Analyzer: Gather operator super calls for mustCallSuper

Fixes #27896

Change-Id: I7017026346a92ffc43a3cfa506f7a257af1a3471
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/164421
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Samuel Rawlins <[email protected]>

Author: srawlins

pkg/analyzer/lib/src/generated/error_verifier.dart

@@ -5395,6 +5395,14 @@ class HiddenElements {
 class _InvocationCollector extends RecursiveAstVisitor<void> {
   final List<String> superCalls = <String>[];
 
+  @override
+  void visitBinaryExpression(BinaryExpression node) {
+    if (node.leftOperand is SuperExpression) {
+      superCalls.add(node.operator.lexeme);
+    }
+    super.visitBinaryExpression(node);
+  }
+
   @override
   void visitMethodInvocation(MethodInvocation node) {
     if (node.target is SuperExpression) {

pkg/analyzer/test/src/diagnostics/must_call_super_test.dart

@@ -82,6 +82,36 @@ class B extends A {
 ''');
   }
 
+  test_fromExtendingClass_operator() async {
+    await assertErrorsInCode(r'''
+import 'package:meta/meta.dart';
+class A {
+  @mustCallSuper
+  operator ==(Object o) => o is A;
+}
+class B extends A {
+  @override
+  operator ==(Object o) => o is B;
+}
+''', [
+      error(HintCode.MUST_CALL_SUPER, 140, 2),
+    ]);
+  }
+
+  test_fromExtendingClass_operator_containsSuperCall() async {
+    await assertNoErrorsInCode(r'''
+import 'package:meta/meta.dart';
+class A {
+  @mustCallSuper
+  operator ==(Object o) => o is A;
+}
+class B extends A {
+  @override
+  operator ==(Object o) => o is B && super == o;
+}
+''');
+  }
+
   test_fromInterface() async {
     await assertNoErrorsInCode(r'''
 import 'package:meta/meta.dart';