This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Extract common code to an inline function
[perl5.git] / toke.c
diff --git a/toke.c b/toke.c
index d3bc457..3ce12e2 100644 (file)
--- a/toke.c
+++ b/toke.c
@@ -553,16 +553,14 @@ S_no_op(pTHX_ const char *const what, char *s)
                NOOP;
            if (t < PL_bufptr && isSPACE(*t))
                Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
-                       "\t(Do you need to predeclare %"SVf"?)\n",
-                   SVfARG(newSVpvn_flags(PL_oldoldbufptr, (STRLEN)(t - PL_oldoldbufptr),
-                                   SVs_TEMP | (UTF ? SVf_UTF8 : 0))));
+                       "\t(Do you need to predeclare %"UTF8f"?)\n",
+                     UTF8fARG(UTF, t - PL_oldoldbufptr, PL_oldoldbufptr));
        }
        else {
            assert(s >= oldbp);
            Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
-                   "\t(Missing operator before %"SVf"?)\n",
-                    SVfARG(newSVpvn_flags(oldbp, (STRLEN)(s - oldbp),
-                                    SVs_TEMP | (UTF ? SVf_UTF8 : 0))));
+                   "\t(Missing operator before %"UTF8f"?)\n",
+                    UTF8fARG(UTF, s - oldbp, oldbp));
        }
     }
     PL_bufptr = oldbp;
@@ -755,9 +753,9 @@ Perl_lex_start(pTHX_ SV *line, PerlIO *rsfp, U32 flags)
        parser->linestr = flags & LEX_START_COPIED
                            ? SvREFCNT_inc_simple_NN(line)
                            : newSVpvn_flags(s, len, SvUTF8(line));
-       sv_catpvs(parser->linestr, "\n;");
+       sv_catpvn(parser->linestr, "\n;", rsfp ? 1 : 2);
     } else {
-       parser->linestr = newSVpvs("\n;");
+       parser->linestr = newSVpvn("\n;", rsfp ? 1 : 2);
     }
     parser->oldoldbufptr =
        parser->oldbufptr =
@@ -1514,14 +1512,16 @@ chunk will not be discarded.
 =cut
 */
 
+#define LEX_NO_INCLINE    0x40000000
 #define LEX_NO_NEXT_CHUNK 0x80000000
 
 void
 Perl_lex_read_space(pTHX_ U32 flags)
 {
     char *s, *bufend;
+    const bool can_incline = !(flags & LEX_NO_INCLINE);
     bool need_incline = 0;
-    if (flags & ~(LEX_KEEP_PREVIOUS|LEX_NO_NEXT_CHUNK))
+    if (flags & ~(LEX_KEEP_PREVIOUS|LEX_NO_NEXT_CHUNK|LEX_NO_INCLINE))
        Perl_croak(aTHX_ "Lexing code internal error (%s)", "lex_read_space");
 #ifdef PERL_MAD
     if (PL_skipwhite) {
@@ -1541,11 +1541,13 @@ Perl_lex_read_space(pTHX_ U32 flags)
            } while (!(c == '\n' || (c == 0 && s == bufend)));
        } else if (c == '\n') {
            s++;
-           PL_parser->linestart = s;
-           if (s == bufend)
-               need_incline = 1;
-           else
-               incline(s);
+           if (can_incline) {
+               PL_parser->linestart = s;
+               if (s == bufend)
+                   need_incline = 1;
+               else
+                   incline(s);
+           }
        } else if (isSPACE(c)) {
            s++;
        } else if (c == 0 && s == bufend) {
@@ -1557,14 +1559,14 @@ Perl_lex_read_space(pTHX_ U32 flags)
            if (flags & LEX_NO_NEXT_CHUNK)
                break;
            PL_parser->bufptr = s;
-           COPLINE_INC_WITH_HERELINES;
+           if (can_incline) COPLINE_INC_WITH_HERELINES;
            got_more = lex_next_chunk(flags);
-           CopLINE_dec(PL_curcop);
+           if (can_incline) CopLINE_dec(PL_curcop);
            s = PL_parser->bufptr;
            bufend = PL_parser->bufend;
            if (!got_more)
                break;
-           if (need_incline && PL_parser->rsfp) {
+           if (can_incline && need_incline && PL_parser->rsfp) {
                incline(s);
                need_incline = 0;
            }
@@ -1580,6 +1582,107 @@ Perl_lex_read_space(pTHX_ U32 flags)
 }
 
