+++ /dev/null
-// Package simple contains a linter for Go source code.
-package simple // import "honnef.co/go/tools/simple"
-
-import (
- "fmt"
- "go/ast"
- "go/constant"
- "go/token"
- "go/types"
- "path/filepath"
- "reflect"
- "sort"
- "strings"
-
- "golang.org/x/tools/go/analysis"
- "golang.org/x/tools/go/types/typeutil"
- . "honnef.co/go/tools/arg"
- "honnef.co/go/tools/code"
- "honnef.co/go/tools/edit"
- "honnef.co/go/tools/internal/passes/buildir"
- "honnef.co/go/tools/internal/sharedcheck"
- . "honnef.co/go/tools/lint/lintdsl"
- "honnef.co/go/tools/pattern"
- "honnef.co/go/tools/report"
-)
-
-var (
- checkSingleCaseSelectQ1 = pattern.MustParse(`
- (ForStmt
- nil nil nil
- select@(SelectStmt
- (CommClause
- (Or
- (UnaryExpr "<-" _)
- (AssignStmt _ _ (UnaryExpr "<-" _)))
- _)))`)
- checkSingleCaseSelectQ2 = pattern.MustParse(`(SelectStmt (CommClause _ _))`)
-)
-
-func CheckSingleCaseSelect(pass *analysis.Pass) (interface{}, error) {
- seen := map[ast.Node]struct{}{}
- fn := func(node ast.Node) {
- if m, ok := Match(pass, checkSingleCaseSelectQ1, node); ok {
- seen[m.State["select"].(ast.Node)] = struct{}{}
- report.Report(pass, node, "should use for range instead of for { select {} }", report.FilterGenerated())
- } else if _, ok := Match(pass, checkSingleCaseSelectQ2, node); ok {
- if _, ok := seen[node]; !ok {
- report.Report(pass, node, "should use a simple channel send/receive instead of select with a single case",
- report.ShortRange(),
- report.FilterGenerated())
- }
- }
- }
- code.Preorder(pass, fn, (*ast.ForStmt)(nil), (*ast.SelectStmt)(nil))
- return nil, nil
-}
-
-var (
- checkLoopCopyQ = pattern.MustParse(`
- (Or
- (RangeStmt
- key value ":=" src@(Ident _)
- [(AssignStmt
- (IndexExpr dst@(Ident _) key)
- "="
- value)])
- (RangeStmt
- key nil ":=" src@(Ident _)
- [(AssignStmt
- (IndexExpr dst@(Ident _) key)
- "="
- (IndexExpr src key))]))`)
- checkLoopCopyR = pattern.MustParse(`(CallExpr (Ident "copy") [dst src])`)
-)
-
-func CheckLoopCopy(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- m, edits, ok := MatchAndEdit(pass, checkLoopCopyQ, checkLoopCopyR, node)
- if !ok {
- return
- }
- t1 := pass.TypesInfo.TypeOf(m.State["src"].(*ast.Ident))
- t2 := pass.TypesInfo.TypeOf(m.State["dst"].(*ast.Ident))
- if _, ok := t1.Underlying().(*types.Slice); !ok {
- return
- }
- if !types.Identical(t1, t2) {
- return
- }
-
- tv, err := types.Eval(pass.Fset, pass.Pkg, node.Pos(), "copy")
- if err == nil && tv.IsBuiltin() {
- report.Report(pass, node,
- "should use copy() instead of a loop",
- report.ShortRange(),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("replace loop with call to copy()", edits...)))
- } else {
- report.Report(pass, node, "should use copy() instead of a loop", report.FilterGenerated())
- }
- }
- code.Preorder(pass, fn, (*ast.RangeStmt)(nil))
- return nil, nil
-}
-
-func CheckIfBoolCmp(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- if code.IsInTest(pass, node) {
- return
- }
-
- expr := node.(*ast.BinaryExpr)
- if expr.Op != token.EQL && expr.Op != token.NEQ {
- return
- }
- x := code.IsBoolConst(pass, expr.X)
- y := code.IsBoolConst(pass, expr.Y)
- if !x && !y {
- return
- }
- var other ast.Expr
- var val bool
- if x {
- val = code.BoolConst(pass, expr.X)
- other = expr.Y
- } else {
- val = code.BoolConst(pass, expr.Y)
- other = expr.X
- }
- basic, ok := pass.TypesInfo.TypeOf(other).Underlying().(*types.Basic)
- if !ok || basic.Kind() != types.Bool {
- return
- }
- op := ""
- if (expr.Op == token.EQL && !val) || (expr.Op == token.NEQ && val) {
- op = "!"
- }
- r := op + report.Render(pass, other)
- l1 := len(r)
- r = strings.TrimLeft(r, "!")
- if (l1-len(r))%2 == 1 {
- r = "!" + r
- }
- report.Report(pass, expr, fmt.Sprintf("should omit comparison to bool constant, can be simplified to %s", r),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("simplify bool comparison", edit.ReplaceWithString(pass.Fset, expr, r))))
- }
- code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
- return nil, nil
-}
-
-var (
- checkBytesBufferConversionsQ = pattern.MustParse(`(CallExpr _ [(CallExpr sel@(SelectorExpr recv _) [])])`)
- checkBytesBufferConversionsRs = pattern.MustParse(`(CallExpr (SelectorExpr recv (Ident "String")) [])`)
- checkBytesBufferConversionsRb = pattern.MustParse(`(CallExpr (SelectorExpr recv (Ident "Bytes")) [])`)
-)
-
-func CheckBytesBufferConversions(pass *analysis.Pass) (interface{}, error) {
- if pass.Pkg.Path() == "bytes" || pass.Pkg.Path() == "bytes_test" {
- // The bytes package can use itself however it wants
- return nil, nil
- }
- fn := func(node ast.Node) {
- m, ok := Match(pass, checkBytesBufferConversionsQ, node)
- if !ok {
- return
- }
- call := node.(*ast.CallExpr)
- sel := m.State["sel"].(*ast.SelectorExpr)
-
- typ := pass.TypesInfo.TypeOf(call.Fun)
- if typ == types.Universe.Lookup("string").Type() && code.IsCallToAST(pass, call.Args[0], "(*bytes.Buffer).Bytes") {
- report.Report(pass, call, fmt.Sprintf("should use %v.String() instead of %v", report.Render(pass, sel.X), report.Render(pass, call)),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("simplify conversion", edit.ReplaceWithPattern(pass, checkBytesBufferConversionsRs, m.State, node))))
- } else if typ, ok := typ.(*types.Slice); ok && typ.Elem() == types.Universe.Lookup("byte").Type() && code.IsCallToAST(pass, call.Args[0], "(*bytes.Buffer).String") {
- report.Report(pass, call, fmt.Sprintf("should use %v.Bytes() instead of %v", report.Render(pass, sel.X), report.Render(pass, call)),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("simplify conversion", edit.ReplaceWithPattern(pass, checkBytesBufferConversionsRb, m.State, node))))
- }
-
- }
- code.Preorder(pass, fn, (*ast.CallExpr)(nil))
- return nil, nil
-}
-
-func CheckStringsContains(pass *analysis.Pass) (interface{}, error) {
- // map of value to token to bool value
