Objective-C doesn't consider the use of incomplete types as method
parameter types to be ill-formed. However, it relies on the
completeness of method parameter types when producing metadata, e.g.,
for a protocol, leading IR generating to crash in such cases.
Since there's no real way to tighten down the semantics of Objective-C
here without breaking existing code, do something safe but lame:
suppress the generation of metadata when this happens.
Fixes <rdar://problem/9123036>.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@132171 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index d978c38..ea084b4 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -2867,6 +2867,16 @@
if ((*Param)->isTemplateParameterPack())
break;
+ // If our template is a template template parameter that hasn't acquired
+ // its proper context yet (e.g., because we're using the template template
+ // parameter in the signature of a function template, before we've built
+ // the function template itself), don't attempt substitution of default
+ // template arguments at this point: we don't have enough context to
+ // do it properly.
+ if (isTemplateTemplateParameter &&
+ Template->getDeclContext()->isTranslationUnit())
+ break;
+
// We have a default template argument that we will use.
TemplateArgumentLoc Arg;