work in progress

Author: NinaRanns

gcc/c-family/c-common.cc

@@ -516,7 +516,6 @@ const struct c_common_resword c_common_reswords[] =
   { "constinit",	RID_CONSTINIT,	D_CXXONLY | D_CXX20 | D_CXXWARN },
   { "const_cast",	RID_CONSTCAST,	D_CXXONLY | D_CXXWARN },
   { "continue",		RID_CONTINUE,	0 },
-  { "contract_assert",	RID_CONTASSERT,	D_CXXONLY | D_CXXWARN }, // removed D_CXX20 in order for contracts to work out of the box
   { "decltype",         RID_DECLTYPE,   D_CXXONLY | D_CXX11 | D_CXXWARN },
   { "default",		RID_DEFAULT,	0 },
   { "delete",		RID_DELETE,	D_CXXONLY | D_CXXWARN },
@@ -599,6 +598,10 @@ const struct c_common_resword c_common_reswords[] =
   { "co_yield",		RID_CO_YIELD,	D_CXX_COROUTINES_FLAGS | D_CXXWARN },
   { "co_return", 	RID_CO_RETURN,	D_CXX_COROUTINES_FLAGS | D_CXXWARN },
 
+  /* Contracts-related keywords */
+  { "contract_assert",	RID_CONTASSERT,	D_CXXONLY | D_CXXWARN }, // removed D_CXX20 in order for contracts to work out of the box
+  { "inherited",	RID_INHERITED,	D_CXXONLY | D_CXXWARN },
+
   /* These Objective-C keywords are recognized only immediately after
      an '@'.  */
   { "compatibility_alias", RID_AT_ALIAS,	D_OBJC },

gcc/c-family/c-common.h

@@ -176,7 +176,7 @@ enum rid
   RID_CONSTEXPR, RID_DECLTYPE, RID_NOEXCEPT, RID_NULLPTR, RID_STATIC_ASSERT,
 
   /* C++20 */
-  RID_CONSTINIT, RID_CONSTEVAL, RID_CONTASSERT,
+  RID_CONSTINIT, RID_CONSTEVAL,
 
   /* char8_t */
   RID_CHAR8,
@@ -190,6 +190,9 @@ enum rid
   /* C++ coroutines */
   RID_CO_AWAIT, RID_CO_YIELD, RID_CO_RETURN,
 
+  /* C++ contracts */
+  RID_CONTASSERT, RID_INHERITED,
+
   /* C++ transactional memory.  */
   RID_ATOMIC_NOEXCEPT, RID_ATOMIC_CANCEL, RID_SYNCHRONIZED,
 

gcc/cp/parser.cc

@@ -31861,6 +31861,51 @@ cp_parser_should_constify_contract (const contract_modifier& modifier)
   return should_constify;
 }
 
+/* Parse an inherited contract. */
+
+static tree
+cp_parse_inherited_contract (cp_parser *parser)
+{
+  cp_token *token = cp_lexer_consume_token (parser->lexer);
+  location_t loc = token->location;
+
+  gcc_checking_assert(token->type == CPP_KEYWORD
+		      && token->keyword == RID_INHERITED);
+
+  matching_parens parens;
+  parens.require_open (parser);
+
+  if (flag_contracts_on_virtual_functions != CONTRACTS_ON_VIRTUALS_P3653)
+    {
+      error_at (loc, "inherited contracts are only available with"
+		" %<-fcontracts-on-virtual-functions=P3653%>");
+
+      cp_parser_skip_to_closing_parenthesis_1 (parser, /*recovering=*/true,
+      					       CPP_CLOSE_PAREN,
+      					       /*consume_paren=*/true);
+      return error_mark_node;
+    }
+
+  /* Otherwise, look for the class-name.  */
+  tree type = cp_parser_class_name (parser,
+			       /*typename_keyword_p=*/true,
+			       /*template_keyword_p=*/false,
+			       none_type,
+			       /*check_dependency_p=*/false,
+			       /*class_head_p=*/false,
+			       /*is_declaration=*/false);
+  type = TREE_TYPE (type);
+  /* ": T...[constant-expression]" is a C++26 pack-index-specifier.  */
+  if (cp_parser_next_tokens_are_pack_index_p (parser))
+    type = cp_parser_pack_index (parser, type);
+
+  cp_parser_skip_to_closing_parenthesis_1 (parser,
+					   /*recovering=*/true,
+					   CPP_CLOSE_PAREN,
+					   /*consume_paren=*/true);
+  return error_mark_node;
+}
+
 /* Parse a natural syntax contract specifier seq.
 
   function-contract-specifier :
@@ -31901,6 +31946,11 @@ cp_parser_function_contract_specifier (cp_parser *parser)
   location_t loc = token->location;
   bool postcondition_p = is_attribute_p ("post", contract_name);
 
+  token = cp_lexer_peek_token (parser->lexer);
+
+  if (token->type == CPP_KEYWORD && token->keyword == RID_INHERITED)
+    return cp_parse_inherited_contract(parser);
+
   /* Parse experimental modifiers on C++26 contracts.  */
   contract_modifier modifier
     = cp_parser_function_contract_modifier_opt (parser);