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/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 03850bb..93ea89d 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -2589,7 +2589,7 @@
Specialization = cast_or_null<FunctionDecl>(
SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner,
MultiLevelTemplateArgumentList(*DeducedArgumentList)));
- if (!Specialization)
+ if (!Specialization || Specialization->isInvalidDecl())
return TDK_SubstitutionFailure;
assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() ==
@@ -2601,6 +2601,14 @@
!Trap.hasErrorOccurred())
Info.take();
+ // There may have been an error that did not prevent us from constructing a
+ // declaration. Mark the declaration invalid and return with a substitution
+ // failure.
+ if (Trap.hasErrorOccurred()) {
+ Specialization->setInvalidDecl(true);
+ return TDK_SubstitutionFailure;
+ }
+
if (OriginalCallArgs) {
// C++ [temp.deduct.call]p4:
// In general, the deduction process attempts to find template argument
@@ -2619,14 +2627,6 @@
}
}
- // There may have been an error that did not prevent us from constructing a
- // declaration. Mark the declaration invalid and return with a substitution
- // failure.
- if (Trap.hasErrorOccurred()) {
- Specialization->setInvalidDecl(true);
- return TDK_SubstitutionFailure;
- }
-
// If we suppressed any diagnostics while performing template argument
// deduction, and if we haven't already instantiated this declaration,
// keep track of these diagnostics. They'll be emitted if this specialization