staticcheck (#313)

* CI: use staticcheck for linting

This commit switches the linter for Go code from golint to staticcheck.
Golint has been deprecated since last year and staticcheck is a
recommended replacement.

Signed-off-by: Lucas Servén Marín <lserven@gmail.com>

* revendor

Signed-off-by: Lucas Servén Marín <lserven@gmail.com>

* cmd,pkg: fix lint warnings

Signed-off-by: Lucas Servén Marín <lserven@gmail.com>

vendor/honnef.co/go/tools/analysis/code/code.go

@@ -0,0 +1,342 @@
+// Package code answers structural and type questions about Go code.
+package code
+
+import (
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/constant"
+	"go/token"
+	"go/types"
+	"strings"
+
+	"honnef.co/go/tools/analysis/facts"
+	"honnef.co/go/tools/go/ast/astutil"
+	"honnef.co/go/tools/go/types/typeutil"
+	"honnef.co/go/tools/pattern"
+
+	"golang.org/x/exp/typeparams"
+	"golang.org/x/tools/go/analysis"
+)
+
+type Positioner interface {
+	Pos() token.Pos
+}
+
+func IsOfType(pass *analysis.Pass, expr ast.Expr, name string) bool {
+	return typeutil.IsType(pass.TypesInfo.TypeOf(expr), name)
+}
+
+func IsInTest(pass *analysis.Pass, node Positioner) bool {
+	// FIXME(dh): this doesn't work for global variables with
+	// initializers
+	f := pass.Fset.File(node.Pos())
+	return f != nil && strings.HasSuffix(f.Name(), "_test.go")
+}
+
+// IsMain reports whether the package being processed is a package
+// main.
+func IsMain(pass *analysis.Pass) bool {
+	return pass.Pkg.Name() == "main"
+}
+
+// IsMainLike reports whether the package being processed is a
+// main-like package. A main-like package is a package that is
+// package main, or that is intended to be used by a tool framework
+// such as cobra to implement a command.
+//
+// Note that this function errs on the side of false positives; it may
+// return true for packages that aren't main-like. IsMainLike is
+// intended for analyses that wish to suppress diagnostics for
+// main-like packages to avoid false positives.
+func IsMainLike(pass *analysis.Pass) bool {
+	if pass.Pkg.Name() == "main" {
+		return true
+	}
+	for _, imp := range pass.Pkg.Imports() {
+		if imp.Path() == "github.com/spf13/cobra" {
+			return true
+		}
+	}
+	return false
+}
+
+func SelectorName(pass *analysis.Pass, expr *ast.SelectorExpr) string {
+	info := pass.TypesInfo
+	sel := info.Selections[expr]
+	if sel == nil {
+		if x, ok := expr.X.(*ast.Ident); ok {
+			pkg, ok := info.ObjectOf(x).(*types.PkgName)
+			if !ok {
+				// This shouldn't happen
+				return fmt.Sprintf("%s.%s", x.Name, expr.Sel.Name)
+			}
+			return fmt.Sprintf("%s.%s", pkg.Imported().Path(), expr.Sel.Name)
+		}
+		panic(fmt.Sprintf("unsupported selector: %v", expr))
+	}
+	if v, ok := sel.Obj().(*types.Var); ok && v.IsField() {
+		return fmt.Sprintf("(%s).%s", typeutil.DereferenceR(sel.Recv()), sel.Obj().Name())
+	} else {
+		return fmt.Sprintf("(%s).%s", sel.Recv(), sel.Obj().Name())
+	}
+}
+
+func IsNil(pass *analysis.Pass, expr ast.Expr) bool {
+	return pass.TypesInfo.Types[expr].IsNil()
+}
+
+func BoolConst(pass *analysis.Pass, expr ast.Expr) bool {
+	val := pass.TypesInfo.ObjectOf(expr.(*ast.Ident)).(*types.Const).Val()
+	return constant.BoolVal(val)
+}
+
+func IsBoolConst(pass *analysis.Pass, expr ast.Expr) bool {
+	// We explicitly don't support typed bools because more often than
+	// not, custom bool types are used as binary enums and the
+	// explicit comparison is desired.
+
+	ident, ok := expr.(*ast.Ident)
+	if !ok {
+		return false
+	}
+	obj := pass.TypesInfo.ObjectOf(ident)
+	c, ok := obj.(*types.Const)
+	if !ok {
+		return false
+	}
+	basic, ok := c.Type().(*types.Basic)
+	if !ok {
+		return false
+	}
+	if basic.Kind() != types.UntypedBool && basic.Kind() != types.Bool {
+		return false
+	}
+	return true
+}
+
+func ExprToInt(pass *analysis.Pass, expr ast.Expr) (int64, bool) {
+	tv := pass.TypesInfo.Types[expr]
+	if tv.Value == nil {
+		return 0, false
+	}
+	if tv.Value.Kind() != constant.Int {
+		return 0, false
+	}
+	return constant.Int64Val(tv.Value)
+}
+
+func ExprToString(pass *analysis.Pass, expr ast.Expr) (string, bool) {
+	val := pass.TypesInfo.Types[expr].Value
+	if val == nil {
+		return "", false
+	}
+	if val.Kind() != constant.String {
+		return "", false
+	}
+	return constant.StringVal(val), true
+}
+
+func CallName(pass *analysis.Pass, call *ast.CallExpr) string {
+	fun := astutil.Unparen(call.Fun)
+
+	// Instantiating a function cannot return another generic function, so doing this once is enough
+	switch idx := fun.(type) {
+	case *ast.IndexExpr:
+		fun = idx.X
+	case *typeparams.IndexListExpr:
+		fun = idx.X
+	}
+
+	// (foo)[T] is not a valid instantiationg, so no need to unparen again.
+
+	switch fun := fun.(type) {
+	case *ast.SelectorExpr:
+		fn, ok := pass.TypesInfo.ObjectOf(fun.Sel).(*types.Func)
+		if !ok {
+			return ""
+		}
+		return typeutil.FuncName(fn)
+	case *ast.Ident:
+		obj := pass.TypesInfo.ObjectOf(fun)
+		switch obj := obj.(type) {
+		case *types.Func:
+			return typeutil.FuncName(obj)
+		case *types.Builtin:
+			return obj.Name()
+		default:
+			return ""
+		}
+	default:
+		return ""
+	}
+}
+
+func IsCallTo(pass *analysis.Pass, node ast.Node, name string) bool {
+	call, ok := node.(*ast.CallExpr)
+	if !ok {
+		return false
+	}
+	return CallName(pass, call) == name
+}
+
+func IsCallToAny(pass *analysis.Pass, node ast.Node, names ...string) bool {
+	call, ok := node.(*ast.CallExpr)
+	if !ok {
+		return false
+	}
+	q := CallName(pass, call)
+	for _, name := range names {
+		if q == name {
+			return true
+		}
+	}
+	return false
+}
+
+func File(pass *analysis.Pass, node Positioner) *ast.File {
+	m := pass.ResultOf[facts.TokenFile].(map[*token.File]*ast.File)
+	return m[pass.Fset.File(node.Pos())]
+}
+
+// IsGenerated reports whether pos is in a generated file, It ignores
+// //line directives.
+func IsGenerated(pass *analysis.Pass, pos token.Pos) bool {
+	_, ok := Generator(pass, pos)
+	return ok
+}
+
+// Generator returns the generator that generated the file containing
+// pos. It ignores //line directives.
+func Generator(pass *analysis.Pass, pos token.Pos) (facts.Generator, bool) {
+	file := pass.Fset.PositionFor(pos, false).Filename
+	m := pass.ResultOf[facts.Generated].(map[string]facts.Generator)
+	g, ok := m[file]
+	return g, ok
+}
+
+// MayHaveSideEffects reports whether expr may have side effects. If
+// the purity argument is nil, this function implements a purely
+// syntactic check, meaning that any function call may have side
+// effects, regardless of the called function's body. Otherwise,
+// purity will be consulted to determine the purity of function calls.
+func MayHaveSideEffects(pass *analysis.Pass, expr ast.Expr, purity facts.PurityResult) bool {
+	switch expr := expr.(type) {
+	case *ast.BadExpr:
+		return true
+	case *ast.Ellipsis:
+		return MayHaveSideEffects(pass, expr.Elt, purity)
+	case *ast.FuncLit:
+		// the literal itself cannot have side effects, only calling it
+		// might, which is handled by CallExpr.
+		return false
+	case *ast.ArrayType, *ast.StructType, *ast.FuncType, *ast.InterfaceType, *ast.MapType, *ast.ChanType:
+		// types cannot have side effects
+		return false
+	case *ast.BasicLit:
+		return false
+	case *ast.BinaryExpr:
+		return MayHaveSideEffects(pass, expr.X, purity) || MayHaveSideEffects(pass, expr.Y, purity)
+	case *ast.CallExpr:
+		if purity == nil {
+			return true
+		}
+		switch obj := typeutil.Callee(pass.TypesInfo, expr).(type) {
+		case *types.Func:
+			if _, ok := purity[obj]; !ok {
+				return true
+			}
+		case *types.Builtin:
+			switch obj.Name() {
+			case "len", "cap":
+			default:
+				return true
+			}
+		default:
+			return true
+		}
+		for _, arg := range expr.Args {
+			if MayHaveSideEffects(pass, arg, purity) {
+				return true
+			}
+		}
+		return false
+	case *ast.CompositeLit:
+		if MayHaveSideEffects(pass, expr.Type, purity) {
+			return true
+		}
+		for _, elt := range expr.Elts {
+			if MayHaveSideEffects(pass, elt, purity) {
+				return true
+			}
+		}
+		return false
+	case *ast.Ident:
+		return false
+	case *ast.IndexExpr:
+		return MayHaveSideEffects(pass, expr.X, purity) || MayHaveSideEffects(pass, expr.Index, purity)
+	case *typeparams.IndexListExpr:
+		// In theory, none of the checks are necessary, as IndexListExpr only involves types. But there is no harm in
+		// being safe.
+		if MayHaveSideEffects(pass, expr.X, purity) {
+			return true
+		}
+		for _, idx := range expr.Indices {
+			if MayHaveSideEffects(pass, idx, purity) {
+				return true
+			}
+		}
+		return false
+	case *ast.KeyValueExpr:
+		return MayHaveSideEffects(pass, expr.Key, purity) || MayHaveSideEffects(pass, expr.Value, purity)
+	case *ast.SelectorExpr:
+		return MayHaveSideEffects(pass, expr.X, purity)
+	case *ast.SliceExpr:
+		return MayHaveSideEffects(pass, expr.X, purity) ||
+			MayHaveSideEffects(pass, expr.Low, purity) ||
+			MayHaveSideEffects(pass, expr.High, purity) ||
+			MayHaveSideEffects(pass, expr.Max, purity)
+	case *ast.StarExpr:
+		return MayHaveSideEffects(pass, expr.X, purity)
+	case *ast.TypeAssertExpr:
+		return MayHaveSideEffects(pass, expr.X, purity)
+	case *ast.UnaryExpr:
+		if MayHaveSideEffects(pass, expr.X, purity) {
+			return true
+		}
+		return expr.Op == token.ARROW || expr.Op == token.AND
+	case *ast.ParenExpr:
+		return MayHaveSideEffects(pass, expr.X, purity)
+	case nil:
+		return false
+	default:
+		panic(fmt.Sprintf("internal error: unhandled type %T", expr))
+	}
+}
+
+func IsGoVersion(pass *analysis.Pass, minor int) bool {
+	f, ok := pass.Analyzer.Flags.Lookup("go").Value.(flag.Getter)
+	if !ok {
+		panic("requested Go version, but analyzer has no version flag")
+	}
+	version := f.Get().(int)
+	return version >= minor
+}
+
+var integerLiteralQ = pattern.MustParse(`(IntegerLiteral tv)`)
+
+func IntegerLiteral(pass *analysis.Pass, node ast.Node) (types.TypeAndValue, bool) {
+	m, ok := Match(pass, integerLiteralQ, node)
+	if !ok {
+		return types.TypeAndValue{}, false
+	}
+	return m.State["tv"].(types.TypeAndValue), true
+}
+
+func IsIntegerLiteral(pass *analysis.Pass, node ast.Node, value constant.Value) bool {
+	tv, ok := IntegerLiteral(pass, node)
+	if !ok {
+		return false
+	}
+	return constant.Compare(tv.Value, token.EQL, value)
+}

