3825 lines
103 KiB
Go
3825 lines
103 KiB
Go
// Package staticcheck contains a linter for Go source code.
|
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package staticcheck // import "honnef.co/go/tools/staticcheck"
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import (
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"fmt"
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"go/ast"
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"go/constant"
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"go/token"
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"go/types"
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htmltemplate "html/template"
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"net/http"
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"reflect"
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"regexp"
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"regexp/syntax"
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"sort"
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"strconv"
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"strings"
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texttemplate "text/template"
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"unicode"
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. "honnef.co/go/tools/arg"
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"honnef.co/go/tools/code"
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"honnef.co/go/tools/deprecated"
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"honnef.co/go/tools/edit"
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"honnef.co/go/tools/facts"
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"honnef.co/go/tools/functions"
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"honnef.co/go/tools/internal/passes/buildir"
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"honnef.co/go/tools/internal/sharedcheck"
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"honnef.co/go/tools/ir"
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"honnef.co/go/tools/ir/irutil"
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"honnef.co/go/tools/lint"
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. "honnef.co/go/tools/lint/lintdsl"
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"honnef.co/go/tools/pattern"
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"honnef.co/go/tools/printf"
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"honnef.co/go/tools/report"
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"golang.org/x/tools/go/analysis"
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"golang.org/x/tools/go/analysis/passes/inspect"
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"golang.org/x/tools/go/ast/astutil"
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"golang.org/x/tools/go/ast/inspector"
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"golang.org/x/tools/go/types/typeutil"
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)
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func checkSortSlice(call *Call) {
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c := call.Instr.Common().StaticCallee()
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arg := call.Args[0]
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T := arg.Value.Value.Type().Underlying()
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switch T.(type) {
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case *types.Interface:
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||
// we don't know.
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||
// TODO(dh): if the value is a phi node we can look at its edges
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||
if k, ok := arg.Value.Value.(*ir.Const); ok && k.Value == nil {
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||
// literal nil, e.g. sort.Sort(nil, ...)
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arg.Invalid(fmt.Sprintf("cannot call %s on nil literal", c))
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}
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case *types.Slice:
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// this is fine
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default:
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// this is not fine
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arg.Invalid(fmt.Sprintf("%s must only be called on slices, was called on %s", c, T))
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}
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}
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func validRegexp(call *Call) {
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arg := call.Args[0]
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err := ValidateRegexp(arg.Value)
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if err != nil {
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arg.Invalid(err.Error())
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}
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}
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type runeSlice []rune
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||
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func (rs runeSlice) Len() int { return len(rs) }
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func (rs runeSlice) Less(i int, j int) bool { return rs[i] < rs[j] }
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func (rs runeSlice) Swap(i int, j int) { rs[i], rs[j] = rs[j], rs[i] }
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func utf8Cutset(call *Call) {
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arg := call.Args[1]
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if InvalidUTF8(arg.Value) {
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arg.Invalid(MsgInvalidUTF8)
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}
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}
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func uniqueCutset(call *Call) {
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arg := call.Args[1]
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if !UniqueStringCutset(arg.Value) {
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arg.Invalid(MsgNonUniqueCutset)
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}
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}
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func unmarshalPointer(name string, arg int) CallCheck {
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return func(call *Call) {
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if !Pointer(call.Args[arg].Value) {
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call.Args[arg].Invalid(fmt.Sprintf("%s expects to unmarshal into a pointer, but the provided value is not a pointer", name))
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}
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}
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}
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func pointlessIntMath(call *Call) {
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if ConvertedFromInt(call.Args[0].Value) {
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call.Invalid(fmt.Sprintf("calling %s on a converted integer is pointless", code.CallName(call.Instr.Common())))
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}
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}
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func checkValidHostPort(arg int) CallCheck {
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return func(call *Call) {
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if !ValidHostPort(call.Args[arg].Value) {
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call.Args[arg].Invalid(MsgInvalidHostPort)
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}
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}
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}
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var (
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checkRegexpRules = map[string]CallCheck{
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"regexp.MustCompile": validRegexp,
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"regexp.Compile": validRegexp,
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"regexp.Match": validRegexp,
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"regexp.MatchReader": validRegexp,
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"regexp.MatchString": validRegexp,
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}
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checkTimeParseRules = map[string]CallCheck{
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"time.Parse": func(call *Call) {
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arg := call.Args[Arg("time.Parse.layout")]
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err := ValidateTimeLayout(arg.Value)
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if err != nil {
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arg.Invalid(err.Error())
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}
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},
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}
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checkEncodingBinaryRules = map[string]CallCheck{
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"encoding/binary.Write": func(call *Call) {
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arg := call.Args[Arg("encoding/binary.Write.data")]
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if !CanBinaryMarshal(call.Pass, arg.Value) {
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arg.Invalid(fmt.Sprintf("value of type %s cannot be used with binary.Write", arg.Value.Value.Type()))
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}
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},
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}
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checkURLsRules = map[string]CallCheck{
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"net/url.Parse": func(call *Call) {
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arg := call.Args[Arg("net/url.Parse.rawurl")]
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err := ValidateURL(arg.Value)
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||
if err != nil {
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arg.Invalid(err.Error())
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}
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},
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}
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checkSyncPoolValueRules = map[string]CallCheck{
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"(*sync.Pool).Put": func(call *Call) {
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arg := call.Args[Arg("(*sync.Pool).Put.x")]
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typ := arg.Value.Value.Type()
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||
if !code.IsPointerLike(typ) {
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arg.Invalid("argument should be pointer-like to avoid allocations")
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}
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},
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}
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checkRegexpFindAllRules = map[string]CallCheck{
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"(*regexp.Regexp).FindAll": RepeatZeroTimes("a FindAll method", 1),
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"(*regexp.Regexp).FindAllIndex": RepeatZeroTimes("a FindAll method", 1),
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"(*regexp.Regexp).FindAllString": RepeatZeroTimes("a FindAll method", 1),
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"(*regexp.Regexp).FindAllStringIndex": RepeatZeroTimes("a FindAll method", 1),
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"(*regexp.Regexp).FindAllStringSubmatch": RepeatZeroTimes("a FindAll method", 1),
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||
"(*regexp.Regexp).FindAllStringSubmatchIndex": RepeatZeroTimes("a FindAll method", 1),
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"(*regexp.Regexp).FindAllSubmatch": RepeatZeroTimes("a FindAll method", 1),
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"(*regexp.Regexp).FindAllSubmatchIndex": RepeatZeroTimes("a FindAll method", 1),
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}
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checkUTF8CutsetRules = map[string]CallCheck{
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"strings.IndexAny": utf8Cutset,
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"strings.LastIndexAny": utf8Cutset,
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"strings.ContainsAny": utf8Cutset,
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"strings.Trim": utf8Cutset,
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"strings.TrimLeft": utf8Cutset,
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"strings.TrimRight": utf8Cutset,
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||
}
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checkUniqueCutsetRules = map[string]CallCheck{
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"strings.Trim": uniqueCutset,
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"strings.TrimLeft": uniqueCutset,
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"strings.TrimRight": uniqueCutset,
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}
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checkUnmarshalPointerRules = map[string]CallCheck{
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"encoding/xml.Unmarshal": unmarshalPointer("xml.Unmarshal", 1),
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"(*encoding/xml.Decoder).Decode": unmarshalPointer("Decode", 0),
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"(*encoding/xml.Decoder).DecodeElement": unmarshalPointer("DecodeElement", 0),
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"encoding/json.Unmarshal": unmarshalPointer("json.Unmarshal", 1),
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"(*encoding/json.Decoder).Decode": unmarshalPointer("Decode", 0),
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}
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checkUnbufferedSignalChanRules = map[string]CallCheck{
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"os/signal.Notify": func(call *Call) {
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arg := call.Args[Arg("os/signal.Notify.c")]
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if UnbufferedChannel(arg.Value) {
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arg.Invalid("the channel used with signal.Notify should be buffered")
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}
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},
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}
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checkMathIntRules = map[string]CallCheck{
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"math.Ceil": pointlessIntMath,
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"math.Floor": pointlessIntMath,
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"math.IsNaN": pointlessIntMath,
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"math.Trunc": pointlessIntMath,
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||
"math.IsInf": pointlessIntMath,
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||
}
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checkStringsReplaceZeroRules = map[string]CallCheck{
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"strings.Replace": RepeatZeroTimes("strings.Replace", 3),
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"bytes.Replace": RepeatZeroTimes("bytes.Replace", 3),
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}
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checkListenAddressRules = map[string]CallCheck{
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"net/http.ListenAndServe": checkValidHostPort(0),
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"net/http.ListenAndServeTLS": checkValidHostPort(0),
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}
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checkBytesEqualIPRules = map[string]CallCheck{
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"bytes.Equal": func(call *Call) {
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if ConvertedFrom(call.Args[Arg("bytes.Equal.a")].Value, "net.IP") &&
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ConvertedFrom(call.Args[Arg("bytes.Equal.b")].Value, "net.IP") {
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call.Invalid("use net.IP.Equal to compare net.IPs, not bytes.Equal")
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}
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},
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}
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checkRegexpMatchLoopRules = map[string]CallCheck{
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"regexp.Match": loopedRegexp("regexp.Match"),
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"regexp.MatchReader": loopedRegexp("regexp.MatchReader"),
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||
"regexp.MatchString": loopedRegexp("regexp.MatchString"),
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}
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||
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checkNoopMarshal = map[string]CallCheck{
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// TODO(dh): should we really flag XML? Even an empty struct
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||
// produces a non-zero amount of data, namely its type name.
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// Let's see if we encounter any false positives.
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//
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// Also, should we flag gob?
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"encoding/json.Marshal": checkNoopMarshalImpl(Arg("json.Marshal.v"), "MarshalJSON", "MarshalText"),
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"encoding/xml.Marshal": checkNoopMarshalImpl(Arg("xml.Marshal.v"), "MarshalXML", "MarshalText"),
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"(*encoding/json.Encoder).Encode": checkNoopMarshalImpl(Arg("(*encoding/json.Encoder).Encode.v"), "MarshalJSON", "MarshalText"),
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||
"(*encoding/xml.Encoder).Encode": checkNoopMarshalImpl(Arg("(*encoding/xml.Encoder).Encode.v"), "MarshalXML", "MarshalText"),
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||
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||
"encoding/json.Unmarshal": checkNoopMarshalImpl(Arg("json.Unmarshal.v"), "UnmarshalJSON", "UnmarshalText"),
|
||
"encoding/xml.Unmarshal": checkNoopMarshalImpl(Arg("xml.Unmarshal.v"), "UnmarshalXML", "UnmarshalText"),
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||
"(*encoding/json.Decoder).Decode": checkNoopMarshalImpl(Arg("(*encoding/json.Decoder).Decode.v"), "UnmarshalJSON", "UnmarshalText"),
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||
"(*encoding/xml.Decoder).Decode": checkNoopMarshalImpl(Arg("(*encoding/xml.Decoder).Decode.v"), "UnmarshalXML", "UnmarshalText"),
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||
}
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checkUnsupportedMarshal = map[string]CallCheck{
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||
"encoding/json.Marshal": checkUnsupportedMarshalImpl(Arg("json.Marshal.v"), "json", "MarshalJSON", "MarshalText"),
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"encoding/xml.Marshal": checkUnsupportedMarshalImpl(Arg("xml.Marshal.v"), "xml", "MarshalXML", "MarshalText"),
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||
"(*encoding/json.Encoder).Encode": checkUnsupportedMarshalImpl(Arg("(*encoding/json.Encoder).Encode.v"), "json", "MarshalJSON", "MarshalText"),
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||
"(*encoding/xml.Encoder).Encode": checkUnsupportedMarshalImpl(Arg("(*encoding/xml.Encoder).Encode.v"), "xml", "MarshalXML", "MarshalText"),
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}
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checkAtomicAlignment = map[string]CallCheck{
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"sync/atomic.AddInt64": checkAtomicAlignmentImpl,
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"sync/atomic.AddUint64": checkAtomicAlignmentImpl,
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"sync/atomic.CompareAndSwapInt64": checkAtomicAlignmentImpl,
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"sync/atomic.CompareAndSwapUint64": checkAtomicAlignmentImpl,
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"sync/atomic.LoadInt64": checkAtomicAlignmentImpl,
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||
"sync/atomic.LoadUint64": checkAtomicAlignmentImpl,
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||
"sync/atomic.StoreInt64": checkAtomicAlignmentImpl,
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"sync/atomic.StoreUint64": checkAtomicAlignmentImpl,
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"sync/atomic.SwapInt64": checkAtomicAlignmentImpl,
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"sync/atomic.SwapUint64": checkAtomicAlignmentImpl,
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}
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// TODO(dh): detect printf wrappers
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checkPrintfRules = map[string]CallCheck{
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"fmt.Errorf": func(call *Call) { checkPrintfCall(call, 0, 1) },
|
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"fmt.Printf": func(call *Call) { checkPrintfCall(call, 0, 1) },
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"fmt.Sprintf": func(call *Call) { checkPrintfCall(call, 0, 1) },
|
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"fmt.Fprintf": func(call *Call) { checkPrintfCall(call, 1, 2) },
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"golang.org/x/xerrors.Errorf": func(call *Call) { checkPrintfCall(call, 0, 1) },
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||
}
|
||
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checkSortSliceRules = map[string]CallCheck{
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||
"sort.Slice": checkSortSlice,
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"sort.SliceIsSorted": checkSortSlice,
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"sort.SliceStable": checkSortSlice,
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}
|
||
|
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checkWithValueKeyRules = map[string]CallCheck{
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"context.WithValue": checkWithValueKey,
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}
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)
|
||
|
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func checkPrintfCall(call *Call, fIdx, vIdx int) {
|
||
f := call.Args[fIdx]
|
||
var args []ir.Value
|
||
switch v := call.Args[vIdx].Value.Value.(type) {
|
||
case *ir.Slice:
|
||
var ok bool
|
||
args, ok = irutil.Vararg(v)
|
||
if !ok {
|
||
// We don't know what the actual arguments to the function are
|
||
return
|
||
}
|
||
case *ir.Const:
|
||
// nil, i.e. no arguments
|
||
default:
|
||
// We don't know what the actual arguments to the function are
|
||
return
|
||
}
|
||
checkPrintfCallImpl(f, f.Value.Value, args)
|
||
}
|
||
|
||
type verbFlag int
|
||
|
||
const (
|
||
isInt verbFlag = 1 << iota
|
||
isBool
|
||
isFP
|
||
isString
|
||
isPointer
|
||
// Verbs that accept "pseudo pointers" will sometimes dereference
|
||
// non-nil pointers. For example, %x on a non-nil *struct will print the
|
||
// individual fields, but on a nil pointer it will print the address.
