Eliminate opASSIGN macro usage from core

This macro is defined as

    (PL_op->op_flags & OPf_STACKED)

and indicates, for ops which support it, that the mutator-variant of the
op is present (e.g. $x += 1).

This macro was mainly used as an arg for the old-style overloading
macros (tryAMAGICbin()) which were eliminated several years ago.

This commit removes its vestigial usage, and instead tests OPf_STACKED
directly at each location, along with adding a comment about the
significance of the flag.

This removes one item of obfuscation from the overloading code.

There is one potentially functional change in this commit:
Perl_try_amagic_bin() was sometimes testing for OPf_STACKED without
first checking that it had been called with the AMGf_assign flag (which
indicates that this op supports a mutator variant). With this commit, it
now checks first, so this is theoretically a bug fix. In practice that
section of code was never reached without AMGf_assign always being set
anyway.

1 files changed, 5 insertions, 0 deletions

diff --git a/op.h b/op.h
index 6d9dae849e..c9f05b2271 100644
--- a/op.h
+++ b/op.h
@@ -99,7 +99,12 @@ Deprecated.  Use C<GIMME_V> instead.
 #define OPf_REF		16	/* Certified reference. */
 				/*  (Return container, not containee). */
 #define OPf_MOD		32	/* Will modify (lvalue). */
+
 #define OPf_STACKED	64	/* Some arg is arriving on the stack. */
+                                /*   Indicates mutator-variant of op for those
+                                 *     ops which support them, e.g. $x += 1
+                                 */
+
 #define OPf_SPECIAL	128	/* Do something weird for this op: */
 				/*  On local LVAL, don't init local value. */
 				/*  On OP_SORT, subroutine is inlined. */