vendor/honnef.co/go/tools/analysis/code/visit.go

@@ -0,0 +1,51 @@
+package code
+
+import (
+	"bytes"
+	"go/ast"
+	"go/format"
+
+	"honnef.co/go/tools/pattern"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+)
+
+func Preorder(pass *analysis.Pass, fn func(ast.Node), types ...ast.Node) {
+	pass.ResultOf[inspect.Analyzer].(*inspector.Inspector).Preorder(types, fn)
+}
+
+func PreorderStack(pass *analysis.Pass, fn func(ast.Node, []ast.Node), types ...ast.Node) {
+	pass.ResultOf[inspect.Analyzer].(*inspector.Inspector).WithStack(types, func(n ast.Node, push bool, stack []ast.Node) (proceed bool) {
+		if push {
+			fn(n, stack)
+		}
+		return true
+	})
+}
+
+func Match(pass *analysis.Pass, q pattern.Pattern, node ast.Node) (*pattern.Matcher, bool) {
+	// Note that we ignore q.Relevant – callers of Match usually use
+	// AST inspectors that already filter on nodes we're interested
+	// in.
+	m := &pattern.Matcher{TypesInfo: pass.TypesInfo}
+	ok := m.Match(q.Root, node)
+	return m, ok
+}
+
+func MatchAndEdit(pass *analysis.Pass, before, after pattern.Pattern, node ast.Node) (*pattern.Matcher, []analysis.TextEdit, bool) {
+	m, ok := Match(pass, before, node)
+	if !ok {
+		return m, nil, false
+	}
+	r := pattern.NodeToAST(after.Root, m.State)
+	buf := &bytes.Buffer{}
+	format.Node(buf, pass.Fset, r)
+	edit := []analysis.TextEdit{{
+		Pos:     node.Pos(),
+		End:     node.End(),
+		NewText: buf.Bytes(),
+	}}
+	return m, edit, true
+}

