When we determine that a function template specialization produced as
part of template argument deduction is ill-formed, we mark it as
invalid and treat it as a deduction failure. If we happen to find that
specialization again, treat it as a deduction failure rather than
silently building a call to the declaration.
Fixes PR11117, a marvelous bug where deduction failed after creating
an invalid specialization, causing overload resolution to pick a
different candidate. Then we performed a similar overload resolution
later, and happily picked the invalid specialization to
call... resulting in a silent link failure.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@141809 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaTemplate/operator-template.cpp b/test/SemaTemplate/operator-template.cpp
index 4300755..777b0f5 100644
--- a/test/SemaTemplate/operator-template.cpp
+++ b/test/SemaTemplate/operator-template.cpp
@@ -2,7 +2,8 @@
// Make sure we accept this
template<class X>struct A{typedef X Y;};
-template<class X>bool operator==(A<X>,typename A<X>::Y);
+template<class X>bool operator==(A<X>,typename A<X>::Y); // expected-note{{candidate template ignored: failed template argument deduction}}
+
int a(A<int> x) { return operator==(x,1); }
int a0(A<int> x) { return x == 1; }
@@ -10,7 +11,8 @@
// FIXME: the location information for the note isn't very good
template<class X>struct B{typedef X Y;};
template<class X>bool operator==(B<X>*,typename B<X>::Y); // \
-expected-error{{overloaded 'operator==' must have at least one parameter of class or enumeration type}} \
-expected-note{{in instantiation of function template specialization}}
-int a(B<int> x) { return operator==(&x,1); }
+// expected-error{{overloaded 'operator==' must have at least one parameter of class or enumeration type}} \
+// expected-note{{in instantiation of function template specialization}} \
+// expected-note{{candidate template ignored: substitution failure [with X = int]}}
+int a(B<int> x) { return operator==(&x,1); } // expected-error{{no matching function for call to 'operator=='}}