From 157420b4bd936f18b64d8143a6b3f32f89689412 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Fri, 16 Jun 2017 22:27:52 -0400
Subject: [PATCH] PR c++/80174 - ICE with partial specialization of member
 template.

	PR c++/71747
	* pt.c (get_partial_spec_bindings): Only coerce innermost args.

From-SVN: r249319
---
 gcc/cp/ChangeLog                              |  4 +++
 gcc/cp/pt.c                                   |  8 ++++--
 .../g++.dg/template/partial-specialization6.C | 28 +++++++++++++++++++
 3 files changed, 37 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/template/partial-specialization6.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 48a9cf698fe..330f0f205a0 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2017-06-16  Jason Merrill  <jason@redhat.com>
 
+	PR c++/80174 - ICE with partial specialization of member template.
+	PR c++/71747
+	* pt.c (get_partial_spec_bindings): Only coerce innermost args.
+
 	PR c++/80831 - ICE with -fsyntax-only.
 	* decl2.c (c_parse_final_cleanups): Use cgraph_node::get_create.
 
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 3dad0fc6741..0a581630347 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -21672,9 +21672,11 @@ get_partial_spec_bindings (tree tmpl, tree spec_tmpl, tree args)
      `T' is `A' but unify () does not check whether `typename T::X'
      is `int'.  */
   spec_args = tsubst (spec_args, deduced_args, tf_none, NULL_TREE);
-  spec_args = coerce_template_parms (DECL_INNERMOST_TEMPLATE_PARMS (tmpl),
-				     spec_args, tmpl,
-				     tf_none, false, false);
+
+  if (spec_args != error_mark_node)
+    spec_args = coerce_template_parms (DECL_INNERMOST_TEMPLATE_PARMS (tmpl),
+				       INNERMOST_TEMPLATE_ARGS (spec_args),
+				       tmpl, tf_none, false, false);
 
   pop_tinst_level ();
 
diff --git a/gcc/testsuite/g++.dg/template/partial-specialization6.C b/gcc/testsuite/g++.dg/template/partial-specialization6.C
new file mode 100644
index 00000000000..51a15905839
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/partial-specialization6.C
@@ -0,0 +1,28 @@
+// PR c++/80174
+
+typedef unsigned char uint8_t; 
+
+template <typename T>
+struct HighestMaxFieldIdx {
+  static const uint8_t maxFieldIdx = T::fieldIdx;
+};
+
+template <typename This>
+struct Outer {
+
+  template <uint8_t _fieldIdx, typename T, T This::*field>
+  struct Varint {};
+
+
+  template <uint8_t _fieldIdx, uint8_t This::*field>
+  struct Varint<_fieldIdx, uint8_t, field> {
+    static const uint8_t fieldIdx = _fieldIdx;
+  };
+};
+
+struct Msg {
+  uint8_t a;
+
+  static const uint8_t t
+  = HighestMaxFieldIdx<Outer<Msg>::Varint<1, uint8_t, &Msg::a> >::maxFieldIdx;
+};
-- 
2.30.2