+)
+
+var printfuncs = flag.String("printfuncs", "", "comma-separated list of print function names to check")
+
+func init() {
+	register("printf",
+		"check printf-like invocations",
+		checkFmtPrintfCall,
+		funcDecl, callExpr)
+}
+
+func initPrintFlags() {
+	if *printfuncs == "" {
+		return
+	}
+	for _, name := range strings.Split(*printfuncs, ",") {
+		if len(name) == 0 {
+			flag.Usage()
+		}
+
+		// Backwards compatibility: skip optional first argument
+		// index after the colon.
+		if colon := strings.LastIndex(name, ":"); colon > 0 {
+			name = name[:colon]
+		}
+
+		isPrint[strings.ToLower(name)] = true
+	}
+}
+
+// TODO(rsc): Incorporate user-defined printf wrappers again.
+// The general plan is to allow vet of one package P to output
+// additional information to supply to later vets of packages
+// importing P. Then vet of P can record a list of printf wrappers
+// and the later vet using P.Printf will find it in the list and check it.
+// That's not ready for Go 1.10.
+// When that does happen, uncomment the user-defined printf
+// wrapper tests in testdata/print.go.
+
+// isPrint records the print functions.
+// If a key ends in 'f' then it is assumed to be a formatted print.
+var isPrint = map[string]bool{
+	"fmt.Errorf":         true,
+	"fmt.Fprint":         true,
+	"fmt.Fprintf":        true,
+	"fmt.Fprintln":       true,
+	"fmt.Print":          true,
+	"fmt.Printf":         true,
+	"fmt.Println":        true,
+	"fmt.Sprint":         true,
+	"fmt.Sprintf":        true,
+	"fmt.Sprintln":       true,
+	"log.Fatal":          true,
+	"log.Fatalf":         true,
+	"log.Fatalln":        true,
+	"log.Logger.Fatal":   true,
+	"log.Logger.Fatalf":  true,
+	"log.Logger.Fatalln": true,
+	"log.Logger.Panic":   true,
+	"log.Logger.Panicf":  true,
+	"log.Logger.Panicln": true,
+	"log.Logger.Printf":  true,
+	"log.Logger.Println": true,
+	"log.Panic":          true,
+	"log.Panicf":         true,
+	"log.Panicln":        true,
+	"log.Print":          true,
+	"log.Printf":         true,
+	"log.Println":        true,
+	"testing.B.Error":    true,
+	"testing.B.Errorf":   true,
+	"testing.B.Fatal":    true,
+	"testing.B.Fatalf":   true,
+	"testing.B.Log":      true,
+	"testing.B.Logf":     true,
+	"testing.B.Skip":     true,
+	"testing.B.Skipf":    true,
+	"testing.T.Error":    true,
+	"testing.T.Errorf":   true,
+	"testing.T.Fatal":    true,
+	"testing.T.Fatalf":   true,
+	"testing.T.Log":      true,
+	"testing.T.Logf":     true,
+	"testing.T.Skip":     true,
+	"testing.T.Skipf":    true,
+	"testing.TB.Error":   true,
+	"testing.TB.Errorf":  true,
+	"testing.TB.Fatal":   true,
+	"testing.TB.Fatalf":  true,
+	"testing.TB.Log":     true,
+	"testing.TB.Logf":    true,
+	"testing.TB.Skip":    true,
+	"testing.TB.Skipf":   true,
+}
+
+// formatString returns the format string argument and its index within
+// the given printf-like call expression.
+//
+// The last parameter before variadic arguments is assumed to be
+// a format string.
+//
+// The first string literal or string constant is assumed to be a format string
+// if the call's signature cannot be determined.
+//
+// If it cannot find any format string parameter, it returns ("", -1).
+func formatString(f *File, call *ast.CallExpr) (format string, idx int) {
+	typ := f.pkg.types[call.Fun].Type
+	if typ != nil {
+		if sig, ok := typ.(*types.Signature); ok {
+			if !sig.Variadic() {
+				// Skip checking non-variadic functions.
+				return "", -1
+			}
+			idx := sig.Params().Len() - 2
+			if idx < 0 {
+				// Skip checking variadic functions without
+				// fixed arguments.
+				return "", -1
+			}
+			s, ok := stringConstantArg(f, call, idx)
+			if !ok {
+				// The last argument before variadic args isn't a string.
+				return "", -1
+			}
+			return s, idx
+		}
+	}
+
+	// Cannot determine call's signature. Fall back to scanning for the first
+	// string constant in the call.
+	for idx := range call.Args {
+		if s, ok := stringConstantArg(f, call, idx); ok {
+			return s, idx
+		}
+		if f.pkg.types[call.Args[idx]].Type == types.Typ[types.String] {
+			// Skip checking a call with a non-constant format
+			// string argument, since its contents are unavailable
+			// for validation.
+			return "", -1
+		}
+	}
+	return "", -1
+}
+
+// stringConstantArg returns call's string constant argument at the index idx.
+//
+// ("", false) is returned if call's argument at the index idx isn't a string
+// constant.
+func stringConstantArg(f *File, call *ast.CallExpr, idx int) (string, bool) {
+	if idx >= len(call.Args) {
+		return "", false
+	}
+	arg := call.Args[idx]
+	lit := f.pkg.types[arg].Value
+	if lit != nil && lit.Kind() == constant.String {
+		return constant.StringVal(lit), true
+	}
+	return "", false
+}
+
+// checkCall triggers the print-specific checks if the call invokes a print function.
+func checkFmtPrintfCall(f *File, node ast.Node) {
+	if f.pkg.typesPkg == nil {
+		// This check now requires type information.
+		return
+	}
+
+	if d, ok := node.(*ast.FuncDecl); ok && isStringer(f, d) {
+		// Remember we saw this.
+		if f.stringerPtrs == nil {
+			f.stringerPtrs = make(map[*ast.Object]bool)
+		}
+		if l := d.Recv.List; len(l) == 1 {
+			if n := l[0].Names; len(n) == 1 {
+				typ := f.pkg.types[l[0].Type]
+				_, ptrRecv := typ.Type.(*types.Pointer)
+				f.stringerPtrs[n[0].Obj] = ptrRecv
+			}
+		}
+		return
+	}
+
+	call, ok := node.(*ast.CallExpr)
+	if !ok {
+		return
+	}
+
+	// Construct name like pkg.Printf or pkg.Type.Printf for lookup.
+	var name string
+	switch x := call.Fun.(type) {
+	case *ast.Ident:
+		if fn, ok := f.pkg.uses[x].(*types.Func); ok {
+			var pkg string
+			if fn.Pkg() == nil || fn.Pkg() == f.pkg.typesPkg {
+				pkg = vcfg.ImportPath
+			} else {
+				pkg = fn.Pkg().Path()
+			}
+			name = pkg + "." + x.Name
+			break
+		}
+
+	case *ast.SelectorExpr:
+		// Check for "fmt.Printf".
+		if id, ok := x.X.(*ast.Ident); ok {
+			if pkgName, ok := f.pkg.uses[id].(*types.PkgName); ok {
+				name = pkgName.Imported().Path() + "." + x.Sel.Name
+				break
+			}
+		}
+
+		// Check for t.Logf where t is a *testing.T.
+		if sel := f.pkg.selectors[x]; sel != nil {
+			recv := sel.Recv()
+			if p, ok := recv.(*types.Pointer); ok {
+				recv = p.Elem()
+			}
+			if named, ok := recv.(*types.Named); ok {
+				obj := named.Obj()
+				var pkg string
+				if obj.Pkg() == nil || obj.Pkg() == f.pkg.typesPkg {
+					pkg = vcfg.ImportPath
+				} else {
+					pkg = obj.Pkg().Path()
+				}
+				name = pkg + "." + obj.Name() + "." + x.Sel.Name
+				break
+			}
+		}
+	}
+	if name == "" {
+		return
+	}
+
+	shortName := name[strings.LastIndex(name, ".")+1:]
+
+	_, ok = isPrint[name]
+	if !ok {
+		// Next look up just "printf", for use with -printfuncs.
+		_, ok = isPrint[strings.ToLower(shortName)]
+	}
+	if ok {
+		if strings.HasSuffix(name, "f") {
+			f.checkPrintf(call, shortName)
+		} else {
+			f.checkPrint(call, shortName)
+		}
+	}
+}
+
+// isStringer returns true if the provided declaration is a "String() string"
+// method, an implementation of fmt.Stringer.
+func isStringer(f *File, d *ast.FuncDecl) bool {
+	return d.Recv != nil && d.Name.Name == "String" && d.Type.Results != nil &&
+		len(d.Type.Params.List) == 0 && len(d.Type.Results.List) == 1 &&
+		f.pkg.types[d.Type.Results.List[0].Type].Type == types.Typ[types.String]
+}
+
+// isFormatter reports whether t satisfies fmt.Formatter.
+// Unlike fmt.Stringer, it's impossible to satisfy fmt.Formatter without importing fmt.
+func (f *File) isFormatter(t types.Type) bool {
+	return formatterType != nil && types.Implements(t, formatterType)
+}
+
+// formatState holds the parsed representation of a printf directive such as "%3.*[4]d".
+// It is constructed by parsePrintfVerb.
+type formatState struct {
+	verb     rune   // the format verb: 'd' for "%d"
+	format   string // the full format directive from % through verb, "%.3d".
+	name     string // Printf, Sprintf etc.
+	flags    []byte // the list of # + etc.