vendor/honnef.co/go/tools/analysis/edit/edit.go

@@ -0,0 +1,83 @@
+// Package edit contains helpers for creating suggested fixes.
+package edit
+
+import (
+	"bytes"
+	"go/ast"
+	"go/format"
+	"go/token"
+
+	"golang.org/x/tools/go/analysis"
+	"honnef.co/go/tools/pattern"
+)
+
+// Ranger describes values that have a start and end position.
+// In most cases these are either ast.Node or manually constructed ranges.
+type Ranger interface {
+	Pos() token.Pos
+	End() token.Pos
+}
+
+// Range implements the Ranger interface.
+type Range [2]token.Pos
+
+func (r Range) Pos() token.Pos { return r[0] }
+func (r Range) End() token.Pos { return r[1] }
+
+// ReplaceWithString replaces a range with a string.
+func ReplaceWithString(old Ranger, new string) analysis.TextEdit {
+	return analysis.TextEdit{
+		Pos:     old.Pos(),
+		End:     old.End(),
+		NewText: []byte(new),
+	}
+}
+
+// ReplaceWithNode replaces a range with an AST node.
+func ReplaceWithNode(fset *token.FileSet, old Ranger, new ast.Node) analysis.TextEdit {
+	buf := &bytes.Buffer{}
+	if err := format.Node(buf, fset, new); err != nil {
+		panic("internal error: " + err.Error())
+	}
+	return analysis.TextEdit{
+		Pos:     old.Pos(),
+		End:     old.End(),
+		NewText: buf.Bytes(),
+	}
+}
+
+// ReplaceWithPattern replaces a range with the result of executing a pattern.
+func ReplaceWithPattern(fset *token.FileSet, old Ranger, new pattern.Pattern, state pattern.State) analysis.TextEdit {
+	r := pattern.NodeToAST(new.Root, state)
+	buf := &bytes.Buffer{}
+	format.Node(buf, fset, r)
+	return analysis.TextEdit{
+		Pos:     old.Pos(),
+		End:     old.End(),
+		NewText: buf.Bytes(),
+	}
+}
+
+// Delete deletes a range of code.
+func Delete(old Ranger) analysis.TextEdit {
+	return analysis.TextEdit{
+		Pos:     old.Pos(),
+		End:     old.End(),
+		NewText: nil,
+	}
+}
+
+func Fix(msg string, edits ...analysis.TextEdit) analysis.SuggestedFix {
+	return analysis.SuggestedFix{
+		Message:   msg,
+		TextEdits: edits,
+	}
+}
+
+// Selector creates a new selector expression.
+func Selector(x, sel string) *ast.SelectorExpr {
+	return &ast.SelectorExpr{
+		X:   &ast.Ident{Name: x},
+		Sel: &ast.Ident{Name: sel},
+	}
+}

vendor/honnef.co/go/tools/analysis/facts/deprecated.go

@@ -0,0 +1,145 @@
+package facts
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+	"reflect"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+type IsDeprecated struct{ Msg string }
+
+func (*IsDeprecated) AFact()           {}
+func (d *IsDeprecated) String() string { return "Deprecated: " + d.Msg }
+
+type DeprecatedResult struct {
+	Objects  map[types.Object]*IsDeprecated
+	Packages map[*types.Package]*IsDeprecated
+}
+
+var Deprecated = &analysis.Analyzer{
+	Name:       "fact_deprecated",
+	Doc:        "Mark deprecated objects",
+	Run:        deprecated,
+	FactTypes:  []analysis.Fact{(*IsDeprecated)(nil)},
+	ResultType: reflect.TypeOf(DeprecatedResult{}),
+}
+
+func deprecated(pass *analysis.Pass) (interface{}, error) {
+	var names []*ast.Ident
+
+	extractDeprecatedMessage := func(docs []*ast.CommentGroup) string {
+		for _, doc := range docs {
+			if doc == nil {
+				continue
+			}
+			parts := strings.Split(doc.Text(), "\n\n")
+			for _, part := range parts {
+				if !strings.HasPrefix(part, "Deprecated: ") {
+					continue
+				}
+				alt := part[len("Deprecated: "):]
+				alt = strings.Replace(alt, "\n", " ", -1)
+				return alt
+			}
+		}
+		return ""
+	}
+	doDocs := func(names []*ast.Ident, docs []*ast.CommentGroup) {
+		alt := extractDeprecatedMessage(docs)
+		if alt == "" {
+			return
+		}
+
+		for _, name := range names {
+			obj := pass.TypesInfo.ObjectOf(name)
+			pass.ExportObjectFact(obj, &IsDeprecated{alt})
+		}
+	}
+
+	var docs []*ast.CommentGroup
+	for _, f := range pass.Files {
+		docs = append(docs, f.Doc)
+	}
+	if alt := extractDeprecatedMessage(docs); alt != "" {
+		// Don't mark package syscall as deprecated, even though
+		// it is. A lot of people still use it for simple
+		// constants like SIGKILL, and I am not comfortable
+		// telling them to use x/sys for that.
+		if pass.Pkg.Path() != "syscall" {
+			pass.ExportPackageFact(&IsDeprecated{alt})
+		}
+	}
+
+	docs = docs[:0]
+	for _, f := range pass.Files {
+		fn := func(node ast.Node) bool {
+			if node == nil {
+				return true
+			}
+			var ret bool
+			switch node := node.(type) {
+			case *ast.GenDecl:
+				switch node.Tok {
+				case token.TYPE, token.CONST, token.VAR:
+					docs = append(docs, node.Doc)
+					return true
+				default:
+					return false
+				}
+			case *ast.FuncDecl:
+				docs = append(docs, node.Doc)
+				names = []*ast.Ident{node.Name}
+				ret = false
+			case *ast.TypeSpec:
+				docs = append(docs, node.Doc)
+				names = []*ast.Ident{node.Name}
+				ret = true
+			case *ast.ValueSpec:
+				docs = append(docs, node.Doc)
+				names = node.Names
+				ret = false
+			case *ast.File:
+				return true
+			case *ast.StructType:
+				for _, field := range node.Fields.List {
+					doDocs(field.Names, []*ast.CommentGroup{field.Doc})
+				}
+				return false
+			case *ast.InterfaceType:
+				for _, field := range node.Methods.List {
+					doDocs(field.Names, []*ast.CommentGroup{field.Doc})
+				}
+				return false
+			default:
+				return false
+			}
+			if len(names) == 0 || len(docs) == 0 {
+				return ret
+			}
+			doDocs(names, docs)
+
+			docs = docs[:0]
+			names = nil
+			return ret
+		}
+		ast.Inspect(f, fn)
+	}
+
+	out := DeprecatedResult{
+		Objects:  map[types.Object]*IsDeprecated{},
+		Packages: map[*types.Package]*IsDeprecated{},
+	}
+
+	for _, fact := range pass.AllObjectFacts() {
+		out.Objects[fact.Object] = fact.Fact.(*IsDeprecated)
+	}
+	for _, fact := range pass.AllPackageFacts() {
+		out.Packages[fact.Package] = fact.Fact.(*IsDeprecated)
+	}
+
+	return out, nil
+}

vendor/honnef.co/go/tools/analysis/facts/directives.go

@@ -0,0 +1,20 @@
+package facts
+
+import (
+	"reflect"
+
+	"golang.org/x/tools/go/analysis"
+	"honnef.co/go/tools/analysis/lint"
+)
+
+func directives(pass *analysis.Pass) (interface{}, error) {
+	return lint.ParseDirectives(pass.Files, pass.Fset), nil
+}
+
+var Directives = &analysis.Analyzer{
+	Name:             "directives",
+	Doc:              "extracts linter directives",
+	Run:              directives,
+	RunDespiteErrors: true,
+	ResultType:       reflect.TypeOf([]lint.Directive{}),
+}

vendor/honnef.co/go/tools/analysis/facts/generated.go

@@ -0,0 +1,97 @@
+package facts
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"os"
+	"reflect"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+type Generator int
+
+// A list of known generators we can detect
+const (
+	Unknown Generator = iota
+	Goyacc
+	Cgo
+	Stringer
+	ProtocGenGo
+)
+
+var (
+	// used by cgo before Go 1.11
+	oldCgo = []byte("// Created by cgo - DO NOT EDIT")
+	prefix = []byte("// Code generated ")
+	suffix = []byte(" DO NOT EDIT.")
+	nl     = []byte("\n")
+	crnl   = []byte("\r\n")
+)
+
+func isGenerated(path string) (Generator, bool) {
+	f, err := os.Open(path)
+	if err != nil {
+		return 0, false
+	}
+	defer f.Close()
+	br := bufio.NewReader(f)
+	for {
+		s, err := br.ReadBytes('\n')
+		if err != nil && err != io.EOF {
+			return 0, false
+		}
+		s = bytes.TrimSuffix(s, crnl)
+		s = bytes.TrimSuffix(s, nl)
+		if bytes.HasPrefix(s, prefix) && bytes.HasSuffix(s, suffix) {
+			if len(s)-len(suffix) < len(prefix) {
+				return Unknown, true
+			}
+
+			text := string(s[len(prefix) : len(s)-len(suffix)])
+			switch text {
+			case "by goyacc.":
+				return Goyacc, true
+			case "by cmd/cgo;":
+				return Cgo, true
+			case "by protoc-gen-go.":
+				return ProtocGenGo, true
+			}
+			if strings.HasPrefix(text, `by "stringer `) {
+				return Stringer, true
+			}
+			if strings.HasPrefix(text, `by goyacc `) {
+				return Goyacc, true
+			}
+
+			return Unknown, true
+		}
+		if bytes.Equal(s, oldCgo) {
+			return Cgo, true
+		}
+		if err == io.EOF {
+			break
+		}
+	}
+	return 0, false
+}
+
+var Generated = &analysis.Analyzer{
+	Name: "isgenerated",
+	Doc:  "annotate file names that have been code generated",
+	Run: func(pass *analysis.Pass) (interface{}, error) {
+		m := map[string]Generator{}
+		for _, f := range pass.Files {
+			path := pass.Fset.PositionFor(f.Pos(), false).Filename
+			g, ok := isGenerated(path)
+			if ok {
+				m[path] = g
+			}
+		}
+		return m, nil
+	},
+	RunDespiteErrors: true,
+	ResultType:       reflect.TypeOf(map[string]Generator{}),
+}