|
||
isPseudoPointer
|
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isSlice
|
||
isAny
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noRecurse
|
||
)
|
||
|
||
var verbs = [...]verbFlag{
|
||
'b': isPseudoPointer | isInt | isFP,
|
||
'c': isInt,
|
||
'd': isPseudoPointer | isInt,
|
||
'e': isFP,
|
||
'E': isFP,
|
||
'f': isFP,
|
||
'F': isFP,
|
||
'g': isFP,
|
||
'G': isFP,
|
||
'o': isPseudoPointer | isInt,
|
||
'O': isPseudoPointer | isInt,
|
||
'p': isSlice | isPointer | noRecurse,
|
||
'q': isInt | isString,
|
||
's': isString,
|
||
't': isBool,
|
||
'T': isAny,
|
||
'U': isInt,
|
||
'v': isAny,
|
||
'X': isPseudoPointer | isInt | isFP | isString,
|
||
'x': isPseudoPointer | isInt | isFP | isString,
|
||
}
|
||
|
||
func checkPrintfCallImpl(carg *Argument, f ir.Value, args []ir.Value) {
|
||
var msCache *typeutil.MethodSetCache
|
||
if f.Parent() != nil {
|
||
msCache = &f.Parent().Prog.MethodSets
|
||
}
|
||
|
||
elem := func(T types.Type, verb rune) ([]types.Type, bool) {
|
||
if verbs[verb]&noRecurse != 0 {
|
||
return []types.Type{T}, false
|
||
}
|
||
switch T := T.(type) {
|
||
case *types.Slice:
|
||
if verbs[verb]&isSlice != 0 {
|
||
return []types.Type{T}, false
|
||
}
|
||
if verbs[verb]&isString != 0 && code.IsType(T.Elem().Underlying(), "byte") {
|
||
return []types.Type{T}, false
|
||
}
|
||
return []types.Type{T.Elem()}, true
|
||
case *types.Map:
|
||
key := T.Key()
|
||
val := T.Elem()
|
||
return []types.Type{key, val}, true
|
||
case *types.Struct:
|
||
out := make([]types.Type, 0, T.NumFields())
|
||
for i := 0; i < T.NumFields(); i++ {
|
||
out = append(out, T.Field(i).Type())
|
||
}
|
||
return out, true
|
||
case *types.Array:
|
||
return []types.Type{T.Elem()}, true
|
||
default:
|
||
return []types.Type{T}, false
|
||
}
|
||
}
|
||
isInfo := func(T types.Type, info types.BasicInfo) bool {
|
||
basic, ok := T.Underlying().(*types.Basic)
|
||
return ok && basic.Info()&info != 0
|
||
}
|
||
|
||
isStringer := func(T types.Type, ms *types.MethodSet) bool {
|
||
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
|
||
}
|
||
isError := func(T types.Type, ms *types.MethodSet) bool {
|
||
sel := ms.Lookup(nil, "Error")
|
||
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
|
||
}
|
||
|
||
isFormatter := func(T types.Type, ms *types.MethodSet) bool {
|
||
sel := ms.Lookup(nil, "Format")
|
||
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() != 2 {
|
||
return false
|
||
}
|
||
// TODO(dh): check the types of the arguments for more
|
||
// precision
|
||
if sig.Results().Len() != 0 {
|
||
return false
|
||
}
|
||
return true
|
||
}
|
||
|
||
seen := map[types.Type]bool{}
|
||
var checkType func(verb rune, T types.Type, top bool) bool
|
||
checkType = func(verb rune, T types.Type, top bool) bool {
|
||
if top {
|
||
for k := range seen {
|
||
delete(seen, k)
|
||
}
|
||
}
|
||
if seen[T] {
|
||
return true
|
||
}
|
||
seen[T] = true
|
||
if int(verb) >= len(verbs) {
|
||
// Unknown verb
|
||
return true
|
||
}
|
||
|
||
flags := verbs[verb]
|
||
if flags == 0 {
|
||
// Unknown verb
|
||
return true
|
||
}
|
||
|
||
ms := msCache.MethodSet(T)
|
||
if isFormatter(T, ms) {
|
||
// the value is responsible for formatting itself
|
||
return true
|
||
}
|
||
|
||
if flags&isString != 0 && (isStringer(T, ms) || isError(T, ms)) {
|
||
// Check for stringer early because we're about to dereference
|
||
return true
|
||
}
|
||
|
||
T = T.Underlying()
|
||
if flags&(isPointer|isPseudoPointer) == 0 && top {
|
||
T = code.Dereference(T)
|
||
}
|
||
if flags&isPseudoPointer != 0 && top {
|
||
t := code.Dereference(T)
|
||
if _, ok := t.Underlying().(*types.Struct); ok {
|
||
T = t
|
||
}
|
||
}
|
||
|
||
if _, ok := T.(*types.Interface); ok {
|
||
// We don't know what's in the interface
|
||
return true
|
||
}
|
||
|
||
var info types.BasicInfo
|
||
if flags&isInt != 0 {
|
||
info |= types.IsInteger
|
||
}
|
||
if flags&isBool != 0 {
|
||
info |= types.IsBoolean
|
||
}
|
||
if flags&isFP != 0 {
|
||
info |= types.IsFloat | types.IsComplex
|
||
}
|
||
if flags&isString != 0 {
|
||
info |= types.IsString
|
||
}
|
||
|
||
if info != 0 && isInfo(T, info) {
|
||
return true
|
||
}
|
||
|
||
if flags&isString != 0 && (code.IsType(T, "[]byte") || isStringer(T, ms) || isError(T, ms)) {
|
||
return true
|
||
}
|
||
|
||
if flags&isPointer != 0 && code.IsPointerLike(T) {
|
||
return true
|
||
}
|
||
if flags&isPseudoPointer != 0 {
|
||
switch U := T.Underlying().(type) {
|
||
case *types.Pointer:
|
||
if !top {
|
||
return true
|
||
}
|
||
|
||
if _, ok := U.Elem().Underlying().(*types.Struct); !ok {
|
||
// TODO(dh): can this condition ever be false? For
|
||
// *T, if T is a struct, we'll already have
|
||
// dereferenced it, meaning the *types.Pointer
|
||
// branch couldn't have been taken. For T that
|
||
// aren't structs, this condition will always
|
||
// evaluate to true.
|
||
return true
|
||
}
|
||
case *types.Chan, *types.Signature:
|
||
// Channels and functions are always treated as
|
||
// pointers and never recursed into.
|
||
return true
|
||
case *types.Basic:
|
||
if U.Kind() == types.UnsafePointer {
|
||
return true
|
||
}
|
||
case *types.Interface:
|
||
// we will already have bailed if the type is an
|
||
// interface.
|
||
panic("unreachable")
|
||
default:
|
||
// other pointer-like types, such as maps or slices,
|
||
// will be printed element-wise.
|
||
}
|
||
}
|
||
|
||
if flags&isSlice != 0 {
|
||
if _, ok := T.(*types.Slice); ok {
|
||
return true
|
||
}
|
||
}
|
||
|
||
if flags&isAny != 0 {
|
||
return true
|
||
}
|
||
|
||
elems, ok := elem(T.Underlying(), verb)
|
||
if !ok {
|
||
return false
|
||
}
|
||
for _, elem := range elems {
|
||
if !checkType(verb, elem, false) {
|
||
return false
|
||
}
|
||
}
|
||
|
||
return true
|
||
}
|
||
|
||
k, ok := f.(*ir.Const)
|
||
if !ok {
|
||
return
|
||
}
|
||
actions, err := printf.Parse(constant.StringVal(k.Value))
|
||
if err != nil {
|
||
carg.Invalid("couldn't parse format string")
|
||
return
|
||
}
|
||
|
||
ptr := 1
|
||
hasExplicit := false
|
||
|
||
checkStar := func(verb printf.Verb, star printf.Argument) bool {
|
||
if star, ok := star.(printf.Star); ok {
|
||
idx := 0
|
||
if star.Index == -1 {
|
||
idx = ptr
|
||
ptr++
|
||
} else {
|
||
hasExplicit = true
|
||
idx = star.Index
|
||
ptr = star.Index + 1
|
||
}
|
||
if idx == 0 {
|
||
carg.Invalid(fmt.Sprintf("Printf format %s reads invalid arg 0; indices are 1-based", verb.Raw))
|
||
return false
|
||
}
|
||
if idx > len(args) {
|
||
carg.Invalid(
|
||
fmt.Sprintf("Printf format %s reads arg #%d, but call has only %d args",
|
||
verb.Raw, idx, len(args)))
|
||
return false
|
||
}
|
||
if arg, ok := args[idx-1].(*ir.MakeInterface); ok {
|
||
if !isInfo(arg.X.Type(), types.IsInteger) {
|
||
carg.Invalid(fmt.Sprintf("Printf format %s reads non-int arg #%d as argument of *", verb.Raw, idx))
|
||
}
|
||
}
|
||
}
|
||
return true
|
||
}
|
||
|
||
// We only report one problem per format string. Making a
|
||
// mistake with an index tends to invalidate all future
|
||
// implicit indices.
|
||
for _, action := range actions {
|
||
verb, ok := action.(printf.Verb)
|
||
if !ok {
|
||
continue
|
||
}
|
||
|
||
if !checkStar(verb, verb.Width) || !checkStar(verb, verb.Precision) {
|
||
return
|
||
}
|
||
|
||
off := ptr
|
||
if verb.Value != -1 {
|
||
hasExplicit = true
|
||
off = verb.Value
|
||
}
|
||
if off > len(args) {
|
||
carg.Invalid(
|
||
fmt.Sprintf("Printf format %s reads arg #%d, but call has only %d args",
|
||
verb.Raw, off, len(args)))
|
||
return
|
||
} else if verb.Value == 0 && verb.Letter != '%' {
|
||
carg.Invalid(fmt.Sprintf("Printf format %s reads invalid arg 0; indices are 1-based", verb.Raw))
|
||
return
|
||
} else if off != 0 {
|
||
arg, ok := args[off-1].(*ir.MakeInterface)
|
||
if ok {
|
||
if !checkType(verb.Letter, arg.X.Type(), true) {
|
||
carg.Invalid(fmt.Sprintf("Printf format %s has arg #%d of wrong type %s",
|
||
verb.Raw, ptr, args[ptr-1].(*ir.MakeInterface).X.Type()))
|
||
return
|
||
}
|
||
}
|
||
}
|
||
|
||
switch verb.Value {
|
||
case -1:
|
||
// Consume next argument
|
||
ptr++
|
||
case 0:
|
||
// Don't consume any arguments
|
||
default:
|
||
ptr = verb.Value + 1
|
||
}
|
||
}
|
||
|
||
if !hasExplicit && ptr <= len(args) {
|
||
carg.Invalid(fmt.Sprintf("Printf call needs %d args but has %d args", ptr-1, len(args)))
|
||
}
|
||
}
|
||
|
||
func checkAtomicAlignmentImpl(call *Call) {
|
||
sizes := call.Pass.TypesSizes
|
||
if sizes.Sizeof(types.Typ[types.Uintptr]) != 4 {
|
||
// Not running on a 32-bit platform
|
||
return
|
||
}
|
||
v, ok := call.Args[0].Value.Value.(*ir.FieldAddr)
|
||
if !ok {
|
||
// TODO(dh): also check indexing into arrays and slices
|
||
return
|
||
}
|
||
T := v.X.Type().Underlying().(*types.Pointer).Elem().Underlying().(*types.Struct)
|
||
fields := make([]*types.Var, 0, T.NumFields())
|
||
for i := 0; i < T.NumFields() && i <= v.Field; i++ {
|
||
fields = append(fields, T.Field(i))
|
||
}
|
||
|
||
off := sizes.Offsetsof(fields)[v.Field]
|
||
if off%8 != 0 {
|
||
msg := fmt.Sprintf("address of non 64-bit aligned field %s passed to %s",
|
||
T.Field(v.Field).Name(),
|
||
code.CallName(call.Instr.Common()))
|
||
call.Invalid(msg)
|
||
}
|
||
}
|
||
|
||
func checkNoopMarshalImpl(argN int, meths ...string) CallCheck {
|
||
return func(call *Call) {
|
||
if code.IsGenerated(call.Pass, call.Instr.Pos()) {
|
||
return
|
||
}
|
||
arg := call.Args[argN]
|
||
T := arg.Value.Value.Type()
|
||
Ts, ok := code.Dereference(T).Underlying().(*types.Struct)
|
||
if !ok {
|
||
return
|
||
}
|
||
if Ts.NumFields() == 0 {
|
||
return
|
||
}
|
||
fields := code.FlattenFields(Ts)
|
||
for _, field := range fields {
|
||
if field.Var.Exported() {
|
||
return
|
||
}
|
||
}
|
||
// OPT(dh): we could use a method set cache here
|
||
ms := call.Instr.Parent().Prog.MethodSets.MethodSet(T)
|
||
// TODO(dh): we're not checking the signature, which can cause false negatives.
|
||
// This isn't a huge problem, however, since vet complains about incorrect signatures.
|
||
for _, meth := range meths {
|
||
if ms.Lookup(nil, meth) != nil {
|
||
return
|
||
}
|
||
}
|
||
arg.Invalid("struct doesn't have any exported fields, nor custom marshaling")
|
||
}
|
||
}
|
||
|
||
func checkUnsupportedMarshalImpl(argN int, tag string, meths ...string) CallCheck {
|
||
// TODO(dh): flag slices and maps of unsupported types
|
||
return func(call *Call) {
|
||
msCache := &call.Instr.Parent().Prog.MethodSets
|
||
|
||
arg := call.Args[argN]
|
||
T := arg.Value.Value.Type()
|
||
Ts, ok := code.Dereference(T).Underlying().(*types.Struct)
|
||
if !ok {
|
||
return
|
||
}
|
||
ms := msCache.MethodSet(T)
|
||
// TODO(dh): we're not checking the signature, which can cause false negatives.
|
||
// This isn't a huge problem, however, since vet complains about incorrect signatures.
|
||
for _, meth := range meths {
|
||
if ms.Lookup(nil, meth) != nil {
|
||
return
|
||
}
|
||
}
|
||
fields := code.FlattenFields(Ts)
|
||
for _, field := range fields {
|
||
if !(field.Var.Exported()) {
|
||
continue
|
||
}
|
||
if reflect.StructTag(field.Tag).Get(tag) == "-" {
|
||
continue
|
||
}
|
||
ms := msCache.MethodSet(field.Var.Type())
|
||
// TODO(dh): we're not checking the signature, which can cause false negatives.
|
||
// This isn't a huge problem, however, since vet complains about incorrect signatures.
|
||
for _, meth := range meths {
|
||
if ms.Lookup(nil, meth) != nil {
|
||
return
|
||
}
|
||
}
|
||
switch field.Var.Type().Underlying().(type) {
|
||
case *types.Chan, *types.Signature:
|
||
arg.Invalid(fmt.Sprintf("trying to marshal chan or func value, field %s", fieldPath(T, field.Path)))
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
func fieldPath(start types.Type, indices []int) string {
|
||
p := start.String()
|
||
for _, idx := range indices {
|
||
field := code.Dereference(start).Underlying().(*types.Struct).Field(idx)
|
||
start = field.Type()
|
||
p += "." + field.Name()
|
||
}
|
||
return p
|
||
}
|
||
|
||
func isInLoop(b *ir.BasicBlock) bool {
|
||
sets := functions.FindLoops(b.Parent())
|
||
for _, set := range sets {
|
||
if set.Has(b) {
|
||
return true
|
||
}
|
||
}
|
||
return false
|
||
}
|
||
|
||
func CheckUntrappableSignal(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
call := node.(*ast.CallExpr)
|
||
if !code.IsCallToAnyAST(pass, call,
|
||
"os/signal.Ignore", "os/signal.Notify", "os/signal.Reset") {
|
||
return
|
||
}
|
||
|
||
hasSigterm := false
|
||
for _, arg := range call.Args {
|
||
if conv, ok := arg.(*ast.CallExpr); ok && isName(pass, conv.Fun, "os.Signal") {
|
||
arg = conv.Args[0]
|
||
}
|
||
|
||
if isName(pass, arg, "syscall.SIGTERM") {
|
||
hasSigterm = true
|
||
break
|
||
}
|
||
|
||
}
|
||
for i, arg := range call.Args {
|
||
if conv, ok := arg.(*ast.CallExpr); ok && isName(pass, conv.Fun, "os.Signal") {
|
||
arg = conv.Args[0]
|
||
}
|
||
|
||
if isName(pass, arg, "os.Kill") || isName(pass, arg, "syscall.SIGKILL") {
|
||
var fixes []analysis.SuggestedFix
|
||
if !hasSigterm {
|
||
nargs := make([]ast.Expr, len(call.Args))
|
||
for j, a := range call.Args {
|
||
if i == j {
|
||
nargs[j] = Selector("syscall", "SIGTERM")
|
||
} else {
|
||
nargs[j] = a
|
||
}
|
||
}
|
||
ncall := *call
|
||
ncall.Args = nargs
|
||
fixes = append(fixes, edit.Fix(fmt.Sprintf("use syscall.SIGTERM instead of %s", report.Render(pass, arg)), edit.ReplaceWithNode(pass.Fset, call, &ncall)))
|
||
}
|
||
nargs := make([]ast.Expr, 0, len(call.Args))
|
||
for j, a := range call.Args {
|
||
if i == j {
|
||
continue
|
||
}
|
||
nargs = append(nargs, a)
|
||
}
|
||
ncall := *call
|
||
ncall.Args = nargs
|
||
fixes = append(fixes, edit.Fix(fmt.Sprintf("remove %s from list of arguments", report.Render(pass, arg)), edit.ReplaceWithNode(pass.Fset, call, &ncall)))
|
||
report.Report(pass, arg, fmt.Sprintf("%s cannot be trapped (did you mean syscall.SIGTERM?)", report.Render(pass, arg)), report.Fixes(fixes...))
