Add staticcheck tool

vendor/honnef.co/go/tools/staticcheck/sa4024/sa4024.go

@@ -0,0 +1,58 @@
+package sa4024
+
+import (
+	"fmt"
+	"go/ast"
+
+	"honnef.co/go/tools/analysis/code"
+	"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:     "SA4024",
+		Run:      run,
+		Requires: code.RequiredAnalyzers,
+	},
+	Doc: &lint.RawDocumentation{
+		Title: `Checking for impossible return value from a builtin function`,
+		Text: `Return values of the \'len\' and \'cap\' builtins cannot be negative.
+
+See https://golang.org/pkg/builtin/#len and https://golang.org/pkg/builtin/#cap.
+
+Example:
+
+    if len(slice) < 0 {
+        fmt.Println("unreachable code")
+    }`,
+		Since:    "2021.1",
+		Severity: lint.SeverityWarning,
+		MergeIf:  lint.MergeIfAny,
+	},
+})
+
+var Analyzer = SCAnalyzer.Analyzer
+
+var builtinLessThanZeroQ = pattern.MustParse(`
+	(Or
+		(BinaryExpr
+			(IntegerLiteral "0")
+			">"
+			(CallExpr builtin@(Builtin (Or "len" "cap")) _))
+		(BinaryExpr
+			(CallExpr builtin@(Builtin (Or "len" "cap")) _)
+			"<"
+			(IntegerLiteral "0")))
+`)
+
+func run(pass *analysis.Pass) (any, error) {
+	for node, matcher := range code.Matches(pass, builtinLessThanZeroQ) {
+		builtin := matcher.State["builtin"].(*ast.Ident)
+		report.Report(pass, node, fmt.Sprintf("builtin function %s does not return negative values", builtin.Name))
+	}
+	return nil, nil
+}