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| author | Patrick Palka <ppalka@redhat.com> | 2024-06-13 10:02:43 -0400 |
|---|---|---|
| committer | Patrick Palka <ppalka@redhat.com> | 2024-06-17 10:14:43 -0400 |
| commit | 4df86402990e2f45e02a367f1734a22ebc041e98 (patch) | |
| tree | 3fcb1374351ffefc5542e7e31b381f84492fc4a1 | |
| parent | 9583f781e17d4da881ee64db43af939402331413 (diff) | |
| download | gcc-4df86402990e2f45e02a367f1734a22ebc041e98.zip gcc-4df86402990e2f45e02a367f1734a22ebc041e98.tar.gz gcc-4df86402990e2f45e02a367f1734a22ebc041e98.tar.bz2 | |
c++: ICE w/ ambig and non-strictly-viable cands [PR115239]
Here during overload resolution we have two strictly viable ambiguous
candidates #1 and #2, and two non-strictly viable candidates #3 and #4
which we hold on to ever since r14-6522. These latter candidates have
an empty second arg conversion since the first arg conversion was deemed
bad, and this trips up joust when called on #3 and #4 which assumes all
arg conversions are there.
We can fix this by making joust robust to empty arg conversions, but in
this situation we shouldn't need to compare #3 and #4 at all given that
we have a strictly viable candidate. To that end, this patch makes
tourney shortcut considering non-strictly viable candidates upon
encountering ambiguity between two strictly viable candidates (taking
advantage of the fact that the candidates list is sorted according to
viability via splice_viable).
PR c++/115239
gcc/cp/ChangeLog:
* call.cc (tourney): Don't consider a non-strictly viable
candidate as the champ if there was ambiguity between two
strictly viable candidates.
gcc/testsuite/ChangeLog:
* g++.dg/overload/error7.C: New test.
Reviewed-by: Jason Merrill <jason@redhat.com>
(cherry picked from commit 7fed7e9bbc57d502e141e079a6be2706bdbd4560)
| -rw-r--r-- | gcc/cp/call.cc | 3 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/overload/error7.C | 10 |
2 files changed, 12 insertions, 1 deletions
diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc index 38b9c4f..f5584c9 100644 --- a/gcc/cp/call.cc +++ b/gcc/cp/call.cc @@ -13488,7 +13488,8 @@ tourney (struct z_candidate *candidates, tsubst_flags_t complain) { previous_worse_champ = nullptr; champ = &(*challenger)->next; - if (!*champ || !(*champ)->viable) + if (!*champ || !(*champ)->viable + || (*champ)->viable < (*challenger)->viable) { champ = nullptr; break; diff --git a/gcc/testsuite/g++.dg/overload/error7.C b/gcc/testsuite/g++.dg/overload/error7.C new file mode 100644 index 0000000..de50ce5 --- /dev/null +++ b/gcc/testsuite/g++.dg/overload/error7.C @@ -0,0 +1,10 @@ +// PR c++/115239 + +bool foo(char *, long); // #1, strictly viable, ambig with #2 +bool foo(char *, unsigned); // #2, strictly viable, ambig with #1 +bool foo(char, long); // #3, non-strictly viable +bool foo(char, unsigned); // #4, non-strictly viable + +int main() { + foo((char *)0, 0); // { dg-error "ambiguous" } +} |