Tested x86_64-pc-linux-gnu, applying to trunk.
-- 8< --
My r16-4115 changed convert_template_argument (when called from
instantiate_alias_template) to take the maybe_convert_nontype_argument path
rather than convert_nontype_argument for this testcase. This meant not
folding the use of the by-ref capture in the template argument to constant
1. When we come back to convert_template_argument again when substituting
into resize<_Np> we strip the IMPLICIT_CONV_EXPR (since the types are the
same) and take the convert_nontype_argument path, but at this point we've
pushed into the alias template context and trying to fold away the capture
fails because current_lambda_expr() is now null.
Taking the convert_nontype_argument path in the same-type case where we
would later strip an IMPLICIT_CONV_EXPR fixes the problem. Note that
maybe_convert_nontype_argument already shares the same-type check with the
stripping, but that isn't enough; it still doesn't fold away the capture
proxy.
PR c++/122127
PR c++/112632
gcc/cp/ChangeLog:
* pt.cc (convert_template_argument): Don't add redundant
IMPLICIT_CONV_EXPR.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/lambda/lambda-template18.C: New test.
---
gcc/cp/pt.cc | 7 +++++--
gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template18.C | 11 +++++++++++
2 files changed, 16 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template18.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index bd60d515653..9b32049e71b 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -8928,8 +8928,11 @@ convert_template_argument (tree parm,
orig_arg = TREE_OPERAND (orig_arg, 0);
if (!uses_template_parms (t)
- && !(force_conv ? uses_template_parms (orig_arg)
- : type_dependent_expression_p (orig_arg)))
+ && !type_dependent_expression_p (orig_arg)
+ && !(force_conv
+ && !(same_type_ignoring_top_level_qualifiers_p
+ (TREE_TYPE (orig_arg), t))
+ && value_dependent_expression_p (orig_arg)))
/* We used to call digest_init here. However, digest_init
will report errors, which we don't want when complain
is zero. More importantly, digest_init will try too
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template18.C
b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template18.C
new file mode 100644
index 00000000000..e5e6e6a875b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template18.C
@@ -0,0 +1,11 @@
+// PR c++/122127
+// { dg-do compile { target c++11 } }
+
+template <int> struct resize;
+template <int _Np> using resize_t = resize<_Np>;
+template <class _Ap> struct basic_mask {
+ void _M_chunk() {
+ constexpr int __rem = 1;
+ [&] { resize_t<__rem>(); }();
+ }
+};
base-commit: a8ecf4580442e463c3a023b6724fb27e6b7e0804
--
2.51.0
