80 lines
2.2 KiB
Go
80 lines
2.2 KiB
Go
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package s1023
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import (
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"go/ast"
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"go/token"
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"honnef.co/go/tools/analysis/code"
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"honnef.co/go/tools/analysis/facts/generated"
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"honnef.co/go/tools/analysis/lint"
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"honnef.co/go/tools/analysis/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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)
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var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
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Analyzer: &analysis.Analyzer{
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Name: "S1023",
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Run: run,
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Requires: []*analysis.Analyzer{inspect.Analyzer, generated.Analyzer},
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},
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Doc: &lint.RawDocumentation{
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Title: `Omit redundant control flow`,
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Text: `Functions that have no return value do not need a return statement as
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the final statement of the function.
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Switches in Go do not have automatic fallthrough, unlike languages
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like C. It is not necessary to have a break statement as the final
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statement in a case block.`,
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Since: "2017.1",
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MergeIf: lint.MergeIfAny,
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},
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})
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var Analyzer = SCAnalyzer.Analyzer
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func run(pass *analysis.Pass) (any, error) {
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fn1 := func(node ast.Node) {
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clause := node.(*ast.CaseClause)
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if len(clause.Body) < 2 {
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return
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}
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branch, ok := clause.Body[len(clause.Body)-1].(*ast.BranchStmt)
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if !ok || branch.Tok != token.BREAK || branch.Label != nil {
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return
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}
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report.Report(pass, branch, "redundant break statement", report.FilterGenerated())
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}
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fn2 := func(node ast.Node) {
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var ret *ast.FieldList
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var body *ast.BlockStmt
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switch x := node.(type) {
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case *ast.FuncDecl:
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ret = x.Type.Results
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body = x.Body
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case *ast.FuncLit:
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ret = x.Type.Results
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body = x.Body
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default:
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lint.ExhaustiveTypeSwitch(node)
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}
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// if the func has results, a return can't be redundant.
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// similarly, if there are no statements, there can be
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// no return.
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if ret != nil || body == nil || len(body.List) < 1 {
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return
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}
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rst, ok := body.List[len(body.List)-1].(*ast.ReturnStmt)
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if !ok {
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return
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}
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// we don't need to check rst.Results as we already
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// checked x.Type.Results to be nil.
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report.Report(pass, rst, "redundant return statement", report.FilterGenerated())
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}
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code.Preorder(pass, fn1, (*ast.CaseClause)(nil))
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code.Preorder(pass, fn2, (*ast.FuncDecl)(nil), (*ast.FuncLit)(nil))
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return nil, nil
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}
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