github.com/amarpal/go-tools@v0.0.0-20240422043104-40142f59f616/staticcheck/sa4001/sa4001.go (about)

     1  package sa4001
     2  
     3  import (
     4  	"go/ast"
     5  	"regexp"
     6  
     7  	"github.com/amarpal/go-tools/analysis/code"
     8  	"github.com/amarpal/go-tools/analysis/lint"
     9  	"github.com/amarpal/go-tools/analysis/report"
    10  	"github.com/amarpal/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:     "SA4001",
    19  		Run:      run,
    20  		Requires: []*analysis.Analyzer{inspect.Analyzer},
    21  	},
    22  	Doc: &lint.Documentation{
    23  		Title:    `\'&*x\' gets simplified to \'x\', it does not copy \'x\'`,
    24  		Since:    "2017.1",
    25  		Severity: lint.SeverityWarning,
    26  		MergeIf:  lint.MergeIfAny,
    27  	},
    28  })
    29  
    30  var Analyzer = SCAnalyzer.Analyzer
    31  
    32  var (
    33  	// cgo produces code like fn(&*_Cvar_kSomeCallbacks) which we don't
    34  	// want to flag.
    35  	cgoIdent               = regexp.MustCompile(`^_C(func|var)_.+$`)
    36  	checkIneffectiveCopyQ1 = pattern.MustParse(`(UnaryExpr "&" (StarExpr obj))`)
    37  	checkIneffectiveCopyQ2 = pattern.MustParse(`(StarExpr (UnaryExpr "&" _))`)
    38  )
    39  
    40  func run(pass *analysis.Pass) (interface{}, error) {
    41  	fn := func(node ast.Node) {
    42  		if m, ok := code.Match(pass, checkIneffectiveCopyQ1, node); ok {
    43  			if ident, ok := m.State["obj"].(*ast.Ident); !ok || !cgoIdent.MatchString(ident.Name) {
    44  				report.Report(pass, node, "&*x will be simplified to x. It will not copy x.")
    45  			}
    46  		} else if _, ok := code.Match(pass, checkIneffectiveCopyQ2, node); ok {
    47  			report.Report(pass, node, "*&x will be simplified to x. It will not copy x.")
    48  		}
    49  	}
    50  	code.Preorder(pass, fn, (*ast.UnaryExpr)(nil), (*ast.StarExpr)(nil))
    51  	return nil, nil
    52  }