vendor/honnef.co/go/tools/analysis/facts/nilness/nilness.go

@@ -0,0 +1,251 @@
+package nilness
+
+import (
+	"fmt"
+	"go/token"
+	"go/types"
+	"reflect"
+
+	"honnef.co/go/tools/go/ir"
+	"honnef.co/go/tools/go/types/typeutil"
+	"honnef.co/go/tools/internal/passes/buildir"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+// neverReturnsNilFact denotes that a function's return value will never
+// be nil (typed or untyped). The analysis errs on the side of false
+// negatives.
+type neverReturnsNilFact struct {
+	Rets []neverNilness
+}
+
+func (*neverReturnsNilFact) AFact() {}
+func (fact *neverReturnsNilFact) String() string {
+	return fmt.Sprintf("never returns nil: %v", fact.Rets)
+}
+
+type Result struct {
+	m map[*types.Func][]neverNilness
+}
+
+var Analysis = &analysis.Analyzer{
+	Name:       "nilness",
+	Doc:        "Annotates return values that will never be nil (typed or untyped)",
+	Run:        run,
+	Requires:   []*analysis.Analyzer{buildir.Analyzer},
+	FactTypes:  []analysis.Fact{(*neverReturnsNilFact)(nil)},
+	ResultType: reflect.TypeOf((*Result)(nil)),
+}
+
+// MayReturnNil reports whether the ret's return value of fn might be
+// a typed or untyped nil value. The value of ret is zero-based. When
+// globalOnly is true, the only possible nil values are global
+// variables.
+//
+// The analysis has false positives: MayReturnNil can incorrectly
+// report true, but never incorrectly reports false.
+func (r *Result) MayReturnNil(fn *types.Func, ret int) (yes bool, globalOnly bool) {
+	if !typeutil.IsPointerLike(fn.Type().(*types.Signature).Results().At(ret).Type()) {
+		return false, false
+	}
+	if len(r.m[fn]) == 0 {
+		return true, false
+	}
+
+	v := r.m[fn][ret]
+	return v != neverNil, v == onlyGlobal
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+	seen := map[*ir.Function]struct{}{}
+	out := &Result{
+		m: map[*types.Func][]neverNilness{},
+	}
+	for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
+		impl(pass, fn, seen)
+	}
+
+	for _, fact := range pass.AllObjectFacts() {
+		out.m[fact.Object.(*types.Func)] = fact.Fact.(*neverReturnsNilFact).Rets
+	}
+
+	return out, nil
+}
+
+type neverNilness uint8
+
+const (
+	neverNil   neverNilness = 1
+	onlyGlobal neverNilness = 2
+	nilly      neverNilness = 3
+)
+
+func (n neverNilness) String() string {
+	switch n {
+	case neverNil:
+		return "never"
+	case onlyGlobal:
+		return "global"
+	case nilly:
+		return "nil"
+	default:
+		return "BUG"
+	}
+}
+
+func impl(pass *analysis.Pass, fn *ir.Function, seenFns map[*ir.Function]struct{}) []neverNilness {
+	if fn.Object() == nil {
+		// TODO(dh): support closures
+		return nil
+	}
+	if fact := new(neverReturnsNilFact); pass.ImportObjectFact(fn.Object(), fact) {
+		return fact.Rets
+	}
+	if fn.Pkg != pass.ResultOf[buildir.Analyzer].(*buildir.IR).Pkg {
+		return nil
+	}
+	if fn.Blocks == nil {
+		return nil
+	}
+	if _, ok := seenFns[fn]; ok {
+		// break recursion
+		return nil
+	}
+
+	seenFns[fn] = struct{}{}
+
+	seen := map[ir.Value]struct{}{}
+
+	var mightReturnNil func(v ir.Value) neverNilness
+	mightReturnNil = func(v ir.Value) neverNilness {
+		if _, ok := seen[v]; ok {
+			// break cycle
+			return nilly
+		}
+		if !typeutil.IsPointerLike(v.Type()) {
+			return neverNil
+		}
+		seen[v] = struct{}{}
+		switch v := v.(type) {
+		case *ir.MakeInterface:
+			return mightReturnNil(v.X)
+		case *ir.Convert:
+			return mightReturnNil(v.X)
+		case *ir.SliceToArrayPointer:
+			if typeutil.CoreType(v.Type()).(*types.Pointer).Elem().Underlying().(*types.Array).Len() == 0 {
+				return mightReturnNil(v.X)
+			} else {
+				// converting a slice to an array pointer of length > 0 panics if the slice is nil
+				return neverNil
+			}
+		case *ir.Slice:
+			return mightReturnNil(v.X)
+		case *ir.Phi:
+			ret := neverNil
+			for _, e := range v.Edges {
+				if n := mightReturnNil(e); n > ret {
+					ret = n
+				}
+			}
+			return ret
+		case *ir.Extract:
+			switch d := v.Tuple.(type) {
+			case *ir.Call:
+				if callee := d.Call.StaticCallee(); callee != nil {
+					ret := impl(pass, callee, seenFns)
+					if len(ret) == 0 {
+						return nilly
+					}
+					return ret[v.Index]
+				} else {
+					return nilly
+				}
+			case *ir.TypeAssert, *ir.Next, *ir.Select, *ir.MapLookup, *ir.TypeSwitch, *ir.Recv, *ir.Sigma:
+				// we don't need to look at the Extract's index
+				// because we've already checked its type.
+				return nilly
+			default:
+				panic(fmt.Sprintf("internal error: unhandled type %T", d))
+			}
+		case *ir.Call:
+			if callee := v.Call.StaticCallee(); callee != nil {
+				ret := impl(pass, callee, seenFns)
+				if len(ret) == 0 {
+					return nilly
+				}
+				return ret[0]
+			} else {
+				return nilly
+			}
+		case *ir.BinOp, *ir.UnOp, *ir.Alloc, *ir.FieldAddr, *ir.IndexAddr, *ir.Global, *ir.MakeSlice, *ir.MakeClosure, *ir.Function, *ir.MakeMap, *ir.MakeChan:
+			return neverNil
+		case *ir.Sigma:
+			iff, ok := v.From.Control().(*ir.If)
+			if !ok {
+				return nilly
+			}
+			binop, ok := iff.Cond.(*ir.BinOp)
+			if !ok {
+				return nilly
+			}
+			isNil := func(v ir.Value) bool {
+				k, ok := v.(*ir.Const)
+				if !ok {
+					return false
+				}
+				return k.Value == nil
+			}
+			if binop.X == v.X && isNil(binop.Y) || binop.Y == v.X && isNil(binop.X) {
+				op := binop.Op
+				if v.From.Succs[0] != v.Block() {
+					// we're in the false branch, negate op
+					switch op {
+					case token.EQL:
+						op = token.NEQ
+					case token.NEQ:
+						op = token.EQL
+					default:
+						panic(fmt.Sprintf("internal error: unhandled token %v", op))
+					}
+				}
+				switch op {
+				case token.EQL:
+					return nilly
+				case token.NEQ:
+					return neverNil
+				default:
+					panic(fmt.Sprintf("internal error: unhandled token %v", op))
+				}
+			}
+			return nilly
+		case *ir.ChangeType:
+			return mightReturnNil(v.X)
+		case *ir.Load:
+			if _, ok := v.X.(*ir.Global); ok {
+				return onlyGlobal
+			}
+			return nilly
+		case *ir.AggregateConst:
+			return neverNil
+		case *ir.TypeAssert, *ir.ChangeInterface, *ir.Field, *ir.Const, *ir.GenericConst, *ir.Index, *ir.MapLookup, *ir.Parameter, *ir.Recv, *ir.TypeSwitch:
+			return nilly
+		default:
+			panic(fmt.Sprintf("internal error: unhandled type %T", v))
+		}
+	}
+	ret := fn.Exit.Control().(*ir.Return)
+	out := make([]neverNilness, len(ret.Results))
+	export := false
+	for i, v := range ret.Results {
+		v := mightReturnNil(v)
+		out[i] = v
+		if v != nilly && typeutil.IsPointerLike(fn.Signature.Results().At(i).Type()) {
+			export = true
+		}
+	}
+	if export {
+		pass.ExportObjectFact(fn.Object(), &neverReturnsNilFact{out})
+	}
+	return out
+}