|
||
}
|
||
if isName(pass, arg, "syscall.SIGSTOP") {
|
||
nargs := make([]ast.Expr, 0, len(call.Args)-1)
|
||
for j, a := range call.Args {
|
||
if i == j {
|
||
continue
|
||
}
|
||
nargs = append(nargs, a)
|
||
}
|
||
ncall := *call
|
||
ncall.Args = nargs
|
||
report.Report(pass, arg, "syscall.SIGSTOP cannot be trapped", report.Fixes(edit.Fix("remove syscall.SIGSTOP from list of arguments", edit.ReplaceWithNode(pass.Fset, call, &ncall))))
|
||
}
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.CallExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckTemplate(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
call := node.(*ast.CallExpr)
|
||
var kind string
|
||
switch code.CallNameAST(pass, call) {
|
||
case "(*text/template.Template).Parse":
|
||
kind = "text"
|
||
case "(*html/template.Template).Parse":
|
||
kind = "html"
|
||
default:
|
||
return
|
||
}
|
||
sel := call.Fun.(*ast.SelectorExpr)
|
||
if !code.IsCallToAnyAST(pass, sel.X, "text/template.New", "html/template.New") {
|
||
// TODO(dh): this is a cheap workaround for templates with
|
||
// different delims. A better solution with less false
|
||
// negatives would use data flow analysis to see where the
|
||
// template comes from and where it has been
|
||
return
|
||
}
|
||
s, ok := code.ExprToString(pass, call.Args[Arg("(*text/template.Template).Parse.text")])
|
||
if !ok {
|
||
return
|
||
}
|
||
var err error
|
||
switch kind {
|
||
case "text":
|
||
_, err = texttemplate.New("").Parse(s)
|
||
case "html":
|
||
_, err = htmltemplate.New("").Parse(s)
|
||
}
|
||
if err != nil {
|
||
// TODO(dominikh): whitelist other parse errors, if any
|
||
if strings.Contains(err.Error(), "unexpected") {
|
||
report.Report(pass, call.Args[Arg("(*text/template.Template).Parse.text")], err.Error())
|
||
}
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.CallExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
var (
|
||
checkTimeSleepConstantPatternRns = pattern.MustParse(`(BinaryExpr duration "*" (SelectorExpr (Ident "time") (Ident "Nanosecond")))`)
|
||
checkTimeSleepConstantPatternRs = pattern.MustParse(`(BinaryExpr duration "*" (SelectorExpr (Ident "time") (Ident "Second")))`)
|
||
)
|
||
|
||
func CheckTimeSleepConstant(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
call := node.(*ast.CallExpr)
|
||
if !code.IsCallToAST(pass, call, "time.Sleep") {
|
||
return
|
||
}
|
||
lit, ok := call.Args[Arg("time.Sleep.d")].(*ast.BasicLit)
|
||
if !ok {
|
||
return
|
||
}
|
||
n, err := strconv.Atoi(lit.Value)
|
||
if err != nil {
|
||
return
|
||
}
|
||
if n == 0 || n > 120 {
|
||
// time.Sleep(0) is a seldom used pattern in concurrency
|
||
// tests. >120 might be intentional. 120 was chosen
|
||
// because the user could've meant 2 minutes.
|
||
return
|
||
}
|
||
|
||
report.Report(pass, lit,
|
||
fmt.Sprintf("sleeping for %d nanoseconds is probably a bug; be explicit if it isn't", n), report.Fixes(
|
||
edit.Fix("explicitly use nanoseconds", edit.ReplaceWithPattern(pass, checkTimeSleepConstantPatternRns, pattern.State{"duration": lit}, lit)),
|
||
edit.Fix("use seconds", edit.ReplaceWithPattern(pass, checkTimeSleepConstantPatternRs, pattern.State{"duration": lit}, lit))))
|
||
}
|
||
code.Preorder(pass, fn, (*ast.CallExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
var checkWaitgroupAddQ = pattern.MustParse(`
|
||
(GoStmt
|
||
(CallExpr
|
||
(FuncLit
|
||
_
|
||
call@(CallExpr (Function "(*sync.WaitGroup).Add") _):_) _))`)
|
||
|
||
func CheckWaitgroupAdd(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
if m, ok := Match(pass, checkWaitgroupAddQ, node); ok {
|
||
call := m.State["call"].(ast.Node)
|
||
report.Report(pass, call, fmt.Sprintf("should call %s before starting the goroutine to avoid a race", report.Render(pass, call)))
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.GoStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckInfiniteEmptyLoop(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
loop := node.(*ast.ForStmt)
|
||
if len(loop.Body.List) != 0 || loop.Post != nil {
|
||
return
|
||
}
|
||
|
||
if loop.Init != nil {
|
||
// TODO(dh): this isn't strictly necessary, it just makes
|
||
// the check easier.
|
||
return
|
||
}
|
||
// An empty loop is bad news in two cases: 1) The loop has no
|
||
// condition. In that case, it's just a loop that spins
|
||
// forever and as fast as it can, keeping a core busy. 2) The
|
||
// loop condition only consists of variable or field reads and
|
||
// operators on those. The only way those could change their
|
||
// value is with unsynchronised access, which constitutes a
|
||
// data race.
|
||
//
|
||
// If the condition contains any function calls, its behaviour
|
||
// is dynamic and the loop might terminate. Similarly for
|
||
// channel receives.
|
||
|
||
if loop.Cond != nil {
|
||
if code.MayHaveSideEffects(pass, loop.Cond, nil) {
|
||
return
|
||
}
|
||
if ident, ok := loop.Cond.(*ast.Ident); ok {
|
||
if k, ok := pass.TypesInfo.ObjectOf(ident).(*types.Const); ok {
|
||
if !constant.BoolVal(k.Val()) {
|
||
// don't flag `for false {}` loops. They're a debug aid.
|
||
return
|
||
}
|
||
}
|
||
}
|
||
report.Report(pass, loop, "loop condition never changes or has a race condition")
|
||
}
|
||
report.Report(pass, loop, "this loop will spin, using 100%% CPU", report.ShortRange())
|
||
}
|
||
code.Preorder(pass, fn, (*ast.ForStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckDeferInInfiniteLoop(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
mightExit := false
|
||
var defers []ast.Stmt
|
||
loop := node.(*ast.ForStmt)
|
||
if loop.Cond != nil {
|
||
return
|
||
}
|
||
fn2 := func(node ast.Node) bool {
|
||
switch stmt := node.(type) {
|
||
case *ast.ReturnStmt:
|
||
mightExit = true
|
||
return false
|
||
case *ast.BranchStmt:
|
||
// TODO(dominikh): if this sees a break in a switch or
|
||
// select, it doesn't check if it breaks the loop or
|
||
// just the select/switch. This causes some false
|
||
// negatives.
|
||
if stmt.Tok == token.BREAK {
|
||
mightExit = true
|
||
return false
|
||
}
|
||
case *ast.DeferStmt:
|
||
defers = append(defers, stmt)
|
||
case *ast.FuncLit:
|
||
// Don't look into function bodies
|
||
return false
|
||
}
|
||
return true
|
||
}
|
||
ast.Inspect(loop.Body, fn2)
|
||
if mightExit {
|
||
return
|
||
}
|
||
for _, stmt := range defers {
|
||
report.Report(pass, stmt, "defers in this infinite loop will never run")
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.ForStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckDubiousDeferInChannelRangeLoop(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
loop := node.(*ast.RangeStmt)
|
||
typ := pass.TypesInfo.TypeOf(loop.X)
|
||
_, ok := typ.Underlying().(*types.Chan)
|
||
if !ok {
|
||
return
|
||
}
|
||
fn2 := func(node ast.Node) bool {
|
||
switch stmt := node.(type) {
|
||
case *ast.DeferStmt:
|
||
report.Report(pass, stmt, "defers in this range loop won't run unless the channel gets closed")
|
||
case *ast.FuncLit:
|
||
// Don't look into function bodies
|
||
return false
|
||
}
|
||
return true
|
||
}
|
||
ast.Inspect(loop.Body, fn2)
|
||
}
|
||
code.Preorder(pass, fn, (*ast.RangeStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckTestMainExit(pass *analysis.Pass) (interface{}, error) {
|
||
var (
|
||
fnmain ast.Node
|
||
callsExit bool
|
||
callsRun bool
|
||
arg types.Object
|
||
)
|
||
fn := func(node ast.Node, push bool) bool {
|
||
if !push {
|
||
if fnmain != nil && node == fnmain {
|
||
if !callsExit && callsRun {
|
||
report.Report(pass, fnmain, "TestMain should call os.Exit to set exit code")
|
||
}
|
||
fnmain = nil
|
||
callsExit = false
|
||
callsRun = false
|
||
arg = nil
|
||
}
|
||
return true
|
||
}
|
||
|
||
switch node := node.(type) {
|
||
case *ast.FuncDecl:
|
||
if fnmain != nil {
|
||
return true
|
||
}
|
||
if !isTestMain(pass, node) {
|
||
return false
|
||
}
|
||
fnmain = node
|
||
arg = pass.TypesInfo.ObjectOf(node.Type.Params.List[0].Names[0])
|
||
return true
|
||
case *ast.CallExpr:
|
||
if code.IsCallToAST(pass, node, "os.Exit") {
|
||
callsExit = true
|
||
return false
|
||
}
|
||
sel, ok := node.Fun.(*ast.SelectorExpr)
|
||
if !ok {
|
||
return true
|
||
}
|
||
ident, ok := sel.X.(*ast.Ident)
|
||
if !ok {
|
||
return true
|
||
}
|
||
if arg != pass.TypesInfo.ObjectOf(ident) {
|
||
return true
|
||
}
|
||
if sel.Sel.Name == "Run" {
|
||
callsRun = true
|
||
return false
|
||
}
|
||
return true
|
||
default:
|
||
ExhaustiveTypeSwitch(node)
|
||
return true
|
||
}
|
||
}
|
||
pass.ResultOf[inspect.Analyzer].(*inspector.Inspector).Nodes([]ast.Node{(*ast.FuncDecl)(nil), (*ast.CallExpr)(nil)}, fn)
|
||
return nil, nil
|
||
}
|
||
|
||
func isTestMain(pass *analysis.Pass, decl *ast.FuncDecl) bool {
|
||
if decl.Name.Name != "TestMain" {
|
||
return false
|
||
}
|
||
if len(decl.Type.Params.List) != 1 {
|
||
return false
|
||
}
|
||
arg := decl.Type.Params.List[0]
|
||
if len(arg.Names) != 1 {
|
||
return false
|
||
}
|
||
return code.IsOfType(pass, arg.Type, "*testing.M")
|
||
}
|
||
|
||
func CheckExec(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
call := node.(*ast.CallExpr)
|
||
if !code.IsCallToAST(pass, call, "os/exec.Command") {
|
||
return
|
||
}
|
||
val, ok := code.ExprToString(pass, call.Args[Arg("os/exec.Command.name")])
|
||
if !ok {
|
||
return
|
||
}
|
||
if !strings.Contains(val, " ") || strings.Contains(val, `\`) || strings.Contains(val, "/") {
|
||
return
|
||
}
|
||
report.Report(pass, call.Args[Arg("os/exec.Command.name")],
|
||
"first argument to exec.Command looks like a shell command, but a program name or path are expected")
|
||
}
|
||
code.Preorder(pass, fn, (*ast.CallExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckLoopEmptyDefault(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
loop := node.(*ast.ForStmt)
|
||
if len(loop.Body.List) != 1 || loop.Cond != nil || loop.Init != nil {
|
||
return
|
||
}
|
||
sel, ok := loop.Body.List[0].(*ast.SelectStmt)
|
||
if !ok {
|
||
return
|
||
}
|
||
for _, c := range sel.Body.List {
|
||
// FIXME this leaves behind an empty line, and possibly
|
||
// comments in the default branch. We can't easily fix
|
||
// either.
|
||
if comm, ok := c.(*ast.CommClause); ok && comm.Comm == nil && len(comm.Body) == 0 {
|
||
report.Report(pass, comm, "should not have an empty default case in a for+select loop; the loop will spin",
|
||
report.Fixes(edit.Fix("remove empty default branch", edit.Delete(comm))))
|
||
// there can only be one default case
|
||
break
|
||
}
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.ForStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckLhsRhsIdentical(pass *analysis.Pass) (interface{}, error) {
|
||
var isFloat func(T types.Type) bool
|
||
isFloat = func(T types.Type) bool {
|
||
switch T := T.Underlying().(type) {
|
||
case *types.Basic:
|
||
kind := T.Kind()
|
||
return kind == types.Float32 || kind == types.Float64
|
||
case *types.Array:
|
||
return isFloat(T.Elem())
|
||
case *types.Struct:
|
||
for i := 0; i < T.NumFields(); i++ {
|
||
if !isFloat(T.Field(i).Type()) {
|
||
return false
|
||
}
|
||
}
|
||
return true
|
||
default:
|
||
return false
|
||
}
|
||
}
|
||
|
||
// TODO(dh): this check ignores the existence of side-effects and
|
||
// happily flags fn() == fn() – so far, we've had nobody complain
|
||
// about a false positive, and it's caught several bugs in real
|
||
// code.
|
||
fn := func(node ast.Node) {
|
||
op := node.(*ast.BinaryExpr)
|
||
switch op.Op {
|
||
case token.EQL, token.NEQ:
|
||
if isFloat(pass.TypesInfo.TypeOf(op.X)) {
|
||
// f == f and f != f might be used to check for NaN
|
||
return
|
||
}
|
||
case token.SUB, token.QUO, token.AND, token.REM, token.OR, token.XOR, token.AND_NOT,
|
||
token.LAND, token.LOR, token.LSS, token.GTR, token.LEQ, token.GEQ:
|
||
default:
|
||
// For some ops, such as + and *, it can make sense to
|
||
// have identical operands
|
||
return
|
||
}
|
||
|
||
if reflect.TypeOf(op.X) != reflect.TypeOf(op.Y) {
|
||
return
|
||
}
|
||
if report.Render(pass, op.X) != report.Render(pass, op.Y) {
|
||
return
|
||
}
|
||
l1, ok1 := op.X.(*ast.BasicLit)
|
||
l2, ok2 := op.Y.(*ast.BasicLit)
|
||
if ok1 && ok2 && l1.Kind == token.INT && l2.Kind == l1.Kind && l1.Value == "0" && l2.Value == l1.Value && code.IsGenerated(pass, l1.Pos()) {
|
||
// cgo generates the following function call:
|
||
// _cgoCheckPointer(_cgoBase0, 0 == 0) – it uses 0 == 0
|
||
// instead of true in case the user shadowed the
|
||
// identifier. Ideally we'd restrict this exception to
|
||
// calls of _cgoCheckPointer, but it's not worth the
|
||
// hassle of keeping track of the stack. <lit> <op> <lit>
|
||
// are very rare to begin with, and we're mostly checking
|
||
// for them to catch typos such as 1 == 1 where the user
|
||
// meant to type i == 1. The odds of a false negative for
|
||
// 0 == 0 are slim.
|
||
return
|
||
}
|
||
report.Report(pass, op, fmt.Sprintf("identical expressions on the left and right side of the '%s' operator", op.Op))
|
||
}
|
||
code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckScopedBreak(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
var body *ast.BlockStmt
|
||
switch node := node.(type) {
|
||
case *ast.ForStmt:
|
||
body = node.Body
|
||
case *ast.RangeStmt:
|
||
body = node.Body
|
||
default:
|
||
ExhaustiveTypeSwitch(node)
|
||
}
|
||
for _, stmt := range body.List {
|
||
var blocks [][]ast.Stmt
|
||
switch stmt := stmt.(type) {
|
||
case *ast.SwitchStmt:
|
||
for _, c := range stmt.Body.List {
|
||
blocks = append(blocks, c.(*ast.CaseClause).Body)
|
||
}
|
||
case *ast.SelectStmt:
|
||
for _, c := range stmt.Body.List {
|
||
blocks = append(blocks, c.(*ast.CommClause).Body)
|
||
}
|
||
default:
|
||
continue
|
||
}
|
||
|
||
for _, body := range blocks {
|
||
if len(body) == 0 {
|
||
continue
|
||
}
|
||
lasts := []ast.Stmt{body[len(body)-1]}
|
||
// TODO(dh): unfold all levels of nested block
|
||
// statements, not just a single level if statement
|
||
if ifs, ok := lasts[0].(*ast.IfStmt); ok {
|
||
if len(ifs.Body.List) == 0 {
|
||
continue
|
||
}
|
||
lasts[0] = ifs.Body.List[len(ifs.Body.List)-1]
|
||
|
||
if block, ok := ifs.Else.(*ast.BlockStmt); ok {
|
||
if len(block.List) != 0 {
|
||
lasts = append(lasts, block.List[len(block.List)-1])
|
||
}
|
||
}
|
||
}
|
||
for _, last := range lasts {
|
||
branch, ok := last.(*ast.BranchStmt)
|
||
if !ok || branch.Tok != token.BREAK || branch.Label != nil {
|
||
continue
|
||
}
|
||
report.Report(pass, branch, "ineffective break statement. Did you mean to break out of the outer loop?")
