gcc/libstdc++-v3
Jason Merrill baf38d2e36 c++: Check abstract type only on object creation. [PR86252]
Abstract checking has been problematic for a while; when I implemented an
earlier issue resolution to do more checking it led to undesirable
instantiations, and so backed some of it out.  During the C++20 process we
decided with P0929R2 that we should go the other way, and only check
abstractness when we're actually creating an object, not when merely forming
an array or function type.  This means that we can remove the machinery for
checking whether a newly complete class makes some earlier declaration
ill-formed.  This change was moved as a DR, so I'm applying it to all
standard levels.  This could be reconsidered if it causes problems, but I
don't expect it to.

The change to the libstdc++ result_of test brings the expected behavior in
line with that for incomplete types, but as in PR97841 I think the libstdc++
handling of incomplete types in this and other type_traits is itself wrong,
so I expect these lines and others to change again before long.

gcc/cp/ChangeLog:

	* decl.c (cp_finish_decl): Only check abstractness on definition.
	(require_complete_types_for_parms): Check abstractness here.
	(create_array_type_for_decl): Not here.
	(grokdeclarator, grokparms, complete_vars): Not here.
	* pt.c (tsubst, tsubst_arg_types, tsubst_function_type): Not here.
	* typeck2.c (struct pending_abstract_type): Remove.
	(struct abstract_type_hasher): Remove.
	(abstract_pending_vars, complete_type_check_abstract): Remove.
	(abstract_virtuals_error_sfinae): Handle arrays.
	* call.c (conv_is_prvalue): Split out from...
	(conv_binds_ref_to_prvalue): ...here.
	(implicit_conversion_1): Rename from implicit_conversion.
	(implicit_conversion): An abstract prvalue is bad.
	(convert_like_internal): Don't complain if expr is already
	error_mark_node.

gcc/testsuite/ChangeLog:

	* g++.dg/other/abstract1.C: Adjust.
	* g++.dg/other/abstract2.C: Adjust.
	* g++.dg/other/abstract4.C: Adjust.
	* g++.dg/other/abstract5.C: Adjust.
	* g++.dg/other/abstract8.C: New test.
	* g++.dg/template/sfinae-dr657.C: Adjust.
	* g++.old-deja/g++.other/decl3.C: Adjust.

libstdc++-v3/ChangeLog:

	* testsuite/20_util/result_of/sfinae_friendly_1.cc: Adjust.
2020-11-15 12:07:13 -05:00
..
config libstdc++: Avoid bad_alloc exceptions when changing locales 2020-11-10 20:33:29 +00:00
doc libstdc++: Document istreambuf_iterator base class change [PR 92285] 2020-11-04 12:46:52 +00:00
include libstdc++: Optimise std::future::wait_for and fix futex polling 2020-11-12 23:47:04 +00:00
libsupc++ libstdc++: Use 'inline' consistently in std::exception_ptr [PR 97729] 2020-11-09 14:28:38 +00:00
po
python
scripts
src libstdc++: Use custom timespec in system calls [PR 93421] 2020-11-13 23:08:35 +00:00
testsuite c++: Check abstract type only on object creation. [PR86252] 2020-11-15 12:07:13 -05:00
acinclude.m4 libstdc++: Exclude cygwin and mingw from linker relro support 2020-11-11 15:36:05 +00:00
aclocal.m4
ChangeLog Daily bump. 2020-11-14 00:16:38 +00:00
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config.h.in
configure libstdc++: Exclude cygwin and mingw from linker relro support 2020-11-11 15:36:05 +00:00
configure.ac
configure.host Scope libstdc++ configuration for vxworks to all versions 2020-10-22 16:40:57 +00:00
crossconfig.m4 Scope libstdc++ configuration for vxworks to all versions 2020-10-22 16:40:57 +00:00
fragment.am
linkage.m4
Makefile.am
Makefile.in
README

file: libstdc++-v3/README

New users may wish to point their web browsers to the file
index.html in the 'doc/html' subdirectory.  It contains brief
building instructions and notes on how to configure the library in
interesting ways.