From: Patrick Palka Date: Wed, 13 Dec 2023 21:46:04 +0000 (-0500) Subject: c++: note other candidates when diagnosing deletedness X-Git-Tag: basepoints/gcc-15~3616 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d6840b3143f617065a070857cb22d826d24c622b;p=thirdparty%2Fgcc.git c++: note other candidates when diagnosing deletedness With the previous two patches in place, we can now extend our deletedness diagnostic to note the other considered candidates, e.g.: deleted.C: In function 'int main()': deleted.C:10:4: error: use of deleted function 'void f(int)' 10 | f(0); | ~^~~ deleted.C:5:6: note: declared here 5 | void f(int) = delete; | ^ deleted.C:5:6: note: candidate: 'void f(int)' (deleted) deleted.C:6:6: note: candidate: 'void f(...)' 6 | void f(...); | ^ deleted.C:7:6: note: candidate: 'void f(int, int)' 7 | void f(int, int); | ^ deleted.C:7:6: note: candidate expects 2 arguments, 1 provided These notes are controlled by a new command line flag -fdiagnostics-all-candidates which also controls whether we note ignored candidates more generally. gcc/ChangeLog: * doc/invoke.texi (C++ Dialect Options): Document -fdiagnostics-all-candidates. gcc/c-family/ChangeLog: * c.opt: Add -fdiagnostics-all-candidates. gcc/cp/ChangeLog: * call.cc (print_z_candidates): Only print ignored candidates when -fdiagnostics-all-candidates is set, otherwise suggest the flag. (build_over_call): When diagnosing deletedness, note other candidates only if -fdiagnostics-all-candidates is set, otherwise suggest the flag. gcc/testsuite/ChangeLog: * g++.dg/overload/error6.C: Pass -fdiagnostics-all-candidates. * g++.dg/cpp0x/deleted16.C: New test. * g++.dg/cpp0x/deleted16a.C: New test. * g++.dg/overload/error6a.C: New test. --- diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt index 3706505f8bf8..03b64d536fa3 100644 --- a/gcc/c-family/c.opt +++ b/gcc/c-family/c.opt @@ -1805,6 +1805,10 @@ fdiagnostics-show-template-tree C++ ObjC++ Var(flag_diagnostics_show_template_tree) Init(0) Print hierarchical comparisons when template types are mismatched. +fdiagnostics-all-candidates +C++ ObjC++ Var(flag_diagnostics_all_candidates) +Note all candidates during overload resolution failure. + fdirectives-only C ObjC C++ ObjC++ Preprocess directives only. diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc index aa4111dda5c7..6ac87a298b29 100644 --- a/gcc/cp/call.cc +++ b/gcc/cp/call.cc @@ -4090,6 +4090,12 @@ print_z_candidates (location_t loc, struct z_candidate *candidates, { if (only_viable_p.is_true () && candidates->viable != 1) break; + if (ignored_candidate_p (candidates) && !flag_diagnostics_all_candidates) + { + inform (loc, "some candidates omitted; " + "use %<-fdiagnostics-all-candidates%> to display them"); + break; + } print_z_candidate (loc, N_("candidate:"), candidates); } } @@ -9967,7 +9973,18 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain) if (DECL_DELETED_FN (fn)) { if (complain & tf_error) - mark_used (fn); + { + mark_used (fn); + if (cand->next) + { + if (flag_diagnostics_all_candidates) + print_z_candidates (input_location, cand, /*only_viable_p=*/false); + else + inform (input_location, + "use %<-fdiagnostics-all-candidates%> to display " + "considered candidates"); + } + } return error_mark_node; } diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 8f885b8c6d69..f89f926a572b 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -3328,6 +3328,11 @@ called. If the handler returns, execution continues normally. @item -fcoroutines Enable support for the C++ coroutines extension (experimental). +@opindex fdiagnostics-all-candidates +@item -fdiagnostics-all-candidates +Permit the C++ front end to note all candidates during overload resolution +failure, including when a deleted function is selected. + @opindex fno-elide-constructors @opindex felide-constructors @item -fno-elide-constructors diff --git a/gcc/testsuite/g++.dg/cpp0x/deleted16.C b/gcc/testsuite/g++.dg/cpp0x/deleted16.C new file mode 100644 index 000000000000..d4347942c42a --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/deleted16.C @@ -0,0 +1,25 @@ +// Verify -fdiagnostics-all-candidates makes us note other candidates +// when a deleted function is selected by overload resolution. +// { dg-do compile { target c++11 } } +// { dg-additional-options "-fdiagnostics-all-candidates" } + +void f(int) = delete; // { dg-message "declared here" } +void f(...); // { dg-message "candidate" } +void f(int, int); // { dg-message "candidate" } + +// An example where the perfect candidate optimization causes us +// to ignore function templates. +void g(int) = delete; // { dg-message "declared here" } +template void g(T); // { dg-message "candidate" } + +// An example where we have a strictly viable candidate and +// an incompletely considered bad candidate. +template void h(T, T) = delete; // { dg-message "declared here|candidate" } +void h(int*, int) = delete; // { dg-message "candidate" } + +int main() { + f(0); // { dg-error "deleted" } + g(0); // { dg-error "deleted" } + h(1, 1); // { dg-error "deleted" } + // { dg-error "invalid conversion" "" { target *-*-* } .-1 } when noting 2nd cand +} diff --git a/gcc/testsuite/g++.dg/cpp0x/deleted16a.C b/gcc/testsuite/g++.dg/cpp0x/deleted16a.C new file mode 100644 index 000000000000..e62306fa3d18 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/deleted16a.C @@ -0,0 +1,12 @@ +// Verify we suggest -fdiagnostics-all-candidates when diagnosing +// overload resolution selecting a deleted function. +// { dg-do compile { target c++11 } } +#include "deleted16.C" + +// { dg-error "deleted" "" { target *-*-* } 21 } +// { dg-error "deleted" "" { target *-*-* } 22 } +// { dg-error "deleted" "" { target *-*-* } 23 } + +// { dg-message "use '-fdiagnostics-all-candidates'" "" { target *-*-* } 21 } +// { dg-message "use '-fdiagnostics-all-candidates'" "" { target *-*-* } 22 } +// { dg-message "use '-fdiagnostics-all-candidates'" "" { target *-*-* } 23 } diff --git a/gcc/testsuite/g++.dg/overload/error6.C b/gcc/testsuite/g++.dg/overload/error6.C index 86a12eaa8de0..3186a297bfc9 100644 --- a/gcc/testsuite/g++.dg/overload/error6.C +++ b/gcc/testsuite/g++.dg/overload/error6.C @@ -1,5 +1,6 @@ // Verify we note even non-template candidates when diagnosing // overload resolution failure for a template-id. +// { dg-additional-options "-fdiagnostics-all-candidates" } template void f(T); // { dg-message "candidate" } void f(int); // { dg-message {candidate: 'void f\(int\)' \(ignored\)} } diff --git a/gcc/testsuite/g++.dg/overload/error6a.C b/gcc/testsuite/g++.dg/overload/error6a.C new file mode 100644 index 000000000000..e86ab5158abc --- /dev/null +++ b/gcc/testsuite/g++.dg/overload/error6a.C @@ -0,0 +1,6 @@ +// Verify we suggest -fdiagnostics-all-candidates when there are +// omitted candidates. +#include "error6.C" + +// { dg-error "no match" "" { target *-*-* } 9 } +// { dg-message "use '-fdiagnostics-all-candidates'" "" { target *-*-* } 9 }