[Bug c++/105637] [12/13 Regression] Wrong overload selected in base class
cvs-commit at gcc dot gnu.org
Fri Jun 3 16:07:50 GMT 2022
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <email@example.com>:
Author: Patrick Palka <firstname.lastname@example.org>
Date: Fri Jun 3 12:06:59 2022 -0400
c++: cv-quals of dummy obj for non-dep memfn call [PR105637]
In non-dependent23.C below we expect the Base::foo calls to
resolve to the second, third and fourth overloads respectively in light
of the cv-qualifiers of 'this' in each case. But ever since
r12-6075-g2decd2cabe5a4f, the calls incorrectly resolve to the first
overload at instantiation time.
This happens because the calls to Base::foo are all deemed
non-dependent (ever since r7-755-g23cb72663051cd made us ignore 'this'
dependence when considering the dependence of a non-static memfn call),
hence we end up checking the call ahead of time, using as the object
argument a dummy object of type Base. Since this object argument is
cv-unqualified, the calls in turn resolve to the unqualified overload
of baseDevice. Before r12-6075 this incorrect result would just get
silently discarded and we'd end up redoing OR at instantiation time
using 'this' as the object argument. But after r12-6075 we now reuse
this incorrect result at instantiation time.
This patch fixes this by making maybe_dummy_object respect the cv-quals
of (the non-lambda) 'this' when returning a dummy object. Thus, ahead
of time OR using a dummy object will give us the right answer that's
consistent with the instantiation time answer.
An earlier version of this patch didn't handle 'this'-capturing lambdas
correctly, which broke lambda-this22.C below.
* tree.cc (maybe_dummy_object): When returning a dummy
object, respect the cv-quals of 'this' if available.
* g++.dg/cpp0x/lambda/lambda-this22.C: New test.
* g++.dg/template/non-dependent23.C: New test.
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