vendor/honnef.co/go/tools/analysis/facts/purity.go

@@ -0,0 +1,178 @@
+package facts
+
+import (
+	"go/types"
+	"reflect"
+
+	"honnef.co/go/tools/go/ir"
+	"honnef.co/go/tools/go/ir/irutil"
+	"honnef.co/go/tools/internal/passes/buildir"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+type IsPure struct{}
+
+func (*IsPure) AFact()           {}
+func (d *IsPure) String() string { return "is pure" }
+
+type PurityResult map[*types.Func]*IsPure
+
+var Purity = &analysis.Analyzer{
+	Name:       "fact_purity",
+	Doc:        "Mark pure functions",
+	Run:        purity,
+	Requires:   []*analysis.Analyzer{buildir.Analyzer},
+	FactTypes:  []analysis.Fact{(*IsPure)(nil)},
+	ResultType: reflect.TypeOf(PurityResult{}),
+}
+
+var pureStdlib = map[string]struct{}{
+	"errors.New":                      {},
+	"fmt.Errorf":                      {},
+	"fmt.Sprintf":                     {},
+	"fmt.Sprint":                      {},
+	"sort.Reverse":                    {},
+	"strings.Map":                     {},
+	"strings.Repeat":                  {},
+	"strings.Replace":                 {},
+	"strings.Title":                   {},
+	"strings.ToLower":                 {},
+	"strings.ToLowerSpecial":          {},
+	"strings.ToTitle":                 {},
+	"strings.ToTitleSpecial":          {},
+	"strings.ToUpper":                 {},
+	"strings.ToUpperSpecial":          {},
+	"strings.Trim":                    {},
+	"strings.TrimFunc":                {},
+	"strings.TrimLeft":                {},
+	"strings.TrimLeftFunc":            {},
+	"strings.TrimPrefix":              {},
+	"strings.TrimRight":               {},
+	"strings.TrimRightFunc":           {},
+	"strings.TrimSpace":               {},
+	"strings.TrimSuffix":              {},
+	"(*net/http.Request).WithContext": {},
+}
+
+func purity(pass *analysis.Pass) (interface{}, error) {
+	seen := map[*ir.Function]struct{}{}
+	irpkg := pass.ResultOf[buildir.Analyzer].(*buildir.IR).Pkg
+	var check func(fn *ir.Function) (ret bool)
+	check = func(fn *ir.Function) (ret bool) {
+		if fn.Object() == nil {
+			// TODO(dh): support closures
+			return false
+		}
+		if pass.ImportObjectFact(fn.Object(), new(IsPure)) {
+			return true
+		}
+		if fn.Pkg != irpkg {
+			// Function is in another package but wasn't marked as
+			// pure, ergo it isn't pure
+			return false
+		}
+		// Break recursion
+		if _, ok := seen[fn]; ok {
+			return false
+		}
+
+		seen[fn] = struct{}{}
+		defer func() {
+			if ret {
+				pass.ExportObjectFact(fn.Object(), &IsPure{})
+			}
+		}()
+
+		if irutil.IsStub(fn) {
+			return false
+		}
+
+		if _, ok := pureStdlib[fn.Object().(*types.Func).FullName()]; ok {
+			return true
+		}
+
+		if fn.Signature.Results().Len() == 0 {
+			// A function with no return values is empty or is doing some
+			// work we cannot see (for example because of build tags);
+			// don't consider it pure.
+			return false
+		}
+
+		for _, param := range fn.Params {
+			// TODO(dh): this may not be strictly correct. pure code
+			// can, to an extent, operate on non-basic types.
+			if _, ok := param.Type().Underlying().(*types.Basic); !ok {
+				return false
+			}
+		}
+
+		// Don't consider external functions pure.
+		if fn.Blocks == nil {
+			return false
+		}
+		checkCall := func(common *ir.CallCommon) bool {
+			if common.IsInvoke() {
+				return false
+			}
+			builtin, ok := common.Value.(*ir.Builtin)
+			if !ok {
+				if common.StaticCallee() != fn {
+					if common.StaticCallee() == nil {
+						return false
+					}
+					if !check(common.StaticCallee()) {
+						return false
+					}
+				}
+			} else {
+				switch builtin.Name() {
+				case "len", "cap":
+				default:
+					return false
+				}
+			}
+			return true
+		}
+		for _, b := range fn.Blocks {
+			for _, ins := range b.Instrs {
+				switch ins := ins.(type) {
+				case *ir.Call:
+					if !checkCall(ins.Common()) {
+						return false
+					}
+				case *ir.Defer:
+					if !checkCall(&ins.Call) {
+						return false
+					}
+				case *ir.Select:
+					return false
+				case *ir.Send:
+					return false
+				case *ir.Go:
+					return false
+				case *ir.Panic:
+					return false
+				case *ir.Store:
+					return false
+				case *ir.FieldAddr:
+					return false
+				case *ir.Alloc:
+					return false
+				case *ir.Load:
+					return false
+				}
+			}
+		}
+		return true
+	}
+	for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
+		check(fn)
+	}
+
+	out := PurityResult{}
+	for _, fact := range pass.AllObjectFacts() {
+		out[fact.Object.(*types.Func)] = fact.Fact.(*IsPure)
+	}
+	return out, nil
+}

vendor/honnef.co/go/tools/analysis/facts/token.go

@@ -0,0 +1,24 @@
+package facts
+
+import (
+	"go/ast"
+	"go/token"
+	"reflect"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+var TokenFile = &analysis.Analyzer{
+	Name: "tokenfileanalyzer",
+	Doc:  "creates a mapping of *token.File to *ast.File",
+	Run: func(pass *analysis.Pass) (interface{}, error) {
+		m := map[*token.File]*ast.File{}
+		for _, af := range pass.Files {
+			tf := pass.Fset.File(af.Pos())
+			m[tf] = af
+		}
+		return m, nil
+	},
+	RunDespiteErrors: true,
+	ResultType:       reflect.TypeOf(map[*token.File]*ast.File{}),
+}