- allowed := map[int64]map[token.Token]bool{
- -1: {token.GTR: true, token.NEQ: true, token.EQL: false},
- 0: {token.GEQ: true, token.LSS: false},
- }
- fn := func(node ast.Node) {
- expr := node.(*ast.BinaryExpr)
- switch expr.Op {
- case token.GEQ, token.GTR, token.NEQ, token.LSS, token.EQL:
- default:
- return
- }
-
- value, ok := code.ExprToInt(pass, expr.Y)
- if !ok {
- return
- }
-
- allowedOps, ok := allowed[value]
- if !ok {
- return
- }
- b, ok := allowedOps[expr.Op]
- if !ok {
- return
- }
-
- call, ok := expr.X.(*ast.CallExpr)
- if !ok {
- return
- }
- sel, ok := call.Fun.(*ast.SelectorExpr)
- if !ok {
- return
- }
- pkgIdent, ok := sel.X.(*ast.Ident)
- if !ok {
- return
- }
- funIdent := sel.Sel
- if pkgIdent.Name != "strings" && pkgIdent.Name != "bytes" {
- return
- }
-
- var r ast.Expr
- switch funIdent.Name {
- case "IndexRune":
- r = &ast.SelectorExpr{
- X: pkgIdent,
- Sel: &ast.Ident{Name: "ContainsRune"},
- }
- case "IndexAny":
- r = &ast.SelectorExpr{
- X: pkgIdent,
- Sel: &ast.Ident{Name: "ContainsAny"},
- }
- case "Index":
- r = &ast.SelectorExpr{
- X: pkgIdent,
- Sel: &ast.Ident{Name: "Contains"},
- }
- default:
- return
- }
-
- r = &ast.CallExpr{
- Fun: r,
- Args: call.Args,
- }
- if !b {
- r = &ast.UnaryExpr{
- Op: token.NOT,
- X: r,
- }
- }
-
- report.Report(pass, node, fmt.Sprintf("should use %s instead", report.Render(pass, r)),
- report.FilterGenerated(),
- report.Fixes(edit.Fix(fmt.Sprintf("simplify use of %s", report.Render(pass, call.Fun)), edit.ReplaceWithNode(pass.Fset, node, r))))
- }
- code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
- return nil, nil
-}
-
-var (
- checkBytesCompareQ = pattern.MustParse(`(BinaryExpr (CallExpr (Function "bytes.Compare") args) op@(Or "==" "!=") (BasicLit "INT" "0"))`)
- checkBytesCompareRn = pattern.MustParse(`(CallExpr (SelectorExpr (Ident "bytes") (Ident "Equal")) args)`)
- checkBytesCompareRe = pattern.MustParse(`(UnaryExpr "!" (CallExpr (SelectorExpr (Ident "bytes") (Ident "Equal")) args))`)
-)
-
-func CheckBytesCompare(pass *analysis.Pass) (interface{}, error) {
- if pass.Pkg.Path() == "bytes" || pass.Pkg.Path() == "bytes_test" {
- // the bytes package is free to use bytes.Compare as it sees fit
- return nil, nil
- }
- fn := func(node ast.Node) {
- m, ok := Match(pass, checkBytesCompareQ, node)
- if !ok {
- return
- }
-
- args := report.RenderArgs(pass, m.State["args"].([]ast.Expr))
- prefix := ""
- if m.State["op"].(token.Token) == token.NEQ {
- prefix = "!"
- }
-
- var fix analysis.SuggestedFix
- switch tok := m.State["op"].(token.Token); tok {
- case token.EQL:
- fix = edit.Fix("simplify use of bytes.Compare", edit.ReplaceWithPattern(pass, checkBytesCompareRe, m.State, node))
- case token.NEQ:
- fix = edit.Fix("simplify use of bytes.Compare", edit.ReplaceWithPattern(pass, checkBytesCompareRn, m.State, node))
- default:
- panic(fmt.Sprintf("unexpected token %v", tok))
- }
- report.Report(pass, node, fmt.Sprintf("should use %sbytes.Equal(%s) instead", prefix, args), report.FilterGenerated(), report.Fixes(fix))
- }
- code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
- return nil, nil
-}
-
-func CheckForTrue(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- loop := node.(*ast.ForStmt)
- if loop.Init != nil || loop.Post != nil {
- return
- }
- if !code.IsBoolConst(pass, loop.Cond) || !code.BoolConst(pass, loop.Cond) {
- return
- }
- report.Report(pass, loop, "should use for {} instead of for true {}",
- report.ShortRange(),
- report.FilterGenerated())
- }
- code.Preorder(pass, fn, (*ast.ForStmt)(nil))
- return nil, nil
-}
-
-func CheckRegexpRaw(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- call := node.(*ast.CallExpr)
- if !code.IsCallToAnyAST(pass, call, "regexp.MustCompile", "regexp.Compile") {
- return
- }
- sel, ok := call.Fun.(*ast.SelectorExpr)
- if !ok {
- return
- }
- lit, ok := call.Args[Arg("regexp.Compile.expr")].(*ast.BasicLit)
- if !ok {
- // TODO(dominikh): support string concat, maybe support constants
- return
- }
- if lit.Kind != token.STRING {
- // invalid function call
- return
- }
- if lit.Value[0] != '"' {
- // already a raw string
- return
- }
- val := lit.Value
- if !strings.Contains(val, `\\`) {
- return
- }
- if strings.Contains(val, "`") {
- return
- }
-
- bs := false
- for _, c := range val {
- if !bs && c == '\\' {
- bs = true
- continue
- }
- if bs && c == '\\' {
- bs = false
- continue
- }
- if bs {
- // backslash followed by non-backslash -> escape sequence
- return
- }
- }
-
- report.Report(pass, call, fmt.Sprintf("should use raw string (`...`) with regexp.%s to avoid having to escape twice", sel.Sel.Name), report.FilterGenerated())
- }
- code.Preorder(pass, fn, (*ast.CallExpr)(nil))
- return nil, nil
-}
-
-var (
- checkIfReturnQIf = pattern.MustParse(`(IfStmt nil cond [(ReturnStmt [ret@(Ident _)])] nil)`)
- checkIfReturnQRet = pattern.MustParse(`(ReturnStmt [ret@(Ident _)])`)
-)
-
-func CheckIfReturn(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- block := node.(*ast.BlockStmt)
- l := len(block.List)
- if l < 2 {
- return
- }
- n1, n2 := block.List[l-2], block.List[l-1]
-
- if len(block.List) >= 3 {
- if _, ok := block.List[l-3].(*ast.IfStmt); ok {
- // Do not flag a series of if statements
- return
- }
- }
- m1, ok := Match(pass, checkIfReturnQIf, n1)
- if !ok {
- return
- }
- m2, ok := Match(pass, checkIfReturnQRet, n2)
- if !ok {
- return
- }
-
- if op, ok := m1.State["cond"].(*ast.BinaryExpr); ok {
- switch op.Op {
- case token.EQL, token.LSS, token.GTR, token.NEQ, token.LEQ, token.GEQ:
- default:
- return
- }
- }
-
- ret1 := m1.State["ret"].(*ast.Ident)
- if !code.IsBoolConst(pass, ret1) {
- return
- }
- ret2 := m2.State["ret"].(*ast.Ident)
- if !code.IsBoolConst(pass, ret2) {
- return
- }
-
- if ret1.Name == ret2.Name {
- // we want the function to return true and false, not the
- // same value both times.