 /*
+
+=for apidoc EXMp|bool|validate_proto|SV *name|SV *proto|bool warn
+
+This function performs syntax checking on a prototype, C<proto>.
+If C<warn> is true, any illegal characters or mismatched brackets
+will trigger illegalproto warnings, declaring that they were
+detected in the prototype for C<name>.
+
+The return value is C<true> if this is a valid prototype, and
+C<false> if it is not, regardless of whether C<warn> was C<true> or
+C<false>.
+
+Note that C<NULL> is a valid C<proto> and will always return C<true>.
+
+=cut
+
+ */
+
+bool
+Perl_validate_proto(pTHX_ SV *name, SV *proto, bool warn)
+{
+    STRLEN len, origlen;
+    char *p = proto ? SvPV(proto, len) : NULL;
+    bool bad_proto = FALSE;
+    bool in_brackets = FALSE;
+    bool after_slash = FALSE;
+    char greedy_proto = ' ';
+    bool proto_after_greedy_proto = FALSE;
+    bool must_be_last = FALSE;
+    bool underscore = FALSE;
+    bool bad_proto_after_underscore = FALSE;
+
+    PERL_ARGS_ASSERT_VALIDATE_PROTO;
+
+    if (!proto)
+       return TRUE;
+
+    origlen = len;
+    for (; len--; p++) {
+       if (!isSPACE(*p)) {
+           if (must_be_last)
+               proto_after_greedy_proto = TRUE;
+           if (underscore) {
+               if (!strchr(";@%", *p))
+                   bad_proto_after_underscore = TRUE;
+               underscore = FALSE;
+           }
+           if (!strchr("$@%*;[]&\\_+", *p) || *p == '\0') {
+               bad_proto = TRUE;
+           }
+           else {
+               if (*p == '[')
+                   in_brackets = TRUE;
+               else if (*p == ']')
+                   in_brackets = FALSE;
+               else if ((*p == '@' || *p == '%') &&
+                   !after_slash &&
+                   !in_brackets ) {
+                   must_be_last = TRUE;
+                   greedy_proto = *p;
+               }
+               else if (*p == '_')
+                   underscore = TRUE;
+           }
+           if (*p == '\\')
+               after_slash = TRUE;
+           else
+               after_slash = FALSE;
+       }
+    }
+
+    if (warn) {
+       SV *tmpsv = newSVpvs_flags("", SVs_TEMP);
+       p -= origlen;
+       p = SvUTF8(proto)
+           ? sv_uni_display(tmpsv, newSVpvn_flags(p, origlen, SVs_TEMP | SVf_UTF8),
+                            origlen, UNI_DISPLAY_ISPRINT)
+           : pv_pretty(tmpsv, p, origlen, 60, NULL, NULL, PERL_PV_ESCAPE_NONASCII);
+
+       if (proto_after_greedy_proto)
+           Perl_warner(aTHX_ packWARN(WARN_ILLEGALPROTO),
+                       "Prototype after '%c' for %"SVf" : %s",
+                       greedy_proto, SVfARG(name), p);
+       if (in_brackets)
+           Perl_warner(aTHX_ packWARN(WARN_ILLEGALPROTO),
+                       "Missing ']' in prototype for %"SVf" : %s",
+                       SVfARG(name), p);
+       if (bad_proto)
+           Perl_warner(aTHX_ packWARN(WARN_ILLEGALPROTO),
+                       "Illegal character in prototype for %"SVf" : %s",
+                       SVfARG(name), p);
+       if (bad_proto_after_underscore)
+           Perl_warner(aTHX_ packWARN(WARN_ILLEGALPROTO),
+                       "Illegal character after '_' in prototype for %"SVf" : %s",
+                       SVfARG(name), p);
+    }
+
+    return (! (proto_after_greedy_proto || bad_proto) );
+}
+
+/*
  * S_incline
  * This subroutine has nothing to do with tilting, whether at windmills
  * or pinball tables.  Its name is short for "increment line".  It
@@ -1650,37 +1753,16 @@ S_incline(pTHX_ const char *s)
 