+	argNums  []int  // the successive argument numbers that are consumed, adjusted to refer to actual arg in call
+	firstArg int    // Index of first argument after the format in the Printf call.
+	// Used only during parse.
+	file         *File
+	call         *ast.CallExpr
+	argNum       int  // Which argument we're expecting to format now.
+	hasIndex     bool // Whether the argument is indexed.
+	indexPending bool // Whether we have an indexed argument that has not resolved.
+	nbytes       int  // number of bytes of the format string consumed.
+}
+
+// checkPrintf checks a call to a formatted print routine such as Printf.
+func (f *File) checkPrintf(call *ast.CallExpr, name string) {
+	format, idx := formatString(f, call)
+	if idx < 0 {
+		if *verbose {
+			f.Warn(call.Pos(), "can't check non-constant format in call to", name)
+		}
+		return
+	}
+
+	firstArg := idx + 1 // Arguments are immediately after format string.
+	if !strings.Contains(format, "%") {
+		if len(call.Args) > firstArg {
+			f.Badf(call.Pos(), "%s call has arguments but no formatting directives", name)
+		}
+		return
+	}
+	// Hard part: check formats against args.
+	argNum := firstArg
+	maxArgNum := firstArg
+	anyIndex := false
+	for i, w := 0, 0; i < len(format); i += w {
+		w = 1
+		if format[i] != '%' {
+			continue
+		}
+		state := f.parsePrintfVerb(call, name, format[i:], firstArg, argNum)
+		if state == nil {
+			return
+		}
+		w = len(state.format)
+		if !f.okPrintfArg(call, state) { // One error per format is enough.
+			return
+		}
+		if state.hasIndex {
+			anyIndex = true
+		}
+		if len(state.argNums) > 0 {
+			// Continue with the next sequential argument.
+			argNum = state.argNums[len(state.argNums)-1] + 1
+		}
+		for _, n := range state.argNums {
+			if n >= maxArgNum {
+				maxArgNum = n + 1
+			}
+		}
+	}
+	// Dotdotdot is hard.
+	if call.Ellipsis.IsValid() && maxArgNum >= len(call.Args)-1 {
+		return
+	}
+	// If any formats are indexed, extra arguments are ignored.
+	if anyIndex {
+		return
+	}
+	// There should be no leftover arguments.
+	if maxArgNum != len(call.Args) {
+		expect := maxArgNum - firstArg
+		numArgs := len(call.Args) - firstArg
+		f.Badf(call.Pos(), "%s call needs %v but has %v", name, count(expect, "arg"), count(numArgs, "arg"))
+	}
+}
+
+// parseFlags accepts any printf flags.
+func (s *formatState) parseFlags() {
+	for s.nbytes < len(s.format) {
+		switch c := s.format[s.nbytes]; c {
+		case '#', '0', '+', '-', ' ':
+			s.flags = append(s.flags, c)
+			s.nbytes++
+		default:
+			return
+		}
+	}
+}
+
+// scanNum advances through a decimal number if present.
+func (s *formatState) scanNum() {
+	for ; s.nbytes < len(s.format); s.nbytes++ {
+		c := s.format[s.nbytes]
+		if c < '0' || '9' < c {
+			return
+		}
+	}
+}
+
+// parseIndex scans an index expression. It returns false if there is a syntax error.
+func (s *formatState) parseIndex() bool {
+	if s.nbytes == len(s.format) || s.format[s.nbytes] != '[' {
+		return true
+	}
+	// Argument index present.
+	s.nbytes++ // skip '['
+	start := s.nbytes
+	s.scanNum()
+	ok := true
+	if s.nbytes == len(s.format) || s.nbytes == start || s.format[s.nbytes] != ']' {
+		ok = false
+		s.nbytes = strings.Index(s.format, "]")
+		if s.nbytes < 0 {
+			s.file.Badf(s.call.Pos(), "%s format %s is missing closing ]", s.name, s.format)
+			return false
+		}
+	}
+	arg32, err := strconv.ParseInt(s.format[start:s.nbytes], 10, 32)
+	if err != nil || !ok || arg32 <= 0 || arg32 > int64(len(s.call.Args)-s.firstArg) {
+		s.file.Badf(s.call.Pos(), "%s format has invalid argument index [%s]", s.name, s.format[start:s.nbytes])
+		return false
+	}
+	s.nbytes++ // skip ']'
+	arg := int(arg32)
+	arg += s.firstArg - 1 // We want to zero-index the actual arguments.
+	s.argNum = arg
+	s.hasIndex = true
+	s.indexPending = true
+	return true
+}
+
+// parseNum scans a width or precision (or *). It returns false if there's a bad index expression.
+func (s *formatState) parseNum() bool {
+	if s.nbytes < len(s.format) && s.format[s.nbytes] == '*' {
+		if s.indexPending { // Absorb it.
+			s.indexPending = false
+		}
+		s.nbytes++
+		s.argNums = append(s.argNums, s.argNum)
+		s.argNum++
+	} else {
+		s.scanNum()
+	}
+	return true
+}
+
+// parsePrecision scans for a precision. It returns false if there's a bad index expression.
+func (s *formatState) parsePrecision() bool {
+	// If there's a period, there may be a precision.
+	if s.nbytes < len(s.format) && s.format[s.nbytes] == '.' {
+		s.flags = append(s.flags, '.') // Treat precision as a flag.
+		s.nbytes++
+		if !s.parseIndex() {
+			return false
+		}
+		if !s.parseNum() {
+			return false
+		}
+	}
+	return true
+}
+
+// parsePrintfVerb looks the formatting directive that begins the format string
+// and returns a formatState that encodes what the directive wants, without looking
+// at the actual arguments present in the call. The result is nil if there is an error.
+func (f *File) parsePrintfVerb(call *ast.CallExpr, name, format string, firstArg, argNum int) *formatState {
+	state := &formatState{
+		format:   format,
+		name:     name,
+		flags:    make([]byte, 0, 5),
+		argNum:   argNum,
+		argNums:  make([]int, 0, 1),
+		nbytes:   1, // There's guaranteed to be a percent sign.
+		firstArg: firstArg,
+		file:     f,
+		call:     call,
+	}
+	// There may be flags.
+	state.parseFlags()
+	// There may be an index.
+	if !state.parseIndex() {
+		return nil
+	}
+	// There may be a width.
+	if !state.parseNum() {
+		return nil
+	}
+	// There may be a precision.
+	if !state.parsePrecision() {
+		return nil
+	}
+	// Now a verb, possibly prefixed by an index (which we may already have).
+	if !state.indexPending && !state.parseIndex() {
+		return nil
+	}
+	if state.nbytes == len(state.format) {
+		f.Badf(call.Pos(), "%s format %s is missing verb at end of string", name, state.format)
+		return nil
+	}
+	verb, w := utf8.DecodeRuneInString(state.format[state.nbytes:])
+	state.verb = verb
+	state.nbytes += w
+	if verb != '%' {
+		state.argNums = append(state.argNums, state.argNum)
+	}
+	state.format = state.format[:state.nbytes]
+	return state
+}
+
+// printfArgType encodes the types of expressions a printf verb accepts. It is a bitmask.
+type printfArgType int
+
+const (
+	argBool printfArgType = 1 << iota
+	argInt
+	argRune
+	argString
+	argFloat
+	argComplex
+	argPointer
+	anyType printfArgType = ^0
+)
+
+type printVerb struct {
+	verb  rune   // User may provide verb through Formatter; could be a rune.
+	flags string // known flags are all ASCII
+	typ   printfArgType
+}
+
+// Common flag sets for printf verbs.
+const (
+	noFlag       = ""
+	numFlag      = " -+.0"
+	sharpNumFlag = " -+.0#"
+	allFlags     = " -+.0#"
+)
+
+// printVerbs identifies which flags are known to printf for each verb.
+var printVerbs = []printVerb{
+	// '-' is a width modifier, always valid.
+	// '.' is a precision for float, max width for strings.
+	// '+' is required sign for numbers, Go format for %v.
+	// '#' is alternate format for several verbs.
+	// ' ' is spacer for numbers
+	{'%', noFlag, 0},
+	{'b', numFlag, argInt | argFloat | argComplex},
+	{'c', "-", argRune | argInt},
+	{'d', numFlag, argInt | argPointer},
+	{'e', sharpNumFlag, argFloat | argComplex},
+	{'E', sharpNumFlag, argFloat | argComplex},
+	{'f', sharpNumFlag, argFloat | argComplex},
+	{'F', sharpNumFlag, argFloat | argComplex},
+	{'g', sharpNumFlag, argFloat | argComplex},
+	{'G', sharpNumFlag, argFloat | argComplex},
+	{'o', sharpNumFlag, argInt},
+	{'p', "-#", argPointer},
+	{'q', " -+.0#", argRune | argInt | argString},
+	{'s', " -+.0", argString},
+	{'t', "-", argBool},
+	{'T', "-", anyType},
+	{'U', "-#", argRune | argInt},
+	{'v', allFlags, anyType},
+	{'x', sharpNumFlag, argRune | argInt | argString | argPointer},
+	{'X', sharpNumFlag, argRune | argInt | argString | argPointer},
+}
+
+// okPrintfArg compares the formatState to the arguments actually present,
+// reporting any discrepancies it can discern. If the final argument is ellipsissed,
