From: paolo <paolo@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 4 Aug 2017 22:13:46 +0000 (+0000)
Subject: /cp
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=390f62dea36c3ba19429c312fc68557b82714be3;p=thirdparty%2Fgcc.git

/cp
2017-08-04  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/79790
	* pt.c (do_class_deduction): Handle the case of no viable implicit
	deduction guides; simplify the code generating implicit deduction
	guides.

/testsuite
2017-08-04  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/79790
	* g++.dg/cpp1z/class-deduction42.C: New.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@250882 138bc75d-0d04-0410-961f-82ee72b054a4
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 041c6c44bbec..f4051080c936 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2017-08-04  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/79790
+	* pt.c (do_class_deduction): Handle the case of no viable implicit
+	deduction guides; simplify the code generating implicit deduction
+	guides.
+
 2017-08-03  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/71440
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index ee4e6b113341..bd61438fc39d 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -25452,11 +25452,7 @@ do_class_deduction (tree ptype, tree tmpl, tree init, int flags,
       if (gtype)
 	{
 	  tree guide = build_deduction_guide (gtype, outer_args, complain);
-	  if ((flags & LOOKUP_ONLYCONVERTING)
-	      && DECL_NONCONVERTING_P (STRIP_TEMPLATE (guide)))
-	    elided = true;
-	  else
-	    cands = lookup_add (guide, cands);
+	  cands = lookup_add (guide, cands);
 	}
     }
 
@@ -25467,6 +25463,12 @@ do_class_deduction (tree ptype, tree tmpl, tree init, int flags,
 	     "user-declared constructors", type);
       return error_mark_node;
     }
+  else if (!cands && call == error_mark_node)
+    {
+      error ("cannot deduce template arguments of %qT, as it has no viable "
+	     "deduction guides", type);
+      return error_mark_node;
+    }
 
   if (call == error_mark_node)
     {
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4203037994dc..c936479fbfb2 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-08-04  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/79790
+	* g++.dg/cpp1z/class-deduction42.C: New.
+
 2017-08-04  Yury Gribov  <tetra2005@gmail.com>
 
 	PR tree-optimization/57371