|
||
}
|
||
}
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.ForStmt)(nil), (*ast.RangeStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckUnsafePrintf(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
call := node.(*ast.CallExpr)
|
||
name := code.CallNameAST(pass, call)
|
||
var arg int
|
||
|
||
switch name {
|
||
case "fmt.Printf", "fmt.Sprintf", "log.Printf":
|
||
arg = Arg("fmt.Printf.format")
|
||
case "fmt.Fprintf":
|
||
arg = Arg("fmt.Fprintf.format")
|
||
default:
|
||
return
|
||
}
|
||
if len(call.Args) != arg+1 {
|
||
return
|
||
}
|
||
switch call.Args[arg].(type) {
|
||
case *ast.CallExpr, *ast.Ident:
|
||
default:
|
||
return
|
||
}
|
||
|
||
alt := name[:len(name)-1]
|
||
report.Report(pass, call,
|
||
"printf-style function with dynamic format string and no further arguments should use print-style function instead",
|
||
report.Fixes(edit.Fix(fmt.Sprintf("use %s instead of %s", alt, name), edit.ReplaceWithString(pass.Fset, call.Fun, alt))))
|
||
}
|
||
code.Preorder(pass, fn, (*ast.CallExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckEarlyDefer(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
block := node.(*ast.BlockStmt)
|
||
if len(block.List) < 2 {
|
||
return
|
||
}
|
||
for i, stmt := range block.List {
|
||
if i == len(block.List)-1 {
|
||
break
|
||
}
|
||
assign, ok := stmt.(*ast.AssignStmt)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if len(assign.Rhs) != 1 {
|
||
continue
|
||
}
|
||
if len(assign.Lhs) < 2 {
|
||
continue
|
||
}
|
||
if lhs, ok := assign.Lhs[len(assign.Lhs)-1].(*ast.Ident); ok && lhs.Name == "_" {
|
||
continue
|
||
}
|
||
call, ok := assign.Rhs[0].(*ast.CallExpr)
|
||
if !ok {
|
||
continue
|
||
}
|
||
sig, ok := pass.TypesInfo.TypeOf(call.Fun).(*types.Signature)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if sig.Results().Len() < 2 {
|
||
continue
|
||
}
|
||
last := sig.Results().At(sig.Results().Len() - 1)
|
||
// FIXME(dh): check that it's error from universe, not
|
||
// another type of the same name
|
||
if last.Type().String() != "error" {
|
||
continue
|
||
}
|
||
lhs, ok := assign.Lhs[0].(*ast.Ident)
|
||
if !ok {
|
||
continue
|
||
}
|
||
def, ok := block.List[i+1].(*ast.DeferStmt)
|
||
if !ok {
|
||
continue
|
||
}
|
||
sel, ok := def.Call.Fun.(*ast.SelectorExpr)
|
||
if !ok {
|
||
continue
|
||
}
|
||
ident, ok := selectorX(sel).(*ast.Ident)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if ident.Obj != lhs.Obj {
|
||
continue
|
||
}
|
||
if sel.Sel.Name != "Close" {
|
||
continue
|
||
}
|
||
report.Report(pass, def, fmt.Sprintf("should check returned error before deferring %s", report.Render(pass, def.Call)))
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.BlockStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func selectorX(sel *ast.SelectorExpr) ast.Node {
|
||
switch x := sel.X.(type) {
|
||
case *ast.SelectorExpr:
|
||
return selectorX(x)
|
||
default:
|
||
return x
|
||
}
|
||
}
|
||
|
||
func CheckEmptyCriticalSection(pass *analysis.Pass) (interface{}, error) {
|
||
if pass.Pkg.Path() == "sync_test" {
|
||
// exception for the sync package's tests
|
||
return nil, nil
|
||
}
|
||
|
||
// Initially it might seem like this check would be easier to
|
||
// implement using IR. After all, we're only checking for two
|
||
// consecutive method calls. In reality, however, there may be any
|
||
// number of other instructions between the lock and unlock, while
|
||
// still constituting an empty critical section. For example,
|
||
// given `m.x().Lock(); m.x().Unlock()`, there will be a call to
|
||
// x(). In the AST-based approach, this has a tiny potential for a
|
||
// false positive (the second call to x might be doing work that
|
||
// is protected by the mutex). In an IR-based approach, however,
|
||
// it would miss a lot of real bugs.
|
||
|
||
mutexParams := func(s ast.Stmt) (x ast.Expr, funcName string, ok bool) {
|
||
expr, ok := s.(*ast.ExprStmt)
|
||
if !ok {
|
||
return nil, "", false
|
||
}
|
||
call, ok := expr.X.(*ast.CallExpr)
|
||
if !ok {
|
||
return nil, "", false
|
||
}
|
||
sel, ok := call.Fun.(*ast.SelectorExpr)
|
||
if !ok {
|
||
return nil, "", false
|
||
}
|
||
|
||
fn, ok := pass.TypesInfo.ObjectOf(sel.Sel).(*types.Func)
|
||
if !ok {
|
||
return nil, "", false
|
||
}
|
||
sig := fn.Type().(*types.Signature)
|
||
if sig.Params().Len() != 0 || sig.Results().Len() != 0 {
|
||
return nil, "", false
|
||
}
|
||
|
||
return sel.X, fn.Name(), true
|
||
}
|
||
|
||
fn := func(node ast.Node) {
|
||
block := node.(*ast.BlockStmt)
|
||
if len(block.List) < 2 {
|
||
return
|
||
}
|
||
for i := range block.List[:len(block.List)-1] {
|
||
sel1, method1, ok1 := mutexParams(block.List[i])
|
||
sel2, method2, ok2 := mutexParams(block.List[i+1])
|
||
|
||
if !ok1 || !ok2 || report.Render(pass, sel1) != report.Render(pass, sel2) {
|
||
continue
|
||
}
|
||
if (method1 == "Lock" && method2 == "Unlock") ||
|
||
(method1 == "RLock" && method2 == "RUnlock") {
|
||
report.Report(pass, block.List[i+1], "empty critical section")
|
||
}
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.BlockStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
var (
|
||
// cgo produces code like fn(&*_Cvar_kSomeCallbacks) which we don't
|
||
// want to flag.
|
||
cgoIdent = regexp.MustCompile(`^_C(func|var)_.+$`)
|
||
checkIneffectiveCopyQ1 = pattern.MustParse(`(UnaryExpr "&" (StarExpr obj))`)
|
||
checkIneffectiveCopyQ2 = pattern.MustParse(`(StarExpr (UnaryExpr "&" _))`)
|
||
)
|
||
|
||
func CheckIneffectiveCopy(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
if m, ok := Match(pass, checkIneffectiveCopyQ1, node); ok {
|
||
if ident, ok := m.State["obj"].(*ast.Ident); !ok || !cgoIdent.MatchString(ident.Name) {
|
||
report.Report(pass, node, "&*x will be simplified to x. It will not copy x.")
|
||
}
|
||
} else if _, ok := Match(pass, checkIneffectiveCopyQ2, node); ok {
|
||
report.Report(pass, node, "*&x will be simplified to x. It will not copy x.")
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.UnaryExpr)(nil), (*ast.StarExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckCanonicalHeaderKey(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node, push bool) bool {
|
||
if !push {
|
||
return false
|
||
}
|
||
assign, ok := node.(*ast.AssignStmt)
|
||
if ok {
|
||
// TODO(dh): This risks missing some Header reads, for
|
||
// example in `h1["foo"] = h2["foo"]` – these edge
|
||
// cases are probably rare enough to ignore for now.
|
||
for _, expr := range assign.Lhs {
|
||
op, ok := expr.(*ast.IndexExpr)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if code.IsOfType(pass, op.X, "net/http.Header") {
|
||
return false
|
||
}
|
||
}
|
||
return true
|
||
}
|
||
op, ok := node.(*ast.IndexExpr)
|
||
if !ok {
|
||
return true
|
||
}
|
||
if !code.IsOfType(pass, op.X, "net/http.Header") {
|
||
return true
|
||
}
|
||
s, ok := code.ExprToString(pass, op.Index)
|
||
if !ok {
|
||
return true
|
||
}
|
||
canonical := http.CanonicalHeaderKey(s)
|
||
if s == canonical {
|
||
return true
|
||
}
|
||
var fix analysis.SuggestedFix
|
||
switch op.Index.(type) {
|
||
case *ast.BasicLit:
|
||
fix = edit.Fix("canonicalize header key", edit.ReplaceWithString(pass.Fset, op.Index, strconv.Quote(canonical)))
|
||
case *ast.Ident:
|
||
call := &ast.CallExpr{
|
||
Fun: Selector("http", "CanonicalHeaderKey"),
|
||
Args: []ast.Expr{op.Index},
|
||
}
|
||
fix = edit.Fix("wrap in http.CanonicalHeaderKey", edit.ReplaceWithNode(pass.Fset, op.Index, call))
|
||
}
|
||
msg := fmt.Sprintf("keys in http.Header are canonicalized, %q is not canonical; fix the constant or use http.CanonicalHeaderKey", s)
|
||
if fix.Message != "" {
|
||
report.Report(pass, op, msg, report.Fixes(fix))
|
||
} else {
|
||
report.Report(pass, op, msg)
|
||
}
|
||
return true
|
||
}
|
||
pass.ResultOf[inspect.Analyzer].(*inspector.Inspector).Nodes([]ast.Node{(*ast.AssignStmt)(nil), (*ast.IndexExpr)(nil)}, fn)
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckBenchmarkN(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
assign := node.(*ast.AssignStmt)
|
||
if len(assign.Lhs) != 1 || len(assign.Rhs) != 1 {
|
||
return
|
||
}
|
||
sel, ok := assign.Lhs[0].(*ast.SelectorExpr)
|
||
if !ok {
|
||
return
|
||
}
|
||
if sel.Sel.Name != "N" {
|
||
return
|
||
}
|
||
if !code.IsOfType(pass, sel.X, "*testing.B") {
|
||
return
|
||
}
|
||
report.Report(pass, assign, fmt.Sprintf("should not assign to %s", report.Render(pass, sel)))
|
||
}
|
||
code.Preorder(pass, fn, (*ast.AssignStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckUnreadVariableValues(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
if code.IsExample(fn) {
|
||
continue
|
||
}
|
||
node := fn.Source()
|
||
if node == nil {
|
||
continue
|
||
}
|
||
if gen, ok := code.Generator(pass, node.Pos()); ok && gen == facts.Goyacc {
|
||
// Don't flag unused values in code generated by goyacc.
|
||
// There may be hundreds of those due to the way the state
|
||
// machine is constructed.
|
||
continue
|
||
}
|
||
|
||
switchTags := map[ir.Value]struct{}{}
|
||
ast.Inspect(node, func(node ast.Node) bool {
|
||
s, ok := node.(*ast.SwitchStmt)
|
||
if !ok {
|
||
return true
|
||
}
|
||
v, _ := fn.ValueForExpr(s.Tag)
|
||
switchTags[v] = struct{}{}
|
||
return true
|
||
})
|
||
|
||
// OPT(dh): don't use a map, possibly use a bitset
|
||
var hasUse func(v ir.Value, seen map[ir.Value]struct{}) bool
|
||
hasUse = func(v ir.Value, seen map[ir.Value]struct{}) bool {
|
||
if _, ok := seen[v]; ok {
|
||
return false
|
||
}
|
||
if _, ok := switchTags[v]; ok {
|
||
return true
|
||
}
|
||
refs := v.Referrers()
|
||
if refs == nil {
|
||
// TODO investigate why refs can be nil
|
||
return true
|
||
}
|
||
for _, ref := range *refs {
|
||
switch ref := ref.(type) {
|
||
case *ir.DebugRef:
|
||
case *ir.Sigma:
|
||
if seen == nil {
|
||
seen = map[ir.Value]struct{}{}
|
||
}
|
||
seen[v] = struct{}{}
|
||
if hasUse(ref, seen) {
|
||
return true
|
||
}
|
||
case *ir.Phi:
|
||
if seen == nil {
|
||
seen = map[ir.Value]struct{}{}
|
||
}
|
||
seen[v] = struct{}{}
|
||
if hasUse(ref, seen) {
|
||
return true
|
||
}
|
||
default:
|
||
return true
|
||
}
|
||
}
|
||
return false
|
||
}
|
||
|
||
ast.Inspect(node, func(node ast.Node) bool {
|
||
assign, ok := node.(*ast.AssignStmt)
|
||
if !ok {
|
||
return true
|
||
}
|
||
if len(assign.Lhs) > 1 && len(assign.Rhs) == 1 {
|
||
// Either a function call with multiple return values,
|
||
// or a comma-ok assignment
|
||
|
||
val, _ := fn.ValueForExpr(assign.Rhs[0])
|
||
if val == nil {
|
||
return true
|
||
}
|
||
refs := val.Referrers()
|
||
if refs == nil {
|
||
return true
|
||
}
|
||
for _, ref := range *refs {
|
||
ex, ok := ref.(*ir.Extract)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if !hasUse(ex, nil) {
|
||
lhs := assign.Lhs[ex.Index]
|
||
if ident, ok := lhs.(*ast.Ident); !ok || ok && ident.Name == "_" {
|
||
continue
|
||
}
|
||
report.Report(pass, assign, fmt.Sprintf("this value of %s is never used", lhs))
|
||
}
|
||
}
|
||
return true
|
||
}
|
||
for i, lhs := range assign.Lhs {
|
||
rhs := assign.Rhs[i]
|
||
if ident, ok := lhs.(*ast.Ident); !ok || ok && ident.Name == "_" {
|
||
continue
|
||
}
|
||
val, _ := fn.ValueForExpr(rhs)
|
||
if val == nil {
|
||
continue
|
||
}
|
||
|
||
if !hasUse(val, nil) {
|
||
report.Report(pass, assign, fmt.Sprintf("this value of %s is never used", lhs))
|
||
}
|
||
}
|
||
return true
|
||
})
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckPredeterminedBooleanExprs(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
binop, ok := ins.(*ir.BinOp)
|
||
if !ok {
|
||
continue
|
||
}
|
||
switch binop.Op {
|
||
case token.GTR, token.LSS, token.EQL, token.NEQ, token.LEQ, token.GEQ:
|
||
default:
|
||
continue
|
||
}
|
||
|
||
xs, ok1 := consts(binop.X, nil, nil)
|
||
ys, ok2 := consts(binop.Y, nil, nil)
|
||
if !ok1 || !ok2 || len(xs) == 0 || len(ys) == 0 {
|
||
continue
|
||
}
|
||
|
||
trues := 0
|
||
for _, x := range xs {
|
||
for _, y := range ys {
|
||
if x.Value == nil {
|
||
if y.Value == nil {
|
||
trues++
|
||
}
|
||
continue
|
||
}
|
||
if constant.Compare(x.Value, binop.Op, y.Value) {
|
||
trues++
|
||
}
|
||
}
|
||
}
|
||
b := trues != 0
|
||
if trues == 0 || trues == len(xs)*len(ys) {
|
||
report.Report(pass, binop, fmt.Sprintf("binary expression is always %t for all possible values (%s %s %s)", b, xs, binop.Op, ys))
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckNilMaps(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
mu, ok := ins.(*ir.MapUpdate)
|
||
if !ok {
|
||
continue
|
||
}
|
||
c, ok := mu.Map.(*ir.Const)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if c.Value != nil {
|
||
continue
|
||
}
|
||
report.Report(pass, mu, "assignment to nil map")
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckExtremeComparison(pass *analysis.Pass) (interface{}, error) {
|
||
isobj := func(expr ast.Expr, name string) bool {
|
||
sel, ok := expr.(*ast.SelectorExpr)
|
||
if !ok {
|
||
return false
|
||
}
|
||
return code.IsObject(pass.TypesInfo.ObjectOf(sel.Sel), name)
|
||
}
|
||
|
||
fn := func(node ast.Node) {
|
||
expr := node.(*ast.BinaryExpr)
|
||
tx := pass.TypesInfo.TypeOf(expr.X)
|
||
basic, ok := tx.Underlying().(*types.Basic)
|
||
if !ok {
|
||
return
|
||
}
|
||
|
||
var max string
|
||
var min string
|
||
|
||
switch basic.Kind() {
|
||
case types.Uint8:
|
||
max = "math.MaxUint8"
|
||
case types.Uint16:
|
||
max = "math.MaxUint16"
|
||
case types.Uint32:
|
||
max = "math.MaxUint32"
|
||
case types.Uint64:
|
||
max = "math.MaxUint64"
|
||
case types.Uint:
|
||
max = "math.MaxUint64"
|
||
|
||
case types.Int8:
|
||
min = "math.MinInt8"
|
||
max = "math.MaxInt8"
|
||
case types.Int16:
|
||
min = "math.MinInt16"
|
||
max = "math.MaxInt16"
|
||
case types.Int32:
|
||
min = "math.MinInt32"
|
||
max = "math.MaxInt32"
|
||
case types.Int64:
|
||
min = "math.MinInt64"
|
||
max = "math.MaxInt64"
|
||
case types.Int:
|
||
min = "math.MinInt64"
|
||
max = "math.MaxInt64"
|
||
}
|
||
|
||
if (expr.Op == token.GTR || expr.Op == token.GEQ) && isobj(expr.Y, max) ||
|
||
(expr.Op == token.LSS || expr.Op == token.LEQ) && isobj(expr.X, max) {
|
||
report.Report(pass, expr, fmt.Sprintf("no value of type %s is greater than %s", basic, max))
|
||
}
|
||
if expr.Op == token.LEQ && isobj(expr.Y, max) ||
|
||
expr.Op == token.GEQ && isobj(expr.X, max) {
|
||
report.Report(pass, expr, fmt.Sprintf("every value of type %s is <= %s", basic, max))
|
||
}
|
||
|
||
if (basic.Info() & types.IsUnsigned) != 0 {
|
||
if (expr.Op == token.LSS && code.IsIntLiteral(expr.Y, "0")) ||
|
||
(expr.Op == token.GTR && code.IsIntLiteral(expr.X, "0")) {
|
||
report.Report(pass, expr, fmt.Sprintf("no value of type %s is less than 0", basic))
|
||
}
|
||
if expr.Op == token.GEQ && code.IsIntLiteral(expr.Y, "0") ||
|
||
expr.Op == token.LEQ && code.IsIntLiteral(expr.X, "0") {
|
||
report.Report(pass, expr, fmt.Sprintf("every value of type %s is >= 0", basic))
|
||
}
|
||
} else {
|
||
if (expr.Op == token.LSS || expr.Op == token.LEQ) && isobj(expr.Y, min) ||
|
||
(expr.Op == token.GTR || expr.Op == token.GEQ) && isobj(expr.X, min) {
|
||
report.Report(pass, expr, fmt.Sprintf("no value of type %s is less than %s", basic, min))
|
||
}
|
||
if expr.Op == token.GEQ && isobj(expr.Y, min) ||
|
||
expr.Op == token.LEQ && isobj(expr.X, min) {
|
||
report.Report(pass, expr, fmt.Sprintf("every value of type %s is >= %s", basic, min))
|
||
}
|
||
}
|
||
|
||
}
|
||
code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func consts(val ir.Value, out []*ir.Const, visitedPhis map[string]bool) ([]*ir.Const, bool) {
|
||
if visitedPhis == nil {
|
||
visitedPhis = map[string]bool{}
|
||
}
|
||
var ok bool
|
||
switch val := val.(type) {
|
||
case *ir.Phi:
|
||
if visitedPhis[val.Name()] {
|
||
break
|
||
}
|
||
visitedPhis[val.Name()] = true
