PR9793: Treat substitution as an instantiation step for the purpose of the
-ftemplate-depth limit.  There are various ways to get an infinite (or merely
huge) stack of substitutions with no intervening instantiations. This is also
consistent with gcc's behavior.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@159907 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaTemplate/instantiation-depth-subst-2.cpp b/test/SemaTemplate/instantiation-depth-subst-2.cpp
new file mode 100644
index 0000000..a29d6b5
--- /dev/null
+++ b/test/SemaTemplate/instantiation-depth-subst-2.cpp
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -verify %s -ftemplate-depth 2
+
+template<int N> struct S { };
+// FIXME: We produce the same 'instantiation depth' error here many times
+// (2^(depth+1) in total), due to additional lookups performed as part of
+// error recovery in DiagnoseTwoPhaseOperatorLookup.
+template<typename T> S<T() + T()> operator+(T, T); // expected-error 8{{}} expected-note 10{{}}
+S<0> s;
+int k = s + s; // expected-error {{invalid operands to binary expression}}