Handle TopLevelVariableDeclaration in ConvertToFunctionDeclaration.

Closes #61819

GitOrigin-RevId: 6113f84
Change-Id: I33d684af2ce9dd050679235c5bd2182fed1f1dfe
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/457560
Reviewed-by: Samuel Rawlins <[email protected]>
Commit-Queue: Samuel Rawlins <[email protected]>

Author: AgamAgarwal

pkg/analysis_server/lib/src/services/correction/dart/convert_to_function_declaration.dart

@@ -48,6 +48,8 @@ class ConvertToFunctionDeclaration extends ResolvedCorrectionProducer {
       grandParentSemicolon = grandParent.semicolon;
     } else if (grandParent is FieldDeclaration) {
       grandParentSemicolon = grandParent.semicolon;
+    } else if (grandParent is TopLevelVariableDeclaration) {
+      grandParentSemicolon = grandParent.semicolon;
     } else {
       return;
     }

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

@@ -270,6 +270,23 @@ void f() {
 ''');
   }
 
+  Future<void> test_top_level_declaration() async {
+    await resolveTestCode('''
+final v1 = () => 42;
+
+void f() {
+  v1();
+}
+''');
+    await assertHasFix('''
+int v1() => 42;
+
+void f() {
+  v1();
+}
+''');
+  }
+
   Future<void> test_type() async {
     await resolveTestCode('''
 void f() {