PR12298 et al: don't recursively instantiate a template specialization from

within the instantiation of that same specialization. This could previously
happen for eagerly-instantiated function templates, variable templates,
exception specifications, default arguments, and a handful of other cases.

We still have an issue here for default template arguments that recursively
make use of themselves and likewise for substitution into the type of a
non-type template parameter, but in those cases we're producing a different
entity each time, so they should instead be caught by the instantiation depth
limit. However, currently we will typically run out of stack before we reach
it. :(

llvm-svn: 280190

1 files changed, 4 insertions, 5 deletions

diff --git a/clang/test/SemaTemplate/instantiation-depth.cpp b/clang/test/SemaTemplate/instantiation-depth.cpp
index c0b8bb2a124..17f84c170c3 100644
--- a/clang/test/SemaTemplate/instantiation-depth.cpp
+++ b/clang/test/SemaTemplate/instantiation-depth.cpp
@@ -19,13 +19,12 @@ void test() {
 // RUN: %clang_cc1 -fsyntax-only -verify -ftemplate-depth 5 -ftemplate-backtrace-limit 4 -std=c++11 -DNOEXCEPT %s
 
 template<typename T> struct S {
-  S() noexcept(noexcept(T()));
-};
-struct T : S<T> {}; \
+  S() noexcept(noexcept(S<S>())); \
 // expected-error{{recursive template instantiation exceeded maximum depth of 5}} \
-// expected-note 4 {{in instantiation of exception spec}} \
+// expected-note 3 {{in instantiation of exception spec}} \
 // expected-note {{skipping 2 contexts in backtrace}} \
 // expected-note {{use -ftemplate-depth=N to increase recursive template instantiation depth}}
-T t; // expected-note {{implicit default constructor for 'T' first required here}}
+};
+S<void> t; // expected-note {{in instantiation of exception spec}}
 
 #endif