github.com/amarpal/go-tools@v0.0.0-20240422043104-40142f59f616/staticcheck/sa4018/sa4018.go (about)

     1  package sa4018
     2  
     3  import (
     4  	"fmt"
     5  	"go/ast"
     6  	"go/token"
     7  	"reflect"
     8  
     9  	"github.com/amarpal/go-tools/analysis/code"
    10  	"github.com/amarpal/go-tools/analysis/facts/generated"
    11  	"github.com/amarpal/go-tools/analysis/facts/purity"
    12  	"github.com/amarpal/go-tools/analysis/lint"
    13  	"github.com/amarpal/go-tools/analysis/report"
    14  
    15  	"golang.org/x/tools/go/analysis"
    16  	"golang.org/x/tools/go/analysis/passes/inspect"
    17  )
    18  
    19  var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
    20  	Analyzer: &analysis.Analyzer{
    21  		Name:     "SA4018",
    22  		Run:      run,
    23  		Requires: []*analysis.Analyzer{inspect.Analyzer, generated.Analyzer, purity.Analyzer},
    24  	},
    25  	Doc: &lint.Documentation{
    26  		Title:    `Self-assignment of variables`,
    27  		Since:    "2017.1",
    28  		Severity: lint.SeverityWarning,
    29  		MergeIf:  lint.MergeIfAny,
    30  	},
    31  })
    32  
    33  var Analyzer = SCAnalyzer.Analyzer
    34  
    35  func run(pass *analysis.Pass) (interface{}, error) {
    36  	pure := pass.ResultOf[purity.Analyzer].(purity.Result)
    37  
    38  	fn := func(node ast.Node) {
    39  		assign := node.(*ast.AssignStmt)
    40  		if assign.Tok != token.ASSIGN || len(assign.Lhs) != len(assign.Rhs) {
    41  			return
    42  		}
    43  		for i, lhs := range assign.Lhs {
    44  			rhs := assign.Rhs[i]
    45  			if reflect.TypeOf(lhs) != reflect.TypeOf(rhs) {
    46  				continue
    47  			}
    48  			if code.MayHaveSideEffects(pass, lhs, pure) || code.MayHaveSideEffects(pass, rhs, pure) {
    49  				continue
    50  			}
    51  
    52  			rlh := report.Render(pass, lhs)
    53  			rrh := report.Render(pass, rhs)
    54  			if rlh == rrh {
    55  				report.Report(pass, assign, fmt.Sprintf("self-assignment of %s to %s", rrh, rlh), report.FilterGenerated())
    56  			}
    57  		}
    58  	}
    59  	code.Preorder(pass, fn, (*ast.AssignStmt)(nil))
    60  	return nil, nil
    61  }