- return
- }
-
- cond := m1.State["cond"].(ast.Expr)
- origCond := cond
- if ret1.Name == "false" {
- cond = negate(cond)
- }
- report.Report(pass, n1,
- fmt.Sprintf("should use 'return %s' instead of 'if %s { return %s }; return %s'",
- report.Render(pass, cond),
- report.Render(pass, origCond), report.Render(pass, ret1), report.Render(pass, ret2)),
- report.FilterGenerated())
- }
- code.Preorder(pass, fn, (*ast.BlockStmt)(nil))
- return nil, nil
-}
-
-func negate(expr ast.Expr) ast.Expr {
- switch expr := expr.(type) {
- case *ast.BinaryExpr:
- out := *expr
- switch expr.Op {
- case token.EQL:
- out.Op = token.NEQ
- case token.LSS:
- out.Op = token.GEQ
- case token.GTR:
- out.Op = token.LEQ
- case token.NEQ:
- out.Op = token.EQL
- case token.LEQ:
- out.Op = token.GTR
- case token.GEQ:
- out.Op = token.LEQ
- }
- return &out
- case *ast.Ident, *ast.CallExpr, *ast.IndexExpr:
- return &ast.UnaryExpr{
- Op: token.NOT,
- X: expr,
- }
- default:
- return &ast.UnaryExpr{
- Op: token.NOT,
- X: &ast.ParenExpr{
- X: expr,
- },
- }
- }
-}
-
-// CheckRedundantNilCheckWithLen checks for the following redundant nil-checks:
-//
-// if x == nil || len(x) == 0 {}
-// if x != nil && len(x) != 0 {}
-// if x != nil && len(x) == N {} (where N != 0)
-// if x != nil && len(x) > N {}
-// if x != nil && len(x) >= N {} (where N != 0)
-//
-func CheckRedundantNilCheckWithLen(pass *analysis.Pass) (interface{}, error) {
- isConstZero := func(expr ast.Expr) (isConst bool, isZero bool) {
- _, ok := expr.(*ast.BasicLit)
- if ok {
- return true, code.IsIntLiteral(expr, "0")
- }
- id, ok := expr.(*ast.Ident)
- if !ok {
- return false, false
- }
- c, ok := pass.TypesInfo.ObjectOf(id).(*types.Const)
- if !ok {
- return false, false
- }
- return true, c.Val().Kind() == constant.Int && c.Val().String() == "0"
- }
-
- fn := func(node ast.Node) {
- // check that expr is "x || y" or "x && y"
- expr := node.(*ast.BinaryExpr)
- if expr.Op != token.LOR && expr.Op != token.LAND {
- return
- }
- eqNil := expr.Op == token.LOR
-
- // check that x is "xx == nil" or "xx != nil"
- x, ok := expr.X.(*ast.BinaryExpr)
- if !ok {
- return
- }
- if eqNil && x.Op != token.EQL {
- return
- }
- if !eqNil && x.Op != token.NEQ {
- return
- }
- xx, ok := x.X.(*ast.Ident)
- if !ok {
- return
- }
- if !code.IsNil(pass, x.Y) {
- return
- }
-
- // check that y is "len(xx) == 0" or "len(xx) ... "
- y, ok := expr.Y.(*ast.BinaryExpr)
- if !ok {
- return
- }
- if eqNil && y.Op != token.EQL { // must be len(xx) *==* 0
- return
- }
- yx, ok := y.X.(*ast.CallExpr)
- if !ok {
- return
- }
- yxFun, ok := yx.Fun.(*ast.Ident)
- if !ok || yxFun.Name != "len" || len(yx.Args) != 1 {
- return
- }
- yxArg, ok := yx.Args[Arg("len.v")].(*ast.Ident)
- if !ok {
- return
- }
- if yxArg.Name != xx.Name {
- return
- }
-
- if eqNil && !code.IsIntLiteral(y.Y, "0") { // must be len(x) == *0*
- return
- }
-
- if !eqNil {
- isConst, isZero := isConstZero(y.Y)
- if !isConst {
- return
- }
- switch y.Op {
- case token.EQL:
- // avoid false positive for "xx != nil && len(xx) == 0"
- if isZero {
- return
- }
- case token.GEQ:
- // avoid false positive for "xx != nil && len(xx) >= 0"
- if isZero {
- return
- }
- case token.NEQ:
- // avoid false positive for "xx != nil && len(xx) != <non-zero>"
- if !isZero {
- return
- }
- case token.GTR:
- // ok
- default:
- return
- }
- }
-
- // finally check that xx type is one of array, slice, map or chan
- // this is to prevent false positive in case if xx is a pointer to an array
- var nilType string
- switch pass.TypesInfo.TypeOf(xx).(type) {
- case *types.Slice:
- nilType = "nil slices"
- case *types.Map:
- nilType = "nil maps"
- case *types.Chan:
- nilType = "nil channels"
- default:
- return
- }
- report.Report(pass, expr, fmt.Sprintf("should omit nil check; len() for %s is defined as zero", nilType), report.FilterGenerated())
- }
- code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
- return nil, nil
-}
-
-var checkSlicingQ = pattern.MustParse(`(SliceExpr x@(Object _) low (CallExpr (Builtin "len") [x]) nil)`)
-
-func CheckSlicing(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- if _, ok := Match(pass, checkSlicingQ, node); ok {
- expr := node.(*ast.SliceExpr)
- report.Report(pass, expr.High,
- "should omit second index in slice, s[a:len(s)] is identical to s[a:]",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("simplify slice expression", edit.Delete(expr.High))))
- }
- }
- code.Preorder(pass, fn, (*ast.SliceExpr)(nil))
- return nil, nil
-}
-
-func refersTo(pass *analysis.Pass, expr ast.Expr, ident types.Object) bool {
- found := false
- fn := func(node ast.Node) bool {
- ident2, ok := node.(*ast.Ident)
- if !ok {
- return true
- }
- if ident == pass.TypesInfo.ObjectOf(ident2) {
- found = true
- return false
- }
- return true
- }
- ast.Inspect(expr, fn)
- return found
-}
-
-var checkLoopAppendQ = pattern.MustParse(`
- (RangeStmt
- (Ident "_")
- val@(Object _)
- _
- x
- [(AssignStmt [lhs] "=" [(CallExpr (Builtin "append") [lhs val])])]) `)
-
-func CheckLoopAppend(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- m, ok := Match(pass, checkLoopAppendQ, node)
- if !ok {
- return
- }
-
- val := m.State["val"].(types.Object)
- if refersTo(pass, m.State["lhs"].(ast.Expr), val) {
- return
- }
-
- src := pass.TypesInfo.TypeOf(m.State["x"].(ast.Expr))
- dst := pass.TypesInfo.TypeOf(m.State["lhs"].(ast.Expr))
- if !types.Identical(src, dst) {
- return
- }
-
- r := &ast.AssignStmt{
- Lhs: []ast.Expr{m.State["lhs"].(ast.Expr)},
- Tok: token.ASSIGN,
- Rhs: []ast.Expr{
- &ast.CallExpr{
- Fun: &ast.Ident{Name: "append"},
- Args: []ast.Expr{
- m.State["lhs"].(ast.Expr),
- m.State["x"].(ast.Expr),
- },
- Ellipsis: 1,
- },
- },
- }
-
- report.Report(pass, node, fmt.Sprintf("should replace loop with %s", report.Render(pass, r)),
- report.ShortRange(),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("replace loop with call to append", edit.ReplaceWithNode(pass.Fset, node, r))))
- }
- code.Preorder(pass, fn, (*ast.RangeStmt)(nil))
- return nil, nil
-}
-
-var (
- checkTimeSinceQ = pattern.MustParse(`(CallExpr (SelectorExpr (CallExpr (Function "time.Now") []) (Function "(time.Time).Sub")) [arg])`)
- checkTimeSinceR = pattern.MustParse(`(CallExpr (SelectorExpr (Ident "time") (Ident "Since")) [arg])`)
-)
-
-func CheckTimeSince(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- if _, edits, ok := MatchAndEdit(pass, checkTimeSinceQ, checkTimeSinceR, node); ok {
- report.Report(pass, node, "should use time.Since instead of time.Now().Sub",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("replace with call to time.Since", edits...)))
