This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
make die/warn and other diagnostics go to wherever STDERR happens
[perl5.git] / op.c
diff --git a/op.c b/op.c
index e7250f1..bc47f6d 100644 (file)
--- a/op.c
+++ b/op.c
 #include "EXTERN.h"
 #define PERL_IN_OP_C
 #include "perl.h"
-
-#ifdef PERL_OBJECT
-#define CHECKCALL this->*PL_check
-#else
-#define CHECKCALL *PL_check
-#endif              
+#include "keywords.h"
 
 /* #define PL_OP_SLAB_ALLOC */
                                                             
@@ -57,7 +52,7 @@ S_Slab_Alloc(pTHX_ int m, size_t sz)
      ? ( op_free((OP*)o),                                      \
         Perl_croak(aTHX_ "%s trapped by operation mask", PL_op_desc[type]),    \
         Nullop )                                               \
-     : (CHECKCALL[type])(aTHX_ (OP*)o))
+     : CALL_FPTR(PL_check[type])(aTHX_ (OP*)o))
 
 #define PAD_MAX 999999999
 
@@ -102,9 +97,9 @@ S_bad_type(pTHX_ I32 n, char *t, char *name, OP *kid)
 STATIC void
 S_no_bareword_allowed(pTHX_ OP *o)
 {
-    Perl_warn(aTHX_ "Bareword \"%s\" not allowed while \"strict subs\" in use",
-         SvPV_nolen(cSVOPo->op_sv));
-    ++PL_error_count;
+    qerror(Perl_mess(aTHX_
+                    "Bareword \"%s\" not allowed while \"strict subs\" in use",
+                    SvPV_nolen(cSVOPo->op_sv)));
 }
 
 /* "register" allocation */
@@ -117,9 +112,10 @@ Perl_pad_allocmy(pTHX_ char *name)
     SV *sv;
 
