[DAS] Fixes infering bool for guard in create fixes

Fixes: #61589
Change-Id: Iaf43927c9d3fcf43b2dfa23c91e17333baeed184
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/452181
Reviewed-by: Samuel Rawlins <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>
Auto-Submit: Felipe Morschel <[email protected]>
Commit-Queue: Brian Wilkerson <[email protected]>

Author: FMorschel

pkg/analysis_server/test/src/services/correction/fix/create_getter_test.dart

@@ -261,6 +261,25 @@ void f(A a) {
 ''');
   }
 
+  Future<void> test_guard() async {
+    await resolveTestCode('''
+class A {
+  void f(Object? x) {
+    if (x case String() when getter) {}
+  }
+}
+''');
+    await assertHasFix('''
+class A {
+  bool get getter => null;
+
+  void f(Object? x) {
+    if (x case String() when getter) {}
+  }
+}
+''');
+  }
+
   Future<void> test_hint_getter() async {
     await resolveTestCode('''
 class A {

pkg/analysis_server_plugin/lib/edit/dart/correction_producer.dart

@@ -658,6 +658,12 @@ abstract class ResolvedCorrectionProducer
           return _coreTypeBool;
         }
       }
+      if (parent is WhenClause) {
+        var clause = parent;
+        if (clause.expression == expression) {
+          return _coreTypeBool;
+        }
+      }
       // `while ( myFunction() ) {}`.
       if (parent is WhileStatement) {
         var statement = parent;