Steps to reproduce on linux:
-bash-4.2$ cat r.cpp
template <class T> void bar(T t = [](decltype(t) i){return 0;}(0)) {}
void foo()
{
  bar<int>();
}
-bash-4.2$ pwd
/home/jtony/workitems/132592
-bash-4.2$ cat r.cpp
template <class T> void bar(T t = [](decltype(t) i){return 0;}(0)) {}
void foo()
{
  bar<int>();
}


bash-4.2$ myclang++ r.cpp  -std=c++11
clang: /home/jtony/build/3_8/llvm-dev.src/tools/clang/lib/Sema/SemaTemplateInstantiate.cpp:2811: llvm::PointerUnion<clang::Decl*, llvm::Smal
lVector<clang::ParmVarDecl*, 4u>*>* clang::LocalInstantiationScope::findInstantiationOf(const clang::Decl*): Assertion `isa<LabelDecl>(D) &&
 "declaration not instantiated in this scope"' failed.
0  clang     0x000000001568c4e4 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 68
...
clang version 3.8.0 (tags/RELEASE_380/final)
Target: powerpc64le-unknown-linux-gnu
Thread model: posix


-bash-4.2$ type myclang
myclang is aliased to `/home/jtony/build/runnable/bin/clang'