feat(fe): parse decorators on class expressions

Author: strager

src/quick-lint-js/fe/parse-expression.cpp

@@ -633,11 +633,18 @@ Expression* Parser::parse_primary_expression(Parse_Visitor_Base& v,
   }
 
   // class {}
+  parse_class:
   case Token_Type::kw_class: {
     Expression* class_expression = this->parse_class_expression(v);
     return class_expression;
   }
 
+  // @myDecorator class {}
+  case Token_Type::at:
+    // TODO(strager): Should we make a Decorated expression type?
+    this->parse_and_visit_decorator(v);
+    goto parse_class;
+
   // new XMLHttpRequest()
   // new.target
   case Token_Type::kw_new: {

test/test-parse-decorator.cpp

@@ -123,6 +123,32 @@ TEST_F(Test_Parse_Decorator, export_default_class_decorator) {
   }
 }
 
+TEST_F(Test_Parse_Decorator, class_expression_decorator) {
+  {
+    Spy_Visitor p = test_parse_and_visit_statement(
+        u8"(@myDecorator class C {});"_sv, no_diags, javascript_options);
+    EXPECT_THAT(p.visits, ElementsAreArray({
+                              "visit_variable_use",            // myDecorator
+                              "visit_enter_class_scope",       // C
+                              "visit_enter_class_scope_body",  // {
+                              "visit_exit_class_scope",        // }
+                          }));
+    EXPECT_THAT(p.variable_uses, ElementsAreArray({u8"myDecorator"_sv}));
+  }
+
+  {
+    Spy_Visitor p = test_parse_and_visit_statement(
+        u8"(@myDecorator class {});"_sv, no_diags, javascript_options);
+    EXPECT_THAT(p.visits, ElementsAreArray({
+                              "visit_variable_use",            // myDecorator
+                              "visit_enter_class_scope",       // class
+                              "visit_enter_class_scope_body",  // {
+                              "visit_exit_class_scope",        // }
+                          }));
+    EXPECT_THAT(p.variable_uses, ElementsAreArray({u8"myDecorator"_sv}));
+  }
+}
+
 TEST_F(Test_Parse_Decorator,
        private_identifiers_are_allowed_as_property_names) {
   Spy_Visitor p = test_parse_and_visit_statement(