- }
- }
- code.Preorder(pass, fn, (*ast.CallExpr)(nil))
- return nil, nil
-}
-
-var (
- checkTimeUntilQ = pattern.MustParse(`(CallExpr (Function "(time.Time).Sub") [(CallExpr (Function "time.Now") [])])`)
- checkTimeUntilR = pattern.MustParse(`(CallExpr (SelectorExpr (Ident "time") (Ident "Until")) [arg])`)
-)
-
-func CheckTimeUntil(pass *analysis.Pass) (interface{}, error) {
- if !code.IsGoVersion(pass, 8) {
- return nil, nil
- }
- fn := func(node ast.Node) {
- if _, ok := Match(pass, checkTimeUntilQ, node); ok {
- if sel, ok := node.(*ast.CallExpr).Fun.(*ast.SelectorExpr); ok {
- r := pattern.NodeToAST(checkTimeUntilR.Root, map[string]interface{}{"arg": sel.X}).(ast.Node)
- report.Report(pass, node, "should use time.Until instead of t.Sub(time.Now())",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("replace with call to time.Until", edit.ReplaceWithNode(pass.Fset, node, r))))
- } else {
- report.Report(pass, node, "should use time.Until instead of t.Sub(time.Now())", report.FilterGenerated())
- }
- }
- }
- code.Preorder(pass, fn, (*ast.CallExpr)(nil))
- return nil, nil
-}
-
-var (
- checkUnnecessaryBlankQ1 = pattern.MustParse(`
- (AssignStmt
- [_ (Ident "_")]
- _
- (Or
- (IndexExpr _ _)
- (UnaryExpr "<-" _))) `)
- checkUnnecessaryBlankQ2 = pattern.MustParse(`
- (AssignStmt
- (Ident "_") _ recv@(UnaryExpr "<-" _))`)
-)
-
-func CheckUnnecessaryBlank(pass *analysis.Pass) (interface{}, error) {
- fn1 := func(node ast.Node) {
- if _, ok := Match(pass, checkUnnecessaryBlankQ1, node); ok {
- r := *node.(*ast.AssignStmt)
- r.Lhs = r.Lhs[0:1]
- report.Report(pass, node, "unnecessary assignment to the blank identifier",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("remove assignment to blank identifier", edit.ReplaceWithNode(pass.Fset, node, &r))))
- } else if m, ok := Match(pass, checkUnnecessaryBlankQ2, node); ok {
- report.Report(pass, node, "unnecessary assignment to the blank identifier",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("simplify channel receive operation", edit.ReplaceWithNode(pass.Fset, node, m.State["recv"].(ast.Node)))))
- }
- }
-
- fn3 := func(node ast.Node) {
- rs := node.(*ast.RangeStmt)
-
- // for _
- if rs.Value == nil && code.IsBlank(rs.Key) {
- report.Report(pass, rs.Key, "unnecessary assignment to the blank identifier",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("remove assignment to blank identifier", edit.Delete(edit.Range{rs.Key.Pos(), rs.TokPos + 1}))))
- }
-
- // for _, _
- if code.IsBlank(rs.Key) && code.IsBlank(rs.Value) {
- // FIXME we should mark both key and value
- report.Report(pass, rs.Key, "unnecessary assignment to the blank identifier",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("remove assignment to blank identifier", edit.Delete(edit.Range{rs.Key.Pos(), rs.TokPos + 1}))))
- }
-
- // for x, _
- if !code.IsBlank(rs.Key) && code.IsBlank(rs.Value) {
- report.Report(pass, rs.Value, "unnecessary assignment to the blank identifier",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("remove assignment to blank identifier", edit.Delete(edit.Range{rs.Key.End(), rs.Value.End()}))))
- }
- }
-
- code.Preorder(pass, fn1, (*ast.AssignStmt)(nil))
- if code.IsGoVersion(pass, 4) {
- code.Preorder(pass, fn3, (*ast.RangeStmt)(nil))
- }
- return nil, nil
-}
-
-func CheckSimplerStructConversion(pass *analysis.Pass) (interface{}, error) {
- var skip ast.Node
- fn := func(node ast.Node) {
- // Do not suggest type conversion between pointers
- if unary, ok := node.(*ast.UnaryExpr); ok && unary.Op == token.AND {
- if lit, ok := unary.X.(*ast.CompositeLit); ok {
- skip = lit
- }
- return
- }
-
- if node == skip {
- return
- }
-
- lit, ok := node.(*ast.CompositeLit)
- if !ok {
- return
- }
- typ1, _ := pass.TypesInfo.TypeOf(lit.Type).(*types.Named)
- if typ1 == nil {
- return
- }
- s1, ok := typ1.Underlying().(*types.Struct)
- if !ok {
- return
- }
-
- var typ2 *types.Named
- var ident *ast.Ident
- getSelType := func(expr ast.Expr) (types.Type, *ast.Ident, bool) {
- sel, ok := expr.(*ast.SelectorExpr)
- if !ok {
- return nil, nil, false
- }
- ident, ok := sel.X.(*ast.Ident)
- if !ok {
- return nil, nil, false
- }
- typ := pass.TypesInfo.TypeOf(sel.X)
- return typ, ident, typ != nil
- }
- if len(lit.Elts) == 0 {
- return
- }
- if s1.NumFields() != len(lit.Elts) {
- return
- }
- for i, elt := range lit.Elts {
- var t types.Type
- var id *ast.Ident
- var ok bool
- switch elt := elt.(type) {
- case *ast.SelectorExpr:
- t, id, ok = getSelType(elt)
- if !ok {
- return
- }
- if i >= s1.NumFields() || s1.Field(i).Name() != elt.Sel.Name {
- return
- }
- case *ast.KeyValueExpr:
- var sel *ast.SelectorExpr
- sel, ok = elt.Value.(*ast.SelectorExpr)
- if !ok {
- return
- }
-
- if elt.Key.(*ast.Ident).Name != sel.Sel.Name {
- return
- }
- t, id, ok = getSelType(elt.Value)
- }
- if !ok {
- return
- }
- // All fields must be initialized from the same object
- if ident != nil && ident.Obj != id.Obj {
- return
- }
- typ2, _ = t.(*types.Named)
- if typ2 == nil {
- return
- }
- ident = id
- }
-
- if typ2 == nil {
- return
- }
-
- if typ1.Obj().Pkg() != typ2.Obj().Pkg() {
- // Do not suggest type conversions between different
- // packages. Types in different packages might only match
- // by coincidence. Furthermore, if the dependency ever
- // adds more fields to its type, it could break the code
- // that relies on the type conversion to work.
- return
- }
-
- s2, ok := typ2.Underlying().(*types.Struct)
- if !ok {
- return
- }
- if typ1 == typ2 {
- return
- }
- if code.IsGoVersion(pass, 8) {
- if !types.IdenticalIgnoreTags(s1, s2) {
- return
- }
- } else {
- if !types.Identical(s1, s2) {
- return
- }
- }
-
- r := &ast.CallExpr{
- Fun: lit.Type,
- Args: []ast.Expr{ident},
- }
- report.Report(pass, node,
- fmt.Sprintf("should convert %s (type %s) to %s instead of using struct literal", ident.Name, typ2.Obj().Name(), typ1.Obj().Name()),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("use type conversion", edit.ReplaceWithNode(pass.Fset, node, r))))
- }
- code.Preorder(pass, fn, (*ast.UnaryExpr)(nil), (*ast.CompositeLit)(nil))
- return nil, nil
-}
-
-func CheckTrim(pass *analysis.Pass) (interface{}, error) {
- sameNonDynamic := func(node1, node2 ast.Node) bool {
- if reflect.TypeOf(node1) != reflect.TypeOf(node2) {
- return false
- }
-
- switch node1 := node1.(type) {
- case *ast.Ident:
- return node1.Obj == node2.(*ast.Ident).Obj
- case *ast.SelectorExpr:
- return report.Render(pass, node1) == report.Render(pass, node2)
- case *ast.IndexExpr:
- return report.Render(pass, node1) == report.Render(pass, node2)
- }