     if (!(
+       PL_in_my == KEY_our ||
        isALPHA(name[1]) ||
        (PL_hints & HINT_UTF8 && (name[1] & 0xc0) == 0xc0) ||
-       name[1] == '_' && (int)strlen(name) > 2))
+       name[1] == '_' && (int)strlen(name) > 2 ))
     {
        if (!isPRINT(name[1]) || strchr("\t\n\r\f", name[1])) {
            /* 1999-02-27 mjd@plover.com */
@@ -151,8 +147,10 @@ Perl_pad_allocmy(pTHX_ char *name)
                && strEQ(name, SvPVX(sv)))
            {
                Perl_warner(aTHX_ WARN_UNSAFE,
-                       "\"my\" variable %s masks earlier declaration in same %s", 
-                       name, (SvIVX(sv) == PAD_MAX ? "scope" : "statement"));
+                       "\"%s\" variable %s masks earlier declaration in same %s", 
+                       (PL_in_my == KEY_our ? "our" : "my"),
+                       name,
+                       (SvIVX(sv) == PAD_MAX ? "scope" : "statement"));
                break;
            }
        }
@@ -170,6 +168,8 @@ Perl_pad_allocmy(pTHX_ char *name)
        SvSTASH(sv) = (HV*)SvREFCNT_inc(PL_in_my_stash);
        PL_sv_objcount++;
     }
+    if (PL_in_my == KEY_our)
+       SvFLAGS(sv) |= SVpad_OUR;
     av_store(PL_comppad_name, off, sv);
     SvNVX(sv) = (NV)PAD_MAX;
     SvIVX(sv) = 0;                     /* Not yet introduced--see newSTATEOP */
@@ -237,6 +237,8 @@ S_pad_findlex(pTHX_ char *name, PADOFFSET newoff, U32 seq, CV* startcv,
                    SvNVX(namesv) = (NV)PL_curcop->cop_seq;
                    SvIVX(namesv) = PAD_MAX;    /* A ref, intro immediately */
                    SvFAKE_on(namesv);          /* A ref, not a real var */
+                   if (SvFLAGS(sv) & SVpad_OUR)/* An "our" variable */
+                       SvFLAGS(namesv) |= SVpad_OUR;
                    if (SvOBJECT(sv)) {         /* A typed var */
                        SvOBJECT_on(namesv);
                        (void)SvUPGRADE(namesv, SVt_PVMG);
@@ -361,7 +363,7 @@ Perl_pad_findmy(pTHX_ char *name)
              seq > I_32(SvNVX(sv)))) &&
            strEQ(SvPVX(sv), name))
        {
-           if (SvIVX(sv))
+           if (SvIVX(sv) || SvFLAGS(sv) & SVpad_OUR)
                return (PADOFFSET)off;
            pendoff = off;      /* this pending def. will override import */
        }
@@ -612,7 +614,7 @@ Perl_find_threadsv(pTHX_ const char *name)
        default:
            sv_magic(sv, 0, 0, name, 1); 
        }
-       DEBUG_S(PerlIO_printf(PerlIO_stderr(),
+       DEBUG_S(PerlIO_printf(Perl_error_log,
                              "find_threadsv: new SV %p for $%s%c\n",
                              sv, (*name < 32) ? "^" : "",
                              (*name < 32) ? toCTRL(*name) : *name));
@@ -1245,6 +1247,91 @@ Perl_mod(pTHX_ OP *o, I32 type)
            null(((LISTOP*)cUNOPo->op_first)->op_first);/* disable pushmark */
            break;
        }
+       else {                          /* lvalue subroutine call */
+           o->op_private |= OPpLVAL_INTRO;
+           if (type == OP_GREPSTART || type == OP_ENTERSUB) {
+               /* Backward compatibility mode: */
+               o->op_private |= OPpENTERSUB_INARGS;
+               break;
+           }
+           else {                      /* Compile-time error message: */
+               OP *kid = cUNOPo->op_first;
+               CV *cv;
+               OP *okid;
+
+               if (kid->op_type == OP_PUSHMARK)
+                   goto skip_kids;
+               if (kid->op_type != OP_NULL || kid->op_targ != OP_LIST)
+                   Perl_croak(aTHX_
+                              "panic: unexpected lvalue entersub "
+                              "args: type/targ %ld:%ld",
+                              (long)kid->op_type,kid->op_targ);
+               kid = kLISTOP->op_first;
+             skip_kids:
+               while (kid->op_sibling)
+                   kid = kid->op_sibling;
+               if (!(kid->op_type == OP_NULL && kid->op_targ == OP_RV2CV)) {
+                   /* Indirect call */
+                   if (kid->op_type == OP_METHOD_NAMED
+                       || kid->op_type == OP_METHOD)
+                   {
+                       OP *newop;
+
+                       if (kid->op_sibling || kid->op_next != kid) {
+                           yyerror("panic: unexpected optree near method call");
+                           break;
+                       }
+                       
+                       NewOp(1101, newop, 1, OP);
+                       newop->op_type = OP_RV2CV;
+                       newop->op_ppaddr = PL_ppaddr[OP_RV2CV];
+                       newop->op_next = newop;
+                       kid->op_sibling = newop;
+                       newop->op_private |= OPpLVAL_INTRO;
+                       break;
+                   }
+                   
+                   if (kid->op_type != OP_RV2CV)
+                       Perl_croak(aTHX_
+                                  "panic: unexpected lvalue entersub "
+                                  "entry via type/targ %ld:%ld",
+                                  (long)kid->op_type,kid->op_targ);
+                   kid->op_private |= OPpLVAL_INTRO;
+                   break;      /* Postpone until runtime */
+               }
+               
+               okid = kid;             
+               kid = kUNOP->op_first;
+               if (kid->op_type == OP_NULL && kid->op_targ == OP_RV2SV)
+                   kid = kUNOP->op_first;
+               if (kid->op_type == OP_NULL)            
+                   Perl_croak(aTHX_
+                              "Unexpected constant lvalue entersub "
+                              "entry via type/targ %ld:%ld",
+                              (long)kid->op_type,kid->op_targ);
+               if (kid->op_type != OP_GV) {
+                   /* Restore RV2CV to check lvalueness */
+                 restore_2cv:
+                   if (kid->op_next && kid->op_next != kid) { /* Happens? */
+                       okid->op_next = kid->op_next;
+                       kid->op_next = okid;
+                   }
+                   else
+                       okid->op_next = Nullop;
+                   okid->op_type = OP_RV2CV;
+                   okid->op_targ = 0;
+                   okid->op_ppaddr = PL_ppaddr[OP_RV2CV];
+                   okid->op_private |= OPpLVAL_INTRO;
+                   break;
+               }
+               
+               cv = GvCV(kGVOP->op_gv);
+               if (!cv) 
+                   goto restore_2cv;
+               if (CvLVALUE(cv))
+                   break;
+           }
+       }
        /* FALL THROUGH */
     default:
       nomod:
@@ -1253,7 +1340,10 @@ Perl_mod(pTHX_ OP *o, I32 type)
            break;
        yyerror(Perl_form(aTHX_ "Can't modify %s in %s",
                     (o->op_type == OP_NULL && (o->op_flags & OPf_SPECIAL)
-                     ? "do block" : PL_op_desc[o->op_type]),
+                     ? "do block"
+                     : (o->op_type == OP_ENTERSUB
+                       ? "non-lvalue subroutine call"
+                       : PL_op_desc[o->op_type])),
                     type ? PL_op_desc[type] : "local"));
        return o;
 