     if (t - s > 0) {
        const STRLEN len = t - s;
-       SV *const temp_sv = CopFILESV(PL_curcop);
-       const char *cf;
-       STRLEN tmplen;
-
-       if (temp_sv) {
-           cf = SvPVX(temp_sv);
-           tmplen = SvCUR(temp_sv);
-       } else {
-           cf = NULL;
-           tmplen = 0;
-       }
 
        if (!PL_rsfp && !PL_parser->filtered) {
            /* must copy *{"::_<(eval N)[oldfilename:L]"}
             * to *{"::_<newfilename"} */
            /* However, the long form of evals is only turned on by the
               debugger - usually they're "(eval %lu)" */
-           char smallbuf[128];
-           char *tmpbuf;
-           GV **gvp;
-           STRLEN tmplen2 = len;
-           if (tmplen + 2 <= sizeof smallbuf)
-               tmpbuf = smallbuf;
-           else
-               Newx(tmpbuf, tmplen + 2, char);
-           tmpbuf[0] = '_';
-           tmpbuf[1] = '<';
-           memcpy(tmpbuf + 2, cf, tmplen);
-           tmplen += 2;
-           gvp = (GV**)hv_fetch(PL_defstash, tmpbuf, tmplen, FALSE);
-           if (gvp) {
+           GV * const cfgv = CopFILEGV(PL_curcop);
+           if (cfgv) {
+               char smallbuf[128];
+               STRLEN tmplen2 = len;
                char *tmpbuf2;
                GV *gv2;
 
@@ -1689,12 +1771,8 @@ S_incline(pTHX_ const char *s)
                else
                    Newx(tmpbuf2, tmplen2 + 2, char);
 
-               if (tmpbuf2 != smallbuf || tmpbuf != smallbuf) {
-                   /* Either they malloc'd it, or we malloc'd it,
-                      so no prefix is present in ours.  */
-                   tmpbuf2[0] = '_';
-                   tmpbuf2[1] = '<';
-               }
+               tmpbuf2[0] = '_';
+               tmpbuf2[1] = '<';
 
                memcpy(tmpbuf2 + 2, s, tmplen2);
                tmplen2 += 2;
@@ -1708,11 +1786,11 @@ S_incline(pTHX_ const char *s)
                       alias the saved lines that are in the array.
                       Otherwise alias the whole array. */
                    if (CopLINE(PL_curcop) == line_num) {
-                       GvHV(gv2) = MUTABLE_HV(SvREFCNT_inc(GvHV(*gvp)));
-                       GvAV(gv2) = MUTABLE_AV(SvREFCNT_inc(GvAV(*gvp)));
+                       GvHV(gv2) = MUTABLE_HV(SvREFCNT_inc(GvHV(cfgv)));
+                       GvAV(gv2) = MUTABLE_AV(SvREFCNT_inc(GvAV(cfgv)));
                    }
-                   else if (GvAV(*gvp)) {
-                       AV * const av = GvAV(*gvp);
+                   else if (GvAV(cfgv)) {
+                       AV * const av = GvAV(cfgv);
                        const I32 start = CopLINE(PL_curcop)+1;
                        I32 items = AvFILLp(av) - start;
                        if (items > 0) {
@@ -1727,7 +1805,6 @@ S_incline(pTHX_ const char *s)
 
                if (tmpbuf2 != smallbuf) Safefree(tmpbuf2);
            }
-           if (tmpbuf != smallbuf) Safefree(tmpbuf);
        }
        CopFILE_free(PL_curcop);
        CopFILE_setn(PL_curcop, s, len);
@@ -1735,6 +1812,8 @@ S_incline(pTHX_ const char *s)
     CopLINE_set(PL_curcop, line_num);
 }
 
+#define skipspace(s) skipspace_flags(s, 0)
+
 #ifdef PERL_MAD
 /* skip space before PL_thistoken */
 