- return false
- }
-
- isLenOnIdent := func(fn ast.Expr, ident ast.Expr) bool {
- call, ok := fn.(*ast.CallExpr)
- if !ok {
- return false
- }
- if fn, ok := call.Fun.(*ast.Ident); !ok || fn.Name != "len" {
- return false
- }
- if len(call.Args) != 1 {
- return false
- }
- return sameNonDynamic(call.Args[Arg("len.v")], ident)
- }
-
- fn := func(node ast.Node) {
- var pkg string
- var fun string
-
- ifstmt := node.(*ast.IfStmt)
- if ifstmt.Init != nil {
- return
- }
- if ifstmt.Else != nil {
- return
- }
- if len(ifstmt.Body.List) != 1 {
- return
- }
- condCall, ok := ifstmt.Cond.(*ast.CallExpr)
- if !ok {
- return
- }
-
- condCallName := code.CallNameAST(pass, condCall)
- switch condCallName {
- case "strings.HasPrefix":
- pkg = "strings"
- fun = "HasPrefix"
- case "strings.HasSuffix":
- pkg = "strings"
- fun = "HasSuffix"
- case "strings.Contains":
- pkg = "strings"
- fun = "Contains"
- case "bytes.HasPrefix":
- pkg = "bytes"
- fun = "HasPrefix"
- case "bytes.HasSuffix":
- pkg = "bytes"
- fun = "HasSuffix"
- case "bytes.Contains":
- pkg = "bytes"
- fun = "Contains"
- default:
- return
- }
-
- assign, ok := ifstmt.Body.List[0].(*ast.AssignStmt)
- if !ok {
- return
- }
- if assign.Tok != token.ASSIGN {
- return
- }
- if len(assign.Lhs) != 1 || len(assign.Rhs) != 1 {
- return
- }
- if !sameNonDynamic(condCall.Args[0], assign.Lhs[0]) {
- return
- }
-
- switch rhs := assign.Rhs[0].(type) {
- case *ast.CallExpr:
- if len(rhs.Args) < 2 || !sameNonDynamic(condCall.Args[0], rhs.Args[0]) || !sameNonDynamic(condCall.Args[1], rhs.Args[1]) {
- return
- }
-
- rhsName := code.CallNameAST(pass, rhs)
- if condCallName == "strings.HasPrefix" && rhsName == "strings.TrimPrefix" ||
- condCallName == "strings.HasSuffix" && rhsName == "strings.TrimSuffix" ||
- condCallName == "strings.Contains" && rhsName == "strings.Replace" ||
- condCallName == "bytes.HasPrefix" && rhsName == "bytes.TrimPrefix" ||
- condCallName == "bytes.HasSuffix" && rhsName == "bytes.TrimSuffix" ||
- condCallName == "bytes.Contains" && rhsName == "bytes.Replace" {
- report.Report(pass, ifstmt, fmt.Sprintf("should replace this if statement with an unconditional %s", rhsName), report.FilterGenerated())
- }
- return
- case *ast.SliceExpr:
- slice := rhs
- if !ok {
- return
- }
- if slice.Slice3 {
- return
- }
- if !sameNonDynamic(slice.X, condCall.Args[0]) {
- return
- }
- var index ast.Expr
- switch fun {
- case "HasPrefix":
- // TODO(dh) We could detect a High that is len(s), but another
- // rule will already flag that, anyway.
- if slice.High != nil {
- return
- }
- index = slice.Low
- case "HasSuffix":
- if slice.Low != nil {
- n, ok := code.ExprToInt(pass, slice.Low)
- if !ok || n != 0 {
- return
- }
- }
- index = slice.High
- }
-
- switch index := index.(type) {
- case *ast.CallExpr:
- if fun != "HasPrefix" {
- return
- }
- if fn, ok := index.Fun.(*ast.Ident); !ok || fn.Name != "len" {
- return
- }
- if len(index.Args) != 1 {
- return
- }
- id3 := index.Args[Arg("len.v")]
- switch oid3 := condCall.Args[1].(type) {
- case *ast.BasicLit:
- if pkg != "strings" {
- return
- }
- lit, ok := id3.(*ast.BasicLit)
- if !ok {
- return
- }
- s1, ok1 := code.ExprToString(pass, lit)
- s2, ok2 := code.ExprToString(pass, condCall.Args[1])
- if !ok1 || !ok2 || s1 != s2 {
- return
- }
- default:
- if !sameNonDynamic(id3, oid3) {
- return
- }
- }
- case *ast.BasicLit, *ast.Ident:
- if fun != "HasPrefix" {
- return
- }
- if pkg != "strings" {
- return
- }
- string, ok1 := code.ExprToString(pass, condCall.Args[1])
- int, ok2 := code.ExprToInt(pass, slice.Low)
- if !ok1 || !ok2 || int != int64(len(string)) {
- return
- }
- case *ast.BinaryExpr:
- if fun != "HasSuffix" {
- return
- }
- if index.Op != token.SUB {
- return
- }
- if !isLenOnIdent(index.X, condCall.Args[0]) ||
- !isLenOnIdent(index.Y, condCall.Args[1]) {
- return
- }
- default:
- return
- }
-
- var replacement string
- switch fun {
- case "HasPrefix":
- replacement = "TrimPrefix"
- case "HasSuffix":
- replacement = "TrimSuffix"
- }
- report.Report(pass, ifstmt, fmt.Sprintf("should replace this if statement with an unconditional %s.%s", pkg, replacement),
- report.ShortRange(),
- report.FilterGenerated())
- }
- }
- code.Preorder(pass, fn, (*ast.IfStmt)(nil))
- return nil, nil
-}
-
-var (
- checkLoopSlideQ = pattern.MustParse(`
- (ForStmt
- (AssignStmt initvar@(Ident _) _ (BasicLit "INT" "0"))
- (BinaryExpr initvar "<" limit@(Ident _))
- (IncDecStmt initvar "++")
- [(AssignStmt
- (IndexExpr slice@(Ident _) initvar)
- "="
- (IndexExpr slice (BinaryExpr offset@(Ident _) "+" initvar)))])`)
- checkLoopSlideR = pattern.MustParse(`
- (CallExpr
- (Ident "copy")
- [(SliceExpr slice nil limit nil)
- (SliceExpr slice offset nil nil)])`)
-)
-
-func CheckLoopSlide(pass *analysis.Pass) (interface{}, error) {
- // TODO(dh): detect bs[i+offset] in addition to bs[offset+i]
- // TODO(dh): consider merging this function with LintLoopCopy
- // TODO(dh): detect length that is an expression, not a variable name
- // TODO(dh): support sliding to a different offset than the beginning of the slice
-
- fn := func(node ast.Node) {
- loop := node.(*ast.ForStmt)
- m, edits, ok := MatchAndEdit(pass, checkLoopSlideQ, checkLoopSlideR, loop)
- if !ok {
- return
- }
- if _, ok := pass.TypesInfo.TypeOf(m.State["slice"].(*ast.Ident)).Underlying().(*types.Slice); !ok {
- return
- }
-
- report.Report(pass, loop, "should use copy() instead of loop for sliding slice elements",
- report.ShortRange(),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("use copy() instead of loop", edits...)))
- }
- code.Preorder(pass, fn, (*ast.ForStmt)(nil))
- return nil, nil
-}
-
-var (
- checkMakeLenCapQ1 = pattern.MustParse(`(CallExpr (Builtin "make") [typ size@(BasicLit "INT" "0")])`)
- checkMakeLenCapQ2 = pattern.MustParse(`(CallExpr (Builtin "make") [typ size size])`)
-)
-
-func CheckMakeLenCap(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- if pass.Pkg.Path() == "runtime_test" && filepath.Base(pass.Fset.Position(node.Pos()).Filename) == "map_test.go" {
- // special case of runtime tests testing map creation
- return
- }
- if m, ok := Match(pass, checkMakeLenCapQ1, node); ok {
- T := m.State["typ"].(ast.Expr)
- size := m.State["size"].(ast.Node)
- if _, ok := pass.TypesInfo.TypeOf(T).Underlying().(*types.Slice); ok {
- return
- }
- report.Report(pass, size, fmt.Sprintf("should use make(%s) instead", report.Render(pass, T)), report.FilterGenerated())
- } else if m, ok := Match(pass, checkMakeLenCapQ2, node); ok {
- // TODO(dh): don't consider sizes identical if they're
- // dynamic. for example: make(T, <-ch, <-ch).