+// there's little it can do for that.
+func (f *File) okPrintfArg(call *ast.CallExpr, state *formatState) (ok bool) {
+	var v printVerb
+	found := false
+	// Linear scan is fast enough for a small list.
+	for _, v = range printVerbs {
+		if v.verb == state.verb {
+			found = true
+			break
+		}
+	}
+
+	// Does current arg implement fmt.Formatter?
+	formatter := false
+	if state.argNum < len(call.Args) {
+		if tv, ok := f.pkg.types[call.Args[state.argNum]]; ok {
+			formatter = f.isFormatter(tv.Type)
+		}
+	}
+
+	if !formatter {
+		if !found {
+			f.Badf(call.Pos(), "%s format %s has unknown verb %c", state.name, state.format, state.verb)
+			return false
+		}
+		for _, flag := range state.flags {
+			// TODO: Disable complaint about '0' for Go 1.10. To be fixed properly in 1.11.
+			// See issues 23598 and 23605.
+			if flag == '0' {
+				continue
+			}
+			if !strings.ContainsRune(v.flags, rune(flag)) {
+				f.Badf(call.Pos(), "%s format %s has unrecognized flag %c", state.name, state.format, flag)
+				return false
+			}
+		}
+	}
+	// Verb is good. If len(state.argNums)>trueArgs, we have something like %.*s and all
+	// but the final arg must be an integer.
+	trueArgs := 1
+	if state.verb == '%' {
+		trueArgs = 0
+	}
+	nargs := len(state.argNums)
+	for i := 0; i < nargs-trueArgs; i++ {
+		argNum := state.argNums[i]
+		if !f.argCanBeChecked(call, i, state) {
+			return
+		}
+		arg := call.Args[argNum]
+		if !f.matchArgType(argInt, nil, arg) {
+			f.Badf(call.Pos(), "%s format %s uses non-int %s as argument of *", state.name, state.format, f.gofmt(arg))
+			return false
+		}
+	}
+	if state.verb == '%' || formatter {
+		return true
+	}
+	argNum := state.argNums[len(state.argNums)-1]
+	if !f.argCanBeChecked(call, len(state.argNums)-1, state) {
+		return false
+	}
+	arg := call.Args[argNum]
+	if f.isFunctionValue(arg) && state.verb != 'p' && state.verb != 'T' {
+		f.Badf(call.Pos(), "%s format %s arg %s is a func value, not called", state.name, state.format, f.gofmt(arg))
+		return false
+	}
+	if !f.matchArgType(v.typ, nil, arg) {
+		typeString := ""
+		if typ := f.pkg.types[arg].Type; typ != nil {
+			typeString = typ.String()
+		}
+		f.Badf(call.Pos(), "%s format %s has arg %s of wrong type %s", state.name, state.format, f.gofmt(arg), typeString)
+		return false
+	}
+	if v.typ&argString != 0 && v.verb != 'T' && !bytes.Contains(state.flags, []byte{'#'}) && f.recursiveStringer(arg) {
+		f.Badf(call.Pos(), "%s format %s with arg %s causes recursive String method call", state.name, state.format, f.gofmt(arg))
+		return false
+	}
+	return true
+}
+
+// recursiveStringer reports whether the provided argument is r or &r for the
+// fmt.Stringer receiver identifier r.
+func (f *File) recursiveStringer(e ast.Expr) bool {
+	if len(f.stringerPtrs) == 0 {
+		return false
+	}
+	ptr := false
+	var obj *ast.Object
+	switch e := e.(type) {
+	case *ast.Ident:
+		obj = e.Obj
+	case *ast.UnaryExpr:
+		if id, ok := e.X.(*ast.Ident); ok && e.Op == token.AND {
+			obj = id.Obj
+			ptr = true
+		}
+	}
+
+	// It's unlikely to be a recursive stringer if it has a Format method.
+	if typ := f.pkg.types[e].Type; typ != nil {
+		if f.isFormatter(typ) {
+			return false
+		}
+	}
+
+	// We compare the underlying Object, which checks that the identifier
+	// is the one we declared as the receiver for the String method in
+	// which this printf appears.
+	ptrRecv, exist := f.stringerPtrs[obj]
+	if !exist {
+		return false
+	}
+	// We also need to check that using &t when we declared String
+	// on (t *T) is ok; in such a case, the address is printed.
+	if ptr && ptrRecv {
+		return false
+	}
+	return true
+}
+
+// isFunctionValue reports whether the expression is a function as opposed to a function call.
+// It is almost always a mistake to print a function value.
+func (f *File) isFunctionValue(e ast.Expr) bool {
+	if typ := f.pkg.types[e].Type; typ != nil {
+		_, ok := typ.(*types.Signature)
+		return ok
+	}
+	return false
+}
+
+// argCanBeChecked reports whether the specified argument is statically present;
+// it may be beyond the list of arguments or in a terminal slice... argument, which
+// means we can't see it.
+func (f *File) argCanBeChecked(call *ast.CallExpr, formatArg int, state *formatState) bool {
+	argNum := state.argNums[formatArg]
+	if argNum <= 0 {
+		// Shouldn't happen, so catch it with prejudice.
+		panic("negative arg num")
+	}
+	if argNum < len(call.Args)-1 {
+		return true // Always OK.
+	}
+	if call.Ellipsis.IsValid() {
+		return false // We just can't tell; there could be many more arguments.
+	}
+	if argNum < len(call.Args) {
+		return true
+	}
+	// There are bad indexes in the format or there are fewer arguments than the format needs.
+	// This is the argument number relative to the format: Printf("%s", "hi") will give 1 for the "hi".
+	arg := argNum - state.firstArg + 1 // People think of arguments as 1-indexed.
+	f.Badf(call.Pos(), "%s format %s reads arg #%d, but call has %v", state.name, state.format, arg, count(len(call.Args)-state.firstArg, "arg"))
+	return false
+}
+
+// printFormatRE is the regexp we match and report as a possible format string
+// in the first argument to unformatted prints like fmt.Print.
+// We exclude the space flag, so that printing a string like "x % y" is not reported as a format.
+var printFormatRE = regexp.MustCompile(`%` + flagsRE + numOptRE + `\.?` + numOptRE + indexOptRE + verbRE)
+
+const (
+	flagsRE    = `[+\-#]*`
+	indexOptRE = `(\[[0-9]+\])?`
+	numOptRE   = `([0-9]+|` + indexOptRE + `\*)?`
+	verbRE     = `[bcdefgopqstvxEFGTUX]`
+)
+
+// checkPrint checks a call to an unformatted print routine such as Println.
+func (f *File) checkPrint(call *ast.CallExpr, name string) {
+	firstArg := 0
+	typ := f.pkg.types[call.Fun].Type
+	if typ == nil {
+		// Skip checking functions with unknown type.
+		return
+	}
+	if sig, ok := typ.(*types.Signature); ok {
+		if !sig.Variadic() {
+			// Skip checking non-variadic functions.
+			return
+		}
+		params := sig.Params()
+		firstArg = params.Len() - 1
+
+		typ := params.At(firstArg).Type()
+		typ = typ.(*types.Slice).Elem()
+		it, ok := typ.(*types.Interface)
+		if !ok || !it.Empty() {
+			// Skip variadic functions accepting non-interface{} args.
+			return
+		}
+	}
+	args := call.Args
+	if len(args) <= firstArg {
+		// Skip calls without variadic args.
+		return
+	}
+	args = args[firstArg:]
+
+	if firstArg == 0 {
+		if sel, ok := call.Args[0].(*ast.SelectorExpr); ok {
+			if x, ok := sel.X.(*ast.Ident); ok {
+				if x.Name == "os" && strings.HasPrefix(sel.Sel.Name, "Std") {
+					f.Badf(call.Pos(), "%s does not take io.Writer but has first arg %s", name, f.gofmt(call.Args[0]))
+				}
+			}
+		}
+	}
+
+	arg := args[0]
+	if lit, ok := arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
+		// Ignore trailing % character in lit.Value.
+		// The % in "abc 0.0%" couldn't be a formatting directive.
+		s := strings.TrimSuffix(lit.Value, `%"`)
+		if strings.Contains(s, "%") {
+			m := printFormatRE.FindStringSubmatch(s)
+			if m != nil {
+				f.Badf(call.Pos(), "%s call has possible formatting directive %s", name, m[0])
+			}
+		}
+	}
+	if strings.HasSuffix(name, "ln") {
+		// The last item, if a string, should not have a newline.
+		arg = args[len(args)-1]
+		if lit, ok := arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
+			str, _ := strconv.Unquote(lit.Value)
+			if strings.HasSuffix(str, "\n") {
+				f.Badf(call.Pos(), "%s arg list ends with redundant newline", name)
+			}
+		}
+	}
+	for _, arg := range args {
+		if f.isFunctionValue(arg) {
+			f.Badf(call.Pos(), "%s arg %s is a func value, not called", name, f.gofmt(arg))
+		}
+		if f.recursiveStringer(arg) {
+			f.Badf(call.Pos(), "%s arg %s causes recursive call to String method", name, f.gofmt(arg))
+		}
+	}
+}
+
+// count(n, what) returns "1 what" or "N whats"
+// (assuming the plural of what is whats).
+func count(n int, what string) string {
+	if n == 1 {
+		return "1 " + what
+	}
+	return fmt.Sprintf("%d %ss", n, what)
+}