|
||
vals := val.Operands(nil)
|
||
for _, phival := range vals {
|
||
out, ok = consts(*phival, out, visitedPhis)
|
||
if !ok {
|
||
return nil, false
|
||
}
|
||
}
|
||
case *ir.Const:
|
||
out = append(out, val)
|
||
case *ir.Convert:
|
||
out, ok = consts(val.X, out, visitedPhis)
|
||
if !ok {
|
||
return nil, false
|
||
}
|
||
default:
|
||
return nil, false
|
||
}
|
||
if len(out) < 2 {
|
||
return out, true
|
||
}
|
||
uniq := []*ir.Const{out[0]}
|
||
for _, val := range out[1:] {
|
||
if val.Value == uniq[len(uniq)-1].Value {
|
||
continue
|
||
}
|
||
uniq = append(uniq, val)
|
||
}
|
||
return uniq, true
|
||
}
|
||
|
||
func CheckLoopCondition(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
cb := func(node ast.Node) bool {
|
||
loop, ok := node.(*ast.ForStmt)
|
||
if !ok {
|
||
return true
|
||
}
|
||
if loop.Init == nil || loop.Cond == nil || loop.Post == nil {
|
||
return true
|
||
}
|
||
init, ok := loop.Init.(*ast.AssignStmt)
|
||
if !ok || len(init.Lhs) != 1 || len(init.Rhs) != 1 {
|
||
return true
|
||
}
|
||
cond, ok := loop.Cond.(*ast.BinaryExpr)
|
||
if !ok {
|
||
return true
|
||
}
|
||
x, ok := cond.X.(*ast.Ident)
|
||
if !ok {
|
||
return true
|
||
}
|
||
lhs, ok := init.Lhs[0].(*ast.Ident)
|
||
if !ok {
|
||
return true
|
||
}
|
||
if x.Obj != lhs.Obj {
|
||
return true
|
||
}
|
||
if _, ok := loop.Post.(*ast.IncDecStmt); !ok {
|
||
return true
|
||
}
|
||
|
||
v, isAddr := fn.ValueForExpr(cond.X)
|
||
if v == nil || isAddr {
|
||
return true
|
||
}
|
||
switch v := v.(type) {
|
||
case *ir.Phi:
|
||
ops := v.Operands(nil)
|
||
if len(ops) != 2 {
|
||
return true
|
||
}
|
||
_, ok := (*ops[0]).(*ir.Const)
|
||
if !ok {
|
||
return true
|
||
}
|
||
sigma, ok := (*ops[1]).(*ir.Sigma)
|
||
if !ok {
|
||
return true
|
||
}
|
||
if sigma.X != v {
|
||
return true
|
||
}
|
||
case *ir.Load:
|
||
return true
|
||
}
|
||
report.Report(pass, cond, "variable in loop condition never changes")
|
||
|
||
return true
|
||
}
|
||
Inspect(fn.Source(), cb)
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckArgOverwritten(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
cb := func(node ast.Node) bool {
|
||
var typ *ast.FuncType
|
||
var body *ast.BlockStmt
|
||
switch fn := node.(type) {
|
||
case *ast.FuncDecl:
|
||
typ = fn.Type
|
||
body = fn.Body
|
||
case *ast.FuncLit:
|
||
typ = fn.Type
|
||
body = fn.Body
|
||
}
|
||
if body == nil {
|
||
return true
|
||
}
|
||
if len(typ.Params.List) == 0 {
|
||
return true
|
||
}
|
||
for _, field := range typ.Params.List {
|
||
for _, arg := range field.Names {
|
||
obj := pass.TypesInfo.ObjectOf(arg)
|
||
var irobj *ir.Parameter
|
||
for _, param := range fn.Params {
|
||
if param.Object() == obj {
|
||
irobj = param
|
||
break
|
||
}
|
||
}
|
||
if irobj == nil {
|
||
continue
|
||
}
|
||
refs := irobj.Referrers()
|
||
if refs == nil {
|
||
continue
|
||
}
|
||
if len(code.FilterDebug(*refs)) != 0 {
|
||
continue
|
||
}
|
||
|
||
var assignment ast.Node
|
||
ast.Inspect(body, func(node ast.Node) bool {
|
||
if assignment != nil {
|
||
return false
|
||
}
|
||
assign, ok := node.(*ast.AssignStmt)
|
||
if !ok {
|
||
return true
|
||
}
|
||
for _, lhs := range assign.Lhs {
|
||
ident, ok := lhs.(*ast.Ident)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if pass.TypesInfo.ObjectOf(ident) == obj {
|
||
assignment = assign
|
||
return false
|
||
}
|
||
}
|
||
return true
|
||
})
|
||
if assignment != nil {
|
||
report.Report(pass, arg, fmt.Sprintf("argument %s is overwritten before first use", arg),
|
||
report.Related(assignment, fmt.Sprintf("assignment to %s", arg)))
|
||
}
|
||
}
|
||
}
|
||
return true
|
||
}
|
||
Inspect(fn.Source(), cb)
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckIneffectiveLoop(pass *analysis.Pass) (interface{}, error) {
|
||
// This check detects some, but not all unconditional loop exits.
|
||
// We give up in the following cases:
|
||
//
|
||
// - a goto anywhere in the loop. The goto might skip over our
|
||
// return, and we don't check that it doesn't.
|
||
//
|
||
// - any nested, unlabelled continue, even if it is in another
|
||
// loop or closure.
|
||
fn := func(node ast.Node) {
|
||
var body *ast.BlockStmt
|
||
switch fn := node.(type) {
|
||
case *ast.FuncDecl:
|
||
body = fn.Body
|
||
case *ast.FuncLit:
|
||
body = fn.Body
|
||
default:
|
||
ExhaustiveTypeSwitch(node)
|
||
}
|
||
if body == nil {
|
||
return
|
||
}
|
||
labels := map[*ast.Object]ast.Stmt{}
|
||
ast.Inspect(body, func(node ast.Node) bool {
|
||
label, ok := node.(*ast.LabeledStmt)
|
||
if !ok {
|
||
return true
|
||
}
|
||
labels[label.Label.Obj] = label.Stmt
|
||
return true
|
||
})
|
||
|
||
ast.Inspect(body, func(node ast.Node) bool {
|
||
var loop ast.Node
|
||
var body *ast.BlockStmt
|
||
switch node := node.(type) {
|
||
case *ast.ForStmt:
|
||
body = node.Body
|
||
loop = node
|
||
case *ast.RangeStmt:
|
||
typ := pass.TypesInfo.TypeOf(node.X)
|
||
if _, ok := typ.Underlying().(*types.Map); ok {
|
||
// looping once over a map is a valid pattern for
|
||
// getting an arbitrary element.
|
||
return true
|
||
}
|
||
body = node.Body
|
||
loop = node
|
||
default:
|
||
return true
|
||
}
|
||
if len(body.List) < 2 {
|
||
// avoid flagging the somewhat common pattern of using
|
||
// a range loop to get the first element in a slice,
|
||
// or the first rune in a string.
|
||
return true
|
||
}
|
||
var unconditionalExit ast.Node
|
||
hasBranching := false
|
||
for _, stmt := range body.List {
|
||
switch stmt := stmt.(type) {
|
||
case *ast.BranchStmt:
|
||
switch stmt.Tok {
|
||
case token.BREAK:
|
||
if stmt.Label == nil || labels[stmt.Label.Obj] == loop {
|
||
unconditionalExit = stmt
|
||
}
|
||
case token.CONTINUE:
|
||
if stmt.Label == nil || labels[stmt.Label.Obj] == loop {
|
||
unconditionalExit = nil
|
||
return false
|
||
}
|
||
}
|
||
case *ast.ReturnStmt:
|
||
unconditionalExit = stmt
|
||
case *ast.IfStmt, *ast.ForStmt, *ast.RangeStmt, *ast.SwitchStmt, *ast.SelectStmt:
|
||
hasBranching = true
|
||
}
|
||
}
|
||
if unconditionalExit == nil || !hasBranching {
|
||
return false
|
||
}
|
||
ast.Inspect(body, func(node ast.Node) bool {
|
||
if branch, ok := node.(*ast.BranchStmt); ok {
|
||
|
||
switch branch.Tok {
|
||
case token.GOTO:
|
||
unconditionalExit = nil
|
||
return false
|
||
case token.CONTINUE:
|
||
if branch.Label != nil && labels[branch.Label.Obj] != loop {
|
||
return true
|
||
}
|
||
unconditionalExit = nil
|
||
return false
|
||
}
|
||
}
|
||
return true
|
||
})
|
||
if unconditionalExit != nil {
|
||
report.Report(pass, unconditionalExit, "the surrounding loop is unconditionally terminated")
|
||
}
|
||
return true
|
||
})
|
||
}
|
||
code.Preorder(pass, fn, (*ast.FuncDecl)(nil), (*ast.FuncLit)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
var checkNilContextQ = pattern.MustParse(`(CallExpr fun@(Function _) (Builtin "nil"):_)`)
|
||
|
||
func CheckNilContext(pass *analysis.Pass) (interface{}, error) {
|
||
todo := &ast.CallExpr{
|
||
Fun: Selector("context", "TODO"),
|
||
}
|
||
bg := &ast.CallExpr{
|
||
Fun: Selector("context", "Background"),
|
||
}
|
||
fn := func(node ast.Node) {
|
||
m, ok := Match(pass, checkNilContextQ, node)
|
||
if !ok {
|
||
return
|
||
}
|
||
|
||
call := node.(*ast.CallExpr)
|
||
fun, ok := m.State["fun"].(*types.Func)
|
||
if !ok {
|
||
// it might also be a builtin
|
||
return
|
||
}
|
||
sig := fun.Type().(*types.Signature)
|
||
if sig.Params().Len() == 0 {
|
||
// Our CallExpr might've matched a method expression, like
|
||
// (*T).Foo(nil) – here, nil isn't the first argument of
|
||
// the Foo method, but the method receiver.
|
||
return
|
||
}
|
||
if !code.IsType(sig.Params().At(0).Type(), "context.Context") {
|
||
return
|
||
}
|
||
report.Report(pass, call.Args[0],
|
||
"do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use", report.Fixes(
|
||
edit.Fix("use context.TODO", edit.ReplaceWithNode(pass.Fset, call.Args[0], todo)),
|
||
edit.Fix("use context.Background", edit.ReplaceWithNode(pass.Fset, call.Args[0], bg))))
|
||
}
|
||
code.Preorder(pass, fn, (*ast.CallExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
var (
|
||
checkSeekerQ = pattern.MustParse(`(CallExpr fun@(SelectorExpr _ (Ident "Seek")) [arg1@(SelectorExpr (Ident "io") (Ident (Or "SeekStart" "SeekCurrent" "SeekEnd"))) arg2])`)
|
||
checkSeekerR = pattern.MustParse(`(CallExpr fun [arg2 arg1])`)
|
||
)
|
||
|
||
func CheckSeeker(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
if _, edits, ok := MatchAndEdit(pass, checkSeekerQ, checkSeekerR, node); ok {
|
||
report.Report(pass, node, "the first argument of io.Seeker is the offset, but an io.Seek* constant is being used instead",
|
||
report.Fixes(edit.Fix("swap arguments", edits...)))
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.CallExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckIneffectiveAppend(pass *analysis.Pass) (interface{}, error) {
|
||
isAppend := func(ins ir.Value) bool {
|
||
call, ok := ins.(*ir.Call)
|
||
if !ok {
|
||
return false
|
||
}
|
||
if call.Call.IsInvoke() {
|
||
return false
|
||
}
|
||
if builtin, ok := call.Call.Value.(*ir.Builtin); !ok || builtin.Name() != "append" {
|
||
return false
|
||
}
|
||
return true
|
||
}
|
||
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
val, ok := ins.(ir.Value)
|
||
if !ok || !isAppend(val) {
|
||
continue
|
||
}
|
||
|
||
isUsed := false
|
||
visited := map[ir.Instruction]bool{}
|
||
var walkRefs func(refs []ir.Instruction)
|
||
walkRefs = func(refs []ir.Instruction) {
|
||
loop:
|
||
for _, ref := range refs {
|
||
if visited[ref] {
|
||
continue
|
||
}
|
||
visited[ref] = true
|
||
if _, ok := ref.(*ir.DebugRef); ok {
|
||
continue
|
||
}
|
||
switch ref := ref.(type) {
|
||
case *ir.Phi:
|
||
walkRefs(*ref.Referrers())
|
||
case *ir.Sigma:
|
||
walkRefs(*ref.Referrers())
|
||
case ir.Value:
|
||
if !isAppend(ref) {
|
||
isUsed = true
|
||
} else {
|
||
walkRefs(*ref.Referrers())
|
||
}
|
||
case ir.Instruction:
|
||
isUsed = true
|
||
break loop
|
||
}
|
||
}
|
||
}
|
||
|
||
refs := val.Referrers()
|
||
if refs == nil {
|
||
continue
|
||
}
|
||
walkRefs(*refs)
|
||
|
||
if !isUsed {
|
||
report.Report(pass, ins, "this result of append is never used, except maybe in other appends")
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckConcurrentTesting(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
gostmt, ok := ins.(*ir.Go)
|
||
if !ok {
|
||
continue
|
||
}
|
||
var fn *ir.Function
|
||
switch val := gostmt.Call.Value.(type) {
|
||
case *ir.Function:
|
||
fn = val
|
||
case *ir.MakeClosure:
|
||
fn = val.Fn.(*ir.Function)
|
||
default:
|
||
continue
|
||
}
|
||
if fn.Blocks == nil {
|
||
continue
|
||
}
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
call, ok := ins.(*ir.Call)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if call.Call.IsInvoke() {
|
||
continue
|
||
}
|
||
callee := call.Call.StaticCallee()
|
||
if callee == nil {
|
||
continue
|
||
}
|
||
recv := callee.Signature.Recv()
|
||
if recv == nil {
|
||
continue
|
||
}
|
||
if !code.IsType(recv.Type(), "*testing.common") {
|
||
continue
|
||
}
|
||
fn, ok := call.Call.StaticCallee().Object().(*types.Func)
|
||
if !ok {
|
||
continue
|
||
}
|
||
name := fn.Name()
|
||
switch name {
|
||
case "FailNow", "Fatal", "Fatalf", "SkipNow", "Skip", "Skipf":
|
||
default:
|
||
continue
|
||
}
|
||
// TODO(dh): don't report multiple diagnostics
|
||
// for multiple calls to T.Fatal, but do
|
||
// collect all of them as related information
|
||
report.Report(pass, gostmt, fmt.Sprintf("the goroutine calls T.%s, which must be called in the same goroutine as the test", name),
|
||
report.Related(call, fmt.Sprintf("call to T.%s", name)))
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func eachCall(fn *ir.Function, cb func(caller *ir.Function, site ir.CallInstruction, callee *ir.Function)) {
|
||
for _, b := range fn.Blocks {
|
||
for _, instr := range b.Instrs {
|
||
if site, ok := instr.(ir.CallInstruction); ok {
|
||
if g := site.Common().StaticCallee(); g != nil {
|
||
cb(fn, site, g)
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
func CheckCyclicFinalizer(pass *analysis.Pass) (interface{}, error) {
|
||
cb := func(caller *ir.Function, site ir.CallInstruction, callee *ir.Function) {
|
||
if callee.RelString(nil) != "runtime.SetFinalizer" {
|
||
return
|
||
}
|
||
arg0 := site.Common().Args[Arg("runtime.SetFinalizer.obj")]
|
||
if iface, ok := arg0.(*ir.MakeInterface); ok {
|
||
arg0 = iface.X
|
||
}
|
||
load, ok := arg0.(*ir.Load)
|
||
if !ok {
|
||
return
|
||
}
|
||
v, ok := load.X.(*ir.Alloc)
|
||
if !ok {
|
||
return
|
||
}
|
||
arg1 := site.Common().Args[Arg("runtime.SetFinalizer.finalizer")]
|
||
if iface, ok := arg1.(*ir.MakeInterface); ok {
|
||
arg1 = iface.X
|
||
}
|
||
mc, ok := arg1.(*ir.MakeClosure)
|
||
if !ok {
|
||
return
|
||
}
|
||
for _, b := range mc.Bindings {
|
||
if b == v {
|
||
pos := lint.DisplayPosition(pass.Fset, mc.Fn.Pos())
|
||
report.Report(pass, site, fmt.Sprintf("the finalizer closes over the object, preventing the finalizer from ever running (at %s)", pos))
|
||
}
|
||
}
|
||
}
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
eachCall(fn, cb)
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
/*
|
||
func CheckSliceOutOfBounds(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
ia, ok := ins.(*ir.IndexAddr)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if _, ok := ia.X.Type().Underlying().(*types.Slice); !ok {
|
||
continue
|
||
}
|
||
sr, ok1 := c.funcDescs.Get(fn).Ranges[ia.X].(vrp.SliceInterval)
|
||
idxr, ok2 := c.funcDescs.Get(fn).Ranges[ia.Index].(vrp.IntInterval)
|
||
if !ok1 || !ok2 || !sr.IsKnown() || !idxr.IsKnown() || sr.Length.Empty() || idxr.Empty() {
|
||
continue
|
||
}
|
||
if idxr.Lower.Cmp(sr.Length.Upper) >= 0 {
|
||
report.Nodef(pass, ia, "index out of bounds")
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
*/
|
||
|
||
func CheckDeferLock(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, block := range fn.Blocks {
|
||
instrs := code.FilterDebug(block.Instrs)
|
||
if len(instrs) < 2 {
|
||
continue
|
||
}
|
||
for i, ins := range instrs[:len(instrs)-1] {
|
||
call, ok := ins.(*ir.Call)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if !code.IsCallToAny(call.Common(), "(*sync.Mutex).Lock", "(*sync.RWMutex).RLock") {
|
||
continue
|
||
}
|
||
nins, ok := instrs[i+1].(*ir.Defer)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if !code.IsCallToAny(&nins.Call, "(*sync.Mutex).Lock", "(*sync.RWMutex).RLock") {
|
||
continue
|
||
}
|
||
if call.Common().Args[0] != nins.Call.Args[0] {
|
||
continue
|
||
}
|
||
name := shortCallName(call.Common())
|
||
alt := ""
|
||
switch name {
|
||
case "Lock":
|
||
alt = "Unlock"
|
||
case "RLock":
|
||
alt = "RUnlock"
|
||
}
|
||
report.Report(pass, nins, fmt.Sprintf("deferring %s right after having locked already; did you mean to defer %s?", name, alt))
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckNaNComparison(pass *analysis.Pass) (interface{}, error) {
|
||
isNaN := func(v ir.Value) bool {
|
||
call, ok := v.(*ir.Call)
|
||
if !ok {
|
||
return false
|
||
}
|
||
return code.IsCallTo(call.Common(), "math.NaN")
|
||
}
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
ins, ok := ins.(*ir.BinOp)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if isNaN(ins.X) || isNaN(ins.Y) {
|
||
report.Report(pass, ins, "no value is equal to NaN, not even NaN itself")
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckInfiniteRecursion(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
eachCall(fn, func(caller *ir.Function, site ir.CallInstruction, callee *ir.Function) {
|
||
if callee != fn {
|
||
return
|
||
}
|
||
if _, ok := site.(*ir.Go); ok {
|
||
// Recursively spawning goroutines doesn't consume
|
||
// stack space infinitely, so don't flag it.
