src

sa4011.go (2246B)

---

 package sa4011
 
 import (
 	"go/ast"
 	"go/token"
 
 	"honnef.co/go/tools/analysis/code"
 	"honnef.co/go/tools/analysis/lint"
 	"honnef.co/go/tools/analysis/report"
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
 )
 
 var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
 	Analyzer: &analysis.Analyzer{
 		Name:     "SA4011",
 		Run:      run,
 		Requires: []*analysis.Analyzer{inspect.Analyzer},
 	},
 	Doc: &lint.RawDocumentation{
 		Title:    `Break statement with no effect. Did you mean to break out of an outer loop?`,
 		Since:    "2017.1",
 		Severity: lint.SeverityWarning,
 		MergeIf:  lint.MergeIfAny,
 	},
 })
 
 var Analyzer = SCAnalyzer.Analyzer
 
 func run(pass *analysis.Pass) (any, 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:
 			lint.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
 }