On 20 May 2016 at 07:05, Ville Voutilainen <ville.voutilai...@gmail.com> wrote:
> On 19 May 2016 at 19:40, Jason Merrill <ja...@redhat.com> wrote:
>> Any thoughts on doing something similar for extern variable declarations?
>
> Ah, we diagnose local extern variable declarations that clash with
> previous declarations,
> but we don't diagnose cases where a subsequent declaration clashes
> with a previous
> local extern declaration. I'll take a look.

As discussed on irc, this requires teaching variable declarations to
work with DECL_ANTICIPATED
and is thus some amounts of surgery, so the recommendation was to go
ahead with this patch.
I added a comment to the new code block, an updated patch attached.
Changelog as before.
Ok for trunk?
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index eb128db..568c75e 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -929,6 +929,24 @@ pushdecl_maybe_friend_1 (tree x, bool is_friend)
              DECL_ANTICIPATED (t) = 1;
              DECL_HIDDEN_FRIEND_P (t) = 1;
            }
+
+         if (TREE_CODE (x) == FUNCTION_DECL
+             && DECL_LOCAL_FUNCTION_P (x)
+             && !DECL_OMP_DECLARE_REDUCTION_P (x)
+             && !type_dependent_expression_p (x))
+           {
+             /* PR c++/69855, a local function declaration
+                is stripped from template info and pushed to
+                the local scope as a hidden declaration. This
+                allows ill-formed overloads even in other scopes
+                to be diagnosed both at the local declaration site
+                and after it.  */
+             tree t2 = copy_decl (t);
+             DECL_USE_TEMPLATE (t2) = 0;
+             DECL_TEMPLATE_INFO (t2) = NULL_TREE;
+             DECL_ANTICIPATED (t2) = 1;
+             push_overloaded_decl (t2, PUSH_GLOBAL, is_friend);
+           }
        }
 
       if (t != x || DECL_FUNCTION_TEMPLATE_P (t))
diff --git a/gcc/testsuite/g++.dg/overload/69855.C 
b/gcc/testsuite/g++.dg/overload/69855.C
new file mode 100644
index 0000000..dc2d733
--- /dev/null
+++ b/gcc/testsuite/g++.dg/overload/69855.C
@@ -0,0 +1,44 @@
+// PR c++/69855
+// { dg-do compile }
+
+int get();
+void f() {
+  char get(); // { dg-error "ambiguating" }
+}
+
+int get2();
+char get2(int);
+void f2() {
+  char get2(); // { dg-error "ambiguating" }
+}
+
+char get3(int);
+void f3() {
+  char get3();
+}
+
+void f4() {
+  char get4();
+}
+int get4(); // { dg-error "ambiguating" }
+
+void get5();
+
+template <class T> struct X
+{
+  void g()
+  {
+    int get5(); // { dg-error "ambiguating" }
+  }
+};
+
+
+template <class T> struct X2
+{
+  void g()
+  {
+    int get6();
+  }
+};
+
+void get6(); // { dg-error "ambiguating" }
diff --git a/gcc/testsuite/g++.old-deja/g++.law/missed-error2.C 
b/gcc/testsuite/g++.old-deja/g++.law/missed-error2.C
index 42f70ae..26ae87d 100644
--- a/gcc/testsuite/g++.old-deja/g++.law/missed-error2.C
+++ b/gcc/testsuite/g++.old-deja/g++.law/missed-error2.C
@@ -25,9 +25,10 @@ int main() {
    foo(4, -37, 14.39, 14.38);
 }
 
-// 971006 we no longer give an error for this since we emit a hard error
-// about the declaration above
-static void foo(int i, int j, double x, double y) { 
+// 971006 we no longer gave an error for this since we emit a hard error
+// about the declaration above, but after the fix for PR c++/69855
+// this declaration emits a diagnostic again
+static void foo(int i, int j, double x, double y) { // { dg-error 
"extern|static" }
 
    std::cout << "Max(int): " << max(i,j) << " Max(double): " <<
 max(x,y) << '\n';
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/crash3.C 
b/gcc/testsuite/g++.old-deja/g++.pt/crash3.C
index 160cbe5..2ba61d9 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/crash3.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/crash3.C
@@ -10,7 +10,7 @@ public:
     }
     CVector<long> g() const
     {
-       CVector<long> v();
-       return v;
+       CVector<long> v2();
+       return v2;
     }
 };

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