Add staticcheck tool

vendor/honnef.co/go/tools/simple/s1033/s1033.go

@@ -0,0 +1,50 @@
+package s1033
+
+import (
+	"go/ast"
+
+	"honnef.co/go/tools/analysis/code"
+	"honnef.co/go/tools/analysis/edit"
+	"honnef.co/go/tools/analysis/facts/generated"
+	"honnef.co/go/tools/analysis/lint"
+	"honnef.co/go/tools/analysis/report"
+	"honnef.co/go/tools/pattern"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
+	Analyzer: &analysis.Analyzer{
+		Name:     "S1033",
+		Run:      run,
+		Requires: append([]*analysis.Analyzer{generated.Analyzer}, code.RequiredAnalyzers...),
+	},
+	Doc: &lint.RawDocumentation{
+		Title:   `Unnecessary guard around call to \"delete\"`,
+		Text:    `Calling \'delete\' on a nil map is a no-op.`,
+		Since:   "2019.2",
+		MergeIf: lint.MergeIfAny,
+	},
+})
+
+var Analyzer = SCAnalyzer.Analyzer
+
+var checkGuardedDeleteQ = pattern.MustParse(`
+	(IfStmt
+		(AssignStmt
+			[(Ident "_") ok@(Ident _)]
+			":="
+			(IndexExpr m key))
+		ok
+		[call@(CallExpr (Builtin "delete") [m key])]
+		nil)`)
+
+func run(pass *analysis.Pass) (any, error) {
+	for node, m := range code.Matches(pass, checkGuardedDeleteQ) {
+		report.Report(pass, node, "unnecessary guard around call to delete",
+			report.ShortRange(),
+			report.FilterGenerated(),
+			report.Fixes(edit.Fix("Remove guard", edit.ReplaceWithNode(pass.Fset, node, m.State["call"].(ast.Node)))))
+	}
+	return nil, nil
+}