Bootstrapped and regtested on x86_64-pc-linux-gnu, pushing as obvious.
-- >8 --
When we enter cp_parser_explicit_template_declaration with the following
tokens being 'template <>', we never parse a parameter list and so with
-fconcepts we crash dereferencing a null pointer. This can currently
only happen after a non-modules 'export' declaration, as all other paths
check early for this case.
PR c++/121832
gcc/cp/ChangeLog:
* parser.cc (cp_parser_explicit_template_declaration): Check for
null.
gcc/testsuite/ChangeLog:
* g++.dg/concepts/pr121832.C: New test.
Signed-off-by: Nathaniel Shead <[email protected]>
---
gcc/cp/parser.cc | 2 +-
gcc/testsuite/g++.dg/concepts/pr121832.C | 10 ++++++++++
2 files changed, 11 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/concepts/pr121832.C
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 392d1f90ac8..4d988c27cb8 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -36275,7 +36275,7 @@ cp_parser_explicit_template_declaration (cp_parser*
parser, bool member_p)
cp_parser_require_end_of_template_parameter_list (parser);
/* Manage template requirements */
- if (flag_concepts)
+ if (flag_concepts && current_template_parms)
{
tree reqs = get_shorthand_constraints (current_template_parms);
if (tree treqs = cp_parser_requires_clause_opt (parser, false))
diff --git a/gcc/testsuite/g++.dg/concepts/pr121832.C
b/gcc/testsuite/g++.dg/concepts/pr121832.C
new file mode 100644
index 00000000000..9a4c5c045d4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/concepts/pr121832.C
@@ -0,0 +1,10 @@
+// { dg-do compile }
+// { dg-additional-options "-fconcepts -fno-modules" }
+
+export template<> a{}; // { dg-error "explicit spec" }
+// { dg-warning "'export' not implemented" "" { target c++98_only } .-1 }
+// { dg-warning "'export' is deprecated" "" { target { c++11 && c++17_down } }
.-2 }
+// { dg-warning "'export' is enabled with '-fmodules'" "" { target c++20 } .-3
}
+
+// { dg-prune-output "'a' does not name a type" }
+// { dg-prune-output "extra ';' outside of a function" }
--
2.51.0
