diff mbox series

[pushed] c++: default template arg, partial ordering [PR105481]

Message ID 20230324163153.3200112-1-jason@redhat.com
State Committed
Commit 4e2cdb1ddb5f6ace909358775e94bfe23046ad5a
Headers
Series [pushed] c++: default template arg, partial ordering [PR105481] |

Commit Message

Jason Merrill March 24, 2023, 4:31 p.m. UTC 
  Tested x86_64-pc-linux-gnu, applying to trunk.

-- 8< --

The default argument code in type_unification_real was assuming that all
targs we've deduced by that point are non-dependent, but that's not the case
for partial ordering.

	PR c++/105481

gcc/cp/ChangeLog:

	* pt.cc (type_unification_real): Adjust for partial ordering.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/fntmpdefarg-partial1.C: New test.
---
 gcc/cp/pt.cc                                   | 18 ++++++++++++++----
 .../g++.dg/cpp0x/fntmpdefarg-partial1.C        |  8 ++++++++
 2 files changed, 22 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/fntmpdefarg-partial1.C


base-commit: c4792bd1de0621932a47fb86aca09fafafdb2972
diff mbox series

Patch

diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 40deedc9ba9..3bb98ebeac1 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -23304,14 +23304,24 @@  type_unification_real (tree tparms,
 	  return unify_parameter_deduction_failure (explain_p, tparm);
 	}
 
+      /* During partial ordering, we deduce dependent template args.  */
+      bool any_dependent_targs = false;
+
       /* Now substitute into the default template arguments.  */
       for (i = 0; i < ntparms; i++)
 	{
 	  tree targ = TREE_VEC_ELT (targs, i);
 	  tree tparm = TREE_VEC_ELT (tparms, i);
 
-	  if (targ || tparm == error_mark_node)
+	  if (targ)
+	    {
+	      if (!any_dependent_targs && dependent_template_arg_p (targ))
+		any_dependent_targs = true;
+	      continue;
+	    }
+	  if (tparm == error_mark_node)
 	    continue;
+
 	  tree parm = TREE_VALUE (tparm);
 	  tree arg = TREE_PURPOSE (tparm);
 	  reopen_deferring_access_checks (*checks);
@@ -23347,9 +23357,9 @@  type_unification_real (tree tparms,
 		 do this substitution without processing_template_decl.  This
 		 is important if the default argument contains something that
 		 might be instantiation-dependent like access (87480).  */
-	      processing_template_decl_sentinel s;
+	      processing_template_decl_sentinel s (!any_dependent_targs);
 	      tree substed = NULL_TREE;
-	      if (saw_undeduced == 1)
+	      if (saw_undeduced == 1 && !any_dependent_targs)
 		{
 		  /* First instatiate in template context, in case we still
 		     depend on undeduced template parameters.  */
@@ -23372,7 +23382,7 @@  type_unification_real (tree tparms,
 						 complain, i, NULL_TREE);
 	      else if (saw_undeduced == 1)
 		arg = NULL_TREE;
-	      else
+	      else if (!any_dependent_targs)
 		arg = error_mark_node;
 	    }
 
diff --git a/gcc/testsuite/g++.dg/cpp0x/fntmpdefarg-partial1.C b/gcc/testsuite/g++.dg/cpp0x/fntmpdefarg-partial1.C
new file mode 100644
index 00000000000..2a6783e566b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/fntmpdefarg-partial1.C
@@ -0,0 +1,8 @@ 
+// PR c++/105481
+// { dg-do compile { target c++11 } }
+
+template<unsigned> struct uint;
+template<unsigned N> uint<N> f(const uint<N> &);
+template<unsigned N, typename T, typename = uint<N>> uint<N> f(T);
+using X = uint<1>;
+X (*fp)(X const &) = f;