@@ -1790,13 +1869,11 @@ STATIC char *
 S_skipspace2(pTHX_ char *s, SV **svp)
 {
     char *start;
-    const I32 bufptroff = PL_bufptr - SvPVX(PL_linestr);
     const I32 startoff = s - SvPVX(PL_linestr);
 
     PERL_ARGS_ASSERT_SKIPSPACE2;
 
     s = skipspace(s);
-    PL_bufptr = SvPVX(PL_linestr) + bufptroff;
     if (!PL_madskills || !svp)
        return s;
     start = SvPVX(PL_linestr) + startoff;
@@ -1824,12 +1901,12 @@ S_update_debugger_info(pTHX_ SV *orig_sv, const char *const buf, STRLEN len)
     if (av) {
        SV * const sv = newSV_type(SVt_PVMG);
        if (orig_sv)
-           sv_setsv(sv, orig_sv);
+           sv_setsv_flags(sv, orig_sv, 0); /* no cow */
        else
            sv_setpvn(sv, buf, len);
        (void)SvIOK_on(sv);
        SvIV_set(sv, 0);
-       av_store(av, (I32)CopLINE(PL_curcop), sv);
+       av_store(av, CopLINE(PL_curcop), sv);
     }
 }
 
@@ -1840,12 +1917,12 @@ S_update_debugger_info(pTHX_ SV *orig_sv, const char *const buf, STRLEN len)
  */
 
 STATIC char *
-S_skipspace(pTHX_ char *s)
+S_skipspace_flags(pTHX_ char *s, U32 flags)
 {
 #ifdef PERL_MAD
     char *start = s;
 #endif /* PERL_MAD */
-    PERL_ARGS_ASSERT_SKIPSPACE;
+    PERL_ARGS_ASSERT_SKIPSPACE_FLAGS;
 #ifdef PERL_MAD
     if (PL_skipwhite) {
        sv_free(PL_skipwhite);
@@ -1858,7 +1935,7 @@ S_skipspace(pTHX_ char *s)
     } else {
        STRLEN bufptr_pos = PL_bufptr - SvPVX(PL_linestr);
        PL_bufptr = s;
-       lex_read_space(LEX_KEEP_PREVIOUS |
+       lex_read_space(flags | LEX_KEEP_PREVIOUS |
                (PL_sublex_info.sub_inwhat || PL_lex_state == LEX_FORMLINE ?
                    LEX_NO_NEXT_CHUNK : 0));
        s = PL_bufptr;
@@ -2114,7 +2191,7 @@ S_newSV_maybe_utf8(pTHX_ const char *const start, STRLEN len)
  */
 
