[analysis_server] Fix semantic tokens for method tear-offs in object patterns

Fixes https://github.com/dart-lang/sdk/issues/59976

Change-Id: I75127a59670522ddfc6526d10bfe9844638fdd99
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/408001
Reviewed-by: Phil Quitslund <pquitslund@google.com>
Commit-Queue: Phil Quitslund <pquitslund@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/lib/src/computer/computer_highlights.dart

@@ -1497,15 +1497,19 @@ class _DartUnitHighlightsComputerVisitor extends RecursiveAstVisitor<void> {
   }
 
   @override
-  void visitPatternFieldName(PatternFieldName node) {
-    var name = node.name;
+  void visitPatternField(PatternField node) {
+    var name = node.name?.name;
     if (name != null) {
-      computer._addRegion_token(
-        node.name,
-        HighlightRegionType.INSTANCE_GETTER_REFERENCE,
-      );
+      // Patterns can be method tear-offs as well as getters:
+      // https://github.com/dart-lang/sdk/issues/59976#issuecomment-2613558317
+      var type = switch (node.element2) {
+        MethodElement2() => HighlightRegionType.INSTANCE_METHOD_TEAR_OFF,
+        _ => HighlightRegionType.INSTANCE_GETTER_REFERENCE,
+      };
+
+      computer._addRegion_token(name, type);
     }
-    super.visitPatternFieldName(node);
+    super.visitPatternField(node);
   }
 
   @override

pkg/analysis_server/test/lsp/semantic_tokens_test.dart

@@ -1726,7 +1726,9 @@ void f() {
     var content = r'''
 void f() {
   switch (1) {
-    case int(isEven: var isEven) when isEven:
+    case int(isEven: var isEven, toString: var toString) when isEven:
+      isEven;
+      toString;
   }
 }
 ''';
@@ -1754,10 +1756,19 @@ void f() {
       _Token('isEven', SemanticTokenTypes.variable, [
         SemanticTokenModifiers.declaration,
       ]),
+      _Token('toString', SemanticTokenTypes.method, [
+        CustomSemanticTokenModifiers.instance,
+      ]),
+      _Token('var', SemanticTokenTypes.keyword),
+      _Token('toString', SemanticTokenTypes.variable, [
+        SemanticTokenModifiers.declaration,
+      ]),
       _Token('when', SemanticTokenTypes.keyword, [
         CustomSemanticTokenModifiers.control,
       ]),
       _Token('isEven', SemanticTokenTypes.variable),
+      _Token('isEven', SemanticTokenTypes.variable),
+      _Token('toString', SemanticTokenTypes.variable),
     ];
 
     await _initializeAndVerifyTokens(content, expected);