From ae83b9deb87787371cd94b4417e160d41dd0322c Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Wed, 13 Nov 2019 08:42:56 +0000 Subject: [C++] Fix interaction between aka changes and DR1558 (PR92206) One of the changes in r277281 was to make the typedef variant handling in strip_typedefs pass the raw DECL_ORIGINAL_TYPE to the recursive call, instead of applying TYPE_MAIN_VARIANT first. This PR shows that that interacts badly with the implementation of DR1558, because we then refuse to strip aliases with dependent template parameters and trip: gcc_assert (!typedef_variant_p (result) || ((flags & STF_USER_VISIBLE) && !user_facing_original_type_p (result))); Keeping the current behaviour but suppressing the ICE leads to a duplicate error (the dg-bogus in the first test), so that didn't seem like a good fix. I assume keeping the alias should never actually be necessary for DECL_ORIGINAL_TYPEs, because it will already have been checked somewhere, even for implicit TYPE_DECLs. This patch therefore passes a flag to say that we can safely strip aliases with dependent template parameters. 2019-11-13 Richard Sandiford gcc/cp/ PR c++/92206 * cp-tree.h (STF_STRIP_DEPENDENT): New constant. * tree.c (strip_typedefs): Add STF_STRIP_DEPENDENT to the flags when calling strip_typedefs recursively on a DECL_ORIGINAL_TYPE. Don't apply the fix for DR1558 in that case; allow aliases with dependent template parameters to be stripped instead. gcc/testsuite/ PR c++/92206 * g++.dg/cpp0x/alias-decl-pr92206-1.C: New test. * g++.dg/cpp0x/alias-decl-pr92206-2.C: Likewise. * g++.dg/cpp0x/alias-decl-pr92206-3.C: Likewise. From-SVN: r278119 --- gcc/cp/tree.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'gcc/cp/tree.c') diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c index ba635d4ddbd..6c39c004b01 100644 --- a/gcc/cp/tree.c +++ b/gcc/cp/tree.c @@ -1488,7 +1488,8 @@ strip_typedefs (tree t, bool *remove_attributes, unsigned int flags) if (t == TYPE_CANONICAL (t)) return t; - if (dependent_alias_template_spec_p (t)) + if (!(flags & STF_STRIP_DEPENDENT) + && dependent_alias_template_spec_p (t)) /* DR 1558: However, if the template-id is dependent, subsequent template argument substitution still applies to the template-id. */ return t; @@ -1673,7 +1674,8 @@ strip_typedefs (tree t, bool *remove_attributes, unsigned int flags) && !user_facing_original_type_p (t)) return t; result = strip_typedefs (DECL_ORIGINAL_TYPE (TYPE_NAME (t)), - remove_attributes, flags); + remove_attributes, + flags | STF_STRIP_DEPENDENT); } else result = TYPE_MAIN_VARIANT (t); -- cgit v1.2.1