@@ -1582,8 +1672,60 @@ Perl_ref(pTHX_ OP *o, I32 type)
 
 }
 
-OP *
-Perl_my(pTHX_ OP *o)
+STATIC OP *
+S_dup_attrlist(pTHX_ OP *o)
+{
+    OP *rop = Nullop;
+
+    /* An attrlist is either a simple OP_CONST or an OP_LIST with kids,
+     * where the first kid is OP_PUSHMARK and the remaining ones
+     * are OP_CONST.  We need to push the OP_CONST values.
+     */
+    if (o->op_type == OP_CONST)
+       rop = newSVOP(OP_CONST, o->op_flags, SvREFCNT_inc(cSVOPo->op_sv));
+    else {
+       assert((o->op_type == OP_LIST) && (o->op_flags & OPf_KIDS));
+       for (o = cLISTOPo->op_first; o; o=o->op_sibling) {
+           if (o->op_type == OP_CONST)
+               rop = append_elem(OP_LIST, rop,
+                                 newSVOP(OP_CONST, o->op_flags,
+                                         SvREFCNT_inc(cSVOPo->op_sv)));
+       }
+    }
+    return rop;
+}
+
+STATIC void
+S_apply_attrs(pTHX_ HV *stash, SV *target, OP *attrs)
+{
+    OP *modname;       /* for 'use' */
+    SV *stashsv;
+
+    /* fake up C<use attributes $pkg,$rv,@attrs> */
+    ENTER;             /* need to protect against side-effects of 'use' */
+    SAVEINT(PL_expect);
+    if (stash && HvNAME(stash))
+       stashsv = newSVpv(HvNAME(stash), 0);
+    else
+       stashsv = &PL_sv_no;
+#define ATTRSMODULE "attributes"
+    modname = newSVOP(OP_CONST, 0,
+                     newSVpvn(ATTRSMODULE, sizeof(ATTRSMODULE)-1));
+    modname->op_private |= OPpCONST_BARE;
+    /* that flag is required to make 'use' work right */
+    utilize(1, start_subparse(FALSE, 0),
+           Nullop, /* version */
+           modname,
+           prepend_elem(OP_LIST,
+                        newSVOP(OP_CONST, 0, stashsv),
+                        prepend_elem(OP_LIST,
+                                     newSVOP(OP_CONST, 0, newRV(target)),
+                                     dup_attrlist(attrs))));
+    LEAVE;
+}
+
+STATIC OP *
+S_my_kid(pTHX_ OP *o, OP *attrs)
 {
     OP *kid;
     I32 type;
@@ -1594,9 +1736,13 @@ Perl_my(pTHX_ OP *o)
     type = o->op_type;
     if (type == OP_LIST) {
        for (kid = cLISTOPo->op_first; kid; kid = kid->op_sibling)
-           my(kid);
+           my_kid(kid, attrs);
     } else if (type == OP_UNDEF) {
        return o;
+    } else if (type == OP_RV2SV ||     /* "our" declaration */
+              type == OP_RV2AV ||
+              type == OP_RV2HV) { /* XXX does this let anything illegal in? */
+       return o;
     } else if (type != OP_PADSV &&
             type != OP_PADAV &&
             type != OP_PADHV &&
@@ -1605,12 +1751,44 @@ Perl_my(pTHX_ OP *o)
        yyerror(Perl_form(aTHX_ "Can't declare %s in my", PL_op_desc[o->op_type]));
        return o;
     }
+    else if (attrs && type != OP_PUSHMARK) {
+       HV *stash;
+       SV *padsv;
+       SV **namesvp;
+
+       /* check for C<my Dog $spot> when deciding package */
+       namesvp = av_fetch(PL_comppad_name, o->op_targ, FALSE);
+       if (namesvp && *namesvp && SvOBJECT(*namesvp) && HvNAME(SvSTASH(*namesvp)))
+           stash = SvSTASH(*namesvp);
+       else
+           stash = PL_curstash;
+       padsv = PAD_SV(o->op_targ);
+       apply_attrs(stash, padsv, attrs);
+    }
     o->op_flags |= OPf_MOD;
     o->op_private |= OPpLVAL_INTRO;
     return o;
 }
 
