&CORE::lock()

This commit allows &CORE::lock to be called through references and
via ampersand syntax.  It adds code to pp_coreargs for handling the
OA_SCALARREF case, though what it adds is currently lock-specific.
(Subsequent commits will address that.)  Since lock returns the scalar
passed to it, not a copy, &CORE::lock needs to use op_leavesublv,
rather than op_leavesub.  But it can’t be an lvalue sub, as
&CORE::lock = 3 should be disallowed.  So we use the sneaky trick of
turning on the lvalue flag before attaching the op tree to the sub
(which causes newATTRSUB to use op_leavesublv), and then turning it
off afterwards.

1 files changed, 12 insertions, 0 deletions

diff --git a/pp.c b/pp.c
index de2b35c2c5..fd17bc1299 100644
--- a/pp.c
+++ b/pp.c
@@ -6109,6 +6109,18 @@ PP(pp_coreargs)
 		));
 	    }
 	    break;
+	case OA_SCALARREF:
+	    if (!svp || !*svp || !SvROK(*svp)
+	     || SvTYPE(SvRV(*svp)) > SVt_PVCV
+	       )
+		DIE(aTHX_
+		/* diag_listed_as: Type of arg %d to &CORE::%s must be %s*/
+		 "Type of arg %d to &CORE::%s must be reference to one of "
+		 "[$@%%&*]",
+		  whicharg, OP_DESC(PL_op->op_next)
+		);
+	    PUSHs(SvRV(*svp));
+	    break;
 	default:
 	    DIE(aTHX_ "panic: unknown OA_*: %x", (unsigned)(oa&7));
 	}