mirror of
git://gcc.gnu.org/git/gcc.git
synced 2025-04-04 03:20:26 +08:00
1dabbfb0f4
We represent deduction guides with FUNCTION_DECLs, but they are built
without DECL_CONTEXT, leading to an ICE in type_dependent_expression_p
on the assert that the type of a function template with no dependent
(innermost!) template arguments must be non-dependent. Consider the
attached class-deduction79.C: we create a deduction guide:
template<class T> G(T)-> E<Z>::G<T>
we deduce T and create a partial instantiation:
G(T) -> E<Z>::G<T> [with T = int]
And then do_class_deduction wants to create a CALL_EXPR from the above
using build_new_function_call -> build_over_call which calls mark_used
-> maybe_instantiate_noexcept -> type_dependent_expression_p.
There, the innermost template arguments are non-dependent (<int>), but
the fntype is dependent -- the return type is a TYPENAME_TYPE, and
since we have no DECL_CONTEXT, this check holds:
/* Otherwise, if the function decl isn't from a dependent scope, it can't be
type-dependent. Checking this is important for functions with auto return
type, which looks like a dependent type. */
if (TREE_CODE (expression) == FUNCTION_DECL
&& !(DECL_CLASS_SCOPE_P (expression)
&& dependent_type_p (DECL_CONTEXT (expression)))
whereupon we ICE.
This patch fixes it by deferring the class deduction until the
enclosing scope is non-dependent. build_deduction_guide and maybe_aggr_guide
needed a little tweaking to make the deduction work in a member
template.
Co-Authored-By: Jason Merrill <jason@redhat.com>
gcc/cp/ChangeLog:
PR c++/97034
PR c++/99009
* pt.c (build_deduction_guide): Use INNERMOST_TEMPLATE_ARGS.
(maybe_aggr_guide): Use the original template type where needed. In
a class member template, partially instantiate the result of
collect_ctor_idx_types.
(do_class_deduction): Defer the deduction until the enclosing
scope is non-dependent.
gcc/testsuite/ChangeLog:
PR c++/97034
PR c++/99009
* g++.dg/cpp1z/class-deduction81.C: New test.
* g++.dg/cpp1z/class-deduction82.C: New test.
* g++.dg/cpp2a/class-deduction-aggr8.C: New test.
* g++.dg/cpp2a/class-deduction-aggr9.C: New test.
* g++.dg/cpp2a/class-deduction-aggr10.C: New test.
This directory contains the GNU Compiler Collection (GCC). The GNU Compiler Collection is free software. See the files whose names start with COPYING for copying permission. The manuals, and some of the runtime libraries, are under different terms; see the individual source files for details. The directory INSTALL contains copies of the installation information as HTML and plain text. The source of this information is gcc/doc/install.texi. The installation information includes details of what is included in the GCC sources and what files GCC installs. See the file gcc/doc/gcc.texi (together with other files that it includes) for usage and porting information. An online readable version of the manual is in the files gcc/doc/gcc.info*. See http://gcc.gnu.org/bugs/ for how to report bugs usefully. Copyright years on GCC source files may be listed using range notation, e.g., 1987-2012, indicating that every year in the range, inclusive, is a copyrightable year that could otherwise be listed individually.