PR c++/69300 - ICE with self-referential noexcept

	* pt.c (maybe_instantiate_noexcept): Check for recursion.

From-SVN: r249757

gcc/cp/ChangeLog

 2017-06-28  Jason Merrill  <jason@redhat.com>
 
+	PR c++/69300 - ICE with self-referential noexcept
+	* pt.c (maybe_instantiate_noexcept): Check for recursion.
+
 	PR c++/61022 - error with variadic template template parm
 	* pt.c (convert_template_argument): Keep the TYPE_PACK_EXPANSION.
 

gcc/cp/pt.c

@@ -22557,8 +22557,20 @@ maybe_instantiate_noexcept (tree fn)
 
   if (TREE_CODE (noex) == DEFERRED_NOEXCEPT)
     {
+      static hash_set<tree>* fns = new hash_set<tree>;
+      bool added = false;
       if (DEFERRED_NOEXCEPT_PATTERN (noex) == NULL_TREE)
 	spec = get_defaulted_eh_spec (fn);
+      else if (!(added = !fns->add (fn)))
+	{
+	  /* If hash_set::add returns true, the element was already there.  */
+	  location_t loc = EXPR_LOC_OR_LOC (DEFERRED_NOEXCEPT_PATTERN (noex),
+					    DECL_SOURCE_LOCATION (fn));
+	  error_at (loc,
+		    "exception specification of %qD depends on itself",
+		    fn);
+	  spec = noexcept_false_spec;
+	}
       else if (push_tinst_level (fn))
 	{
 	  push_access_scope (fn);
@@ -22579,6 +22591,9 @@ maybe_instantiate_noexcept (tree fn)
       else
 	spec = noexcept_false_spec;
 
+      if (added)
+	fns->remove (fn);
+
       TREE_TYPE (fn) = build_exception_variant (fntype, spec);
     }
 

gcc/testsuite/g++.dg/cpp0x/noexcept30.C

+// PR c++/69300
+// { dg-do compile { target c++11 } }
+
+template<typename A>
+struct F {
+  template<typename B>
+  void f() noexcept(&F::template f<B>) {} // { dg-error "exception specification" }
+};
+
+int main () {
+  F<void>().f<int>();
+}