Implement C++ [over.ics.user]p3, which restricts the final conversion
from a conversion function template specialization to one of exact
match rank. We only know how to test this in C++0x with default
function template arguments, but it's also in the C++03 spec. Fixes
PR6285.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101089 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index fa8e360..cfc8068 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -2819,6 +2819,17 @@
switch (ICS.getKind()) {
case ImplicitConversionSequence::StandardConversion:
Candidate.FinalConversion = ICS.Standard;
+
+ // C++ [over.ics.user]p3:
+ // If the user-defined conversion is specified by a specialization of a
+ // conversion function template, the second standard conversion sequence
+ // shall have exact match rank.
+ if (Conversion->getPrimaryTemplate() &&
+ GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) {
+ Candidate.Viable = false;
+ Candidate.FailureKind = ovl_fail_final_conversion_not_exact;
+ }
+
break;
case ImplicitConversionSequence::BadConversion:
@@ -4628,6 +4639,7 @@
case ovl_fail_trivial_conversion:
case ovl_fail_bad_final_conversion:
+ case ovl_fail_final_conversion_not_exact:
return S.NoteOverloadCandidate(Fn);
case ovl_fail_bad_conversion: {
diff --git a/lib/Sema/SemaOverload.h b/lib/Sema/SemaOverload.h
index d6b46e9..2b9604a 100644
--- a/lib/Sema/SemaOverload.h
+++ b/lib/Sema/SemaOverload.h
@@ -440,7 +440,11 @@
/// This conversion candidate is not viable because its result
/// type is not implicitly convertible to the desired type.
- ovl_fail_bad_final_conversion
+ ovl_fail_bad_final_conversion,
+
+ /// This conversion function template specialization candidate is not
+ /// viable because the final conversion was not an exact match.
+ ovl_fail_final_conversion_not_exact
};
/// OverloadCandidate - A single candidate in an overload set (C++ 13.3).