[gcc(refs/users/marxin/heads/marxin-gcc-benchmark-branch)] c++: Fix useless using-declaration.

[gcc(refs/users/marxin/heads/marxin-gcc-benchmark-branch)] c++: Fix useless using-declaration.

[Martin Liska]

https://gcc.gnu.org/g:9a0c4f5b373e236cb4af5491f50862d41fd8775a

commit 9a0c4f5b373e236cb4af5491f50862d41fd8775a
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Feb 13 16:56:08 2020 +0100

    c++: Fix useless using-declaration.
    
    Here reintroducing the same declarations into the global namespace via
    using-declaration is useless but OK.  And a function and a function template
    with the same parameters do not conflict.
    
    gcc/cp/ChangeLog
    2020-02-13  Jason Merrill  <jason@redhat.com>
    
            PR c++/93713
            * name-lookup.c (matching_fn_p): A function does not match a
            template.

Diff:
---
 gcc/cp/ChangeLog                      | 4 ++++
 gcc/cp/name-lookup.c                  | 6 ++++--
 gcc/testsuite/g++.dg/lookup/using62.C | 3 +++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 8d7d91ce719..793e4afffcb 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2020-02-13  Jason Merrill  <jason@redhat.com>
 
+	PR c++/93713
+	* name-lookup.c (matching_fn_p): A function does not match a
+	template.
+
 	PR c++/93643
 	PR c++/91476
 	* tree.c (decl_linkage): Always lk_none for locals.
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 2a9bae53162..e5638d2df91 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -2321,12 +2321,14 @@ update_local_overload (cxx_binding *binding, tree newval)
 static bool
 matching_fn_p (tree one, tree two)
 {
+  if (TREE_CODE (one) != TREE_CODE (two))
+    return false;
+
   if (!compparms (TYPE_ARG_TYPES (TREE_TYPE (one)),
 		  TYPE_ARG_TYPES (TREE_TYPE (two))))
     return false;
 
-  if (TREE_CODE (one) == TEMPLATE_DECL
-      && TREE_CODE (two) == TEMPLATE_DECL)
+  if (TREE_CODE (one) == TEMPLATE_DECL)
     {
       /* Compare template parms.  */
       if (!comp_template_parms (DECL_TEMPLATE_PARMS (one),
diff --git a/gcc/testsuite/g++.dg/lookup/using62.C b/gcc/testsuite/g++.dg/lookup/using62.C
new file mode 100644
index 00000000000..e7a952ace08
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lookup/using62.C
@@ -0,0 +1,3 @@
+template <class T> T bar ();
+void bar () {}
+using :: bar;