 STATIC char *
-S_force_word(pTHX_ char *start, int token, int check_keyword, int allow_pack, int allow_initial_tick)
+S_force_word(pTHX_ char *start, int token, int check_keyword, int allow_pack)
 {
     dVAR;
     char *s;
@@ -2125,8 +2202,7 @@ S_force_word(pTHX_ char *start, int token, int check_keyword, int allow_pack, in
     start = SKIPSPACE1(start);
     s = start;
     if (isIDFIRST_lazy_if(s,UTF) ||
-       (allow_pack && *s == ':') ||
-       (allow_initial_tick && *s == '\'') )
+       (allow_pack && *s == ':') )
     {
        s = scan_word(s, PL_tokenbuf, sizeof PL_tokenbuf, allow_pack, &len);
        if (check_keyword) {
@@ -2472,7 +2548,7 @@ S_sublex_start(pTHX)
        return THING;
     }
     else if (op_type == OP_BACKTICK && PL_lex_op) {
-       /* readpipe() vas overriden */
+       /* readpipe() was overridden */
        cSVOPx(cLISTOPx(cUNOPx(PL_lex_op)->op_first)->op_first->op_sibling)->op_sv = tokeq(PL_lex_stuff);
        pl_yylval.opval = PL_lex_op;
        PL_lex_op = NULL;
@@ -3029,7 +3105,7 @@ S_scan_const(pTHX_ char *start)
                    char *e = d++;
                    while (e-- > c)
                        *(e + 1) = *e;
-                   *c = (char)UTF_TO_NATIVE(0xff);
+                   *c = (char)I8_TO_NATIVE_UTF8(0xff);
                    /* mark the range as done, and continue */
                    dorange = FALSE;
                    didrange = TRUE;
@@ -3100,13 +3176,7 @@ S_scan_const(pTHX_ char *start)
                    for (i = min; i <= max; i++)
 #ifdef EBCDIC
                         if (has_utf8) {
-                            const U8 ch = (U8)NATIVE_TO_UTF(i);
-                            if (UNI_IS_INVARIANT(ch))
-                                *d++ = (U8)i;
-                            else {
-                                *d++ = (U8)UTF8_EIGHT_BIT_HI(ch);
-                                *d++ = (U8)UTF8_EIGHT_BIT_LO(ch);
-                            }
+                            append_utf8_from_native_byte(i, &d);
                         }
                         else
 #endif
@@ -3141,7 +3211,7 @@ S_scan_const(pTHX_ char *start)
                    && !native_range
 #endif
                    ) {
-                   *d++ = (char)UTF_TO_NATIVE(0xff);   /* use illegal utf8 byte--see pmtrans */
+                   *d++ = (char)I8_TO_NATIVE_UTF8(0xff);       /* use illegal utf8 byte--see pmtrans */
                    s++;
                    continue;
                }
@@ -3181,12 +3251,12 @@ S_scan_const(pTHX_ char *start)
         * char, which will be done separately.
         * Stop on (?{..}) and friends */
 
-       else if (*s == '(' && PL_lex_inpat && s[1] == '?') {
+       else if (*s == '(' && PL_lex_inpat && s[1] == '?' && !in_charclass) {
            if (s[2] == '#') {
                while (s+1 < send && *s != ')')
                    *d++ = NATIVE_TO_NEED(has_utf8,*s++);
            }
-           else if (!PL_lex_casemods && !in_charclass &&
+           else if (!PL_lex_casemods &&
                     (    s[2] == '{' /* This should match regcomp.c */
                      || (s[2] == '?' && s[3] == '{')))
            {
@@ -3195,7 +3265,7 @@ S_scan_const(pTHX_ char *start)
        }
 
        /* likewise skip #-initiated comments in //x patterns */
-       else if (*s == '#' && PL_lex_inpat &&
+       else if (*s == '#' && PL_lex_inpat && !in_charclass &&
          ((PMOP*)PL_lex_inpat)->op_pmflags & RXf_PMf_EXTENDED) {
            while (s+1 < send && *s != '\n')
                *d++ = NATIVE_TO_NEED(has_utf8,*s++);
@@ -3686,7 +3756,7 @@ S_scan_const(pTHX_ char *start)
                *d++ = ASCII_TO_NEED(has_utf8,'\033');
                break;
            case 'a':
-               *d++ = ASCII_TO_NEED(has_utf8,'\007');
+               *d++ = NATIVE_TO_NEED(has_utf8,'\a');
                break;
            } /* end switch */
 
@@ -3996,13 +4066,13 @@ S_intuit_method(pTHX_ char *start, GV *gv, CV *cv)
     if (gv && SvTYPE(gv) == SVt_PVGV && GvIO(gv))
            return 0;
     if (cv && SvPOK(cv)) {
-               const char *proto = CvPROTO(cv);
-               if (proto) {
-                   if (*proto == ';')
-                       proto++;
-                   if (*proto == '*')
-                       return 0;
-               }
+       const char *proto = CvPROTO(cv);
+       if (proto) {
+           while (*proto && (isSPACE(*proto) || *proto == ';'))
+               proto++;
+           if (*proto == '*')
+               return 0;
+       }
     }
 
     if (*start == '$') {
@@ -4557,12 +4627,12 @@ S_tokenize_use(pTHX_ int is_use, char *s) {
            force_next(WORD);
        }
        else if (*s == 'v') {
-           s = force_word(s,WORD,FALSE,TRUE,FALSE);
+           s = force_word(s,WORD,FALSE,TRUE);
            s = force_version(s, FALSE);
        }
     }
     else {
-       s = force_word(s,WORD,FALSE,TRUE,FALSE);
+       s = force_word(s,WORD,FALSE,TRUE);
        s = force_version(s, FALSE);
     }
     pl_yylval.ival = is_use;
@@ -4641,6 +4711,7 @@ Perl_yylex(pTHX)
     char *d;
     STRLEN len;
     bool bof = FALSE;
+    const bool saw_infix_sigil = PL_parser->saw_infix_sigil;
     U8 formbrack = 0;
     U32 fake_eof = 0;
 