vendor/github.com/golang/go/rangeloop.go

@@ -0,0 +1,105 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+This file contains the code to check range loop variables bound inside function
+literals that are deferred or launched in new goroutines. We only check
+instances where the defer or go statement is the last statement in the loop
+body, as otherwise we would need whole program analysis.
+
+For example:
+
+	for i, v := range s {
+		go func() {
+			println(i, v) // not what you might expect
+		}()
+	}
+
+See: https://golang.org/doc/go_faq.html#closures_and_goroutines
+*/
+
+package govet
+
+import "go/ast"
+
+func init() {
+	register("rangeloops",
+		"check that loop variables are used correctly",
+		checkLoop,
+		rangeStmt, forStmt)
+}
+
+// checkLoop walks the body of the provided loop statement, checking whether
+// its index or value variables are used unsafely inside goroutines or deferred
+// function literals.
+func checkLoop(f *File, node ast.Node) {
+	// Find the variables updated by the loop statement.
+	var vars []*ast.Ident
+	addVar := func(expr ast.Expr) {
+		if id, ok := expr.(*ast.Ident); ok {
+			vars = append(vars, id)
+		}
+	}
+	var body *ast.BlockStmt
+	switch n := node.(type) {
+	case *ast.RangeStmt:
+		body = n.Body
+		addVar(n.Key)
+		addVar(n.Value)
+	case *ast.ForStmt:
+		body = n.Body
+		switch post := n.Post.(type) {
+		case *ast.AssignStmt:
+			// e.g. for p = head; p != nil; p = p.next
+			for _, lhs := range post.Lhs {
+				addVar(lhs)
+			}
+		case *ast.IncDecStmt:
+			// e.g. for i := 0; i < n; i++
+			addVar(post.X)
+		}
+	}
+	if vars == nil {
+		return
+	}
+
+	// Inspect a go or defer statement
+	// if it's the last one in the loop body.
+	// (We give up if there are following statements,
+	// because it's hard to prove go isn't followed by wait,
+	// or defer by return.)
+	if len(body.List) == 0 {
+		return
+	}
+	var last *ast.CallExpr
+	switch s := body.List[len(body.List)-1].(type) {
+	case *ast.GoStmt:
+		last = s.Call
+	case *ast.DeferStmt:
+		last = s.Call
+	default:
+		return
+	}
+	lit, ok := last.Fun.(*ast.FuncLit)
+	if !ok {
+		return
+	}
+	ast.Inspect(lit.Body, func(n ast.Node) bool {
+		id, ok := n.(*ast.Ident)
+		if !ok || id.Obj == nil {
+			return true
+		}
+		if f.pkg.types[id].Type == nil {
+			// Not referring to a variable (e.g. struct field name)
+			return true
+		}
+		for _, v := range vars {
+			if v.Obj == id.Obj {
+				f.Badf(id.Pos(), "loop variable %s captured by func literal",
+					id.Name)
+			}
+		}
+		return true
+	})
+}

vendor/github.com/golang/go/shadow.go

@@ -0,0 +1,246 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+This file contains the code to check for shadowed variables.
+A shadowed variable is a variable declared in an inner scope
+with the same name and type as a variable in an outer scope,
+and where the outer variable is mentioned after the inner one
+is declared.
+
+(This definition can be refined; the module generates too many
+false positives and is not yet enabled by default.)
+
+For example:
+
+	func BadRead(f *os.File, buf []byte) error {
+		var err error
+		for {
+			n, err := f.Read(buf) // shadows the function variable 'err'
+			if err != nil {
+				break // causes return of wrong value
+			}
+			foo(buf)
+		}
+		return err
+	}
+
+*/
+
+package govet
+
+import (
+	"flag"
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+var strictShadowing = flag.Bool("shadowstrict", false, "whether to be strict about shadowing; can be noisy")
+
+func init() {
+	register("shadow",
+		"check for shadowed variables (experimental; must be set explicitly)",
+		checkShadow,
+		assignStmt, genDecl)
+	experimental["shadow"] = true
+}
+
+func checkShadow(f *File, node ast.Node) {
+	switch n := node.(type) {
+	case *ast.AssignStmt:
+		checkShadowAssignment(f, n)
+	case *ast.GenDecl:
+		checkShadowDecl(f, n)
+	}
+}
+
+// Span stores the minimum range of byte positions in the file in which a
+// given variable (types.Object) is mentioned. It is lexically defined: it spans
+// from the beginning of its first mention to the end of its last mention.
+// A variable is considered shadowed (if *strictShadowing is off) only if the
+// shadowing variable is declared within the span of the shadowed variable.
+// In other words, if a variable is shadowed but not used after the shadowed
+// variable is declared, it is inconsequential and not worth complaining about.
+// This simple check dramatically reduces the nuisance rate for the shadowing
+// check, at least until something cleverer comes along.
+//
+// One wrinkle: A "naked return" is a silent use of a variable that the Span
+// will not capture, but the compilers catch naked returns of shadowed
+// variables so we don't need to.
+//
+// Cases this gets wrong (TODO):
+// - If a for loop's continuation statement mentions a variable redeclared in
+// the block, we should complain about it but don't.
+// - A variable declared inside a function literal can falsely be identified
+// as shadowing a variable in the outer function.
+//
+type Span struct {
+	min token.Pos
+	max token.Pos
+}
+
+// contains reports whether the position is inside the span.
+func (s Span) contains(pos token.Pos) bool {
+	return s.min <= pos && pos < s.max
+}
+
+// growSpan expands the span for the object to contain the instance represented
+// by the identifier.
+func (pkg *Package) growSpan(ident *ast.Ident, obj types.Object) {
+	if *strictShadowing {
+		return // No need
+	}
+	pos := ident.Pos()
+	end := ident.End()
+	span, ok := pkg.spans[obj]
+	if ok {
+		if span.min > pos {
+			span.min = pos
+		}
+		if span.max < end {
+			span.max = end
+		}
+	} else {
+		span = Span{pos, end}
+	}
+	pkg.spans[obj] = span
+}
+
+// checkShadowAssignment checks for shadowing in a short variable declaration.
+func checkShadowAssignment(f *File, a *ast.AssignStmt) {
+	if a.Tok != token.DEFINE {
+		return
+	}
+	if f.idiomaticShortRedecl(a) {
+		return
+	}
+	for _, expr := range a.Lhs {
+		ident, ok := expr.(*ast.Ident)
+		if !ok {
+			f.Badf(expr.Pos(), "invalid AST: short variable declaration of non-identifier")
+			return
+		}
+		checkShadowing(f, ident)
+	}
+}
+
+// idiomaticShortRedecl reports whether this short declaration can be ignored for
+// the purposes of shadowing, that is, that any redeclarations it contains are deliberate.
+func (f *File) idiomaticShortRedecl(a *ast.AssignStmt) bool {
+	// Don't complain about deliberate redeclarations of the form
+	//	i := i
+	// Such constructs are idiomatic in range loops to create a new variable
+	// for each iteration. Another example is
+	//	switch n := n.(type)
+	if len(a.Rhs) != len(a.Lhs) {
+		return false
+	}
+	// We know it's an assignment, so the LHS must be all identifiers. (We check anyway.)
+	for i, expr := range a.Lhs {
+		lhs, ok := expr.(*ast.Ident)
+		if !ok {
+			f.Badf(expr.Pos(), "invalid AST: short variable declaration of non-identifier")
+			return true // Don't do any more processing.
+		}
+		switch rhs := a.Rhs[i].(type) {
+		case *ast.Ident:
+			if lhs.Name != rhs.Name {
+				return false
+			}
+		case *ast.TypeAssertExpr:
+			if id, ok := rhs.X.(*ast.Ident); ok {
+				if lhs.Name != id.Name {
+					return false
+				}
+			}
+		default:
+			return false
+		}
+	}
+	return true
+}
+
+// idiomaticRedecl reports whether this declaration spec can be ignored for
+// the purposes of shadowing, that is, that any redeclarations it contains are deliberate.
+func (f *File) idiomaticRedecl(d *ast.ValueSpec) bool {
+	// Don't complain about deliberate redeclarations of the form
+	//	var i, j = i, j
+	if len(d.Names) != len(d.Values) {
+		return false
+	}
+	for i, lhs := range d.Names {
+		if rhs, ok := d.Values[i].(*ast.Ident); ok {
+			if lhs.Name != rhs.Name {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// checkShadowDecl checks for shadowing in a general variable declaration.
+func checkShadowDecl(f *File, d *ast.GenDecl) {
+	if d.Tok != token.VAR {
+		return
+	}
+	for _, spec := range d.Specs {
+		valueSpec, ok := spec.(*ast.ValueSpec)
+		if !ok {
+			f.Badf(spec.Pos(), "invalid AST: var GenDecl not ValueSpec")
+			return
+		}
+		// Don't complain about deliberate redeclarations of the form
+		//	var i = i
+		if f.idiomaticRedecl(valueSpec) {
+			return
+		}
+		for _, ident := range valueSpec.Names {
+			checkShadowing(f, ident)
+		}
+	}
+}
+
+// checkShadowing checks whether the identifier shadows an identifier in an outer scope.
+func checkShadowing(f *File, ident *ast.Ident) {
+	if ident.Name == "_" {
+		// Can't shadow the blank identifier.
+		return
+	}
+	obj := f.pkg.defs[ident]
+	if obj == nil {
+		return
+	}
+	// obj.Parent.Parent is the surrounding scope. If we can find another declaration
+	// starting from there, we have a shadowed identifier.
+	_, shadowed := obj.Parent().Parent().LookupParent(obj.Name(), obj.Pos())
+	if shadowed == nil {
+		return
+	}
+	// Don't complain if it's shadowing a universe-declared identifier; that's fine.
+	if shadowed.Parent() == types.Universe {
+		return
+	}
+	if *strictShadowing {
+		// The shadowed identifier must appear before this one to be an instance of shadowing.
+		if shadowed.Pos() > ident.Pos() {
+			return
+		}
+	} else {
+		// Don't complain if the span of validity of the shadowed identifier doesn't include
+		// the shadowing identifier.
+		span, ok := f.pkg.spans[shadowed]
+		if !ok {
+			f.Badf(ident.Pos(), "internal error: no range for %q", ident.Name)
+			return
+		}
+		if !span.contains(ident.Pos()) {
+			return
+		}
+	}
+	// Don't complain if the types differ: that implies the programmer really wants two different things.
+	if types.Identical(obj.Type(), shadowed.Type()) {
+		f.Badf(ident.Pos(), "declaration of %q shadows declaration at %s", obj.Name(), f.loc(shadowed.Pos()))
+	}
+}