|
||
return
|
||
}
|
||
|
||
block := site.Block()
|
||
canReturn := false
|
||
for _, b := range fn.Blocks {
|
||
if block.Dominates(b) {
|
||
continue
|
||
}
|
||
if len(b.Instrs) == 0 {
|
||
continue
|
||
}
|
||
if _, ok := b.Control().(*ir.Return); ok {
|
||
canReturn = true
|
||
break
|
||
}
|
||
}
|
||
if canReturn {
|
||
return
|
||
}
|
||
report.Report(pass, site, "infinite recursive call")
|
||
})
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func objectName(obj types.Object) string {
|
||
if obj == nil {
|
||
return "<nil>"
|
||
}
|
||
var name string
|
||
if obj.Pkg() != nil && obj.Pkg().Scope().Lookup(obj.Name()) == obj {
|
||
s := obj.Pkg().Path()
|
||
if s != "" {
|
||
name += s + "."
|
||
}
|
||
}
|
||
name += obj.Name()
|
||
return name
|
||
}
|
||
|
||
func isName(pass *analysis.Pass, expr ast.Expr, name string) bool {
|
||
var obj types.Object
|
||
switch expr := expr.(type) {
|
||
case *ast.Ident:
|
||
obj = pass.TypesInfo.ObjectOf(expr)
|
||
case *ast.SelectorExpr:
|
||
obj = pass.TypesInfo.ObjectOf(expr.Sel)
|
||
}
|
||
return objectName(obj) == name
|
||
}
|
||
|
||
func CheckLeakyTimeTick(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
if code.IsMainLike(pass) || code.IsInTest(pass, fn) {
|
||
continue
|
||
}
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
call, ok := ins.(*ir.Call)
|
||
if !ok || !code.IsCallTo(call.Common(), "time.Tick") {
|
||
continue
|
||
}
|
||
if !functions.Terminates(call.Parent()) {
|
||
continue
|
||
}
|
||
report.Report(pass, call, "using time.Tick leaks the underlying ticker, consider using it only in endless functions, tests and the main package, and use time.NewTicker here")
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
var checkDoubleNegationQ = pattern.MustParse(`(UnaryExpr "!" single@(UnaryExpr "!" x))`)
|
||
|
||
func CheckDoubleNegation(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
if m, ok := Match(pass, checkDoubleNegationQ, node); ok {
|
||
report.Report(pass, node, "negating a boolean twice has no effect; is this a typo?", report.Fixes(
|
||
edit.Fix("turn into single negation", edit.ReplaceWithNode(pass.Fset, node, m.State["single"].(ast.Node))),
|
||
edit.Fix("remove double negation", edit.ReplaceWithNode(pass.Fset, node, m.State["x"].(ast.Node)))))
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.UnaryExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckRepeatedIfElse(pass *analysis.Pass) (interface{}, error) {
|
||
seen := map[ast.Node]bool{}
|
||
|
||
var collectConds func(ifstmt *ast.IfStmt, conds []ast.Expr) ([]ast.Expr, bool)
|
||
collectConds = func(ifstmt *ast.IfStmt, conds []ast.Expr) ([]ast.Expr, bool) {
|
||
seen[ifstmt] = true
|
||
// Bail if any if-statement has an Init statement or side effects in its condition
|
||
if ifstmt.Init != nil {
|
||
return nil, false
|
||
}
|
||
if code.MayHaveSideEffects(pass, ifstmt.Cond, nil) {
|
||
return nil, false
|
||
}
|
||
|
||
conds = append(conds, ifstmt.Cond)
|
||
if elsestmt, ok := ifstmt.Else.(*ast.IfStmt); ok {
|
||
return collectConds(elsestmt, conds)
|
||
}
|
||
return conds, true
|
||
}
|
||
fn := func(node ast.Node) {
|
||
ifstmt := node.(*ast.IfStmt)
|
||
if seen[ifstmt] {
|
||
// this if-statement is part of an if/else-if chain that we've already processed
|
||
return
|
||
}
|
||
if ifstmt.Else == nil {
|
||
// there can be at most one condition
|
||
return
|
||
}
|
||
conds, ok := collectConds(ifstmt, nil)
|
||
if !ok {
|
||
return
|
||
}
|
||
if len(conds) < 2 {
|
||
return
|
||
}
|
||
counts := map[string]int{}
|
||
for _, cond := range conds {
|
||
s := report.Render(pass, cond)
|
||
counts[s]++
|
||
if counts[s] == 2 {
|
||
report.Report(pass, cond, "this condition occurs multiple times in this if/else if chain")
|
||
}
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.IfStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckSillyBitwiseOps(pass *analysis.Pass) (interface{}, error) {
|
||
// FIXME(dh): what happened here?
|
||
if false {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
ins, ok := ins.(*ir.BinOp)
|
||
if !ok {
|
||
continue
|
||
}
|
||
|
||
if c, ok := ins.Y.(*ir.Const); !ok || c.Value == nil || c.Value.Kind() != constant.Int || c.Uint64() != 0 {
|
||
continue
|
||
}
|
||
switch ins.Op {
|
||
case token.AND, token.OR, token.XOR:
|
||
default:
|
||
// we do not flag shifts because too often, x<<0 is part
|
||
// of a pattern, x<<0, x<<8, x<<16, ...
|
||
continue
|
||
}
|
||
path, _ := astutil.PathEnclosingInterval(code.File(pass, ins), ins.Pos(), ins.Pos())
|
||
if len(path) == 0 {
|
||
continue
|
||
}
|
||
|
||
if node, ok := path[0].(*ast.BinaryExpr); !ok || !code.IsIntLiteral(node.Y, "0") {
|
||
continue
|
||
}
|
||
|
||
switch ins.Op {
|
||
case token.AND:
|
||
report.Report(pass, ins, "x & 0 always equals 0")
|
||
case token.OR, token.XOR:
|
||
report.Report(pass, ins, fmt.Sprintf("x %s 0 always equals x", ins.Op))
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
fn := func(node ast.Node) {
|
||
binop := node.(*ast.BinaryExpr)
|
||
b, ok := pass.TypesInfo.TypeOf(binop).Underlying().(*types.Basic)
|
||
if !ok {
|
||
return
|
||
}
|
||
if (b.Info() & types.IsInteger) == 0 {
|
||
return
|
||
}
|
||
switch binop.Op {
|
||
case token.AND, token.OR, token.XOR:
|
||
default:
|
||
// we do not flag shifts because too often, x<<0 is part
|
||
// of a pattern, x<<0, x<<8, x<<16, ...
|
||
return
|
||
}
|
||
switch y := binop.Y.(type) {
|
||
case *ast.Ident:
|
||
obj, ok := pass.TypesInfo.ObjectOf(y).(*types.Const)
|
||
if !ok {
|
||
return
|
||
}
|
||
if v, _ := constant.Int64Val(obj.Val()); v != 0 {
|
||
return
|
||
}
|
||
path, _ := astutil.PathEnclosingInterval(code.File(pass, obj), obj.Pos(), obj.Pos())
|
||
if len(path) < 2 {
|
||
return
|
||
}
|
||
spec, ok := path[1].(*ast.ValueSpec)
|
||
if !ok {
|
||
return
|
||
}
|
||
if len(spec.Names) != 1 || len(spec.Values) != 1 {
|
||
// TODO(dh): we could support this
|
||
return
|
||
}
|
||
ident, ok := spec.Values[0].(*ast.Ident)
|
||
if !ok {
|
||
return
|
||
}
|
||
if !isIota(pass.TypesInfo.ObjectOf(ident)) {
|
||
return
|
||
}
|
||
switch binop.Op {
|
||
case token.AND:
|
||
report.Report(pass, node,
|
||
fmt.Sprintf("%s always equals 0; %s is defined as iota and has value 0, maybe %s is meant to be 1 << iota?", report.Render(pass, binop), report.Render(pass, binop.Y), report.Render(pass, binop.Y)))
|
||
case token.OR, token.XOR:
|
||
report.Report(pass, node,
|
||
fmt.Sprintf("%s always equals %s; %s is defined as iota and has value 0, maybe %s is meant to be 1 << iota?", report.Render(pass, binop), report.Render(pass, binop.X), report.Render(pass, binop.Y), report.Render(pass, binop.Y)))
|
||
}
|
||
case *ast.BasicLit:
|
||
if !code.IsIntLiteral(binop.Y, "0") {
|
||
return
|
||
}
|
||
switch binop.Op {
|
||
case token.AND:
|
||
report.Report(pass, node, fmt.Sprintf("%s always equals 0", report.Render(pass, binop)))
|
||
case token.OR, token.XOR:
|
||
report.Report(pass, node, fmt.Sprintf("%s always equals %s", report.Render(pass, binop), report.Render(pass, binop.X)))
|
||
}
|
||
default:
|
||
return
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func isIota(obj types.Object) bool {
|
||
if obj.Name() != "iota" {
|
||
return false
|
||
}
|
||
c, ok := obj.(*types.Const)
|
||
if !ok {
|
||
return false
|
||
}
|
||
return c.Pkg() == nil
|
||
}
|
||
|
||
func CheckNonOctalFileMode(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
call := node.(*ast.CallExpr)
|
||
sig, ok := pass.TypesInfo.TypeOf(call.Fun).(*types.Signature)
|
||
if !ok {
|
||
return
|
||
}
|
||
n := sig.Params().Len()
|
||
for i := 0; i < n; i++ {
|
||
typ := sig.Params().At(i).Type()
|
||
if !code.IsType(typ, "os.FileMode") {
|
||
continue
|
||
}
|
||
|
||
lit, ok := call.Args[i].(*ast.BasicLit)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if len(lit.Value) == 3 &&
|
||
lit.Value[0] != '0' &&
|
||
lit.Value[0] >= '0' && lit.Value[0] <= '7' &&
|
||
lit.Value[1] >= '0' && lit.Value[1] <= '7' &&
|
||
lit.Value[2] >= '0' && lit.Value[2] <= '7' {
|
||
|
||
v, err := strconv.ParseInt(lit.Value, 10, 64)
|
||
if err != nil {
|
||
continue
|
||
}
|
||
report.Report(pass, call.Args[i], fmt.Sprintf("file mode '%s' evaluates to %#o; did you mean '0%s'?", lit.Value, v, lit.Value),
|
||
report.Fixes(edit.Fix("fix octal literal", edit.ReplaceWithString(pass.Fset, call.Args[i], "0"+lit.Value))))
|
||
}
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.CallExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckPureFunctions(pass *analysis.Pass) (interface{}, error) {
|
||
pure := pass.ResultOf[facts.Purity].(facts.PurityResult)
|
||
|
||
fnLoop:
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
if code.IsInTest(pass, fn) {
|
||
params := fn.Signature.Params()
|
||
for i := 0; i < params.Len(); i++ {
|
||
param := params.At(i)
|
||
if code.IsType(param.Type(), "*testing.B") {
|
||
// Ignore discarded pure functions in code related
|
||
// to benchmarks. Instead of matching BenchmarkFoo
|
||
// functions, we match any function accepting a
|
||
// *testing.B. Benchmarks sometimes call generic
|
||
// functions for doing the actual work, and
|
||
// checking for the parameter is a lot easier and
|
||
// faster than analyzing call trees.
|
||
continue fnLoop
|
||
}
|
||
}
|
||
}
|
||
|
||
for _, b := range fn.Blocks {
|
||
for _, ins := range b.Instrs {
|
||
ins, ok := ins.(*ir.Call)
|
||
if !ok {
|
||
continue
|
||
}
|
||
refs := ins.Referrers()
|
||
if refs == nil || len(code.FilterDebug(*refs)) > 0 {
|
||
continue
|
||
}
|
||
|
||
callee := ins.Common().StaticCallee()
|
||
if callee == nil {
|
||
continue
|
||
}
|
||
if callee.Object() == nil {
|
||
// TODO(dh): support anonymous functions
|
||
continue
|
||
}
|
||
if _, ok := pure[callee.Object().(*types.Func)]; ok {
|
||
if pass.Pkg.Path() == "fmt_test" && callee.Object().(*types.Func).FullName() == "fmt.Sprintf" {
|
||
// special case for benchmarks in the fmt package
|
||
continue
|
||
}
|
||
report.Report(pass, ins, fmt.Sprintf("%s is a pure function but its return value is ignored", callee.Name()))
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckDeprecated(pass *analysis.Pass) (interface{}, error) {
|
||
deprs := pass.ResultOf[facts.Deprecated].(facts.DeprecatedResult)
|
||
|
||
// Selectors can appear outside of function literals, e.g. when
|
||
// declaring package level variables.
