fix: fix regression in avoid-unnecessary-type-assertions

Author: incendial

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 4.18.3
+
+* fix: fix regression in is! checks for [`avoid-unnecessary-type-assertions`](https://dartcodemetrics.dev/docs/rules/common/avoid-unnecessary-type-assertions).
+
 ## 4.18.2
 
 * fix: use empty analysis options exclude to properly resolve units and speed up commands analysis.

lib/src/analyzers/lint_analyzer/rules/rules_list/avoid_unnecessary_type_assertions/visitor.dart

@@ -45,6 +45,7 @@ class _Visitor extends RecursiveAstVisitor<void> {
 
     if (node.notOperator != null) {
       if (objectType != null &&
+          objectType is! TypeParameterType &&
           !objectType.isDynamic &&
           !objectType.isDartCoreObject &&
           _isUselessTypeCheck(castedType, objectType, true)) {

test/resources/unnecessary_nullable_analyzer/suppressed_file.dart

@@ -1,4 +1,4 @@
-// ignore_for_file: unnecessary-nullable
+// ignore_for_file: unnecessary-nullable, avoid-unused-parameters, no-empty-block
 
 class IgnoredClassWithMethods {
   void someMethod(String? value) {}

test/src/analyzers/lint_analyzer/rules/rules_list/avoid_unnecessary_type_assertions/examples/example_with_not_is.dart

@@ -26,3 +26,8 @@ void checkSameOrInheritor() {
   final Object b;
   final check = b is! int;
 }
+
+void check<T>() {
+  final T b;
+  final check = b is! int;
+}