On Dec 14, 2018, Jason Merrill <ja...@redhat.com> wrote:
> Yes, like that, thanks. It might be a bit of an optimization to skip
> this when t == TREE_TYPE (parm). OK either way.
Thanks, I've put the suggested optimization in.
Here's what I'm about to install.
[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.
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 | 3 +++
gcc/testsuite/g++.dg/cpp0x/pr87012.C | 11 +++++++++++
2 files changed, 14 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/pr87012.C
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 79eef12112fb..e99de71ea9e2 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -8019,6 +8019,9 @@ convert_template_argument (tree parm,
if (invalid_nontype_parm_type_p (t, complain))
return error_mark_node;
+ if (t != TREE_TYPE (parm))
+ 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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