Attempt at fixing role A { method m {} }; role B does A {}; class C does A does B {} : apparently just checking for =:= is not enough

gistfile1.txt

diff --git a/src/Perl6/Metamodel/RoleToRoleApplier.nqp b/src/Perl6/Metamodel/RoleToRoleApplier.nqp
index b115bc5..4f34cff 100644
--- a/src/Perl6/Metamodel/RoleToRoleApplier.nqp
+++ b/src/Perl6/Metamodel/RoleToRoleApplier.nqp
@@ -86,7 +86,18 @@ my class RoleToRoleApplier {
                         $target.HOW.add_method($target, $name, @add_meths[0]);
                     }
                     else {
-                        $target.HOW.add_collision($target, $name, %meth_providers{$name});
+                        my $first := @impl_meths[0];
+                        my int $i := 0;
+                        while ($i := $i + 1) < +@impl_meths {
+                            last unless @impl_meths[$i] =:= $first;
+                        }
+                        # possible collisions are all the same
+                        if $i == +@impl_meths {
+                            $target.HOW.add_method($target, $name, $first);
+                        }
+                        else {
+                          $target.HOW.add_collision($target, $name, %meth_providers{$name});
+                        }
                     }
                 }
             }