On Dec 5, 2018, Jason Merrill <ja...@redhat.com> wrote:
> I would expect that this same issue would come up with other types; I
> think we want to fix this sooner, when we are figuring out what type
> we want to convert the argument to.
You mean like this?
[PR87012] canonicalize ref type for tmpl arg
When binding an object to a template parameter of reference type, we
take the address of the object and dereference that address. The type
of the address may still carry (template) typedefs, but
verify_unstripped_args_1 rejects such typedefs other than in the top
level of template arguments.
Canonicalizing the type we want to convert to right after any
substitutions or deductions avoids that issue.
Regstrapped on x86_64- and i686-linux-gnu. Ok to install?
for gcc/cp/ChangeLog
PR c++/87012
* pt.c (convert_template_argument): Canonicalize type after
tsubst/deduce.
for gcc/testsuite/ChangeLog
PR c++/87012
* g++.dg/cpp0x/pr87012.C: New.
---
gcc/cp/pt.c | 2 ++
gcc/testsuite/g++.dg/cpp0x/pr87012.C | 11 +++++++++++
2 files changed, 13 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/pr87012.C
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 72ae7173d92c..0d388c67459a 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -8018,6 +8018,8 @@ convert_template_argument (tree parm,
if (invalid_nontype_parm_type_p (t, complain))
return error_mark_node;
+ t = canonicalize_type_argument (t, complain);
+
if (!type_dependent_expression_p (orig_arg)
&& !uses_template_parms (t))
/* We used to call digest_init here. However, digest_init
diff --git a/gcc/testsuite/g++.dg/cpp0x/pr87012.C
b/gcc/testsuite/g++.dg/cpp0x/pr87012.C
new file mode 100644
index 000000000000..fd3eea47c390
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/pr87012.C
@@ -0,0 +1,11 @@
+// { dg-do compile { target c++11 } }
+
+template<class T>
+using ref = T&;
+
+int x;
+
+template<template<class> class T, T<int>>
+struct X { };
+
+struct Y : X<ref, x> { };
--
Alexandre Oliva, freedom fighter https://FSFLA.org/blogs/lxo
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