fix: handle property access for unnecessary nullable tear-offs

Author: incendial

lib/src/analyzers/unnecessary_nullable_analyzer/invocations_visitor.dart

@@ -21,6 +21,15 @@ class InvocationsVisitor extends RecursiveAstVisitor<void> {
     }
   }
 
+  @override
+  void visitPropertyAccess(PropertyAccess node) {
+    super.visitPropertyAccess(node);
+
+    if (node.propertyName.staticType is FunctionType) {
+      _recordUsedElement(node.propertyName.staticElement, null);
+    }
+  }
+
   @override
   void visitPrefixedIdentifier(PrefixedIdentifier node) {
     super.visitPrefixedIdentifier(node);

test/resources/unnecessary_nullable_analyzer/nullable_method_parameters.dart

@@ -1,6 +1,8 @@
 // ignore_for_file: avoid-unused-parameters, no-empty-block
 
 class ClassWithMethods {
+  final inner = ClassWithMethods();
+
   void someMethod(String? value) {}
 
   // LINT
@@ -24,4 +26,6 @@ class ClassWithMethods {
   void ignoredAlwaysNonNullable(String? anotherValue) {}
 
   void tearOff(String? anotherValue) {}
+
+  void anotherTearOff(String? anotherValue) {}
 }

test/resources/unnecessary_nullable_analyzer/unnecessary_nullable_example.dart

@@ -47,6 +47,7 @@ void main() {
   MyWidget(GlobalKey());
 
   AnotherWidget(onSubmit: withMethods.tearOff);
+  AnotherWidget(onSubmit: withMethods.inner.anotherTearOff);
 }
 
 class _Test {

test/src/analyzers/unnecessary_nullable_analyzer/unnecessary_nullable_analyzer_test.dart

@@ -73,7 +73,7 @@ void main() {
           expect(firstIssue.declarationName, 'alwaysNonNullable');
           expect(firstIssue.declarationType, 'method');
           expect(firstIssue.parameters.toString(), '(String? anotherValue)');
-          expect(firstIssue.location.line, 7);
+          expect(firstIssue.location.line, 9);
           expect(firstIssue.location.column, 3);
 
           final secondIssue = report.issues.last;
@@ -83,7 +83,7 @@ void main() {
             secondIssue.parameters.toString(),
             '(String? value, required String? name)',
           );
-          expect(secondIssue.location.line, 16);
+          expect(secondIssue.location.line, 18);
           expect(secondIssue.location.column, 3);
         });