Improve our handling of user-defined conversions as part of overload
resolution. There are two sources of problems involving user-defined
conversions that this change eliminates, along with providing simpler
interfaces for checking implicit conversions:
- It eliminates a case of infinite recursion found in Boost.
- It eliminates the search for the constructor needed to copy a temporary
generated by an implicit conversion from overload
resolution. Overload resolution assumes that, if it gets a value
of the parameter's class type (or a derived class thereof), there
is a way to copy if... even if there isn't. We now model this
properly.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101680 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaOverload.h b/lib/Sema/SemaOverload.h
index 2b9604a..5e61111 100644
--- a/lib/Sema/SemaOverload.h
+++ b/lib/Sema/SemaOverload.h
@@ -381,6 +381,33 @@
assert(isInitialized() && "querying uninitialized conversion");
return Kind(ConversionKind);
}
+
+ /// \brief Return a ranking of the implicit conversion sequence
+ /// kind, where smaller ranks represent better conversion
+ /// sequences.
+ ///
+ /// In particular, this routine gives user-defined conversion
+ /// sequences and ambiguous conversion sequences the same rank,
+ /// per C++ [over.best.ics]p10.
+ unsigned getKindRank() const {
+ switch (getKind()) {
+ case StandardConversion:
+ return 0;
+
+ case UserDefinedConversion:
+ case AmbiguousConversion:
+ return 1;
+
+ case EllipsisConversion:
+ return 2;
+
+ case BadConversion:
+ return 3;
+ }
+
+ return 3;
+ }
+
bool isBad() const { return getKind() == BadConversion; }
bool isStandard() const { return getKind() == StandardConversion; }
bool isEllipsis() const { return getKind() == EllipsisConversion; }