From 66ce8ff7603b3b717fff93d706b1cf3548ba4671 Mon Sep 17 00:00:00 2001
From: Nathan Sidwell <nathan@acm.org>
Date: Tue, 23 Jan 2018 14:08:11 +0000
Subject: [PATCH] [PR c++/839888] Baselink tsubst ICE

https://gcc.gnu.org/ml/gcc-patches/2018-01/msg01954.html
	PR c++/83988
	* pt.c (tsubst_baselink): Remove optype assert.
	* ptree.c (cxx_print_xnode): <case BASELINK> Print BASELINK_OPTYPE.

	PR c++/83988
	* g++.dg/template/pr83988.C: New.

From-SVN: r256986
---
 gcc/cp/ChangeLog                        |  6 ++++++
 gcc/cp/pt.c                             |  7 ++-----
 gcc/cp/ptree.c                          |  1 +
 gcc/testsuite/ChangeLog                 |  5 +++++
 gcc/testsuite/g++.dg/template/pr83988.C | 16 ++++++++++++++++
 5 files changed, 30 insertions(+), 5 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/template/pr83988.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 5adf93075d5..97c54ac9a00 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2018-01-23  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/83988
+	* pt.c (tsubst_baselink): Remove optype assert.
+	* ptree.c (cxx_print_xnode): <case BASELINK> Print BASELINK_OPTYPE.
+
 2018-01-23  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/83958
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 0296845a31b..695870da32c 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -14447,11 +14447,8 @@ tsubst_baselink (tree baselink, tree object_type,
 	fns = BASELINK_FUNCTIONS (baselink);
     }
   else
-    {
-      gcc_assert (optype == BASELINK_OPTYPE (baselink));
-      /* We're going to overwrite pieces below, make a duplicate.  */
-      baselink = copy_node (baselink);
-    }
+    /* We're going to overwrite pieces below, make a duplicate.  */
+    baselink = copy_node (baselink);
 
   /* If lookup found a single function, mark it as used at this point.
      (If lookup found multiple functions the one selected later by
diff --git a/gcc/cp/ptree.c b/gcc/cp/ptree.c
index 8e7697a012d..40535c7c06a 100644
--- a/gcc/cp/ptree.c
+++ b/gcc/cp/ptree.c
@@ -215,6 +215,7 @@ cxx_print_xnode (FILE *file, tree node, int indent)
       print_node (file, "binfo", BASELINK_BINFO (node), indent + 4);
       print_node (file, "access_binfo", BASELINK_ACCESS_BINFO (node),
 		  indent + 4);
+      print_node (file, "optype", BASELINK_OPTYPE (node), indent + 4);
       break;
     case OVERLOAD:
       print_node (file, "function", OVL_FUNCTION (node), indent+4);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 5c1d57f7ed2..17399f97a80 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-01-23  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/83988
+	* g++.dg/template/pr83988.C: New.
+
 2018-01-23  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/82882
diff --git a/gcc/testsuite/g++.dg/template/pr83988.C b/gcc/testsuite/g++.dg/template/pr83988.C
new file mode 100644
index 00000000000..bd2762cd68f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/pr83988.C
@@ -0,0 +1,16 @@
+// PR 83988 ICE
+
+template<class T> struct optional {};
+struct get_from_json {
+  template<typename GetWhat>
+  operator optional<GetWhat>() const {return optional<GetWhat> ();}
+  template<typename AsWhat>
+  optional<AsWhat> maybe() const
+  {
+    return this->operator optional<AsWhat>();
+  }
+};
+void test()
+{
+  get_from_json().maybe<int>();
+}
-- 
2.30.2