vendor/github.com/golang/go/shift.go

@@ -0,0 +1,98 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+This file contains the code to check for suspicious shifts.
+*/
+
+package govet
+
+import (
+	"go/ast"
+	"go/constant"
+	"go/token"
+	"go/types"
+)
+
+func init() {
+	register("shift",
+		"check for useless shifts",
+		checkShift,
+		binaryExpr, assignStmt)
+}
+
+func checkShift(f *File, node ast.Node) {
+	if f.dead[node] {
+		// Skip shift checks on unreachable nodes.
+		return
+	}
+
+	switch node := node.(type) {
+	case *ast.BinaryExpr:
+		if node.Op == token.SHL || node.Op == token.SHR {
+			checkLongShift(f, node, node.X, node.Y)
+		}
+	case *ast.AssignStmt:
+		if len(node.Lhs) != 1 || len(node.Rhs) != 1 {
+			return
+		}
+		if node.Tok == token.SHL_ASSIGN || node.Tok == token.SHR_ASSIGN {
+			checkLongShift(f, node, node.Lhs[0], node.Rhs[0])
+		}
+	}
+}
+
+// checkLongShift checks if shift or shift-assign operations shift by more than
+// the length of the underlying variable.
+func checkLongShift(f *File, node ast.Node, x, y ast.Expr) {
+	if f.pkg.types[x].Value != nil {
+		// Ignore shifts of constants.
+		// These are frequently used for bit-twiddling tricks
+		// like ^uint(0) >> 63 for 32/64 bit detection and compatibility.
+		return
+	}
+
+	v := f.pkg.types[y].Value
+	if v == nil {
+		return
+	}
+	amt, ok := constant.Int64Val(v)
+	if !ok {
+		return
+	}
+	t := f.pkg.types[x].Type
+	if t == nil {
+		return
+	}
+	b, ok := t.Underlying().(*types.Basic)
+	if !ok {
+		return
+	}
+	var size int64
+	switch b.Kind() {
+	case types.Uint8, types.Int8:
+		size = 8
+	case types.Uint16, types.Int16:
+		size = 16
+	case types.Uint32, types.Int32:
+		size = 32
+	case types.Uint64, types.Int64:
+		size = 64
+	case types.Int, types.Uint:
+		size = uintBitSize
+	case types.Uintptr:
+		size = uintptrBitSize
+	default:
+		return
+	}
+	if amt >= size {
+		ident := f.gofmt(x)
+		f.Badf(node.Pos(), "%s (%d bits) too small for shift of %d", ident, size, amt)
+	}
+}
+
+var (
+	uintBitSize    = 8 * archSizes.Sizeof(types.Typ[types.Uint])
+	uintptrBitSize = 8 * archSizes.Sizeof(types.Typ[types.Uintptr])
+)