vendor/honnef.co/go/tools/analysis/facts/typedness/typedness.go

@@ -0,0 +1,253 @@
+package typedness
+
+import (
+	"fmt"
+	"go/token"
+	"go/types"
+	"reflect"
+
+	"honnef.co/go/tools/go/ir"
+	"honnef.co/go/tools/go/ir/irutil"
+	"honnef.co/go/tools/internal/passes/buildir"
+
+	"golang.org/x/exp/typeparams"
+	"golang.org/x/tools/go/analysis"
+)
+
+// alwaysTypedFact denotes that a function's return value will never
+// be untyped nil. The analysis errs on the side of false negatives.
+type alwaysTypedFact struct {
+	Rets uint8
+}
+
+func (*alwaysTypedFact) AFact() {}
+func (fact *alwaysTypedFact) String() string {
+	return fmt.Sprintf("always typed: %08b", fact.Rets)
+}
+
+type Result struct {
+	m map[*types.Func]uint8
+}
+
+var Analysis = &analysis.Analyzer{
+	Name:       "typedness",
+	Doc:        "Annotates return values that are always typed values",
+	Run:        run,
+	Requires:   []*analysis.Analyzer{buildir.Analyzer},
+	FactTypes:  []analysis.Fact{(*alwaysTypedFact)(nil)},
+	ResultType: reflect.TypeOf((*Result)(nil)),
+}
+
+// MustReturnTyped reports whether the ret's return value of fn must
+// be a typed value, i.e. an interface value containing a concrete
+// type or trivially a concrete type. The value of ret is zero-based.
+//
+// The analysis has false negatives: MustReturnTyped may incorrectly
+// report false, but never incorrectly reports true.
+func (r *Result) MustReturnTyped(fn *types.Func, ret int) bool {
+	if _, ok := fn.Type().(*types.Signature).Results().At(ret).Type().Underlying().(*types.Interface); !ok {
+		return true
+	}
+	return (r.m[fn] & (1 << ret)) != 0
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+	seen := map[*ir.Function]struct{}{}
+	out := &Result{
+		m: map[*types.Func]uint8{},
+	}
+	for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
+		impl(pass, fn, seen)
+	}
+
+	for _, fact := range pass.AllObjectFacts() {
+		out.m[fact.Object.(*types.Func)] = fact.Fact.(*alwaysTypedFact).Rets
+	}
+
+	return out, nil
+}
+
+func impl(pass *analysis.Pass, fn *ir.Function, seenFns map[*ir.Function]struct{}) (out uint8) {
+	if fn.Signature.Results().Len() > 8 {
+		return 0
+	}
+	if fn.Object() == nil {
+		// TODO(dh): support closures
+		return 0
+	}
+	if fact := new(alwaysTypedFact); pass.ImportObjectFact(fn.Object(), fact) {
+		return fact.Rets
+	}
+	if fn.Pkg != pass.ResultOf[buildir.Analyzer].(*buildir.IR).Pkg {
+		return 0
+	}
+	if fn.Blocks == nil {
+		return 0
+	}
+	if irutil.IsStub(fn) {
+		return 0
+	}
+	if _, ok := seenFns[fn]; ok {
+		// break recursion
+		return 0
+	}
+
+	seenFns[fn] = struct{}{}
+	defer func() {
+		for i := 0; i < fn.Signature.Results().Len(); i++ {
+			if _, ok := fn.Signature.Results().At(i).Type().Underlying().(*types.Interface); !ok {
+				// we don't need facts to know that non-interface
+				// types can't be untyped nil. zeroing out those bits
+				// may result in all bits being zero, in which case we
+				// don't have to save any fact.
+				out &= ^(1 << i)
+			}
+		}
+		if out > 0 {
+			pass.ExportObjectFact(fn.Object(), &alwaysTypedFact{out})
+		}
+	}()
+
+	isUntypedNil := func(v ir.Value) bool {
+		k, ok := v.(*ir.Const)
+		if !ok {
+			return false
+		}
+		if _, ok := k.Type().Underlying().(*types.Interface); !ok {
+			return false
+		}
+		return k.Value == nil
+	}
+
+	var do func(v ir.Value, seen map[ir.Value]struct{}) bool
+	do = func(v ir.Value, seen map[ir.Value]struct{}) bool {
+		if _, ok := seen[v]; ok {
+			// break cycle
+			return false
+		}
+		seen[v] = struct{}{}
+		switch v := v.(type) {
+		case *ir.Const:
+			// can't be a typed nil, because then we'd be returning the
+			// result of MakeInterface.
+			return false
+		case *ir.ChangeInterface:
+			return do(v.X, seen)
+		case *ir.Extract:
+			call, ok := v.Tuple.(*ir.Call)
+			if !ok {
+				// We only care about extracts of function results. For
+				// everything else (e.g. channel receives and map
+				// lookups), we can either not deduce any information, or
+				// will see a MakeInterface.
+				return false
+			}
+			if callee := call.Call.StaticCallee(); callee != nil {
+				return impl(pass, callee, seenFns)&(1<<v.Index) != 0
+			} else {
+				// we don't know what function we're calling. no need
+				// to look at the signature, though. if it weren't an
+				// interface, we'd be seeing a MakeInterface
+				// instruction.
+				return false
+			}
+		case *ir.Call:
+			if callee := v.Call.StaticCallee(); callee != nil {
+				return impl(pass, callee, seenFns)&1 != 0
+			} else {
+				// we don't know what function we're calling. no need
+				// to look at the signature, though. if it weren't an
+				// interface, we'd be seeing a MakeInterface
+				// instruction.
+				return false
+			}
+		case *ir.Sigma:
+			iff, ok := v.From.Control().(*ir.If)
+			if !ok {
+				// give up
+				return false
+			}
+
+			binop, ok := iff.Cond.(*ir.BinOp)
+			if !ok {
+				// give up
+				return false
+			}
+
+			if (binop.X == v.X && isUntypedNil(binop.Y)) || (isUntypedNil(binop.X) && binop.Y == v.X) {
+				op := binop.Op
+				if v.From.Succs[0] != v.Block() {
+					// we're in the false branch, negate op
+					switch op {
+					case token.EQL:
+						op = token.NEQ
+					case token.NEQ:
+						op = token.EQL
+					default:
+						panic(fmt.Sprintf("internal error: unhandled token %v", op))
+					}
+				}
+
+				switch op {
+				case token.EQL:
+					// returned value equals untyped nil
+					return false
+				case token.NEQ:
+					// returned value does not equal untyped nil
+					return true
+				default:
+					panic(fmt.Sprintf("internal error: unhandled token %v", op))
+				}
+			}
+
+			// TODO(dh): handle comparison with typed nil
+
+			// give up
+			return false
+		case *ir.Phi:
+			for _, pv := range v.Edges {
+				if !do(pv, seen) {
+					return false
+				}
+			}
+			return true
+		case *ir.MakeInterface:
+			terms, err := typeparams.NormalTerms(v.X.Type())
+			if len(terms) == 0 || err != nil {
+				// Type is a type parameter with no type terms (or we couldn't determine the terms). Such a type
+				// _can_ be nil when put in an interface value.
+				//
+				// There is no instruction that can create a guaranteed non-nil instance of a type parameter without
+				// type constraints, so we return false right away, without checking v.X's typedness.
+				return false
+			}
+			return true
+		case *ir.TypeAssert:
+			// type assertions fail for untyped nils. Either we have a
+			// single lhs and the type assertion succeeds or panics,
+			// or we have two lhs and we'll return Extract instead.
+			return true
+		case *ir.ChangeType:
+			// we'll only see interface->interface conversions, which
+			// don't tell us anything about the nilness.
+			return false
+		case *ir.MapLookup, *ir.Index, *ir.Recv, *ir.Parameter, *ir.Load, *ir.Field:
+			// All other instructions that tell us nothing about the
+			// typedness of interface values.
+			return false
+		default:
+			panic(fmt.Sprintf("internal error: unhandled type %T", v))
+		}
+	}
+
+	ret := fn.Exit.Control().(*ir.Return)
+	for i, v := range ret.Results {
+		typ := fn.Signature.Results().At(i).Type()
+		if _, ok := typ.Underlying().(*types.Interface); ok && !typeparams.IsTypeParam(typ) {
+			if do(v, map[ir.Value]struct{}{}) {
+				out |= 1 << i
+			}
+		}
+	}
+	return out
+}