- T := m.State["typ"].(ast.Expr)
- size := m.State["size"].(ast.Node)
- report.Report(pass, size,
- fmt.Sprintf("should use make(%s, %s) instead", report.Render(pass, T), report.Render(pass, size)),
- report.FilterGenerated())
- }
- }
- code.Preorder(pass, fn, (*ast.CallExpr)(nil))
- return nil, nil
-}
-
-var (
- checkAssertNotNilFn1Q = pattern.MustParse(`
- (IfStmt
- (AssignStmt [(Ident "_") ok@(Object _)] _ [(TypeAssertExpr assert@(Object _) _)])
- (Or
- (BinaryExpr ok "&&" (BinaryExpr assert "!=" (Builtin "nil")))
- (BinaryExpr (BinaryExpr assert "!=" (Builtin "nil")) "&&" ok))
- _
- _)`)
- checkAssertNotNilFn2Q = pattern.MustParse(`
- (IfStmt
- nil
- (BinaryExpr lhs@(Object _) "!=" (Builtin "nil"))
- [
- ifstmt@(IfStmt
- (AssignStmt [(Ident "_") ok@(Object _)] _ [(TypeAssertExpr lhs _)])
- ok
- _
- _)
- ]
- nil)`)
-)
-
-func CheckAssertNotNil(pass *analysis.Pass) (interface{}, error) {
- fn1 := func(node ast.Node) {
- m, ok := Match(pass, checkAssertNotNilFn1Q, node)
- if !ok {
- return
- }
- assert := m.State["assert"].(types.Object)
- assign := m.State["ok"].(types.Object)
- report.Report(pass, node, fmt.Sprintf("when %s is true, %s can't be nil", assign.Name(), assert.Name()),
- report.ShortRange(),
- report.FilterGenerated())
- }
- fn2 := func(node ast.Node) {
- m, ok := Match(pass, checkAssertNotNilFn2Q, node)
- if !ok {
- return
- }
- ifstmt := m.State["ifstmt"].(*ast.IfStmt)
- lhs := m.State["lhs"].(types.Object)
- assignIdent := m.State["ok"].(types.Object)
- report.Report(pass, ifstmt, fmt.Sprintf("when %s is true, %s can't be nil", assignIdent.Name(), lhs.Name()),
- report.ShortRange(),
- report.FilterGenerated())
- }
- code.Preorder(pass, fn1, (*ast.IfStmt)(nil))
- code.Preorder(pass, fn2, (*ast.IfStmt)(nil))
- return nil, nil
-}
-
-func CheckDeclareAssign(pass *analysis.Pass) (interface{}, error) {
- hasMultipleAssignments := func(root ast.Node, ident *ast.Ident) bool {
- num := 0
- ast.Inspect(root, func(node ast.Node) bool {
- if num >= 2 {
- return false
- }
- assign, ok := node.(*ast.AssignStmt)
- if !ok {
- return true
- }
- for _, lhs := range assign.Lhs {
- if oident, ok := lhs.(*ast.Ident); ok {
- if oident.Obj == ident.Obj {
- num++
- }
- }
- }
-
- return true
- })
- return num >= 2
- }
- fn := func(node ast.Node) {
- block := node.(*ast.BlockStmt)
- if len(block.List) < 2 {
- return
- }
- for i, stmt := range block.List[:len(block.List)-1] {
- _ = i
- decl, ok := stmt.(*ast.DeclStmt)
- if !ok {
- continue
- }
- gdecl, ok := decl.Decl.(*ast.GenDecl)
- if !ok || gdecl.Tok != token.VAR || len(gdecl.Specs) != 1 {
- continue
- }
- vspec, ok := gdecl.Specs[0].(*ast.ValueSpec)
- if !ok || len(vspec.Names) != 1 || len(vspec.Values) != 0 {
- continue
- }
-
- assign, ok := block.List[i+1].(*ast.AssignStmt)
- if !ok || assign.Tok != token.ASSIGN {
- continue
- }
- if len(assign.Lhs) != 1 || len(assign.Rhs) != 1 {
- continue
- }
- ident, ok := assign.Lhs[0].(*ast.Ident)
- if !ok {
- continue
- }
- if vspec.Names[0].Obj != ident.Obj {
- continue
- }
-
- if refersTo(pass, assign.Rhs[0], pass.TypesInfo.ObjectOf(ident)) {
- continue
- }
- if hasMultipleAssignments(block, ident) {
- continue
- }
-
- r := &ast.GenDecl{
- Specs: []ast.Spec{
- &ast.ValueSpec{
- Names: vspec.Names,
- Values: []ast.Expr{assign.Rhs[0]},
- Type: vspec.Type,
- },
- },
- Tok: gdecl.Tok,
- }
- report.Report(pass, decl, "should merge variable declaration with assignment on next line",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("merge declaration with assignment", edit.ReplaceWithNode(pass.Fset, edit.Range{decl.Pos(), assign.End()}, r))))
- }
- }
- code.Preorder(pass, fn, (*ast.BlockStmt)(nil))
- return nil, nil
-}
-
-func CheckRedundantBreak(pass *analysis.Pass) (interface{}, error) {
- fn1 := func(node ast.Node) {
- clause := node.(*ast.CaseClause)
- if len(clause.Body) < 2 {
- return
- }
- branch, ok := clause.Body[len(clause.Body)-1].(*ast.BranchStmt)
- if !ok || branch.Tok != token.BREAK || branch.Label != nil {
- return
- }
- report.Report(pass, branch, "redundant break statement", report.FilterGenerated())
- }
- fn2 := func(node ast.Node) {
- var ret *ast.FieldList
- var body *ast.BlockStmt
- switch x := node.(type) {
- case *ast.FuncDecl:
- ret = x.Type.Results
- body = x.Body
- case *ast.FuncLit:
- ret = x.Type.Results
- body = x.Body
- default:
- ExhaustiveTypeSwitch(node)
- }
- // if the func has results, a return can't be redundant.
- // similarly, if there are no statements, there can be
- // no return.
- if ret != nil || body == nil || len(body.List) < 1 {
- return
- }
- rst, ok := body.List[len(body.List)-1].(*ast.ReturnStmt)
- if !ok {
- return
- }
- // we don't need to check rst.Results as we already
- // checked x.Type.Results to be nil.
- report.Report(pass, rst, "redundant return statement", report.FilterGenerated())
- }
- code.Preorder(pass, fn1, (*ast.CaseClause)(nil))
- code.Preorder(pass, fn2, (*ast.FuncDecl)(nil), (*ast.FuncLit)(nil))
- return nil, nil
-}
-
-func isStringer(T types.Type, msCache *typeutil.MethodSetCache) bool {
- ms := msCache.MethodSet(T)
- sel := ms.Lookup(nil, "String")
- if sel == nil {
- return false
- }
- fn, ok := sel.Obj().(*types.Func)
- if !ok {
- // should be unreachable
- return false
- }
- sig := fn.Type().(*types.Signature)
- if sig.Params().Len() != 0 {
- return false
- }
- if sig.Results().Len() != 1 {
- return false
- }
- if !code.IsType(sig.Results().At(0).Type(), "string") {
- return false
- }
- return true
-}
-
-var checkRedundantSprintfQ = pattern.MustParse(`(CallExpr (Function "fmt.Sprintf") [format arg])`)
-
-func CheckRedundantSprintf(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- m, ok := Match(pass, checkRedundantSprintfQ, node)
- if !ok {
- return
- }
-
- format := m.State["format"].(ast.Expr)
- arg := m.State["arg"].(ast.Expr)
- if s, ok := code.ExprToString(pass, format); !ok || s != "%s" {
- return
- }
- typ := pass.TypesInfo.TypeOf(arg)
-
- irpkg := pass.ResultOf[buildir.Analyzer].(*buildir.IR).Pkg
- if types.TypeString(typ, nil) != "reflect.Value" && isStringer(typ, &irpkg.Prog.MethodSets) {
- replacement := &ast.CallExpr{
- Fun: &ast.SelectorExpr{
- X: arg,
- Sel: &ast.Ident{Name: "String"},
- },
- }
- report.Report(pass, node, "should use String() instead of fmt.Sprintf",
- report.Fixes(edit.Fix("replace with call to String method", edit.ReplaceWithNode(pass.Fset, node, replacement))))
- return
- }
-
- if typ.Underlying() == types.Universe.Lookup("string").Type() {
- if typ == types.Universe.Lookup("string").Type() {
- report.Report(pass, node, "the argument is already a string, there's no need to use fmt.Sprintf",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("remove unnecessary call to fmt.Sprintf", edit.ReplaceWithNode(pass.Fset, node, arg))))
- } else {
- replacement := &ast.CallExpr{
- Fun: &ast.Ident{Name: "string"},
- Args: []ast.Expr{arg},
- }
- report.Report(pass, node, "the argument's underlying type is a string, should use a simple conversion instead of fmt.Sprintf",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("replace with conversion to string", edit.ReplaceWithNode(pass.Fset, node, replacement))))
- }
- }
- }
- code.Preorder(pass, fn, (*ast.CallExpr)(nil))
- return nil, nil
-}
-
-var (
- checkErrorsNewSprintfQ = pattern.MustParse(`(CallExpr (Function "errors.New") [(CallExpr (Function "fmt.Sprintf") args)])`)
- checkErrorsNewSprintfR = pattern.MustParse(`(CallExpr (SelectorExpr (Ident "fmt") (Ident "Errorf")) args)`)
-)
-
-func CheckErrorsNewSprintf(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- if _, edits, ok := MatchAndEdit(pass, checkErrorsNewSprintfQ, checkErrorsNewSprintfR, node); ok {
- // TODO(dh): the suggested fix may leave an unused import behind
- report.Report(pass, node, "should use fmt.Errorf(...) instead of errors.New(fmt.Sprintf(...))",
- report.FilterGenerated(),
- report.Fixes(edit.Fix("use fmt.Errorf", edits...)))
