[perl #44895] += warning on uninit magic var

The only uses of USE_LEFT in core now occur when SvGETMAGIC has
already been called.  So returning true for magical SVs is not neces-
sary.  In fact, it was never correct.

Also, the code in do_vop (which handles bitwise operations on strings)
to avoid an uninitialized warning had the same buggy SvGMAGICAL check.

Now, the warning from $uninit += 1 is suppressed for all undefined
vars, not just amagical ones.

This causes 6 to-do tests in assignwarn.t to pass.

3 files changed, 5 insertions, 6 deletions

diff --git a/doop.c b/doop.c
index 231b3d86e0..f1304772c2 100644
--- a/doop.c
+++ b/doop.c
@@ -1014,7 +1014,7 @@ Perl_do_vop(pTHX_ I32 optype, SV *sv, SV *left, SV *right)
 
     PERL_ARGS_ASSERT_DO_VOP;
 
-    if (sv != left || (optype != OP_BIT_AND && !SvOK(sv) && !SvGMAGICAL(sv)))
+    if (sv != left || (optype != OP_BIT_AND && !SvOK(sv)))
 	sv_setpvs(sv, "");	/* avoid undef warning on |= and ^= */
     if (sv == left) {
 	lsave = lc = SvPV_force_nomg(left, leftlen);
diff --git a/pp.h b/pp.h
index aaadd404c7..63b22340f9 100644
--- a/pp.h
+++ b/pp.h
@@ -345,7 +345,7 @@ Does not use C<TARG>.  See also C<XPUSHu>, C<mPUSHu> and C<PUSHu>.
 #define dPOPXiirl(X)	IV right = POPi; IV left = CAT2(X,i)
 
 #define USE_LEFT(sv) \
-	(SvOK(sv) || SvGMAGICAL(sv) || !(PL_op->op_flags & OPf_STACKED))
+	(SvOK(sv) || !(PL_op->op_flags & OPf_STACKED))
 #define dPOPXiirl_ul_nomg(X) \
     IV right = (sp--, SvIV_nomg(TOPp1s));		\
     SV *leftsv = CAT2(X,s);				\
diff --git a/t/op/assignwarn.t b/t/op/assignwarn.t
index 8d5487ac57..19b8e1de2c 100644
--- a/t/op/assignwarn.t
+++ b/t/op/assignwarn.t
@@ -19,11 +19,10 @@ my (%should_warn, %should_not);
 ++$should_warn{$_} foreach qw(* / x & ** << >>);
 ++$should_not{$_} foreach qw(+ - . | ^ && ||);
 
-my %todo_as_tie = reverse (add => '+', subtract => '-',
-			   bit_or => '|', bit_xor => '^');
+my %todo_as_tie;
 
-my %integer = reverse (i_add => '+', i_subtract => '-');
-$integer{$_} = 0 foreach qw(* / %);
+my %integer;
+$integer{$_} = 0 foreach qw(* / % + -);
 
 sub TIESCALAR { my $x; bless \$x }
 sub FETCH { ${$_[0]} }