The substitution we do in build_deduction_guide needs
processing_template_decl set, since it's only partial instantiation,
and also needs to be done on the template; substituting the
FUNCTION_DECL pattern doesn't properly adjust the template parameters
on the template, which we will use in building the deduction guide.
Tested x86_64-pc-linux-gnu, applying to trunk and 7.
commit a1ecbf88833602a7d37fd44f831d4c1efd6ffaf8
Author: Jason Merrill <ja...@redhat.com>
Date: Thu Jun 29 14:12:09 2017 -0400
PR c++/81180 - ICE with C++17 deduction of member class template.
* pt.c (build_deduction_guide): Correct member template handling.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 047d3ba..3ecacbd 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -25216,17 +25216,16 @@ build_deduction_guide (tree ctor, tree outer_args,
tsubst_flags_t complain)
}
else
{
+ ++processing_template_decl;
+
+ tree fn_tmpl
+ = (TREE_CODE (ctor) == TEMPLATE_DECL ? ctor
+ : DECL_TI_TEMPLATE (ctor));
if (outer_args)
- ctor = tsubst (ctor, outer_args, complain, ctor);
+ fn_tmpl = tsubst (fn_tmpl, outer_args, complain, ctor);
+ ctor = DECL_TEMPLATE_RESULT (fn_tmpl);
+
type = DECL_CONTEXT (ctor);
- tree fn_tmpl;
- if (TREE_CODE (ctor) == TEMPLATE_DECL)
- {
- fn_tmpl = ctor;
- ctor = DECL_TEMPLATE_RESULT (fn_tmpl);
- }
- else
- fn_tmpl = DECL_TI_TEMPLATE (ctor);
tparms = DECL_TEMPLATE_PARMS (fn_tmpl);
/* If type is a member class template, DECL_TI_ARGS (ctor) will have
@@ -25248,7 +25247,6 @@ build_deduction_guide (tree ctor, tree outer_args,
tsubst_flags_t complain)
/* For a member template constructor, we need to flatten the two
template parameter lists into one, and then adjust the function
signature accordingly. This gets...complicated. */
- ++processing_template_decl;
tree save_parms = current_template_parms;
/* For a member template we should have two levels of parms/args, one
@@ -25309,8 +25307,8 @@ build_deduction_guide (tree ctor, tree outer_args,
tsubst_flags_t complain)
ci = tsubst_constraint_info (ci, tsubst_args, complain, ctor);
current_template_parms = save_parms;
- --processing_template_decl;
}
+ --processing_template_decl;
}
if (!memtmpl)
diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction40.C
b/gcc/testsuite/g++.dg/cpp1z/class-deduction40.C
new file mode 100644
index 0000000..eeffa69
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction40.C
@@ -0,0 +1,19 @@
+// PR c++/81180
+// { dg-options -std=c++1z }
+
+template < int I > struct int_{};
+
+template < typename T >
+struct A{
+ template < typename U, int I >
+ struct B{
+ B(U u, int_< I >){}
+ };
+};
+
+
+int main(){
+ A< int >::B v(0, int_< 0 >());
+ (void)v;
+}
+
