Allow ampersand calls for CORE subs with $*$$**$ protos

This enables ampersand calls and calls through references for CORE
subs that have * and $ in their prototypes and a fixed number of
arguments.

Usually, the *-prototyped ops have their child ops wrapped in rv2gv’s
(*{}) implicitly.  The rv2gv op is sometimes flagged as an autoviv-
ificatory op, such as the first argument to accept() or open().
S_is_handle_constructor contains the list of ops that turn on
that flag.

This commit makes the coreargs op use a couple of flags to serve the
same purpose.  pp_coreargs itself calls S_rv2gv (split out from
pp_rv2gv recently for precisely this purpose) with arguments based on
its own flags.

Currently the autovivified glob gets a name like main::_GEN_0 instead
of main::$a.  I think we can live with that.

1 files changed, 10 insertions, 2 deletions

diff --git a/op.c b/op.c
index 4577bcc54f..606e086825 100644
--- a/op.c
+++ b/op.c
@@ -10332,6 +10332,7 @@ Perl_coresub_op(pTHX_ SV * const coreargssv, const int code,
                       const int opnum)
 {
     OP * const argop = newSVOP(OP_COREARGS,0,coreargssv);
+    OP *o;
 
     PERL_ARGS_ASSERT_CORESUB_OP;
 
@@ -10353,9 +10354,16 @@ Perl_coresub_op(pTHX_ SV * const coreargssv, const int code,
 	                      opnum == OP_WANTARRAY ? OPpOFFBYONE << 8 : 0)
 	           );
 	case OA_BASEOP_OR_UNOP:
-	    return newUNOP(opnum,0,argop);
+	    o = newUNOP(opnum,0,argop);
+	  onearg:
+	    if (is_handle_constructor(o, 1))
+		argop->op_private |= OPpCOREARGS_DEREF1;
+	    return o;
 	default:
-	    return convert(opnum,0,argop);
+	    o = convert(opnum,0,argop);
+	    if (is_handle_constructor(o, 2))
+		argop->op_private |= OPpCOREARGS_DEREF2;
+	    goto onearg;
 	}
     }
 }