re PR c++/82085 (ICE: Template variable reference used in nested template alias)

/cp
2017-10-30  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/82085
	* pt.c (tsubst_copy_and_build, [INDIRECT_REF]): For a REFERENCE_REF_P,
	unconditionally call convert_from_reference.

/testsuite
2017-10-30  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/82085
	* g++.dg/cpp1y/var-templ56.C: New.

From-SVN: r254239

gcc/cp/ChangeLog

+2017-10-30  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/82085
+	* pt.c (tsubst_copy_and_build, [INDIRECT_REF]): For a REFERENCE_REF_P,
+	unconditionally call convert_from_reference.
+
 2017-10-30  Nathan Sidwell  <nathan@acm.org>
 
 	* call.c (build_op_call_1): Test for FUNCTION_DECL in same manner

gcc/cp/pt.c

@@ -17079,8 +17079,7 @@ tsubst_copy_and_build (tree t,
 	    /* A type conversion to reference type will be enclosed in
 	       such an indirect ref, but the substitution of the cast
 	       will have also added such an indirect ref.  */
-	    if (TREE_CODE (TREE_TYPE (r)) == REFERENCE_TYPE)
-	      r = convert_from_reference (r);
+	    r = convert_from_reference (r);
 	  }
 	else
 	  r = build_x_indirect_ref (input_location, r, RO_UNARY_STAR,

gcc/testsuite/ChangeLog

+2017-10-30  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/82085
+	* g++.dg/cpp1y/var-templ56.C: New.
+
 2017-10-30  Nathan Sidwell  <nathan@acm.org>
 
 	* g++.dg/other/operator2.C: Adjust diagnostic.

gcc/testsuite/g++.dg/cpp1y/var-templ56.C

+// PR c++/82085
+// { dg-do compile { target c++14 } }
+
+template <const char& V>
+using char_sequence_t = int;
+
+template <typename T>
+constexpr char name_of_v = 'x';
+
+template <typename T>
+using type = char_sequence_t<name_of_v<T>>;