 OP *
+Perl_my_attrs(pTHX_ OP *o, OP *attrs)
+{
+    if (o->op_flags & OPf_PARENS)
+       list(o);
+    PL_in_my = FALSE;
+    PL_in_my_stash = Nullhv;
+    if (attrs)
+       SAVEFREEOP(attrs);
+    return my_kid(o, attrs);
+}
+
+OP *
+Perl_my(pTHX_ OP *o)
+{
+    return my_kid(o, Nullop);
+}
+
+OP *
 Perl_sawparens(pTHX_ OP *o)
 {
     if (o)
@@ -1890,7 +2068,8 @@ Perl_fold_constants(pTHX_ register OP *o)
        goto nope;              /* Don't try to run w/ errors */
 
     for (curop = LINKLIST(o); curop != o; curop = LINKLIST(curop)) {
-       if (curop->op_type != OP_CONST &&
+       if ((curop->op_type != OP_CONST ||
+            (curop->op_private & OPpCONST_BARE)) &&
            curop->op_type != OP_LIST &&
            curop->op_type != OP_SCALAR &&
            curop->op_type != OP_NULL &&
@@ -2812,9 +2991,10 @@ Perl_utilize(pTHX_ int aver, I32 floor, OP *version, OP *id, OP *arg)
     }
 
     /* Fake up the BEGIN {}, which does its thing immediately. */
-    newSUB(floor,
+    newATTRSUB(floor,
        newSVOP(OP_CONST, 0, newSVpvn("BEGIN", 5)),
        Nullop,
+       Nullop,
        append_elem(OP_LINESEQ,
            append_elem(OP_LINESEQ,
                newSTATEOP(0, Nullch, rqop),
@@ -3901,14 +4081,35 @@ Perl_op_const_sv(pTHX_ OP *o, CV *cv)
     return sv;
 }
 
