The concepts overhaul isn't ready yet, but we should at least support concept
definitions without bool; that has been the one thing that prevents people from
writing code that works in both TS and C++20 concepts.
Tested x86_64-pc-linux-gnu, applying to trunk.
* parser.c (cp_parser_decl_specifier_seq): Support C++20
concept-definition syntax without 'bool'.
---
gcc/cp/parser.c | 9 +++++++++
gcc/testsuite/g++.dg/concepts/no-bool1.C | 4 ++++
gcc/cp/ChangeLog | 5 +++++
3 files changed, 18 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/concepts/no-bool1.C
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 14da1a14501..b8a0245ce57 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -13964,6 +13964,15 @@ cp_parser_decl_specifier_seq (cp_parser* parser,
case RID_CONCEPT:
ds = ds_concept;
cp_lexer_consume_token (parser->lexer);
+ /* In C++20 a concept definition is just 'concept name = expr;'
+ Support that syntax by pretending we've seen 'bool'. */
+ if (cp_lexer_next_token_is (parser->lexer, CPP_NAME)
+ && cp_lexer_nth_token_is (parser->lexer, 2, CPP_EQ))
+ {
+ cp_parser_set_decl_spec_type (decl_specs, boolean_type_node,
+ token, /*type_definition*/false);
+ decl_specs->any_type_specifiers_p = true;
+ }
break;
/* function-specifier:
diff --git a/gcc/testsuite/g++.dg/concepts/no-bool1.C
b/gcc/testsuite/g++.dg/concepts/no-bool1.C
new file mode 100644
index 00000000000..be9b73a0689
--- /dev/null
+++ b/gcc/testsuite/g++.dg/concepts/no-bool1.C
@@ -0,0 +1,4 @@
+// { dg-do compile { target c++14 } }
+// { dg-additional-options -fconcepts }
+
+template <class T> concept True = true;
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 054a891bcef..6c96c24430f 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2019-03-14 Jason Merrill <ja...@redhat.com>
+
+ * parser.c (cp_parser_decl_specifier_seq): Support C++20
+ concept-definition syntax without 'bool'.
+
2019-03-14 Jakub Jelinek <ja...@redhat.com>
PR c++/89512
base-commit: a95b8a4616e5112976bf5ba3e63e344fa74c578a
--
2.20.1