vendor/honnef.co/go/tools/analysis/lint/lint.go

@@ -0,0 +1,283 @@
+// Package lint provides abstractions on top of go/analysis.
+// These abstractions add extra information to analyzes, such as structured documentation and severities.
+package lint
+
+import (
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/build"
+	"go/token"
+	"strconv"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+// Analyzer wraps a go/analysis.Analyzer and provides structured documentation.
+type Analyzer struct {
+	// The analyzer's documentation. Unlike go/analysis.Analyzer.Doc,
+	// this field is structured, providing access to severity, options
+	// etc.
+	Doc      *Documentation
+	Analyzer *analysis.Analyzer
+}
+
+func (a *Analyzer) initialize() {
+	a.Analyzer.Doc = a.Doc.String()
+	if a.Analyzer.Flags.Usage == nil {
+		fs := flag.NewFlagSet("", flag.PanicOnError)
+		fs.Var(newVersionFlag(), "go", "Target Go version")
+		a.Analyzer.Flags = *fs
+	}
+}
+
+// InitializeAnalyzers takes a map of documentation and a map of go/analysis.Analyzers and returns a slice of Analyzers.
+// The map keys are the analyzer names.
+func InitializeAnalyzers(docs map[string]*Documentation, analyzers map[string]*analysis.Analyzer) []*Analyzer {
+	out := make([]*Analyzer, 0, len(analyzers))
+	for k, v := range analyzers {
+		v.Name = k
+		a := &Analyzer{
+			Doc:      docs[k],
+			Analyzer: v,
+		}
+		a.initialize()
+		out = append(out, a)
+	}
+	return out
+}
+
+// Severity describes the severity of diagnostics reported by an analyzer.
+type Severity int
+
+const (
+	SeverityNone Severity = iota
+	SeverityError
+	SeverityDeprecated
+	SeverityWarning
+	SeverityInfo
+	SeverityHint
+)
+
+// MergeStrategy sets how merge mode should behave for diagnostics of an analyzer.
+type MergeStrategy int
+
+const (
+	MergeIfAny MergeStrategy = iota
+	MergeIfAll
+)
+
+type RawDocumentation struct {
+	Title      string
+	Text       string
+	Before     string
+	After      string
+	Since      string
+	NonDefault bool
+	Options    []string
+	Severity   Severity
+	MergeIf    MergeStrategy
+}
+
+type Documentation struct {
+	Title string
+	Text  string
+
+	TitleMarkdown string
+	TextMarkdown  string
+
+	Before     string
+	After      string
+	Since      string
+	NonDefault bool
+	Options    []string
+	Severity   Severity
+	MergeIf    MergeStrategy
+}
+
+func Markdownify(m map[string]*RawDocumentation) map[string]*Documentation {
+	out := make(map[string]*Documentation, len(m))
+	for k, v := range m {
+		out[k] = &Documentation{
+			Title: strings.TrimSpace(stripMarkdown(v.Title)),
+			Text:  strings.TrimSpace(stripMarkdown(v.Text)),
+
+			TitleMarkdown: strings.TrimSpace(toMarkdown(v.Title)),
+			TextMarkdown:  strings.TrimSpace(toMarkdown(v.Text)),
+
+			Before:     strings.TrimSpace(v.Before),
+			After:      strings.TrimSpace(v.After),
+			Since:      v.Since,
+			NonDefault: v.NonDefault,
+			Options:    v.Options,
+			Severity:   v.Severity,
+			MergeIf:    v.MergeIf,
+		}
+	}
+	return out
+}
+
+func toMarkdown(s string) string {
+	return strings.NewReplacer(`\'`, "`", `\"`, "`").Replace(s)
+}
+
+func stripMarkdown(s string) string {
+	return strings.NewReplacer(`\'`, "", `\"`, "'").Replace(s)
+}
+
+func (doc *Documentation) Format(metadata bool) string {
+	return doc.format(false, metadata)
+}
+
+func (doc *Documentation) FormatMarkdown(metadata bool) string {
+	return doc.format(true, metadata)
+}
+
+func (doc *Documentation) format(markdown bool, metadata bool) string {
+	b := &strings.Builder{}
+	if markdown {
+		fmt.Fprintf(b, "%s\n\n", doc.TitleMarkdown)
+		if doc.Text != "" {
+			fmt.Fprintf(b, "%s\n\n", doc.TextMarkdown)
+		}
+	} else {
+		fmt.Fprintf(b, "%s\n\n", doc.Title)
+		if doc.Text != "" {
+			fmt.Fprintf(b, "%s\n\n", doc.Text)
+		}
+	}
+
+	if doc.Before != "" {
+		fmt.Fprintln(b, "Before:")
+		fmt.Fprintln(b, "")
+		for _, line := range strings.Split(doc.Before, "\n") {
+			fmt.Fprint(b, "    ", line, "\n")
+		}
+		fmt.Fprintln(b, "")
+		fmt.Fprintln(b, "After:")
+		fmt.Fprintln(b, "")
+		for _, line := range strings.Split(doc.After, "\n") {
+			fmt.Fprint(b, "    ", line, "\n")
+		}
+		fmt.Fprintln(b, "")
+	}
+
+	if metadata {
+		fmt.Fprint(b, "Available since\n    ")
+		if doc.Since == "" {
+			fmt.Fprint(b, "unreleased")
+		} else {
+			fmt.Fprintf(b, "%s", doc.Since)
+		}
+		if doc.NonDefault {
+			fmt.Fprint(b, ", non-default")
+		}
+		fmt.Fprint(b, "\n")
+		if len(doc.Options) > 0 {
+			fmt.Fprintf(b, "\nOptions\n")
+			for _, opt := range doc.Options {
+				fmt.Fprintf(b, "    %s", opt)
+			}
+			fmt.Fprint(b, "\n")
+		}
+	}
+
+	return b.String()
+}
+
+func (doc *Documentation) String() string {
+	return doc.Format(true)
+}
+
+func newVersionFlag() flag.Getter {
+	tags := build.Default.ReleaseTags
+	v := tags[len(tags)-1][2:]
+	version := new(VersionFlag)
+	if err := version.Set(v); err != nil {
+		panic(fmt.Sprintf("internal error: %s", err))
+	}
+	return version
+}
+
+type VersionFlag int
+
+func (v *VersionFlag) String() string {
+	return fmt.Sprintf("1.%d", *v)
+}
+
+func (v *VersionFlag) Set(s string) error {
+	if len(s) < 3 {
+		return fmt.Errorf("invalid Go version: %q", s)
+	}
+	if s[0] != '1' {
+		return fmt.Errorf("invalid Go version: %q", s)
+	}
+	if s[1] != '.' {
+		return fmt.Errorf("invalid Go version: %q", s)
+	}
+	i, err := strconv.Atoi(s[2:])
+	if err != nil {
+		return fmt.Errorf("invalid Go version: %q", s)
+	}
+	*v = VersionFlag(i)
+	return nil
+}
+
+func (v *VersionFlag) Get() interface{} {
+	return int(*v)
+}
+
+// ExhaustiveTypeSwitch panics when called. It can be used to ensure
+// that type switches are exhaustive.
+func ExhaustiveTypeSwitch(v interface{}) {
+	panic(fmt.Sprintf("internal error: unhandled case %T", v))
+}
+
+// A directive is a comment of the form '//lint:<command>
+// [arguments...]'. It represents instructions to the static analysis
+// tool.
+type Directive struct {
+	Command   string
+	Arguments []string
+	Directive *ast.Comment
+	Node      ast.Node
+}
+
+func parseDirective(s string) (cmd string, args []string) {
+	if !strings.HasPrefix(s, "//lint:") {
+		return "", nil
+	}
+	s = strings.TrimPrefix(s, "//lint:")
+	fields := strings.Split(s, " ")
+	return fields[0], fields[1:]
+}
+
+// ParseDirectives extracts all directives from a list of Go files.
+func ParseDirectives(files []*ast.File, fset *token.FileSet) []Directive {
+	var dirs []Directive
+	for _, f := range files {
+		// OPT(dh): in our old code, we skip all the comment map work if we
+		// couldn't find any directives, benchmark if that's actually
+		// worth doing
+		cm := ast.NewCommentMap(fset, f, f.Comments)
+		for node, cgs := range cm {
+			for _, cg := range cgs {
+				for _, c := range cg.List {
+					if !strings.HasPrefix(c.Text, "//lint:") {
+						continue
+					}
+					cmd, args := parseDirective(c.Text)
+					d := Directive{
+						Command:   cmd,
+						Arguments: args,
+						Directive: c,
+						Node:      node,
+					}
+					dirs = append(dirs, d)
+				}
+			}
+		}
+	}
+	return dirs
+}

