From: Jason Merrill <jason@redhat.com>
Date: Thu, 7 Mar 2019 16:15:56 +0000 (-0500)
Subject: PR c++/88820 - ICE with CTAD and member template used in DMI.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ae9b289201b6c6996b9c701109658adfb551327b;p=gcc.git

PR c++/88820 - ICE with CTAD and member template used in DMI.

Here the problem was that in order to form a FUNCTION_DECL for foo<int> in
the uninstantiated template, we were trying to deduce template args for S
from the template parm itself, and failing.

	* pt.c (do_class_deduction): Handle parm used as its own arg.

From-SVN: r269463
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index c2162a4a3d4..94e278dc944 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2019-03-07  Jason Merrill  <jason@redhat.com>
+
+	PR c++/88820 - ICE with CTAD and member template used in DMI.
+	* pt.c (do_class_deduction): Handle parm used as its own arg.
+
 2019-03-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/89585
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 8a5a0b38b2d..906cfe0a58c 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -27184,6 +27184,9 @@ do_class_deduction (tree ptype, tree tmpl, tree init, int flags,
 	error ("non-class template %qT used without template arguments", tmpl);
       return error_mark_node;
     }
+  if (init && TREE_TYPE (init) == ptype)
+    /* Using the template parm as its own argument.  */
+    return ptype;
 
   tree type = TREE_TYPE (tmpl);
 
diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction64.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction64.C
new file mode 100644
index 00000000000..3a06e6fb522
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction64.C
@@ -0,0 +1,9 @@
+// PR c++/88820
+// { dg-do compile { target c++17 } }
+
+template <int> struct S;
+
+template <S> struct W {
+  template <typename> static int foo();
+  bool b = foo<int>();
+};