- }
- }
- code.Preorder(pass, fn, (*ast.CallExpr)(nil))
- return nil, nil
-}
-
-func CheckRangeStringRunes(pass *analysis.Pass) (interface{}, error) {
- return sharedcheck.CheckRangeStringRunes(pass)
-}
-
-var checkNilCheckAroundRangeQ = pattern.MustParse(`
- (IfStmt
- nil
- (BinaryExpr x@(Object _) "!=" (Builtin "nil"))
- [(RangeStmt _ _ _ x _)]
- nil)`)
-
-func CheckNilCheckAroundRange(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- m, ok := Match(pass, checkNilCheckAroundRangeQ, node)
- if !ok {
- return
- }
- switch m.State["x"].(types.Object).Type().Underlying().(type) {
- case *types.Slice, *types.Map:
- report.Report(pass, node, "unnecessary nil check around range",
- report.ShortRange(),
- report.FilterGenerated())
-
- }
- }
- code.Preorder(pass, fn, (*ast.IfStmt)(nil))
- return nil, nil
-}
-
-func isPermissibleSort(pass *analysis.Pass, node ast.Node) bool {
- call := node.(*ast.CallExpr)
- typeconv, ok := call.Args[0].(*ast.CallExpr)
- if !ok {
- return true
- }
-
- sel, ok := typeconv.Fun.(*ast.SelectorExpr)
- if !ok {
- return true
- }
- name := code.SelectorName(pass, sel)
- switch name {
- case "sort.IntSlice", "sort.Float64Slice", "sort.StringSlice":
- default:
- return true
- }
-
- return false
-}
-
-func CheckSortHelpers(pass *analysis.Pass) (interface{}, error) {
- type Error struct {
- node ast.Node
- msg string
- }
- var allErrors []Error
- fn := func(node ast.Node) {
- var body *ast.BlockStmt
- switch node := node.(type) {
- case *ast.FuncLit:
- body = node.Body
- case *ast.FuncDecl:
- body = node.Body
- default:
- ExhaustiveTypeSwitch(node)
- }
- if body == nil {
- return
- }
-
- var errors []Error
- permissible := false
- fnSorts := func(node ast.Node) bool {
- if permissible {
- return false
- }
- if !code.IsCallToAST(pass, node, "sort.Sort") {
- return true
- }
- if isPermissibleSort(pass, node) {
- permissible = true
- return false
- }
- call := node.(*ast.CallExpr)
- typeconv := call.Args[Arg("sort.Sort.data")].(*ast.CallExpr)
- sel := typeconv.Fun.(*ast.SelectorExpr)
- name := code.SelectorName(pass, sel)
-
- switch name {
- case "sort.IntSlice":
- errors = append(errors, Error{node, "should use sort.Ints(...) instead of sort.Sort(sort.IntSlice(...))"})
- case "sort.Float64Slice":
- errors = append(errors, Error{node, "should use sort.Float64s(...) instead of sort.Sort(sort.Float64Slice(...))"})
- case "sort.StringSlice":
- errors = append(errors, Error{node, "should use sort.Strings(...) instead of sort.Sort(sort.StringSlice(...))"})
- }
- return true
- }
- ast.Inspect(body, fnSorts)
-
- if permissible {
- return
- }
- allErrors = append(allErrors, errors...)
- }
- code.Preorder(pass, fn, (*ast.FuncLit)(nil), (*ast.FuncDecl)(nil))
- sort.Slice(allErrors, func(i, j int) bool {
- return allErrors[i].node.Pos() < allErrors[j].node.Pos()
- })
- var prev token.Pos
- for _, err := range allErrors {
- if err.node.Pos() == prev {
- continue
- }
- prev = err.node.Pos()
- report.Report(pass, err.node, err.msg, report.FilterGenerated())
- }
- return nil, nil
-}
-
-var checkGuardedDeleteQ = pattern.MustParse(`
- (IfStmt
- (AssignStmt
- [(Ident "_") ok@(Ident _)]
- ":="
- (IndexExpr m key))
- ok
- [call@(CallExpr (Builtin "delete") [m key])]
- nil)`)
-
-func CheckGuardedDelete(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- if m, ok := Match(pass, checkGuardedDeleteQ, node); ok {
- report.Report(pass, node, "unnecessary guard around call to delete",
- report.ShortRange(),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("remove guard", edit.ReplaceWithNode(pass.Fset, node, m.State["call"].(ast.Node)))))
- }
- }
-
- code.Preorder(pass, fn, (*ast.IfStmt)(nil))
- return nil, nil
-}
-
-var (
- checkSimplifyTypeSwitchQ = pattern.MustParse(`
- (TypeSwitchStmt
- nil
- expr@(TypeAssertExpr ident@(Ident _) _)
- body)`)
- checkSimplifyTypeSwitchR = pattern.MustParse(`(AssignStmt ident ":=" expr)`)
-)
-
-func CheckSimplifyTypeSwitch(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- m, ok := Match(pass, checkSimplifyTypeSwitchQ, node)
- if !ok {
- return
- }
- stmt := node.(*ast.TypeSwitchStmt)
- expr := m.State["expr"].(ast.Node)
- ident := m.State["ident"].(*ast.Ident)
-
- x := pass.TypesInfo.ObjectOf(ident)
- var allOffenders []*ast.TypeAssertExpr
- canSuggestFix := true
- for _, clause := range stmt.Body.List {
- clause := clause.(*ast.CaseClause)
- if len(clause.List) != 1 {
- continue
- }
- hasUnrelatedAssertion := false
- var offenders []*ast.TypeAssertExpr
- ast.Inspect(clause, func(node ast.Node) bool {
- assert2, ok := node.(*ast.TypeAssertExpr)
- if !ok {
- return true
- }
- ident, ok := assert2.X.(*ast.Ident)
- if !ok {
- hasUnrelatedAssertion = true
- return false
- }
- if pass.TypesInfo.ObjectOf(ident) != x {
- hasUnrelatedAssertion = true
- return false
- }
-
- if !types.Identical(pass.TypesInfo.TypeOf(clause.List[0]), pass.TypesInfo.TypeOf(assert2.Type)) {
- hasUnrelatedAssertion = true
- return false
- }
- offenders = append(offenders, assert2)
- return true
- })
- if !hasUnrelatedAssertion {
- // don't flag cases that have other type assertions
- // unrelated to the one in the case clause. often
- // times, this is done for symmetry, when two
- // different values have to be asserted to the same
- // type.