+void
+Perl_newMYSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block)
+{
+    if (o)
+       SAVEFREEOP(o);
+    if (proto)
+       SAVEFREEOP(proto);
+    if (attrs)
+       SAVEFREEOP(attrs);
+    if (block)
+       SAVEFREEOP(block);
+    Perl_croak(aTHX_ "\"my sub\" not yet implemented");
+}
+
 CV *
 Perl_newSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *block)
 {
+    return Perl_newATTRSUB(aTHX_ floor, o, proto, Nullop, block);
+}
+
+CV *
+Perl_newATTRSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block)
+{
     dTHR;
     STRLEN n_a;
     char *name = o ? SvPVx(cSVOPo->op_sv, n_a) : Nullch;
     GV *gv = gv_fetchpv(name ? name : "__ANON__",
-                       GV_ADDMULTI | (block ? 0 : GV_NOINIT), SVt_PVCV);
+                       GV_ADDMULTI | ((block || attrs) ? 0 : GV_NOINIT),
+                       SVt_PVCV);
     char *ps = proto ? SvPVx(((SVOP*)proto)->op_sv, n_a) : Nullch;
     register CV *cv=0;
     I32 ix;
@@ -3917,8 +4118,10 @@ Perl_newSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *block)
        SAVEFREEOP(o);
     if (proto)
        SAVEFREEOP(proto);
+    if (attrs)
+       SAVEFREEOP(attrs);
 
-    if (SvTYPE(gv) != SVt_PVGV) {      /* Prototype now, and had
+    if (SvTYPE(gv) != SVt_PVGV) {      /* Maybe prototype now, and had at
                                           maximum a prototype before. */
        if (SvTYPE(gv) > SVt_NULL) {
            if (!SvPOK((SV*)gv) && !(SvIOK((SV*)gv) && SvIVX((SV*)gv) == -1)
@@ -3946,7 +4149,7 @@ Perl_newSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *block)
        if (CvROOT(cv) || CvXSUB(cv) || GvASSUMECV(gv)) {
            SV* const_sv;
            bool const_changed = TRUE;
-           if (!block) {
+           if (!block && !attrs) {
                /* just a "sub foo;" when &foo is already defined */
                SAVEFREESV(PL_compcv);
                goto done;
@@ -3954,6 +4157,8 @@ Perl_newSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *block)
            /* ahem, death to those who redefine active sort subs */
            if (PL_curstackinfo->si_type == PERLSI_SORT && PL_sortcop == CvSTART(cv))
                Perl_croak(aTHX_ "Can't redefine active sort subroutine %s", name);
+           if (!block)
+               goto withattrs;
            if(const_sv = cv_const_sv(cv))
                const_changed = sv_cmp(const_sv, op_const_sv(block, Nullcv));
            if ((const_sv && const_changed) || ckWARN(WARN_REDEFINE) 
@@ -3965,14 +4170,46 @@ Perl_newSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *block)
                PL_curcop->cop_line = PL_copline;
                Perl_warner(aTHX_ WARN_REDEFINE,
                        const_sv ? "Constant subroutine %s redefined"
-                                : "Subroutine %s redefined", name);
+                                : "Subroutine %s redefined", name);
                PL_curcop->cop_line = oldline;
            }
            SvREFCNT_dec(cv);
            cv = Nullcv;
        }
     }
+  withattrs:
+    if (attrs) {
+       HV *stash;
+       SV *rcv;
+
+       /* Need to do a C<use attributes $stash_of_cv,\&cv,@attrs>
+        * before we clobber PL_compcv.
+        */
+       if (cv && !block) {
+           rcv = (SV*)cv;
+           if (CvGV(cv) && GvSTASH(CvGV(cv)) && HvNAME(GvSTASH(CvGV(cv))))
+               stash = GvSTASH(CvGV(cv));
+           else if (CvSTASH(cv) && HvNAME(CvSTASH(cv)))
+               stash = CvSTASH(cv);
+           else
+               stash = PL_curstash;
+       }
+       else {
+           /* possibly about to re-define existing subr -- ignore old cv */
+           rcv = (SV*)PL_compcv;
+           if (name && GvSTASH(gv) && HvNAME(GvSTASH(gv)))
+               stash = GvSTASH(gv);
+           else
+               stash = PL_curstash;
+       }
+       apply_attrs(stash, rcv, attrs);
+    }
     if (cv) {                          /* must reuse cv if autoloaded */
+       if (!block) {
+           /* got here with just attrs -- work done, so bug out */
+           SAVEFREESV(PL_compcv);
+           goto done;
+       }
        cv_undef(cv);
        CvFLAGS(cv) = CvFLAGS(PL_compcv);
        CvOUTSIDE(cv) = CvOUTSIDE(PL_compcv);
@@ -4070,7 +4307,12 @@ Perl_newSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *block)
        }
     }
 
