sa4021.go raw

   1  package sa4021
   2  
   3  import (
   4  	"go/ast"
   5  
   6  	"honnef.co/go/tools/analysis/code"
   7  	"honnef.co/go/tools/analysis/facts/generated"
   8  	"honnef.co/go/tools/analysis/lint"
   9  	"honnef.co/go/tools/analysis/report"
  10  	"honnef.co/go/tools/pattern"
  11  
  12  	"golang.org/x/tools/go/analysis"
  13  	"golang.org/x/tools/go/analysis/passes/inspect"
  14  )
  15  
  16  var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
  17  	Analyzer: &analysis.Analyzer{
  18  		Name:     "SA4021",
  19  		Run:      run,
  20  		Requires: []*analysis.Analyzer{inspect.Analyzer, generated.Analyzer},
  21  	},
  22  	Doc: &lint.RawDocumentation{
  23  		Title:    `\"x = append(y)\" is equivalent to \"x = y\"`,
  24  		Since:    "2019.2",
  25  		Severity: lint.SeverityWarning,
  26  		MergeIf:  lint.MergeIfAny,
  27  	},
  28  })
  29  
  30  var Analyzer = SCAnalyzer.Analyzer
  31  
  32  var checkSingleArgAppendQ = pattern.MustParse(`(CallExpr (Builtin "append") [_])`)
  33  
  34  func run(pass *analysis.Pass) (interface{}, error) {
  35  	fn := func(node ast.Node) {
  36  		_, ok := code.Match(pass, checkSingleArgAppendQ, node)
  37  		if !ok {
  38  			return
  39  		}
  40  		report.Report(pass, node, "x = append(y) is equivalent to x = y", report.FilterGenerated())
  41  	}
  42  	code.Preorder(pass, fn, (*ast.CallExpr)(nil))
  43  	return nil, nil
  44  }
  45