vendor/github.com/golang/go/structtag.go

@@ -0,0 +1,226 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains the test for canonical struct tags.
+
+package govet
+
+import (
+	"errors"
+	"go/ast"
+	"go/token"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+func init() {
+	register("structtags",
+		"check that struct field tags have canonical format and apply to exported fields as needed",
+		checkStructFieldTags,
+		structType)
+}
+
+// checkStructFieldTags checks all the field tags of a struct, including checking for duplicates.
+func checkStructFieldTags(f *File, node ast.Node) {
+	var seen map[[2]string]token.Pos
+	for _, field := range node.(*ast.StructType).Fields.List {
+		checkCanonicalFieldTag(f, field, &seen)
+	}
+}
+
+var checkTagDups = []string{"json", "xml"}
+var checkTagSpaces = map[string]bool{"json": true, "xml": true, "asn1": true}
+
+// checkCanonicalFieldTag checks a single struct field tag.
+func checkCanonicalFieldTag(f *File, field *ast.Field, seen *map[[2]string]token.Pos) {
+	if field.Tag == nil {
+		return
+	}
+
+	tag, err := strconv.Unquote(field.Tag.Value)
+	if err != nil {
+		f.Badf(field.Pos(), "unable to read struct tag %s", field.Tag.Value)
+		return
+	}
+
+	if err := validateStructTag(tag); err != nil {
+		raw, _ := strconv.Unquote(field.Tag.Value) // field.Tag.Value is known to be a quoted string
+		f.Badf(field.Pos(), "struct field tag %#q not compatible with reflect.StructTag.Get: %s", raw, err)
+	}
+
+	for _, key := range checkTagDups {
+		val := reflect.StructTag(tag).Get(key)
+		if val == "" || val == "-" || val[0] == ',' {
+			continue
+		}
+		if key == "xml" && len(field.Names) > 0 && field.Names[0].Name == "XMLName" {
+			// XMLName defines the XML element name of the struct being
+			// checked. That name cannot collide with element or attribute
+			// names defined on other fields of the struct. Vet does not have a
+			// check for untagged fields of type struct defining their own name
+			// by containing a field named XMLName; see issue 18256.
+			continue
+		}
+		if i := strings.Index(val, ","); i >= 0 {
+			if key == "xml" {
+				// Use a separate namespace for XML attributes.
+				for _, opt := range strings.Split(val[i:], ",") {
+					if opt == "attr" {
+						key += " attribute" // Key is part of the error message.
+						break
+					}
+				}
+			}
+			val = val[:i]
+		}
+		if *seen == nil {
+			*seen = map[[2]string]token.Pos{}
+		}
+		if pos, ok := (*seen)[[2]string{key, val}]; ok {
+			var name string
+			if len(field.Names) > 0 {
+				name = field.Names[0].Name
+			} else {
+				name = field.Type.(*ast.Ident).Name
+			}
+			f.Badf(field.Pos(), "struct field %s repeats %s tag %q also at %s", name, key, val, f.loc(pos))
+		} else {
+			(*seen)[[2]string{key, val}] = field.Pos()
+		}
+	}
+
+	// Check for use of json or xml tags with unexported fields.
+
+	// Embedded struct. Nothing to do for now, but that
+	// may change, depending on what happens with issue 7363.
+	if len(field.Names) == 0 {
+		return
+	}
+
+	if field.Names[0].IsExported() {
+		return
+	}
+
+	for _, enc := range [...]string{"json", "xml"} {
+		if reflect.StructTag(tag).Get(enc) != "" {
+			f.Badf(field.Pos(), "struct field %s has %s tag but is not exported", field.Names[0].Name, enc)
+			return
+		}
+	}
+}
+
+var (
+	errTagSyntax      = errors.New("bad syntax for struct tag pair")
+	errTagKeySyntax   = errors.New("bad syntax for struct tag key")
+	errTagValueSyntax = errors.New("bad syntax for struct tag value")
+	errTagValueSpace  = errors.New("suspicious space in struct tag value")
+	errTagSpace       = errors.New("key:\"value\" pairs not separated by spaces")
+)
+
+// validateStructTag parses the struct tag and returns an error if it is not
+// in the canonical format, which is a space-separated list of key:"value"
+// settings. The value may contain spaces.
+func validateStructTag(tag string) error {
+	// This code is based on the StructTag.Get code in package reflect.
+
+	n := 0
+	for ; tag != ""; n++ {
+		if n > 0 && tag != "" && tag[0] != ' ' {
+			// More restrictive than reflect, but catches likely mistakes
+			// like `x:"foo",y:"bar"`, which parses as `x:"foo" ,y:"bar"` with second key ",y".
+			return errTagSpace
+		}
+		// Skip leading space.
+		i := 0
+		for i < len(tag) && tag[i] == ' ' {
+			i++
+		}
+		tag = tag[i:]
+		if tag == "" {
+			break
+		}
+
+		// Scan to colon. A space, a quote or a control character is a syntax error.
+		// Strictly speaking, control chars include the range [0x7f, 0x9f], not just
+		// [0x00, 0x1f], but in practice, we ignore the multi-byte control characters
+		// as it is simpler to inspect the tag's bytes than the tag's runes.
+		i = 0
+		for i < len(tag) && tag[i] > ' ' && tag[i] != ':' && tag[i] != '"' && tag[i] != 0x7f {
+			i++
+		}
+		if i == 0 {
+			return errTagKeySyntax
+		}
+		if i+1 >= len(tag) || tag[i] != ':' {
+			return errTagSyntax
+		}
+		if tag[i+1] != '"' {
+			return errTagValueSyntax
+		}
+		key := tag[:i]
+		tag = tag[i+1:]
+
+		// Scan quoted string to find value.
+		i = 1
+		for i < len(tag) && tag[i] != '"' {
+			if tag[i] == '\\' {
+				i++
+			}
+			i++
+		}
+		if i >= len(tag) {
+			return errTagValueSyntax
+		}
+		qvalue := tag[:i+1]
+		tag = tag[i+1:]
+
+		value, err := strconv.Unquote(qvalue)
+		if err != nil {
+			return errTagValueSyntax
+		}
+
+		if !checkTagSpaces[key] {
+			continue
+		}
+
+		switch key {
+		case "xml":
+			// If the first or last character in the XML tag is a space, it is
+			// suspicious.
+			if strings.Trim(value, " ") != value {
+				return errTagValueSpace
+			}
+
+			// If there are multiple spaces, they are suspicious.
+			if strings.Count(value, " ") > 1 {
+				return errTagValueSpace
+			}
+
+			// If there is no comma, skip the rest of the checks.
+			comma := strings.IndexRune(value, ',')
+			if comma < 0 {
+				continue
+			}
+
+			// If the character before a comma is a space, this is suspicious.
+			if comma > 0 && value[comma-1] == ' ' {
+				return errTagValueSpace
+			}
+			value = value[comma+1:]
+		case "json":
+			// JSON allows using spaces in the name, so skip it.
+			comma := strings.IndexRune(value, ',')
+			if comma < 0 {
+				continue
+			}
+			value = value[comma+1:]
+		}
+
+		if strings.IndexByte(value, ' ') >= 0 {
+			return errTagValueSpace
+		}
+	}
+	return nil
+}

vendor/github.com/golang/go/tests.go

@@ -0,0 +1,187 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package govet
+
+import (
+	"go/ast"
+	"go/types"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+func init() {
+	register("tests",
+		"check for common mistaken usages of tests/documentation examples",
+		checkTestFunctions,
+		funcDecl)
+}
+
+func isExampleSuffix(s string) bool {
+	r, size := utf8.DecodeRuneInString(s)
+	return size > 0 && unicode.IsLower(r)
+}
+
+func isTestSuffix(name string) bool {
+	if len(name) == 0 {
+		// "Test" is ok.
+		return true
+	}
+	r, _ := utf8.DecodeRuneInString(name)
+	return !unicode.IsLower(r)
+}
+
+func isTestParam(typ ast.Expr, wantType string) bool {
+	ptr, ok := typ.(*ast.StarExpr)
+	if !ok {
+		// Not a pointer.
+		return false
+	}
+	// No easy way of making sure it's a *testing.T or *testing.B:
+	// ensure the name of the type matches.
+	if name, ok := ptr.X.(*ast.Ident); ok {
+		return name.Name == wantType
+	}
+	if sel, ok := ptr.X.(*ast.SelectorExpr); ok {
+		return sel.Sel.Name == wantType
+	}
+	return false
+}
+
+func lookup(name string, scopes []*types.Scope) types.Object {
+	for _, scope := range scopes {
+		if o := scope.Lookup(name); o != nil {
+			return o
+		}
+	}
+	return nil
+}
+
+func extendedScope(f *File) []*types.Scope {
+	scopes := []*types.Scope{f.pkg.typesPkg.Scope()}
+	if f.basePkg != nil {
+		scopes = append(scopes, f.basePkg.typesPkg.Scope())
+	} else {
+		// If basePkg is not specified (e.g. when checking a single file) try to
+		// find it among imports.
+		pkgName := f.pkg.typesPkg.Name()
+		if strings.HasSuffix(pkgName, "_test") {
+			basePkgName := strings.TrimSuffix(pkgName, "_test")
+			for _, p := range f.pkg.typesPkg.Imports() {
+				if p.Name() == basePkgName {
+					scopes = append(scopes, p.Scope())
+					break
+				}
+			}
+		}
+	}
+	return scopes
+}
+
+func checkExample(fn *ast.FuncDecl, f *File, report reporter) {
+	fnName := fn.Name.Name
+	if params := fn.Type.Params; len(params.List) != 0 {
+		report("%s should be niladic", fnName)
+	}
+	if results := fn.Type.Results; results != nil && len(results.List) != 0 {
+		report("%s should return nothing", fnName)
+	}
+
+	if filesRun && !includesNonTest {
+		// The coherence checks between a test and the package it tests
+		// will report false positives if no non-test files have
+		// been provided.
+		return
+	}
+
+	if fnName == "Example" {
+		// Nothing more to do.
+		return
+	}
+
+	var (
+		exName = strings.TrimPrefix(fnName, "Example")
+		elems  = strings.SplitN(exName, "_", 3)
+		ident  = elems[0]
+		obj    = lookup(ident, extendedScope(f))
+	)
+	if ident != "" && obj == nil {
+		// Check ExampleFoo and ExampleBadFoo.
+		report("%s refers to unknown identifier: %s", fnName, ident)
+		// Abort since obj is absent and no subsequent checks can be performed.
+		return
+	}
+	if len(elems) < 2 {
+		// Nothing more to do.
+		return
+	}
+
+	if ident == "" {
+		// Check Example_suffix and Example_BadSuffix.
+		if residual := strings.TrimPrefix(exName, "_"); !isExampleSuffix(residual) {
+			report("%s has malformed example suffix: %s", fnName, residual)
+		}
+		return
+	}
+
+	mmbr := elems[1]
+	if !isExampleSuffix(mmbr) {
+		// Check ExampleFoo_Method and ExampleFoo_BadMethod.
+		if obj, _, _ := types.LookupFieldOrMethod(obj.Type(), true, obj.Pkg(), mmbr); obj == nil {
+			report("%s refers to unknown field or method: %s.%s", fnName, ident, mmbr)
+		}
+	}
+	if len(elems) == 3 && !isExampleSuffix(elems[2]) {
+		// Check ExampleFoo_Method_suffix and ExampleFoo_Method_Badsuffix.
+		report("%s has malformed example suffix: %s", fnName, elems[2])
+	}
+}
+
+func checkTest(fn *ast.FuncDecl, prefix string, report reporter) {
+	// Want functions with 0 results and 1 parameter.
+	if fn.Type.Results != nil && len(fn.Type.Results.List) > 0 ||
+		fn.Type.Params == nil ||
+		len(fn.Type.Params.List) != 1 ||
+		len(fn.Type.Params.List[0].Names) > 1 {
+		return
+	}
+
+	// The param must look like a *testing.T or *testing.B.
+	if !isTestParam(fn.Type.Params.List[0].Type, prefix[:1]) {
+		return
+	}
+
+	if !isTestSuffix(fn.Name.Name[len(prefix):]) {
+		report("%s has malformed name: first letter after '%s' must not be lowercase", fn.Name.Name, prefix)
+	}
+}
+
+type reporter func(format string, args ...interface{})
+
+// checkTestFunctions walks Test, Benchmark and Example functions checking
+// malformed names, wrong signatures and examples documenting nonexistent
+// identifiers.
+func checkTestFunctions(f *File, node ast.Node) {
+	if !strings.HasSuffix(f.name, "_test.go") {
+		return
+	}
+
+	fn, ok := node.(*ast.FuncDecl)
+	if !ok || fn.Recv != nil {
+		// Ignore non-functions or functions with receivers.
+		return
+	}
+
+	report := func(format string, args ...interface{}) { f.Badf(node.Pos(), format, args...) }
+
+	switch {
+	case strings.HasPrefix(fn.Name.Name, "Example"):
+		checkExample(fn, f, report)
+	case strings.HasPrefix(fn.Name.Name, "Test"):
+		checkTest(fn, "Test", report)
+	case strings.HasPrefix(fn.Name.Name, "Benchmark"):
+		checkTest(fn, "Benchmark", report)
+	}
+}

