[DAS] Convert to switch statement considers operator

Fixes: #60429
Change-Id: Ie3fa5b9ed1fa9677017a694144b0809ba47c284a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/420841
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Phil Quitslund <[email protected]>
Auto-Submit: Felipe Morschel <[email protected]>
Reviewed-by: Phil Quitslund <[email protected]>

Author: FMorschel

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

@@ -394,7 +394,9 @@ class ConvertSwitchExpressionToSwitchStatement
         switchExpression: switchExpression,
         builder: builder,
         indent: indent,
-        beforeCaseExpression: '${variableId.token.lexeme} = ',
+        beforeCaseExpression:
+            '${variableId.token.lexeme} '
+            '${assignment.operator.lexeme} ',
         semicolon: semicolon,
       );
     });

pkg/analysis_server/test/src/services/correction/assist/convert_to_switch_statement_test.dart

@@ -521,6 +521,29 @@ int f(int x) {
 ''');
   }
 
+  Future<void> test_operatorAssignment() async {
+    await resolveTestCode('''
+void f(int x) {
+  int v = 0;
+  v += switch (x) {
+    0 => 0,
+    _ => 1,
+  };
+}
+''');
+    await assertHasAssistAt('switch', '''
+void f(int x) {
+  int v = 0;
+  switch (x) {
+    case 0:
+      v += 0;
+    default:
+      v += 1;
+  }
+}
+''');
+  }
+
   Future<void> test_returnStatement() async {
     await resolveTestCode('''
 int f(int x) {