@@ -5040,9 +5111,12 @@ Perl_yylex(pTHX)
        return yylex();
     }
 
+    /* We really do *not* want PL_linestr ever becoming a COW. */
+    assert (!SvIsCOW(PL_linestr));
     s = PL_bufptr;
     PL_oldoldbufptr = PL_oldbufptr;
     PL_oldbufptr = s;
+    PL_parser->saw_infix_sigil = 0;
 
   retry:
 #ifdef PERL_MAD
@@ -5513,14 +5587,19 @@ Perl_yylex(pTHX)
                s = SKIPSPACE0(s);
            }
            else {
-/*             if (PL_madskills && PL_lex_formbrack) { */
-                   d = s;
-                   while (d < PL_bufend && *d != '\n')
-                       d++;
-                   if (d < PL_bufend)
-                       d++;
-                   else if (d > PL_bufend) /* Found by Ilya: feed random input to Perl. */
+#endif
+                   if (PL_madskills) d = s;
+                   while (s < PL_bufend && *s != '\n')
+                       s++;
+                   if (s < PL_bufend)
+                   {
+                       s++;
+                       if (s < PL_bufend)
+                           incline(s);
+                   }
+                   else if (s > PL_bufend) /* Found by Ilya: feed random input to Perl. */
                      Perl_croak(aTHX_ "panic: input overflow");
+#ifdef PERL_MAD
                    if (PL_madskills && CopLINE(PL_curcop) >= 1) {
                        if (!PL_thiswhite)
                            PL_thiswhite = newSVpvs("");
@@ -5528,16 +5607,9 @@ Perl_yylex(pTHX)
                            sv_setpvs(PL_thiswhite, "");
                            PL_faketokens = 0;
                        }
-                       sv_catpvn(PL_thiswhite, s, d - s);
+                       sv_catpvn(PL_thiswhite, d, s - d);
                    }
-                   s = d;
-/*             }
-               *s = '\0';
-               PL_bufend = s; */
            }
-#else
-           *s = '\0';
-           PL_bufend = s;
 #endif
        }
        goto retry;
@@ -5554,7 +5626,7 @@ Perl_yylex(pTHX)
                s++;
 
            if (strnEQ(s,"=>",2)) {
-               s = force_word(PL_bufptr,WORD,FALSE,FALSE,FALSE);
+               s = force_word(PL_bufptr,WORD,FALSE,FALSE);
                DEBUG_T( { printbuf("### Saw unary minus before =>, forcing word %s\n", s); } );
                OPERATOR('-');          /* unary minus */
            }
@@ -5626,7 +5698,7 @@ Perl_yylex(pTHX)
                s++;
                s = SKIPSPACE1(s);
                if (isIDFIRST_lazy_if(s,UTF)) {
-                   s = force_word(s,METHOD,FALSE,TRUE,FALSE);
+                   s = force_word(s,METHOD,FALSE,TRUE);
                    TOKEN(ARROW);
                }
                else if (*s == '$')
@@ -5698,6 +5770,7 @@ Perl_yylex(pTHX)
            s--;
            TOKEN(0);
        }
+       PL_parser->saw_infix_sigil = 1;
        Mop(OP_MULTIPLY);
 
