From 586b016cd48f5a5f6f2ba9f179105fabaa3e85dd Mon Sep 17 00:00:00 2001 From: Jason Merrill Date: Fri, 28 Feb 2020 13:43:55 -0500 Subject: c++: Fix constrained conversion op. We don't want to promote a conversion from viable == 0 to viable == -1. Found in ranges-v3. gcc/cp/ChangeLog 2020-02-28 Jason Merrill * call.c (build_user_type_conversion_1): Don't look at the second conversion of a non-viable candidate. --- gcc/cp/ChangeLog | 5 +++++ gcc/cp/call.c | 4 ++++ gcc/testsuite/g++.dg/cpp2a/concepts-conv1.C | 15 +++++++++++++++ 3 files changed, 24 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-conv1.C (limited to 'gcc') diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 4dc30e0..8a8de32 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,8 @@ +2020-02-28 Jason Merrill + + * call.c (build_user_type_conversion_1): Don't look at the second + conversion of a non-viable candidate. + 2020-02-28 Jakub Jelinek P1937R2 - Fixing inconsistencies between const{expr,eval} functions diff --git a/gcc/cp/call.c b/gcc/cp/call.c index e07ee85..85bbd04 100644 --- a/gcc/cp/call.c +++ b/gcc/cp/call.c @@ -4083,6 +4083,10 @@ build_user_type_conversion_1 (tree totype, tree expr, int flags, for (cand = candidates; cand != old_candidates; cand = cand->next) { + if (cand->viable == 0) + /* Already rejected, don't change to -1. */ + continue; + tree rettype = TREE_TYPE (TREE_TYPE (cand->fn)); conversion *ics = implicit_conversion (totype, diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-conv1.C b/gcc/testsuite/g++.dg/cpp2a/concepts-conv1.C new file mode 100644 index 0000000..aa29acb --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-conv1.C @@ -0,0 +1,15 @@ +// { dg-do compile { target concepts } } + +template concept False = false; + +template +struct A +{ + explicit operator bool (); + explicit operator bool () requires False; +}; + +int main() +{ + int i { A() }; // { dg-error "" } +} -- cgit v1.1