Refactor: move { } parsing into parse_and_visit_class_body

Reduce some duplication between statement parsing and expression parsing
for classes.

This commit should not change behavior.

Author: strager

src/quick-lint-js/parse-expression-inl.h

@@ -2482,22 +2482,15 @@ expression* parser::parse_class_expression(Visitor& v) {
   this->parse_and_visit_class_heading(
       v, /*require_name=*/name_requirement::optional);
 
-  const char8* span_end;
   if (this->peek().type == token_type::left_curly) {
-    this->skip();
-
     this->parse_and_visit_class_body(v);
-
-    QLJS_PARSER_UNIMPLEMENTED_IF_NOT_TOKEN(token_type::right_curly);
-    span_end = this->peek().end;
-    this->skip();
   } else {
-    span_end = this->lexer_.end_of_previous_token();
     this->error_reporter_->report(error_missing_body_for_class{
         .class_keyword_and_name_and_heritage =
-            source_code_span(span_begin, span_end),
+            source_code_span(span_begin, this->lexer_.end_of_previous_token()),
     });
   }
+  const char8* span_end = this->lexer_.end_of_previous_token();
 
   v.visit_exit_class_scope();
   return this->make_expression<expression::_class>(

src/quick-lint-js/parse-statement-inl.h

@@ -1101,14 +1101,9 @@ void parser::parse_and_visit_class(Visitor &v,
 
   switch (this->peek().type) {
   case token_type::left_curly:
-    this->skip();
-
     v.visit_enter_class_scope();
     this->parse_and_visit_class_body(v);
     v.visit_exit_class_scope();
-
-    QLJS_PARSER_UNIMPLEMENTED_IF_NOT_TOKEN(token_type::right_curly);
-    this->skip();
     break;
 
   default: {
@@ -1202,9 +1197,15 @@ void parser::parse_and_visit_class_heading(
 template <QLJS_PARSE_VISITOR Visitor>
 void parser::parse_and_visit_class_body(Visitor &v) {
   class_guard g(this, std::exchange(this->in_class_, true));
+
+  this->skip();
+
   while (this->peek().type != token_type::right_curly) {
     this->parse_and_visit_class_member(v);
   }
+
+  QLJS_PARSER_UNIMPLEMENTED_IF_NOT_TOKEN(token_type::right_curly);
+  this->skip();
 }
 
 template <QLJS_PARSE_VISITOR Visitor>