vendor/github.com/golang/go/types.go

@@ -0,0 +1,313 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains the pieces of the tool that use typechecking from the go/types package.
+
+package govet
+
+import (
+	"go/ast"
+	"go/build"
+	"go/importer"
+	"go/token"
+	"go/types"
+)
+
+// stdImporter is the importer we use to import packages.
+// It is shared so that all packages are imported by the same importer.
+var stdImporter types.Importer
+
+var (
+	errorType     *types.Interface
+	stringerType  *types.Interface // possibly nil
+	formatterType *types.Interface // possibly nil
+)
+
+func inittypes() {
+	errorType = types.Universe.Lookup("error").Type().Underlying().(*types.Interface)
+
+	if typ := importType("fmt", "Stringer"); typ != nil {
+		stringerType = typ.Underlying().(*types.Interface)
+	}
+	if typ := importType("fmt", "Formatter"); typ != nil {
+		formatterType = typ.Underlying().(*types.Interface)
+	}
+}
+
+// isNamedType reports whether t is the named type path.name.
+func isNamedType(t types.Type, path, name string) bool {
+	n, ok := t.(*types.Named)
+	if !ok {
+		return false
+	}
+	obj := n.Obj()
+	return obj.Name() == name && obj.Pkg() != nil && obj.Pkg().Path() == path
+}
+
+// importType returns the type denoted by the qualified identifier
+// path.name, and adds the respective package to the imports map
+// as a side effect. In case of an error, importType returns nil.
+func importType(path, name string) types.Type {
+	pkg, err := stdImporter.Import(path)
+	if err != nil {
+		// This can happen if the package at path hasn't been compiled yet.
+		warnf("import failed: %v", err)
+		return nil
+	}
+	if obj, ok := pkg.Scope().Lookup(name).(*types.TypeName); ok {
+		return obj.Type()
+	}
+	warnf("invalid type name %q", name)
+	return nil
+}
+
+func (pkg *Package) check(fs *token.FileSet, astFiles []*ast.File) []error {
+	if stdImporter == nil {
+		if *source {
+			stdImporter = importer.For("source", nil)
+		} else {
+			stdImporter = importer.Default()
+		}
+		inittypes()
+	}
+	pkg.defs = make(map[*ast.Ident]types.Object)
+	pkg.uses = make(map[*ast.Ident]types.Object)
+	pkg.selectors = make(map[*ast.SelectorExpr]*types.Selection)
+	pkg.spans = make(map[types.Object]Span)
+	pkg.types = make(map[ast.Expr]types.TypeAndValue)
+
+	var allErrors []error
+	config := types.Config{
+		// We use the same importer for all imports to ensure that
+		// everybody sees identical packages for the given paths.
+		Importer: stdImporter,
+		// By providing a Config with our own error function, it will continue
+		// past the first error. We collect them all for printing later.
+		Error: func(e error) {
+			allErrors = append(allErrors, e)
+		},
+
+		Sizes: archSizes,
+	}
+	info := &types.Info{
+		Selections: pkg.selectors,
+		Types:      pkg.types,
+		Defs:       pkg.defs,
+		Uses:       pkg.uses,
+	}
+	typesPkg, err := config.Check(pkg.path, fs, astFiles, info)
+	if len(allErrors) == 0 && err != nil {
+		allErrors = append(allErrors, err)
+	}
+	pkg.typesPkg = typesPkg
+	// update spans
+	for id, obj := range pkg.defs {
+		pkg.growSpan(id, obj)
+	}
+	for id, obj := range pkg.uses {
+		pkg.growSpan(id, obj)
+	}
+	return allErrors
+}
+
+// matchArgType reports an error if printf verb t is not appropriate
+// for operand arg.
+//
+// typ is used only for recursive calls; external callers must supply nil.
+//
+// (Recursion arises from the compound types {map,chan,slice} which
+// may be printed with %d etc. if that is appropriate for their element
+// types.)
+func (f *File) matchArgType(t printfArgType, typ types.Type, arg ast.Expr) bool {
+	return f.matchArgTypeInternal(t, typ, arg, make(map[types.Type]bool))
+}
+
+// matchArgTypeInternal is the internal version of matchArgType. It carries a map
+// remembering what types are in progress so we don't recur when faced with recursive
+// types or mutually recursive types.
+func (f *File) matchArgTypeInternal(t printfArgType, typ types.Type, arg ast.Expr, inProgress map[types.Type]bool) bool {
+	// %v, %T accept any argument type.
+	if t == anyType {
+		return true
+	}
+	if typ == nil {
+		// external call
+		typ = f.pkg.types[arg].Type
+		if typ == nil {
+			return true // probably a type check problem
+		}
+	}
+	// If the type implements fmt.Formatter, we have nothing to check.
+	if f.isFormatter(typ) {
+		return true
+	}
+	// If we can use a string, might arg (dynamically) implement the Stringer or Error interface?
+	if t&argString != 0 && isConvertibleToString(typ) {
+		return true
+	}
+
+	typ = typ.Underlying()
+	if inProgress[typ] {
+		// We're already looking at this type. The call that started it will take care of it.
+		return true
+	}
+	inProgress[typ] = true
+
+	switch typ := typ.(type) {
+	case *types.Signature:
+		return t&argPointer != 0
+
+	case *types.Map:
+		// Recur: map[int]int matches %d.
+		return t&argPointer != 0 ||
+			(f.matchArgTypeInternal(t, typ.Key(), arg, inProgress) && f.matchArgTypeInternal(t, typ.Elem(), arg, inProgress))
+
+	case *types.Chan:
+		return t&argPointer != 0
+
+	case *types.Array:
+		// Same as slice.
+		if types.Identical(typ.Elem().Underlying(), types.Typ[types.Byte]) && t&argString != 0 {
+			return true // %s matches []byte
+		}
+		// Recur: []int matches %d.
+		return t&argPointer != 0 || f.matchArgTypeInternal(t, typ.Elem(), arg, inProgress)
+
+	case *types.Slice:
+		// Same as array.
+		if types.Identical(typ.Elem().Underlying(), types.Typ[types.Byte]) && t&argString != 0 {
+			return true // %s matches []byte
+		}
+		// Recur: []int matches %d. But watch out for
+		//	type T []T
+		// If the element is a pointer type (type T[]*T), it's handled fine by the Pointer case below.
+		return t&argPointer != 0 || f.matchArgTypeInternal(t, typ.Elem(), arg, inProgress)
+
+	case *types.Pointer:
+		// Ugly, but dealing with an edge case: a known pointer to an invalid type,
+		// probably something from a failed import.
+		if typ.Elem().String() == "invalid type" {
+			if *verbose {
+				f.Warnf(arg.Pos(), "printf argument %v is pointer to invalid or unknown type", f.gofmt(arg))
+			}
+			return true // special case
+		}
+		// If it's actually a pointer with %p, it prints as one.
+		if t == argPointer {
+			return true
+		}
+		// If it's pointer to struct, that's equivalent in our analysis to whether we can print the struct.
+		if str, ok := typ.Elem().Underlying().(*types.Struct); ok {
+			return f.matchStructArgType(t, str, arg, inProgress)
+		}
+		// Check whether the rest can print pointers.
+		return t&argPointer != 0
+
+	case *types.Struct:
+		return f.matchStructArgType(t, typ, arg, inProgress)
+
+	case *types.Interface:
+		// There's little we can do.
+		// Whether any particular verb is valid depends on the argument.
+		// The user may have reasonable prior knowledge of the contents of the interface.
+		return true
+
+	case *types.Basic:
+		switch typ.Kind() {
+		case types.UntypedBool,
+			types.Bool:
+			return t&argBool != 0
+
+		case types.UntypedInt,
+			types.Int,
+			types.Int8,
+			types.Int16,
+			types.Int32,
+			types.Int64,
+			types.Uint,
+			types.Uint8,
+			types.Uint16,
+			types.Uint32,
+			types.Uint64,
+			types.Uintptr:
+			return t&argInt != 0
+
+		case types.UntypedFloat,
+			types.Float32,
+			types.Float64:
+			return t&argFloat != 0
+
+		case types.UntypedComplex,
+			types.Complex64,
+			types.Complex128:
+			return t&argComplex != 0
+
+		case types.UntypedString,
+			types.String:
+			return t&argString != 0
+
+		case types.UnsafePointer:
+			return t&(argPointer|argInt) != 0
+
+		case types.UntypedRune:
+			return t&(argInt|argRune) != 0
+
+		case types.UntypedNil:
+			return false
+
+		case types.Invalid:
+			if *verbose {
+				f.Warnf(arg.Pos(), "printf argument %v has invalid or unknown type", f.gofmt(arg))
+			}
+			return true // Probably a type check problem.
+		}
+		panic("unreachable")
+	}
+
+	return false
+}
+
+func isConvertibleToString(typ types.Type) bool {
+	if bt, ok := typ.(*types.Basic); ok && bt.Kind() == types.UntypedNil {
+		// We explicitly don't want untyped nil, which is
+		// convertible to both of the interfaces below, as it
+		// would just panic anyway.
+		return false
+	}
+	if types.ConvertibleTo(typ, errorType) {
+		return true // via .Error()
+	}
+	if stringerType != nil && types.ConvertibleTo(typ, stringerType) {
+		return true // via .String()
+	}
+	return false
+}
+
+// hasBasicType reports whether x's type is a types.Basic with the given kind.
+func (f *File) hasBasicType(x ast.Expr, kind types.BasicKind) bool {
+	t := f.pkg.types[x].Type
+	if t != nil {
+		t = t.Underlying()
+	}
+	b, ok := t.(*types.Basic)
+	return ok && b.Kind() == kind
+}
+
+// matchStructArgType reports whether all the elements of the struct match the expected
+// type. For instance, with "%d" all the elements must be printable with the "%d" format.
+func (f *File) matchStructArgType(t printfArgType, typ *types.Struct, arg ast.Expr, inProgress map[types.Type]bool) bool {
+	for i := 0; i < typ.NumFields(); i++ {
+		typf := typ.Field(i)
+		if !f.matchArgTypeInternal(t, typf.Type(), arg, inProgress) {
+			return false
+		}
+		if t&argString != 0 && !typf.Exported() && isConvertibleToString(typf.Type()) {
+			// Issue #17798: unexported Stringer or error cannot be properly fomatted.
+			return false
+		}
+	}
+	return true
+}
+
+var archSizes = types.SizesFor("gc", build.Default.GOARCH)