|
||
|
||
var tfn types.Object
|
||
stack := 0
|
||
fn := func(node ast.Node, push bool) bool {
|
||
if !push {
|
||
stack--
|
||
return false
|
||
}
|
||
stack++
|
||
if stack == 1 {
|
||
tfn = nil
|
||
}
|
||
if fn, ok := node.(*ast.FuncDecl); ok {
|
||
tfn = pass.TypesInfo.ObjectOf(fn.Name)
|
||
}
|
||
sel, ok := node.(*ast.SelectorExpr)
|
||
if !ok {
|
||
return true
|
||
}
|
||
|
||
obj := pass.TypesInfo.ObjectOf(sel.Sel)
|
||
if obj.Pkg() == nil {
|
||
return true
|
||
}
|
||
if pass.Pkg == obj.Pkg() || obj.Pkg().Path()+"_test" == pass.Pkg.Path() {
|
||
// Don't flag stuff in our own package
|
||
return true
|
||
}
|
||
if depr, ok := deprs.Objects[obj]; ok {
|
||
// Look for the first available alternative, not the first
|
||
// version something was deprecated in. If a function was
|
||
// deprecated in Go 1.6, an alternative has been available
|
||
// already in 1.0, and we're targeting 1.2, it still
|
||
// makes sense to use the alternative from 1.0, to be
|
||
// future-proof.
|
||
minVersion := deprecated.Stdlib[code.SelectorName(pass, sel)].AlternativeAvailableSince
|
||
if !code.IsGoVersion(pass, minVersion) {
|
||
return true
|
||
}
|
||
|
||
if tfn != nil {
|
||
if _, ok := deprs.Objects[tfn]; ok {
|
||
// functions that are deprecated may use deprecated
|
||
// symbols
|
||
return true
|
||
}
|
||
}
|
||
report.Report(pass, sel, fmt.Sprintf("%s is deprecated: %s", report.Render(pass, sel), depr.Msg))
|
||
return true
|
||
}
|
||
return true
|
||
}
|
||
|
||
fn2 := func(node ast.Node) {
|
||
spec := node.(*ast.ImportSpec)
|
||
var imp *types.Package
|
||
if spec.Name != nil {
|
||
imp = pass.TypesInfo.ObjectOf(spec.Name).(*types.PkgName).Imported()
|
||
} else {
|
||
imp = pass.TypesInfo.Implicits[spec].(*types.PkgName).Imported()
|
||
}
|
||
|
||
p := spec.Path.Value
|
||
path := p[1 : len(p)-1]
|
||
if depr, ok := deprs.Packages[imp]; ok {
|
||
if path == "github.com/golang/protobuf/proto" {
|
||
gen, ok := code.Generator(pass, spec.Path.Pos())
|
||
if ok && gen == facts.ProtocGenGo {
|
||
return
|
||
}
|
||
}
|
||
report.Report(pass, spec, fmt.Sprintf("package %s is deprecated: %s", path, depr.Msg))
|
||
}
|
||
}
|
||
pass.ResultOf[inspect.Analyzer].(*inspector.Inspector).Nodes(nil, fn)
|
||
code.Preorder(pass, fn2, (*ast.ImportSpec)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func callChecker(rules map[string]CallCheck) func(pass *analysis.Pass) (interface{}, error) {
|
||
return func(pass *analysis.Pass) (interface{}, error) {
|
||
return checkCalls(pass, rules)
|
||
}
|
||
}
|
||
|
||
func checkCalls(pass *analysis.Pass, rules map[string]CallCheck) (interface{}, error) {
|
||
cb := func(caller *ir.Function, site ir.CallInstruction, callee *ir.Function) {
|
||
obj, ok := callee.Object().(*types.Func)
|
||
if !ok {
|
||
return
|
||
}
|
||
|
||
r, ok := rules[lint.FuncName(obj)]
|
||
if !ok {
|
||
return
|
||
}
|
||
var args []*Argument
|
||
irargs := site.Common().Args
|
||
if callee.Signature.Recv() != nil {
|
||
irargs = irargs[1:]
|
||
}
|
||
for _, arg := range irargs {
|
||
if iarg, ok := arg.(*ir.MakeInterface); ok {
|
||
arg = iarg.X
|
||
}
|
||
args = append(args, &Argument{Value: Value{arg}})
|
||
}
|
||
call := &Call{
|
||
Pass: pass,
|
||
Instr: site,
|
||
Args: args,
|
||
Parent: site.Parent(),
|
||
}
|
||
r(call)
|
||
path, _ := astutil.PathEnclosingInterval(code.File(pass, site), site.Pos(), site.Pos())
|
||
var astcall *ast.CallExpr
|
||
for _, el := range path {
|
||
if expr, ok := el.(*ast.CallExpr); ok {
|
||
astcall = expr
|
||
break
|
||
}
|
||
}
|
||
for idx, arg := range call.Args {
|
||
for _, e := range arg.invalids {
|
||
if astcall != nil {
|
||
report.Report(pass, astcall.Args[idx], e)
|
||
} else {
|
||
report.Report(pass, site, e)
|
||
}
|
||
}
|
||
}
|
||
for _, e := range call.invalids {
|
||
report.Report(pass, call.Instr, e)
|
||
}
|
||
}
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
eachCall(fn, cb)
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func shortCallName(call *ir.CallCommon) string {
|
||
if call.IsInvoke() {
|
||
return ""
|
||
}
|
||
switch v := call.Value.(type) {
|
||
case *ir.Function:
|
||
fn, ok := v.Object().(*types.Func)
|
||
if !ok {
|
||
return ""
|
||
}
|
||
return fn.Name()
|
||
case *ir.Builtin:
|
||
return v.Name()
|
||
}
|
||
return ""
|
||
}
|
||
|
||
func CheckWriterBufferModified(pass *analysis.Pass) (interface{}, error) {
|
||
// TODO(dh): this might be a good candidate for taint analysis.
|
||
// Taint the argument as MUST_NOT_MODIFY, then propagate that
|
||
// through functions like bytes.Split
|
||
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
sig := fn.Signature
|
||
if fn.Name() != "Write" || sig.Recv() == nil || sig.Params().Len() != 1 || sig.Results().Len() != 2 {
|
||
continue
|
||
}
|
||
tArg, ok := sig.Params().At(0).Type().(*types.Slice)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if basic, ok := tArg.Elem().(*types.Basic); !ok || basic.Kind() != types.Byte {
|
||
continue
|
||
}
|
||
if basic, ok := sig.Results().At(0).Type().(*types.Basic); !ok || basic.Kind() != types.Int {
|
||
continue
|
||
}
|
||
if named, ok := sig.Results().At(1).Type().(*types.Named); !ok || !code.IsType(named, "error") {
|
||
continue
|
||
}
|
||
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
switch ins := ins.(type) {
|
||
case *ir.Store:
|
||
addr, ok := ins.Addr.(*ir.IndexAddr)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if addr.X != fn.Params[1] {
|
||
continue
|
||
}
|
||
report.Report(pass, ins, "io.Writer.Write must not modify the provided buffer, not even temporarily")
|
||
case *ir.Call:
|
||
if !code.IsCallTo(ins.Common(), "append") {
|
||
continue
|
||
}
|
||
if ins.Common().Args[0] != fn.Params[1] {
|
||
continue
|
||
}
|
||
report.Report(pass, ins, "io.Writer.Write must not modify the provided buffer, not even temporarily")
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func loopedRegexp(name string) CallCheck {
|
||
return func(call *Call) {
|
||
if len(extractConsts(call.Args[0].Value.Value)) == 0 {
|
||
return
|
||
}
|
||
if !isInLoop(call.Instr.Block()) {
|
||
return
|
||
}
|
||
call.Invalid(fmt.Sprintf("calling %s in a loop has poor performance, consider using regexp.Compile", name))
|
||
}
|
||
}
|
||
|
||
func CheckEmptyBranch(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
if fn.Source() == nil {
|
||
continue
|
||
}
|
||
if code.IsExample(fn) {
|
||
continue
|
||
}
|
||
cb := func(node ast.Node) bool {
|
||
ifstmt, ok := node.(*ast.IfStmt)
|
||
if !ok {
|
||
return true
|
||
}
|
||
if ifstmt.Else != nil {
|
||
b, ok := ifstmt.Else.(*ast.BlockStmt)
|
||
if !ok || len(b.List) != 0 {
|
||
return true
|
||
}
|
||
report.Report(pass, ifstmt.Else, "empty branch", report.FilterGenerated(), report.ShortRange())
|
||
}
|
||
if len(ifstmt.Body.List) != 0 {
|
||
return true
|
||
}
|
||
report.Report(pass, ifstmt, "empty branch", report.FilterGenerated(), report.ShortRange())
|
||
return true
|
||
}
|
||
Inspect(fn.Source(), cb)
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckMapBytesKey(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, b := range fn.Blocks {
|
||
insLoop:
|
||
for _, ins := range b.Instrs {
|
||
// find []byte -> string conversions
|
||
conv, ok := ins.(*ir.Convert)
|
||
if !ok || conv.Type() != types.Universe.Lookup("string").Type() {
|
||
continue
|
||
}
|
||
if s, ok := conv.X.Type().(*types.Slice); !ok || s.Elem() != types.Universe.Lookup("byte").Type() {
|
||
continue
|
||
}
|
||
refs := conv.Referrers()
|
||
// need at least two (DebugRef) references: the
|
||
// conversion and the *ast.Ident
|
||
if refs == nil || len(*refs) < 2 {
|
||
continue
|
||
}
|
||
ident := false
|
||
// skip first reference, that's the conversion itself
|
||
for _, ref := range (*refs)[1:] {
|
||
switch ref := ref.(type) {
|
||
case *ir.DebugRef:
|
||
if _, ok := ref.Expr.(*ast.Ident); !ok {
|
||
// the string seems to be used somewhere
|
||
// unexpected; the default branch should
|
||
// catch this already, but be safe
|
||
continue insLoop
|
||
} else {
|
||
ident = true
|
||
}
|
||
case *ir.MapLookup:
|
||
default:
|
||
// the string is used somewhere else than a
|
||
// map lookup
|
||
continue insLoop
|
||
}
|
||
}
|
||
|
||
// the result of the conversion wasn't assigned to an
|
||
// identifier
|
||
if !ident {
|
||
continue
|
||
}
|
||
report.Report(pass, conv, "m[string(key)] would be more efficient than k := string(key); m[k]")
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckRangeStringRunes(pass *analysis.Pass) (interface{}, error) {
|
||
return sharedcheck.CheckRangeStringRunes(pass)
|
||
}
|
||
|
||
func CheckSelfAssignment(pass *analysis.Pass) (interface{}, error) {
|
||
pure := pass.ResultOf[facts.Purity].(facts.PurityResult)
|
||
|
||
fn := func(node ast.Node) {
|
||
assign := node.(*ast.AssignStmt)
|
||
if assign.Tok != token.ASSIGN || len(assign.Lhs) != len(assign.Rhs) {
|
||
return
|
||
}
|
||
for i, lhs := range assign.Lhs {
|
||
rhs := assign.Rhs[i]
|
||
if reflect.TypeOf(lhs) != reflect.TypeOf(rhs) {
|
||
continue
|
||
}
|
||
if code.MayHaveSideEffects(pass, lhs, pure) || code.MayHaveSideEffects(pass, rhs, pure) {
|
||
continue
|
||
}
|
||
|
||
rlh := report.Render(pass, lhs)
|
||
rrh := report.Render(pass, rhs)
|
||
if rlh == rrh {
|
||
report.Report(pass, assign, fmt.Sprintf("self-assignment of %s to %s", rrh, rlh), report.FilterGenerated())
|
||
}
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.AssignStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func buildTagsIdentical(s1, s2 []string) bool {
|
||
if len(s1) != len(s2) {
|
||
return false
|
||
}
|
||
s1s := make([]string, len(s1))
|
||
copy(s1s, s1)
|
||
sort.Strings(s1s)
|
||
s2s := make([]string, len(s2))
|
||
copy(s2s, s2)
|
||
sort.Strings(s2s)
|
||
for i, s := range s1s {
|
||
if s != s2s[i] {
|
||
return false
|
||
}
|
||
}
|
||
return true
|
||
}
|
||
|
||
func CheckDuplicateBuildConstraints(pass *analysis.Pass) (interface{}, error) {
|
||
for _, f := range pass.Files {
|
||
constraints := buildTags(f)
|
||
for i, constraint1 := range constraints {
|
||
for j, constraint2 := range constraints {
|
||
if i >= j {
|
||
continue
|
||
}
|
||
if buildTagsIdentical(constraint1, constraint2) {
|
||
msg := fmt.Sprintf("identical build constraints %q and %q",
|
||
strings.Join(constraint1, " "),
|
||
strings.Join(constraint2, " "))
|
||
report.Report(pass, f, msg, report.FilterGenerated(), report.ShortRange())
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckSillyRegexp(pass *analysis.Pass) (interface{}, error) {
|
||
// We could use the rule checking engine for this, but the
|
||
// arguments aren't really invalid.
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, b := range fn.Blocks {
|
||
for _, ins := range b.Instrs {
|
||
call, ok := ins.(*ir.Call)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if !code.IsCallToAny(call.Common(), "regexp.MustCompile", "regexp.Compile", "regexp.Match", "regexp.MatchReader", "regexp.MatchString") {
|
||
continue
|
||
}
|
||
c, ok := call.Common().Args[0].(*ir.Const)
|
||
if !ok {
|
||
continue
|
||
}
|
||
s := constant.StringVal(c.Value)
|
||
re, err := syntax.Parse(s, 0)
|
||
if err != nil {
|
||
continue
|
||
}
|
||
if re.Op != syntax.OpLiteral && re.Op != syntax.OpEmptyMatch {
|
||
continue
|
||
}
|
||
report.Report(pass, call, "regular expression does not contain any meta characters")
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckMissingEnumTypesInDeclaration(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
decl := node.(*ast.GenDecl)
|
||
if !decl.Lparen.IsValid() {
|
||
return
|
||
}
|
||
if decl.Tok != token.CONST {
|
||
return
|
||
}
|
||
|
||
groups := code.GroupSpecs(pass.Fset, decl.Specs)
|
||
groupLoop:
|
||
for _, group := range groups {
|
||
if len(group) < 2 {
|
||
continue
|
||
}
|
||
if group[0].(*ast.ValueSpec).Type == nil {
|
||
// first constant doesn't have a type
|
||
continue groupLoop
|
||
}
|
||
for i, spec := range group {
|
||
spec := spec.(*ast.ValueSpec)
|
||
if len(spec.Names) != 1 || len(spec.Values) != 1 {
|
||
continue groupLoop
|
||
}
|
||
switch v := spec.Values[0].(type) {
|
||
case *ast.BasicLit:
|
||
case *ast.UnaryExpr:
|
||
if _, ok := v.X.(*ast.BasicLit); !ok {
|
||
continue groupLoop
|
||
}
|
||
default:
|
||
// if it's not a literal it might be typed, such as
|
||
// time.Microsecond = 1000 * Nanosecond
|
||
continue groupLoop
|
||
}
|
||
if i == 0 {
|
||
continue
|
||
}
|
||
if spec.Type != nil {
|
||
continue groupLoop
|
||
}
|
||
}
|
||
var edits []analysis.TextEdit
|
||
typ := group[0].(*ast.ValueSpec).Type
|
||
for _, spec := range group[1:] {
|
||
nspec := *spec.(*ast.ValueSpec)
|
||
nspec.Type = typ
|
||
edits = append(edits, edit.ReplaceWithNode(pass.Fset, spec, &nspec))
|
||
}
|
||
report.Report(pass, group[0], "only the first constant in this group has an explicit type", report.Fixes(edit.Fix("add type to all constants in group", edits...)))
