From 29d8838c5ecaf70ce552fea7639ec1f34adb2e04 Mon Sep 17 00:00:00 2001
From: Marek Polacek <polacek@redhat.com>
Date: Mon, 19 Apr 2021 16:21:46 -0400
Subject: [PATCH] c++: ICE with concept defined in function [PR97536]
This is an ICE-on-invalid, but I keep seeing it when reducing code so
I'd like to fix it. We crash on
template <typename> void forward() {
concept C = true;
}
which breaks two requirements:
[temp.concept]/1: A concept is a template ...
[temp.concept]/3: A concept-definition shall inhabit a namespace scope.
This patch adds a test that exercises broken code and fixes the ICE
by checking that a concept-definition is defined at namespace scope.
gcc/cp/ChangeLog:
PR c++/97536
* decl.c (grokvardecl): Given an error when a concept is not defined
at namespace scope.
gcc/testsuite/ChangeLog:
PR c++/97536
* g++.dg/concepts/diagnostic16.C: New test.
---
gcc/cp/decl.c | 6 +++
gcc/testsuite/g++.dg/concepts/diagnostic16.C | 45 ++++++++++++++++++++
2 files changed, 51 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/concepts/diagnostic16.C
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 942eb318f2c1..b81de8ef9349 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -10365,6 +10365,12 @@ grokvardecl (tree type,
"a non-template variable cannot be %<concept%>");
return NULL_TREE;
}
+ else if (!at_namespace_scope_p ())
+ {
+ error_at (declspecs->locations[ds_concept],
+ "concept must be defined at namespace scope");
+ return NULL_TREE;
+ }
else
DECL_DECLARED_CONCEPT_P (decl) = true;
if (!same_type_ignoring_top_level_qualifiers_p (type, boolean_type_node))
diff --git a/gcc/testsuite/g++.dg/concepts/diagnostic16.C b/gcc/testsuite/g++.dg/concepts/diagnostic16.C
new file mode 100644
index 000000000000..fcba535a8766
--- /dev/null
+++ b/gcc/testsuite/g++.dg/concepts/diagnostic16.C
@@ -0,0 +1,45 @@
+// PR c++/97536
+// { dg-do compile { target concepts } }
+
+template<typename>
+concept C1 = true;
+
+concept C2 = true; // { dg-error "non-template variable cannot be .concept." }
+// { dg-error "concept definition syntax is" "" { target *-*-* } .-1 }
+
+template<typename>
+void fn1 ()
+{
+ concept bar = true; // { dg-error "concept must be defined at namespace scope" }
+// { dg-error "concept definition syntax is" "" { target *-*-* } .-1 }
+}
+
+void fn2 ()
+{
+ concept bar = true; // { dg-error "non-template variable cannot be .concept." }
+// { dg-error "concept definition syntax is" "" { target *-*-* } .-1 }
+}
+
+template<typename>
+void fn3 ()
+{
+ template<typename> // { dg-error "template declaration cannot appear at block scope" }
+ concept bar = true;
+}
+
+void fn4 ()
+{
+ template<typename> // { dg-error "template declaration cannot appear at block scope" }
+ concept bar = true;
+}
+
+void fn5 ()
+{
+ C1 auto x = 42;
+}
+
+template<typename>
+void fn6 ()
+{
+ C1 auto x = 42;
+}
--
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