fix(seenmapbool): eliminate duplicate diagnostics for set-maps in closures

pkg/linters/seenmapbool/seenmapbool.go

@@ -67,7 +67,15 @@ func inspectBody(pass *analysis.Pass, body *ast.BlockStmt, noLintLinesByFile map
 	candidates := make(map[types.Object]ast.Node) // object -> declaration node for reporting
 
 	// First pass: collect declarations of map[string]bool locals.
+	// Stop at nested FuncLit boundaries so each closure is handled by its own
+	// Preorder visit — preventing duplicate diagnostics.
 	ast.Inspect(body, func(n ast.Node) bool {
+		if n == nil {
+			return false
+		}
+		if _, ok := n.(*ast.FuncLit); ok {
+			return false // do not descend into nested closures
+		}
 		switch stmt := n.(type) {
 		case *ast.AssignStmt:
 			// seen := make(map[string]bool)  or  seen := map[string]bool{}

pkg/linters/seenmapbool/testdata/src/seenmapbool/seenmapbool.go

@@ -39,3 +39,44 @@ func GoodBoolMapWithFalse() {
 	flags["disabled"] = false
 	_ = flags
 }
+
+func BadSetBoolInClosure() []string {
+	// Set-map declared inside a closure must be reported exactly once.
+	unique := func(in []string) []string {
+		seen := make(map[string]bool) // want `map\[string\]bool "seen" used as a set`
+		var out []string
+		for _, x := range in {
+			if !seen[x] {
+				seen[x] = true
+				out = append(out, x)
+			}
+		}
+		return out
+	}
+	return unique([]string{"a", "b", "a"})
+}
+
+func BadSetBoolInNestedClosure() {
+	// Two levels of nesting: each set-map is reported exactly once.
+	outer := func() {
+		inner := func() {
+			seen := make(map[string]bool) // want `map\[string\]bool "seen" used as a set`
+			seen["x"] = true
+			_ = seen
+		}
+		inner()
+	}
+	outer()
+}
+
+func GoodOuterMapWrittenFalseInClosure() {
+	// Map declared in outer function but written false inside a closure — not a
+	// pure set; must NOT be reported.
+	flags := make(map[string]bool)
+	modify := func() {
+		flags["disabled"] = false
+	}
+	flags["enabled"] = true
+	modify()
+	_ = flags
+}