- allOffenders = append(allOffenders, offenders...)
- }
- canSuggestFix = canSuggestFix && !hasUnrelatedAssertion
- }
- if len(allOffenders) != 0 {
- var opts []report.Option
- for _, offender := range allOffenders {
- opts = append(opts, report.Related(offender, "could eliminate this type assertion"))
- }
- opts = append(opts, report.FilterGenerated())
-
- msg := fmt.Sprintf("assigning the result of this type assertion to a variable (switch %s := %s.(type)) could eliminate type assertions in switch cases",
- report.Render(pass, ident), report.Render(pass, ident))
- if canSuggestFix {
- var edits []analysis.TextEdit
- edits = append(edits, edit.ReplaceWithPattern(pass, checkSimplifyTypeSwitchR, m.State, expr))
- for _, offender := range allOffenders {
- edits = append(edits, edit.ReplaceWithNode(pass.Fset, offender, offender.X))
- }
- opts = append(opts, report.Fixes(edit.Fix("simplify type switch", edits...)))
- report.Report(pass, expr, msg, opts...)
- } else {
- report.Report(pass, expr, msg, opts...)
- }
- }
- }
- code.Preorder(pass, fn, (*ast.TypeSwitchStmt)(nil))
- return nil, nil
-}
-
-func CheckRedundantCanonicalHeaderKey(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- call := node.(*ast.CallExpr)
- callName := code.CallNameAST(pass, call)
- switch callName {
- case "(net/http.Header).Add", "(net/http.Header).Del", "(net/http.Header).Get", "(net/http.Header).Set":
- default:
- return
- }
-
- if !code.IsCallToAST(pass, call.Args[0], "net/http.CanonicalHeaderKey") {
- return
- }
-
- report.Report(pass, call,
- fmt.Sprintf("calling net/http.CanonicalHeaderKey on the 'key' argument of %s is redundant", callName),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("remove call to CanonicalHeaderKey", edit.ReplaceWithNode(pass.Fset, call.Args[0], call.Args[0].(*ast.CallExpr).Args[0]))))
- }
- code.Preorder(pass, fn, (*ast.CallExpr)(nil))
- return nil, nil
-}
-
-var checkUnnecessaryGuardQ = pattern.MustParse(`
- (Or
- (IfStmt
- (AssignStmt [(Ident "_") ok@(Ident _)] ":=" indexexpr@(IndexExpr _ _))
- ok
- set@(AssignStmt indexexpr "=" (CallExpr (Builtin "append") indexexpr:values))
- (AssignStmt indexexpr "=" (CompositeLit _ values)))
- (IfStmt
- (AssignStmt [(Ident "_") ok] ":=" indexexpr@(IndexExpr _ _))
- ok
- set@(AssignStmt indexexpr "+=" value)
- (AssignStmt indexexpr "=" value))
- (IfStmt
- (AssignStmt [(Ident "_") ok] ":=" indexexpr@(IndexExpr _ _))
- ok
- set@(IncDecStmt indexexpr "++")
- (AssignStmt indexexpr "=" (BasicLit "INT" "1"))))`)
-
-func CheckUnnecessaryGuard(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- if m, ok := Match(pass, checkUnnecessaryGuardQ, node); ok {
- if code.MayHaveSideEffects(pass, m.State["indexexpr"].(ast.Expr), nil) {
- return
- }
- report.Report(pass, node, "unnecessary guard around map access",
- report.ShortRange(),
- report.Fixes(edit.Fix("simplify map access", edit.ReplaceWithNode(pass.Fset, node, m.State["set"].(ast.Node)))))
- }
- }
- code.Preorder(pass, fn, (*ast.IfStmt)(nil))
- return nil, nil
-}
-
-var (
- checkElaborateSleepQ = pattern.MustParse(`(SelectStmt (CommClause (UnaryExpr "<-" (CallExpr (Function "time.After") [arg])) body))`)
- checkElaborateSleepR = pattern.MustParse(`(CallExpr (SelectorExpr (Ident "time") (Ident "Sleep")) [arg])`)
-)
-
-func CheckElaborateSleep(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- if m, ok := Match(pass, checkElaborateSleepQ, node); ok {
- if body, ok := m.State["body"].([]ast.Stmt); ok && len(body) == 0 {
- report.Report(pass, node, "should use time.Sleep instead of elaborate way of sleeping",
- report.ShortRange(),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("Use time.Sleep", edit.ReplaceWithPattern(pass, checkElaborateSleepR, m.State, node))))
- } else {
- // TODO(dh): we could make a suggested fix if the body
- // doesn't declare or shadow any identifiers
- report.Report(pass, node, "should use time.Sleep instead of elaborate way of sleeping",
- report.ShortRange(),
- report.FilterGenerated())
- }
- }
- }
- code.Preorder(pass, fn, (*ast.SelectStmt)(nil))
- return nil, nil
-}
-
-var checkPrintSprintQ = pattern.MustParse(`
- (Or
- (CallExpr
- fn@(Or
- (Function "fmt.Print")
- (Function "fmt.Sprint")
- (Function "fmt.Println")
- (Function "fmt.Sprintln"))
- [(CallExpr (Function "fmt.Sprintf") f:_)])
- (CallExpr
- fn@(Or
- (Function "fmt.Fprint")
- (Function "fmt.Fprintln"))
- [_ (CallExpr (Function "fmt.Sprintf") f:_)]))`)
-
-func CheckPrintSprintf(pass *analysis.Pass) (interface{}, error) {
- fn := func(node ast.Node) {
- m, ok := Match(pass, checkPrintSprintQ, node)
- if !ok {
- return
- }
-
- name := m.State["fn"].(*types.Func).Name()
- var msg string
- switch name {
- case "Print", "Fprint", "Sprint":
- newname := name + "f"
- msg = fmt.Sprintf("should use fmt.%s instead of fmt.%s(fmt.Sprintf(...))", newname, name)
- case "Println", "Fprintln", "Sprintln":
- if _, ok := m.State["f"].(*ast.BasicLit); !ok {
- // This may be an instance of
- // fmt.Println(fmt.Sprintf(arg, ...)) where arg is an
- // externally provided format string and the caller
- // cannot guarantee that the format string ends with a
- // newline.
- return
- }
- newname := name[:len(name)-2] + "f"
- msg = fmt.Sprintf("should use fmt.%s instead of fmt.%s(fmt.Sprintf(...)) (but don't forget the newline)", newname, name)
- }
- report.Report(pass, node, msg,
- report.FilterGenerated())
- }
- code.Preorder(pass, fn, (*ast.CallExpr)(nil))
- return nil, nil
-}
-
-var checkSprintLiteralQ = pattern.MustParse(`
- (CallExpr
- fn@(Or
- (Function "fmt.Sprint")
- (Function "fmt.Sprintf"))
- [lit@(BasicLit "STRING" _)])`)
-
-func CheckSprintLiteral(pass *analysis.Pass) (interface{}, error) {
- // We only flag calls with string literals, not expressions of
- // type string, because some people use fmt.Sprint(s) as a pattern
- // for copying strings, which may be useful when extracing a small
- // substring from a large string.
- fn := func(node ast.Node) {
- m, ok := Match(pass, checkSprintLiteralQ, node)
- if !ok {
- return
- }
- callee := m.State["fn"].(*types.Func)
- lit := m.State["lit"].(*ast.BasicLit)
- if callee.Name() == "Sprintf" {
- if strings.ContainsRune(lit.Value, '%') {
- // This might be a format string
- return
- }
- }
- report.Report(pass, node, fmt.Sprintf("unnecessary use of fmt.%s", callee.Name()),
- report.FilterGenerated(),
- report.Fixes(edit.Fix("Replace with string literal", edit.ReplaceWithNode(pass.Fset, node, lit))))
- }
- code.Preorder(pass, fn, (*ast.CallExpr)(nil))
- return nil, nil
-}
projects / dotfiles / .git / blobdiff