-    CvROOT(cv) = newUNOP(OP_LEAVESUB, 0, scalarseq(block));
+    if(CvLVALUE(cv)) {
+       CvROOT(cv) = newUNOP(OP_LEAVESUBLV, 0, scalarseq(block));
+    }
+    else {
+       CvROOT(cv) = newUNOP(OP_LEAVESUB, 0, scalarseq(block));
+    }
     CvSTART(cv) = LINKLIST(CvROOT(cv));
     CvROOT(cv)->op_next = 0;
     peep(CvSTART(cv));
@@ -4160,10 +4402,11 @@ Perl_newCONSTSUB(pTHX_ HV *stash, char *name, SV *sv)
     if(stash)
        PL_curstash = PL_curcop->cop_stash = stash;
 
-    newSUB(
+    newATTRSUB(
        start_subparse(FALSE, 0),
        newSVOP(OP_CONST, 0, newSVpv(name,0)),
        newSVOP(OP_CONST, 0, &PL_sv_no),        /* SvPV(&PL_sv_no) == "" -- GMB */
+       Nullop,
        newSTATEOP(0, Nullch, newSVOP(OP_CONST, 0, sv))
     );
 
@@ -4316,8 +4559,15 @@ Perl_newANONHASH(pTHX_ OP *o)
 OP *
 Perl_newANONSUB(pTHX_ I32 floor, OP *proto, OP *block)
 {
+    return newANONATTRSUB(floor, proto, Nullop, block);
+}
+
+OP *
+Perl_newANONATTRSUB(pTHX_ I32 floor, OP *proto, OP *attrs, OP *block)
+{
     return newUNOP(OP_REFGEN, 0,
-       newSVOP(OP_ANONCODE, 0, (SV*)newSUB(floor, 0, proto, block)));
+       newSVOP(OP_ANONCODE, 0,
+               (SV*)newATTRSUB(floor, 0, proto, attrs, block)));
 }
 
