From 23e57329c6516a81a8d3eb21b365ca8a0ec0c41b Mon Sep 17 00:00:00 2001
From: Patrick Palka <ppalka@redhat.com>
Date: Mon, 28 Mar 2022 14:15:39 -0400
Subject: [PATCH] c++: reject concept w/ multiple tparm lists [PR105067]
We weren't rejecting a concept declared with multiple template
parameter lists.
PR c++/105067
gcc/cp/ChangeLog:
* pt.cc (finish_concept_definition): Check that a concept is
declared with exactly one template parameter list.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-err4.C: New test.
---
gcc/cp/pt.cc | 6 ++++++
gcc/testsuite/g++.dg/cpp2a/concepts-err4.C | 6 ++++++
2 files changed, 12 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-err4.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 3df509bbed01..cd07e48cb5a0 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -28815,6 +28815,12 @@ finish_concept_definition (cp_expr id, tree init)
return error_mark_node;
}
+ if (current_template_depth > 1)
+ {
+ error_at (loc, "concept %qE has multiple template parameter lists", *id);
+ return error_mark_node;
+ }
+
/* Initially build the concept declaration; its type is bool. */
tree decl = build_lang_decl_loc (loc, CONCEPT_DECL, *id, boolean_type_node);
DECL_CONTEXT (decl) = current_scope ();
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-err4.C b/gcc/testsuite/g++.dg/cpp2a/concepts-err4.C
new file mode 100644
index 000000000000..57a96a095c78
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-err4.C
@@ -0,0 +1,6 @@
+// PR c++/105067
+// { dg-do compile { target c++20 } }
+
+template<class>
+template<class>
+concept C = true; // { dg-error "parameter list" }
--
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