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https://github.com/golang/go
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45 lines
1.1 KiB
Go
45 lines
1.1 KiB
Go
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// Copyright 2013 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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/*
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This file contains the code to check for useless assignments.
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*/
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package main
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import (
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"go/ast"
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"go/token"
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"reflect"
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)
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// TODO: should also check for assignments to struct fields inside methods
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// that are on T instead of *T.
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// checkAssignStmt checks for assignments of the form "<expr> = <expr>".
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// These are almost always useless, and even when they aren't they are usually a mistake.
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func (f *File) checkAssignStmt(stmt *ast.AssignStmt) {
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if !vet("assign") {
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return
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}
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if stmt.Tok != token.ASSIGN {
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return // ignore :=
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}
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if len(stmt.Lhs) != len(stmt.Rhs) {
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// If LHS and RHS have different cardinality, they can't be the same.
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return
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}
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for i, lhs := range stmt.Lhs {
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rhs := stmt.Rhs[i]
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if reflect.TypeOf(lhs) != reflect.TypeOf(rhs) {
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continue // short-circuit the heavy-weight gofmt check
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}
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le := f.gofmt(lhs)
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re := f.gofmt(rhs)
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if le == re {
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f.Warnf(stmt.Pos(), "self-assignment of %s to %s", re, le)
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}
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}
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}
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