 OP *
@@ -4798,10 +5048,17 @@ Perl_ck_fun(pTHX_ OP *o)
                    char *name = SvPVx(((SVOP*)kid)->op_sv, n_a);
                    OP *newop = newAVREF(newGVOP(OP_GV, 0,
                        gv_fetchpv(name, TRUE, SVt_PVAV) ));
+#ifdef IV_IS_QUAD
+                   if (ckWARN(WARN_SYNTAX))
+                       Perl_warner(aTHX_ WARN_SYNTAX,
+                           "Array @%s missing the @ in argument %" PERL_PRId64 " of %s()",
+                           name, (IV)numargs, PL_op_desc[type]);
+#else
                    if (ckWARN(WARN_SYNTAX))
                        Perl_warner(aTHX_ WARN_SYNTAX,
                            "Array @%s missing the @ in argument %ld of %s()",
                            name, (long)numargs, PL_op_desc[type]);
+#endif
                    op_free(kid);
                    kid = newop;
                    kid->op_sibling = sibl;
@@ -4818,10 +5075,17 @@ Perl_ck_fun(pTHX_ OP *o)
                    char *name = SvPVx(((SVOP*)kid)->op_sv, n_a);
                    OP *newop = newHVREF(newGVOP(OP_GV, 0,
                        gv_fetchpv(name, TRUE, SVt_PVHV) ));
+#ifdef IV_IS_QUAD
+                   if (ckWARN(WARN_SYNTAX))
+                       Perl_warner(aTHX_ WARN_SYNTAX,
+                           "Hash %%%s missing the %% in argument %" PERL_PRId64 " of %s()",
+                           name, (IV)numargs, PL_op_desc[type]);
+#else
                    if (ckWARN(WARN_SYNTAX))
                        Perl_warner(aTHX_ WARN_SYNTAX,
                            "Hash %%%s missing the %% in argument %ld of %s()",
                            name, (long)numargs, PL_op_desc[type]);
+#endif
                    op_free(kid);
                    kid = newop;
                    kid->op_sibling = sibl;
@@ -5031,6 +5295,7 @@ Perl_ck_defined(pTHX_ OP *o)              /* 19990527 MJD */
     if ((o->op_flags & OPf_KIDS) && ckWARN(WARN_DEPRECATED)) {
        switch (cUNOPo->op_first->op_type) {
        case OP_RV2AV:
+           break;                      /* Globals via GV can be undef */ 
        case OP_PADAV:
        case OP_AASSIGN:                /* Is this a good idea? */
            Perl_warner(aTHX_ WARN_DEPRECATED,
@@ -5039,6 +5304,7 @@ Perl_ck_defined(pTHX_ OP *o)              /* 19990527 MJD */
                        "(Maybe you should just omit the defined()?)\n");
        break;
        case OP_RV2HV:
+           break;                      /* Globals via GV can be undef */ 
        case OP_PADHV:
            Perl_warner(aTHX_ WARN_DEPRECATED,
                        "defined(%hash) is deprecated");
@@ -5123,13 +5389,33 @@ Perl_ck_sassign(pTHX_ OP *o)
        OP *kkid = kid->op_sibling;
 
        /* Can just relocate the target. */
-       if (kkid && kkid->op_type == OP_PADSV) {
+       if (kkid && kkid->op_type == OP_PADSV
+           && !(kkid->op_private & OPpLVAL_INTRO))
+       {
            /* Concat has problems if target is equal to right arg. */
-           if (kid->op_type == OP_CONCAT
-               && kLISTOP->op_first->op_sibling->op_type == OP_PADSV
-               && kLISTOP->op_first->op_sibling->op_targ == kkid->op_targ)
-           {
-               return o;
+           if (kid->op_type == OP_CONCAT) {
+               if (kLISTOP->op_first->op_sibling->op_type == OP_PADSV
+                   && kLISTOP->op_first->op_sibling->op_targ == kkid->op_targ)
+                   return o;
+           }
+           else if (kid->op_type == OP_JOIN) {
+               /* do_join has problems if the arguments coincide with target.
+                  In fact the second argument *can* safely coincide,
+                  but ignore=pessimize this rare occasion. */
+               OP *arg = kLISTOP->op_first->op_sibling; /* Skip PUSHMARK */
+
+               while (arg) {
+                   if (arg->op_type == OP_PADSV
+                       && arg->op_targ == kkid->op_targ)
+                       return o;
+                   arg = arg->op_sibling;
+               }
+           }
+           else if (kid->op_type == OP_QUOTEMETA) {
+               /* quotemeta has problems if the argument coincides with target. */
+               if (kLISTOP->op_first->op_type == OP_PADSV
+                   && kLISTOP->op_first->op_targ == kkid->op_targ)
+                   return o;
            }
            kid->op_targ = kkid->op_targ;
            /* Now we do not need PADSV and SASSIGN. */
@@ -5390,9 +5676,10 @@ S_simplify_sort(pTHX_ OP *o)
        o->op_private |= OPpSORT_NUMERIC;
     if (k->op_type == OP_I_NCMP)
        o->op_private |= OPpSORT_NUMERIC | OPpSORT_INTEGER;
-    op_free(cLISTOPo->op_first->op_sibling);   /* delete comparison block */
-    cLISTOPo->op_first->op_sibling = cLISTOPo->op_last;
-    cLISTOPo->op_children = 1;
+    kid = cLISTOPo->op_first->op_sibling;
+    cLISTOPo->op_first->op_sibling = kid->op_sibling; /* bypass old block */
+    op_free(kid);                                    /* then delete it */
+    cLISTOPo->op_children--;
 }
 