vendor/honnef.co/go/tools/analysis/report/report.go

@@ -0,0 +1,247 @@
+package report
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/format"
+	"go/token"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"honnef.co/go/tools/analysis/facts"
+	"honnef.co/go/tools/go/ast/astutil"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+type Options struct {
+	ShortRange      bool
+	FilterGenerated bool
+	Fixes           []analysis.SuggestedFix
+	Related         []analysis.RelatedInformation
+}
+
+type Option func(*Options)
+
+func ShortRange() Option {
+	return func(opts *Options) {
+		opts.ShortRange = true
+	}
+}
+
+func FilterGenerated() Option {
+	return func(opts *Options) {
+		opts.FilterGenerated = true
+	}
+}
+
+func Fixes(fixes ...analysis.SuggestedFix) Option {
+	return func(opts *Options) {
+		opts.Fixes = append(opts.Fixes, fixes...)
+	}
+}
+
+func Related(node Positioner, message string) Option {
+	return func(opts *Options) {
+		pos, end, ok := getRange(node, opts.ShortRange)
+		if !ok {
+			return
+		}
+		r := analysis.RelatedInformation{
+			Pos:     pos,
+			End:     end,
+			Message: message,
+		}
+		opts.Related = append(opts.Related, r)
+	}
+}
+
+type Positioner interface {
+	Pos() token.Pos
+}
+
+type fullPositioner interface {
+	Pos() token.Pos
+	End() token.Pos
+}
+
+type sourcer interface {
+	Source() ast.Node
+}
+
+// shortRange returns the position and end of the main component of an
+// AST node. For nodes that have no body, the short range is identical
+// to the node's Pos and End. For nodes that do have a body, the short
+// range excludes the body.
+func shortRange(node ast.Node) (pos, end token.Pos) {
+	switch node := node.(type) {
+	case *ast.File:
+		return node.Pos(), node.Name.End()
+	case *ast.CaseClause:
+		return node.Pos(), node.Colon + 1
+	case *ast.CommClause:
+		return node.Pos(), node.Colon + 1
+	case *ast.DeferStmt:
+		return node.Pos(), node.Defer + token.Pos(len("defer"))
+	case *ast.ExprStmt:
+		return shortRange(node.X)
+	case *ast.ForStmt:
+		if node.Post != nil {
+			return node.For, node.Post.End()
+		} else if node.Cond != nil {
+			return node.For, node.Cond.End()
+		} else if node.Init != nil {
+			// +1 to catch the semicolon, for gofmt'ed code
+			return node.Pos(), node.Init.End() + 1
+		} else {
+			return node.Pos(), node.For + token.Pos(len("for"))
+		}
+	case *ast.FuncDecl:
+		return node.Pos(), node.Type.End()
+	case *ast.FuncLit:
+		return node.Pos(), node.Type.End()
+	case *ast.GoStmt:
+		if _, ok := astutil.Unparen(node.Call.Fun).(*ast.FuncLit); ok {
+			return node.Pos(), node.Go + token.Pos(len("go"))
+		} else {
+			return node.Pos(), node.End()
+		}
+	case *ast.IfStmt:
+		return node.Pos(), node.Cond.End()
+	case *ast.RangeStmt:
+		return node.Pos(), node.X.End()
+	case *ast.SelectStmt:
+		return node.Pos(), node.Pos() + token.Pos(len("select"))
+	case *ast.SwitchStmt:
+		if node.Tag != nil {
+			return node.Pos(), node.Tag.End()
+		} else if node.Init != nil {
+			// +1 to catch the semicolon, for gofmt'ed code
+			return node.Pos(), node.Init.End() + 1
+		} else {
+			return node.Pos(), node.Pos() + token.Pos(len("switch"))
+		}
+	case *ast.TypeSwitchStmt:
+		return node.Pos(), node.Assign.End()
+	default:
+		return node.Pos(), node.End()
+	}
+}
+
+func HasRange(node Positioner) bool {
+	// we don't know if getRange will be called with shortRange set to
+	// true, so make sure that both work.
+	_, _, ok := getRange(node, false)
+	if !ok {
+		return false
+	}
+	_, _, ok = getRange(node, true)
+	return ok
+}
+
+func getRange(node Positioner, short bool) (pos, end token.Pos, ok bool) {
+	switch n := node.(type) {
+	case sourcer:
+		s := n.Source()
+		if s == nil {
+			return 0, 0, false
+		}
+		if short {
+			p, e := shortRange(s)
+			return p, e, true
+		}
+		return s.Pos(), s.End(), true
+	case fullPositioner:
+		if short {
+			p, e := shortRange(n)
+			return p, e, true
+		}
+		return n.Pos(), n.End(), true
+	default:
+		return n.Pos(), token.NoPos, true
+	}
+}
+
+func Report(pass *analysis.Pass, node Positioner, message string, opts ...Option) {
+	cfg := &Options{}
+	for _, opt := range opts {
+		opt(cfg)
+	}
+
+	file := DisplayPosition(pass.Fset, node.Pos()).Filename
+	if cfg.FilterGenerated {
+		m := pass.ResultOf[facts.Generated].(map[string]facts.Generator)
+		if _, ok := m[file]; ok {
+			return
+		}
+	}
+
+	pos, end, ok := getRange(node, cfg.ShortRange)
+	if !ok {
+		panic(fmt.Sprintf("no valid position for reporting node %v", node))
+	}
+	d := analysis.Diagnostic{
+		Pos:            pos,
+		End:            end,
+		Message:        message,
+		SuggestedFixes: cfg.Fixes,
+		Related:        cfg.Related,
+	}
+	pass.Report(d)
+}
+
+func Render(pass *analysis.Pass, x interface{}) string {
+	var buf bytes.Buffer
+	if err := format.Node(&buf, pass.Fset, x); err != nil {
+		panic(err)
+	}
+	return buf.String()
+}
+
+func RenderArgs(pass *analysis.Pass, args []ast.Expr) string {
+	var ss []string
+	for _, arg := range args {
+		ss = append(ss, Render(pass, arg))
+	}
+	return strings.Join(ss, ", ")
+}
+
+func DisplayPosition(fset *token.FileSet, p token.Pos) token.Position {
+	if p == token.NoPos {
+		return token.Position{}
+	}
+
+	// Only use the adjusted position if it points to another Go file.
+	// This means we'll point to the original file for cgo files, but
+	// we won't point to a YACC grammar file.
+	pos := fset.PositionFor(p, false)
+	adjPos := fset.PositionFor(p, true)
+
+	if filepath.Ext(adjPos.Filename) == ".go" {
+		return adjPos
+	}
+
+	return pos
+}
+
+func Ordinal(n int) string {
+	suffix := "th"
+	if n < 10 || n > 20 {
+		switch n % 10 {
+		case 0:
+			suffix = "th"
+		case 1:
+			suffix = "st"
+		case 2:
+			suffix = "nd"
+		case 3:
+			suffix = "rd"
+		default:
+			suffix = "th"
+		}
+	}
+
+	return strconv.Itoa(n) + suffix
+}