vendor/github.com/golang/go/unsafeptr.go

@@ -0,0 +1,97 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Check for invalid uintptr -> unsafe.Pointer conversions.
+
+package govet
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+func init() {
+	register("unsafeptr",
+		"check for misuse of unsafe.Pointer",
+		checkUnsafePointer,
+		callExpr)
+}
+
+func checkUnsafePointer(f *File, node ast.Node) {
+	x := node.(*ast.CallExpr)
+	if len(x.Args) != 1 {
+		return
+	}
+	if f.hasBasicType(x.Fun, types.UnsafePointer) && f.hasBasicType(x.Args[0], types.Uintptr) && !f.isSafeUintptr(x.Args[0]) {
+		f.Badf(x.Pos(), "possible misuse of unsafe.Pointer")
+	}
+}
+
+// isSafeUintptr reports whether x - already known to be a uintptr -
+// is safe to convert to unsafe.Pointer. It is safe if x is itself derived
+// directly from an unsafe.Pointer via conversion and pointer arithmetic
+// or if x is the result of reflect.Value.Pointer or reflect.Value.UnsafeAddr
+// or obtained from the Data field of a *reflect.SliceHeader or *reflect.StringHeader.
+func (f *File) isSafeUintptr(x ast.Expr) bool {
+	switch x := x.(type) {
+	case *ast.ParenExpr:
+		return f.isSafeUintptr(x.X)
+
+	case *ast.SelectorExpr:
+		switch x.Sel.Name {
+		case "Data":
+			// reflect.SliceHeader and reflect.StringHeader are okay,
+			// but only if they are pointing at a real slice or string.
+			// It's not okay to do:
+			//	var x SliceHeader
+			//	x.Data = uintptr(unsafe.Pointer(...))
+			//	... use x ...
+			//	p := unsafe.Pointer(x.Data)
+			// because in the middle the garbage collector doesn't
+			// see x.Data as a pointer and so x.Data may be dangling
+			// by the time we get to the conversion at the end.
+			// For now approximate by saying that *Header is okay
+			// but Header is not.
+			pt, ok := f.pkg.types[x.X].Type.(*types.Pointer)
+			if ok {
+				t, ok := pt.Elem().(*types.Named)
+				if ok && t.Obj().Pkg().Path() == "reflect" {
+					switch t.Obj().Name() {
+					case "StringHeader", "SliceHeader":
+						return true
+					}
+				}
+			}
+		}
+
+	case *ast.CallExpr:
+		switch len(x.Args) {
+		case 0:
+			// maybe call to reflect.Value.Pointer or reflect.Value.UnsafeAddr.
+			sel, ok := x.Fun.(*ast.SelectorExpr)
+			if !ok {
+				break
+			}
+			switch sel.Sel.Name {
+			case "Pointer", "UnsafeAddr":
+				t, ok := f.pkg.types[sel.X].Type.(*types.Named)
+				if ok && t.Obj().Pkg().Path() == "reflect" && t.Obj().Name() == "Value" {
+					return true
+				}
+			}
+
+		case 1:
+			// maybe conversion of uintptr to unsafe.Pointer
+			return f.hasBasicType(x.Fun, types.Uintptr) && f.hasBasicType(x.Args[0], types.UnsafePointer)
+		}
+
+	case *ast.BinaryExpr:
+		switch x.Op {
+		case token.ADD, token.SUB, token.AND_NOT:
+			return f.isSafeUintptr(x.X) && !f.isSafeUintptr(x.Y)
+		}
+	}
+	return false
+}

vendor/github.com/golang/go/unused.go

@@ -0,0 +1,93 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file defines the check for unused results of calls to certain
+// pure functions.
+
+package govet
+
+import (
+	"flag"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"strings"
+)
+
+var unusedFuncsFlag = flag.String("unusedfuncs",
+	"errors.New,fmt.Errorf,fmt.Sprintf,fmt.Sprint,sort.Reverse",
+	"comma-separated list of functions whose results must be used")
+
+var unusedStringMethodsFlag = flag.String("unusedstringmethods",
+	"Error,String",
+	"comma-separated list of names of methods of type func() string whose results must be used")
+
+func init() {
+	register("unusedresult",
+		"check for unused result of calls to functions in -unusedfuncs list and methods in -unusedstringmethods list",
+		checkUnusedResult,
+		exprStmt)
+}
+
+// func() string
+var sigNoArgsStringResult = types.NewSignature(nil, nil,
+	types.NewTuple(types.NewVar(token.NoPos, nil, "", types.Typ[types.String])),
+	false)
+
+var unusedFuncs = make(map[string]bool)
+var unusedStringMethods = make(map[string]bool)
+
+func initUnusedFlags() {
+	commaSplit := func(s string, m map[string]bool) {
+		if s != "" {
+			for _, name := range strings.Split(s, ",") {
+				if len(name) == 0 {
+					flag.Usage()
+				}
+				m[name] = true
+			}
+		}
+	}
+	commaSplit(*unusedFuncsFlag, unusedFuncs)
+	commaSplit(*unusedStringMethodsFlag, unusedStringMethods)
+}
+
+func checkUnusedResult(f *File, n ast.Node) {
+	call, ok := unparen(n.(*ast.ExprStmt).X).(*ast.CallExpr)
+	if !ok {
+		return // not a call statement
+	}
+	fun := unparen(call.Fun)
+
+	if f.pkg.types[fun].IsType() {
+		return // a conversion, not a call
+	}
+
+	selector, ok := fun.(*ast.SelectorExpr)
+	if !ok {
+		return // neither a method call nor a qualified ident
+	}
+
+	sel, ok := f.pkg.selectors[selector]
+	if ok && sel.Kind() == types.MethodVal {
+		// method (e.g. foo.String())
+		obj := sel.Obj().(*types.Func)
+		sig := sel.Type().(*types.Signature)
+		if types.Identical(sig, sigNoArgsStringResult) {
+			if unusedStringMethods[obj.Name()] {
+				f.Badf(call.Lparen, "result of (%s).%s call not used",
+					sig.Recv().Type(), obj.Name())
+			}
+		}
+	} else if !ok {
+		// package-qualified function (e.g. fmt.Errorf)
+		obj := f.pkg.uses[selector.Sel]
+		if obj, ok := obj.(*types.Func); ok {
+			qname := obj.Pkg().Path() + "." + obj.Name()
+			if unusedFuncs[qname] {
+				f.Badf(call.Lparen, "result of %v call not used", qname)
+			}
+		}
+	}
+}