 OP *
@@ -5447,6 +5734,23 @@ Perl_ck_split(pTHX_ OP *o)
 }
 
 OP *
+Perl_ck_join(pTHX_ OP *o) 
+{
+    if (ckWARN(WARN_SYNTAX)) {
+       OP *kid = cLISTOPo->op_first->op_sibling;
+       if (kid && kid->op_type == OP_MATCH) {
+           char *pmstr = "STRING";
+           if (kPMOP->op_pmregexp)
+               pmstr = kPMOP->op_pmregexp->precomp;
+           Perl_warner(aTHX_ WARN_SYNTAX,
+                       "/%s/ should probably be written as \"%s\"",
+                       pmstr, pmstr);
+       }
+    }
+    return ck_fun(o);
+}
+
+OP *
 Perl_ck_subr(pTHX_ OP *o)
 {
     dTHR;
@@ -5461,6 +5765,7 @@ Perl_ck_subr(pTHX_ OP *o)
     I32 arg = 0;
     STRLEN n_a;
 
+    o->op_private |= OPpENTERSUB_HASTARG;
     for (cvop = o2; cvop->op_sibling; cvop = cvop->op_sibling) ;
     if (cvop->op_type == OP_RV2CV) {
        SVOP* tmpop;
@@ -5647,6 +5952,7 @@ Perl_peep(pTHX_ register OP *o)
     dTHR;
     register OP* oldop = 0;
     STRLEN n_a;
+    OP *last_composite = Nullop;
 
     if (!o || o->op_seq)
        return;
@@ -5665,6 +5971,7 @@ Perl_peep(pTHX_ register OP *o)
        case OP_DBSTATE:
            PL_curcop = ((COP*)o);              /* for warnings */
            o->op_seq = PL_op_seqmax++;
+           last_composite = Nullop;
            break;
 
        case OP_CONST:
@@ -5693,8 +6000,10 @@ Perl_peep(pTHX_ register OP *o)
                            && (((LISTOP*)o)->op_first->op_sibling->op_targ
                                == o->op_next->op_targ))) {
                        goto ignore_optimization;
-                   } else {
+                   }
+                   else {
                        o->op_targ = o->op_next->op_targ;
+                       o->op_private |= OPpTARGET_MY;
                    }
                }
                null(o->op_next);
@@ -5861,6 +6170,40 @@ Perl_peep(pTHX_ register OP *o)
            break;
        }
 
+       case OP_RV2AV:
+       case OP_RV2HV:
+           if (!(o->op_flags & OPf_WANT)
+               || o->op_flags & OPf_WANT == OPf_WANT_LIST)
+               last_composite = o;
+           o->op_seq = PL_op_seqmax++;
+           break;
+
+       case OP_RETURN:
+           if (o->op_next->op_type != OP_LEAVESUBLV) {
+               o->op_seq = PL_op_seqmax++;
+               break;
+           }
+           /* FALL THROUGH */
+
+       case OP_LEAVESUBLV:
+           if (last_composite) {
+               OP *r = last_composite;
+
+               while (r->op_sibling)
+                  r = r->op_sibling;
+               if (r->op_next == o 
+                   || (r->op_next->op_type == OP_LIST
+                       && r->op_next->op_next == o))
+               {
+                   if (last_composite->op_type == OP_RV2AV)
+                       yyerror("Lvalue subs returning arrays not implemented yet");
+                   else
+                       yyerror("Lvalue subs returning hashes not implemented yet");
+                       ;
+               }               
+           }
+           /* FALL THROUGH */
+
        default:
            o->op_seq = PL_op_seqmax++;
            break;