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.GenDecl)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckTimerResetReturnValue(pass *analysis.Pass) (interface{}, error) {
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, block := range fn.Blocks {
|
||
for _, ins := range block.Instrs {
|
||
call, ok := ins.(*ir.Call)
|
||
if !ok {
|
||
continue
|
||
}
|
||
if !code.IsCallTo(call.Common(), "(*time.Timer).Reset") {
|
||
continue
|
||
}
|
||
refs := call.Referrers()
|
||
if refs == nil {
|
||
continue
|
||
}
|
||
for _, ref := range code.FilterDebug(*refs) {
|
||
ifstmt, ok := ref.(*ir.If)
|
||
if !ok {
|
||
continue
|
||
}
|
||
|
||
found := false
|
||
for _, succ := range ifstmt.Block().Succs {
|
||
if len(succ.Preds) != 1 {
|
||
// Merge point, not a branch in the
|
||
// syntactical sense.
|
||
|
||
// FIXME(dh): this is broken for if
|
||
// statements a la "if x || y"
|
||
continue
|
||
}
|
||
irutil.Walk(succ, func(b *ir.BasicBlock) bool {
|
||
if !succ.Dominates(b) {
|
||
// We've reached the end of the branch
|
||
return false
|
||
}
|
||
for _, ins := range b.Instrs {
|
||
// TODO(dh): we should check that
|
||
// we're receiving from the channel of
|
||
// a time.Timer to further reduce
|
||
// false positives. Not a key
|
||
// priority, considering the rarity of
|
||
// Reset and the tiny likeliness of a
|
||
// false positive
|
||
if ins, ok := ins.(*ir.Recv); ok && code.IsType(ins.Chan.Type(), "<-chan time.Time") {
|
||
found = true
|
||
return false
|
||
}
|
||
}
|
||
return true
|
||
})
|
||
}
|
||
|
||
if found {
|
||
report.Report(pass, call, "it is not possible to use Reset's return value correctly, as there is a race condition between draining the channel and the new timer expiring")
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
var (
|
||
checkToLowerToUpperComparisonQ = pattern.MustParse(`
|
||
(BinaryExpr
|
||
(CallExpr fun@(Function (Or "strings.ToLower" "strings.ToUpper")) [a])
|
||
tok@(Or "==" "!=")
|
||
(CallExpr fun [b]))`)
|
||
checkToLowerToUpperComparisonR = pattern.MustParse(`(CallExpr (SelectorExpr (Ident "strings") (Ident "EqualFold")) [a b])`)
|
||
)
|
||
|
||
func CheckToLowerToUpperComparison(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
m, ok := Match(pass, checkToLowerToUpperComparisonQ, node)
|
||
if !ok {
|
||
return
|
||
}
|
||
rn := pattern.NodeToAST(checkToLowerToUpperComparisonR.Root, m.State).(ast.Expr)
|
||
if m.State["tok"].(token.Token) == token.NEQ {
|
||
rn = &ast.UnaryExpr{
|
||
Op: token.NOT,
|
||
X: rn,
|
||
}
|
||
}
|
||
|
||
report.Report(pass, node, "should use strings.EqualFold instead", report.Fixes(edit.Fix("replace with strings.EqualFold", edit.ReplaceWithNode(pass.Fset, node, rn))))
|
||
}
|
||
|
||
code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckUnreachableTypeCases(pass *analysis.Pass) (interface{}, error) {
|
||
// Check if T subsumes V in a type switch. T subsumes V if T is an interface and T's method set is a subset of V's method set.
|
||
subsumes := func(T, V types.Type) bool {
|
||
tIface, ok := T.Underlying().(*types.Interface)
|
||
if !ok {
|
||
return false
|
||
}
|
||
|
||
return types.Implements(V, tIface)
|
||
}
|
||
|
||
subsumesAny := func(Ts, Vs []types.Type) (types.Type, types.Type, bool) {
|
||
for _, T := range Ts {
|
||
for _, V := range Vs {
|
||
if subsumes(T, V) {
|
||
return T, V, true
|
||
}
|
||
}
|
||
}
|
||
|
||
return nil, nil, false
|
||
}
|
||
|
||
fn := func(node ast.Node) {
|
||
tsStmt := node.(*ast.TypeSwitchStmt)
|
||
|
||
type ccAndTypes struct {
|
||
cc *ast.CaseClause
|
||
types []types.Type
|
||
}
|
||
|
||
// All asserted types in the order of case clauses.
|
||
ccs := make([]ccAndTypes, 0, len(tsStmt.Body.List))
|
||
for _, stmt := range tsStmt.Body.List {
|
||
cc, _ := stmt.(*ast.CaseClause)
|
||
|
||
// Exclude the 'default' case.
|
||
if len(cc.List) == 0 {
|
||
continue
|
||
}
|
||
|
||
Ts := make([]types.Type, len(cc.List))
|
||
for i, expr := range cc.List {
|
||
Ts[i] = pass.TypesInfo.TypeOf(expr)
|
||
}
|
||
|
||
ccs = append(ccs, ccAndTypes{cc: cc, types: Ts})
|
||
}
|
||
|
||
if len(ccs) <= 1 {
|
||
// Zero or one case clauses, nothing to check.
|
||
return
|
||
}
|
||
|
||
// Check if case clauses following cc have types that are subsumed by cc.
|
||
for i, cc := range ccs[:len(ccs)-1] {
|
||
for _, next := range ccs[i+1:] {
|
||
if T, V, yes := subsumesAny(cc.types, next.types); yes {
|
||
report.Report(pass, next.cc, fmt.Sprintf("unreachable case clause: %s will always match before %s", T.String(), V.String()),
|
||
report.ShortRange())
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
code.Preorder(pass, fn, (*ast.TypeSwitchStmt)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
var checkSingleArgAppendQ = pattern.MustParse(`(CallExpr (Builtin "append") [_])`)
|
||
|
||
func CheckSingleArgAppend(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
_, ok := Match(pass, checkSingleArgAppendQ, node)
|
||
if !ok {
|
||
return
|
||
}
|
||
report.Report(pass, node, "x = append(y) is equivalent to x = y", report.FilterGenerated())
|
||
}
|
||
code.Preorder(pass, fn, (*ast.CallExpr)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func CheckStructTags(pass *analysis.Pass) (interface{}, error) {
|
||
importsGoFlags := false
|
||
|
||
// we use the AST instead of (*types.Package).Imports to work
|
||
// around vendored packages in GOPATH mode. A vendored package's
|
||
// path will include the vendoring subtree as a prefix.
|
||
for _, f := range pass.Files {
|
||
for _, imp := range f.Imports {
|
||
v := imp.Path.Value
|
||
if v[1:len(v)-1] == "github.com/jessevdk/go-flags" {
|
||
importsGoFlags = true
|
||
break
|
||
}
|
||
}
|
||
}
|
||
|
||
fn := func(node ast.Node) {
|
||
for _, field := range node.(*ast.StructType).Fields.List {
|
||
if field.Tag == nil {
|
||
continue
|
||
}
|
||
tags, err := parseStructTag(field.Tag.Value[1 : len(field.Tag.Value)-1])
|
||
if err != nil {
|
||
report.Report(pass, field.Tag, fmt.Sprintf("unparseable struct tag: %s", err))
|
||
continue
|
||
}
|
||
for k, v := range tags {
|
||
if len(v) > 1 {
|
||
isGoFlagsTag := importsGoFlags &&
|
||
(k == "choice" || k == "optional-value" || k == "default")
|
||
if !isGoFlagsTag {
|
||
report.Report(pass, field.Tag, fmt.Sprintf("duplicate struct tag %q", k))
|
||
}
|
||
}
|
||
|
||
switch k {
|
||
case "json":
|
||
checkJSONTag(pass, field, v[0])
|
||
case "xml":
|
||
checkXMLTag(pass, field, v[0])
|
||
}
|
||
}
|
||
}
|
||
}
|
||
code.Preorder(pass, fn, (*ast.StructType)(nil))
|
||
return nil, nil
|
||
}
|
||
|
||
func checkJSONTag(pass *analysis.Pass, field *ast.Field, tag string) {
|
||
if pass.Pkg.Path() == "encoding/json" || pass.Pkg.Path() == "encoding/json_test" {
|
||
// don't flag malformed JSON tags in the encoding/json
|
||
// package; it knows what it is doing, and it is testing
|
||
// itself.
|
||
return
|
||
}
|
||
//lint:ignore SA9003 TODO(dh): should we flag empty tags?
|
||
if len(tag) == 0 {
|
||
}
|
||
fields := strings.Split(tag, ",")
|
||
for _, r := range fields[0] {
|
||
if !unicode.IsLetter(r) && !unicode.IsDigit(r) && !strings.ContainsRune("!#$%&()*+-./:<=>?@[]^_{|}~ ", r) {
|
||
report.Report(pass, field.Tag, fmt.Sprintf("invalid JSON field name %q", fields[0]))
|
||
}
|
||
}
|
||
var co, cs, ci int
|
||
for _, s := range fields[1:] {
|
||
switch s {
|
||
case "omitempty":
|
||
co++
|
||
case "":
|
||
// allow stuff like "-,"
|
||
case "string":
|
||
cs++
|
||
// only for string, floating point, integer and bool
|
||
T := code.Dereference(pass.TypesInfo.TypeOf(field.Type).Underlying()).Underlying()
|
||
basic, ok := T.(*types.Basic)
|
||
if !ok || (basic.Info()&(types.IsBoolean|types.IsInteger|types.IsFloat|types.IsString)) == 0 {
|
||
report.Report(pass, field.Tag, "the JSON string option only applies to fields of type string, floating point, integer or bool, or pointers to those")
|
||
}
|
||
case "inline":
|
||
ci++
|
||
default:
|
||
report.Report(pass, field.Tag, fmt.Sprintf("unknown JSON option %q", s))
|
||
}
|
||
}
|
||
if co > 1 {
|
||
report.Report(pass, field.Tag, `duplicate JSON option "omitempty"`)
|
||
}
|
||
if cs > 1 {
|
||
report.Report(pass, field.Tag, `duplicate JSON option "string"`)
|
||
}
|
||
if ci > 1 {
|
||
report.Report(pass, field.Tag, `duplicate JSON option "inline"`)
|
||
}
|
||
}
|
||
|
||
func checkXMLTag(pass *analysis.Pass, field *ast.Field, tag string) {
|
||
//lint:ignore SA9003 TODO(dh): should we flag empty tags?
|
||
if len(tag) == 0 {
|
||
}
|
||
fields := strings.Split(tag, ",")
|
||
counts := map[string]int{}
|
||
var exclusives []string
|
||
for _, s := range fields[1:] {
|
||
switch s {
|
||
case "attr", "chardata", "cdata", "innerxml", "comment":
|
||
counts[s]++
|
||
if counts[s] == 1 {
|
||
exclusives = append(exclusives, s)
|
||
}
|
||
case "omitempty", "any":
|
||
counts[s]++
|
||
case "":
|
||
default:
|
||
report.Report(pass, field.Tag, fmt.Sprintf("unknown XML option %q", s))
|
||
}
|
||
}
|
||
for k, v := range counts {
|
||
if v > 1 {
|
||
report.Report(pass, field.Tag, fmt.Sprintf("duplicate XML option %q", k))
|
||
}
|
||
}
|
||
if len(exclusives) > 1 {
|
||
report.Report(pass, field.Tag, fmt.Sprintf("XML options %s are mutually exclusive", strings.Join(exclusives, " and ")))
|
||
}
|
||
}
|
||
|
||
func CheckImpossibleTypeAssertion(pass *analysis.Pass) (interface{}, error) {
|
||
type entry struct {
|
||
l, r *types.Func
|
||
}
|
||
|
||
msc := &pass.ResultOf[buildir.Analyzer].(*buildir.IR).Pkg.Prog.MethodSets
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
for _, b := range fn.Blocks {
|
||
for _, instr := range b.Instrs {
|
||
assert, ok := instr.(*ir.TypeAssert)
|
||
if !ok {
|
||
continue
|
||
}
|
||
var wrong []entry
|
||
left := assert.X.Type()
|
||
right := assert.AssertedType
|
||
righti, ok := right.Underlying().(*types.Interface)
|
||
|
||
if !ok {
|
||
// We only care about interface->interface
|
||
// assertions. The Go compiler already catches
|
||
// impossible interface->concrete assertions.
|
||
continue
|
||
}
|
||
|
||
ms := msc.MethodSet(left)
|
||
for i := 0; i < righti.NumMethods(); i++ {
|
||
mr := righti.Method(i)
|
||
sel := ms.Lookup(mr.Pkg(), mr.Name())
|
||
if sel == nil {
|
||
continue
|
||
}
|
||
ml := sel.Obj().(*types.Func)
|
||
if types.AssignableTo(ml.Type(), mr.Type()) {
|
||
continue
|
||
}
|
||
|
||
wrong = append(wrong, entry{ml, mr})
|
||
}
|
||
|
||
if len(wrong) != 0 {
|
||
s := fmt.Sprintf("impossible type assertion; %s and %s contradict each other:",
|
||
types.TypeString(left, types.RelativeTo(pass.Pkg)),
|
||
types.TypeString(right, types.RelativeTo(pass.Pkg)))
|
||
for _, e := range wrong {
|
||
s += fmt.Sprintf("\n\twrong type for %s method", e.l.Name())
|
||
s += fmt.Sprintf("\n\t\thave %s", e.l.Type())
|
||
s += fmt.Sprintf("\n\t\twant %s", e.r.Type())
|
||
}
|
||
report.Report(pass, assert, s)
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return nil, nil
|
||
}
|
||
|
||
func checkWithValueKey(call *Call) {
|
||
arg := call.Args[1]
|
||
T := arg.Value.Value.Type()
|
||
if T, ok := T.(*types.Basic); ok {
|
||
arg.Invalid(
|
||
fmt.Sprintf("should not use built-in type %s as key for value; define your own type to avoid collisions", T))
|
||
}
|
||
if !types.Comparable(T) {
|
||
arg.Invalid(fmt.Sprintf("keys used with context.WithValue must be comparable, but type %s is not comparable", T))
|
||
}
|
||
}
|
||
|
||
func CheckMaybeNil(pass *analysis.Pass) (interface{}, error) {
|
||
// This is an extremely trivial check that doesn't try to reason
|
||
// about control flow. That is, phis and sigmas do not propagate
|
||
// any information. As such, we can flag this:
|
||
//
|
||
// _ = *x
|
||
// if x == nil { return }
|
||
//
|
||
// but we cannot flag this:
|
||
//
|
||
// if x == nil { println(x) }
|
||
// _ = *x
|
||
//
|
||
// nor many other variations of conditional uses of or assignments to x.
|
||
//
|
||
// However, even this trivial implementation finds plenty of
|
||
// real-world bugs, such as dereference before nil pointer check,
|
||
// or using t.Error instead of t.Fatal when encountering nil
|
||
// pointers.
|
||
//
|
||
// On the flip side, our naive implementation avoids false positives in branches, such as
|
||
//
|
||
// if x != nil { _ = *x }
|
||
//
|
||
// due to the same lack of propagating information through sigma
|
||
// nodes. x inside the branch will be independent of the x in the
|
||
// nil pointer check.
|
||
//
|
||
//
|
||
// We could implement a more powerful check, but then we'd be
|
||
// getting false positives instead of false negatives because
|
||
// we're incapable of deducing relationships between variables.
|
||
// For example, a function might return a pointer and an error,
|
||
// and the error being nil guarantees that the pointer is not nil.
|
||
// Depending on the surrounding code, the pointer may still end up
|
||
// being checked against nil in one place, and guarded by a check
|
||
// on the error in another, which would lead to us marking some
|
||
// loads as unsafe.
|
||
//
|
||
// Unfortunately, simply hard-coding the relationship between
|
||
// return values wouldn't eliminate all false positives, either.
|
||
// Many other more subtle relationships exist. An abridged example
|
||
// from real code:
|
||
//
|
||
// if a == nil && b == nil { return }
|
||
// c := fn(a)
|
||
// if c != "" { _ = *a }
|
||
//
|
||
// where `fn` is guaranteed to return a non-empty string if a
|
||
// isn't nil.
|
||
//
|
||
// We choose to err on the side of false negatives.
|
||
|
||
isNilConst := func(v ir.Value) bool {
|
||
if code.IsPointerLike(v.Type()) {
|
||
if k, ok := v.(*ir.Const); ok {
|
||
return k.IsNil()
|
||
}
|
||
}
|
||
return false
|
||
}
|
||
|
||
for _, fn := range pass.ResultOf[buildir.Analyzer].(*buildir.IR).SrcFuncs {
|
||
maybeNil := map[ir.Value]ir.Instruction{}
|
||
for _, b := range fn.Blocks {
|
||
for _, instr := range b.Instrs {
|
||
if instr, ok := instr.(*ir.BinOp); ok {
|
||
var ptr ir.Value
|
||
if isNilConst(instr.X) {
|
||
ptr = instr.Y
|
||
} else if isNilConst(instr.Y) {
|
||
ptr = instr.X
|
||
}
|
||
maybeNil[ptr] = instr
|
||
}
|
||
}
|
||
}
|
||
|
||
for _, b := range fn.Blocks {
|
||
for _, instr := range b.Instrs {
|
||
var ptr ir.Value
|
||
switch instr := instr.(type) {
|
||
case *ir.Load:
|
||
ptr = instr.X
|
||
case *ir.Store:
|
||
ptr = instr.Addr
|
||
case *ir.IndexAddr:
|
||
ptr = instr.X
|
||
case *ir.FieldAddr:
|
||
ptr = instr.X
|
||
}
|
||
if ptr != nil {
|
||
switch ptr.(type) {
|
||
case *ir.Alloc, *ir.FieldAddr, *ir.IndexAddr:
|
||
// these cannot be nil
|
||
continue
|
||
}
|
||
if r, ok := maybeNil[ptr]; ok {
|
||
report.Report(pass, instr, "possible nil pointer dereference",
|
||
report.Related(r, "this check suggests that the pointer can be nil"))
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
return nil, nil
|
||
}
|
||
|
||
var checkAddressIsNilQ = pattern.MustParse(
|
||
`(BinaryExpr
|
||
(UnaryExpr "&" _)
|
||
(Or "==" "!=")
|
||
(Builtin "nil"))`)
|
||
|
||
func CheckAddressIsNil(pass *analysis.Pass) (interface{}, error) {
|
||
fn := func(node ast.Node) {
|
||
_, ok := Match(pass, checkAddressIsNilQ, node)
|
||
if !ok {
|
||
return
|
||
}
|
||
report.Report(pass, node, "the address of a variable cannot be nil")
|
||
}
|
||
code.Preorder(pass, fn, (*ast.BinaryExpr)(nil))
|
||
return nil, nil
|
||
}
|