mirror of
https://github.com/golang/go
synced 2024-09-30 18:18:32 -06:00
f895b43688
This removes much of the AST logic out of main.go, and makes it easier to build custom vet binaries The trade-off in this change is for flexibility. There's very little change in the per-check files, a lot less code in main.go (specifically the AST walking logic has shrunk), and it makes it much easier to build custom vet binaries simply by dropping new source files in the directory. LGTM=josharian, r R=r, josharian, kamil.kisiel CC=golang-codereviews https://golang.org/cl/83400043
50 lines
1.2 KiB
Go
50 lines
1.2 KiB
Go
// 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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func init() {
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register("assign",
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"check for useless assignments",
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checkAssignStmt,
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assignStmt)
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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 checkAssignStmt(f *File, node ast.Node) {
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stmt := node.(*ast.AssignStmt)
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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.Badf(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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