mirror of
https://github.com/autc04/Retro68.git
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94 lines
2.4 KiB
Go
94 lines
2.4 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// This file defines the check for unused results of calls to certain
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// pure functions.
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package main
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import (
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"flag"
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"go/ast"
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"go/token"
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"go/types"
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"strings"
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)
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var unusedFuncsFlag = flag.String("unusedfuncs",
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"errors.New,fmt.Errorf,fmt.Sprintf,fmt.Sprint,sort.Reverse",
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"comma-separated list of functions whose results must be used")
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var unusedStringMethodsFlag = flag.String("unusedstringmethods",
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"Error,String",
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"comma-separated list of names of methods of type func() string whose results must be used")
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func init() {
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register("unusedresult",
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"check for unused result of calls to functions in -unusedfuncs list and methods in -unusedstringmethods list",
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checkUnusedResult,
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exprStmt)
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}
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// func() string
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var sigNoArgsStringResult = types.NewSignature(nil, nil,
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types.NewTuple(types.NewVar(token.NoPos, nil, "", types.Typ[types.String])),
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false)
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var unusedFuncs = make(map[string]bool)
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var unusedStringMethods = make(map[string]bool)
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func initUnusedFlags() {
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commaSplit := func(s string, m map[string]bool) {
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if s != "" {
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for _, name := range strings.Split(s, ",") {
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if len(name) == 0 {
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flag.Usage()
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}
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m[name] = true
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}
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}
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}
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commaSplit(*unusedFuncsFlag, unusedFuncs)
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commaSplit(*unusedStringMethodsFlag, unusedStringMethods)
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}
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func checkUnusedResult(f *File, n ast.Node) {
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call, ok := unparen(n.(*ast.ExprStmt).X).(*ast.CallExpr)
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if !ok {
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return // not a call statement
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}
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fun := unparen(call.Fun)
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if f.pkg.types[fun].IsType() {
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return // a conversion, not a call
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}
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selector, ok := fun.(*ast.SelectorExpr)
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if !ok {
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return // neither a method call nor a qualified ident
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}
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sel, ok := f.pkg.selectors[selector]
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if ok && sel.Kind() == types.MethodVal {
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// method (e.g. foo.String())
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obj := sel.Obj().(*types.Func)
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sig := sel.Type().(*types.Signature)
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if types.Identical(sig, sigNoArgsStringResult) {
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if unusedStringMethods[obj.Name()] {
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f.Badf(call.Lparen, "result of (%s).%s call not used",
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sig.Recv().Type(), obj.Name())
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}
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}
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} else if !ok {
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// package-qualified function (e.g. fmt.Errorf)
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obj := f.pkg.uses[selector.Sel]
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if obj, ok := obj.(*types.Func); ok {
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qname := obj.Pkg().Path() + "." + obj.Name()
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if unusedFuncs[qname] {
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f.Badf(call.Lparen, "result of %v call not used", qname)
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}
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}
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}
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}
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