     case '%':
@@ -5706,6 +5779,7 @@ Perl_yylex(pTHX)
                    PL_lex_fakeeof >= LEX_FAKEEOF_ASSIGN)
                TOKEN(0);
            ++s;
+           PL_parser->saw_infix_sigil = 1;
            Mop(OP_MODULO);
        }
        PL_tokenbuf[0] = '%';
@@ -5989,7 +6063,7 @@ Perl_yylex(pTHX)
                    d++;
                if (*d == '}') {
                    const char minus = (PL_tokenbuf[0] == '-');
-                   s = force_word(s + minus, WORD, FALSE, TRUE, FALSE);
+                   s = force_word(s + minus, WORD, FALSE, TRUE);
                    if (minus)
                        force_next('-');
                }
@@ -6199,6 +6273,7 @@ Perl_yylex(pTHX)
                s--;
                TOKEN(0);
            }
+           PL_parser->saw_infix_sigil = 1;
            BAop(OP_BIT_AND);
        }
 
@@ -6502,9 +6577,8 @@ Perl_yylex(pTHX)
                                if (*t == ';'
                                        && get_cvn_flags(tmpbuf, len, UTF ? SVf_UTF8 : 0))
                                    Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
-                                               "You need to quote \"%"SVf"\"",
-                                                 SVfARG(newSVpvn_flags(tmpbuf, len, 
-                                                    SVs_TEMP | (UTF ? SVf_UTF8 : 0))));
+                                       "You need to quote \"%"UTF8f"\"",
+                                        UTF8fARG(UTF, len, tmpbuf));
                            }
                        }
                }
@@ -6589,11 +6663,9 @@ Perl_yylex(pTHX)
                        PL_bufptr = PEEKSPACE(PL_bufptr); /* XXX can realloc */
        /* diag_listed_as: Scalar value @%s[%s] better written as $%s[%s] */
                        Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
-                           "Scalar value %"SVf" better written as $%"SVf,
-                           SVfARG(newSVpvn_flags(PL_bufptr, (STRLEN)(t-PL_bufptr),
-                                                SVs_TEMP | (UTF ? SVf_UTF8 : 0 ))),
-                            SVfARG(newSVpvn_flags(PL_bufptr+1, (STRLEN)(t-PL_bufptr-1),
-                                                SVs_TEMP | (UTF ? SVf_UTF8 : 0 ))));
+                        "Scalar value %"UTF8f" better written as $%"UTF8f,
+                         UTF8fARG(UTF, t-PL_bufptr, PL_bufptr),
+                         UTF8fARG(UTF, t-PL_bufptr-1, PL_bufptr+1));
                    }
                }
            }
@@ -6865,6 +6937,7 @@ Perl_yylex(pTHX)
 
        /* Is this a word before a => operator? */
        if (*d == '=' && d[1] == '>') {
+         fat_arrow:
            CLINE;
            pl_yylval.opval
                = (OP*)newSVOP(OP_CONST, 0,
@@ -6998,6 +7071,18 @@ Perl_yylex(pTHX)
            }
        }
 
+       if (tmp && tmp != KEY___DATA__ && tmp != KEY___END__
+        && (!anydelim || *s != '#')) {
+           /* no override, and not s### either; skipspace is safe here
+            * check for => on following line */
+           STRLEN bufoff = PL_bufptr - SvPVX(PL_linestr);
+           STRLEN   soff = s         - SvPVX(PL_linestr);
+           s = skipspace_flags(s, LEX_NO_INCLINE);
+           if (*s == '=' && s[1] == '>') goto fat_arrow;
+           PL_bufptr = SvPVX(PL_linestr) + bufoff;
+           s         = SvPVX(PL_linestr) +   soff;
+       }
+
       reserved_word:
        switch (tmp) {
 
@@ -7036,9 +7121,8 @@ Perl_yylex(pTHX)
                    s = scan_word(s, PL_tokenbuf + len, sizeof PL_tokenbuf - len,
                                  TRUE, &morelen);
                    if (!morelen)
-                       Perl_croak(aTHX_ "Bad name after %"SVf"%s",
-                                        SVfARG(newSVpvn_flags(PL_tokenbuf, len,
-                                            (UTF ? SVf_UTF8 : 0) | SVs_TEMP )),
+                       Perl_croak(aTHX_ "Bad name after %"UTF8f"%s",
+                               UTF8fARG(UTF, len, PL_tokenbuf),
                                *s == '\'' ? "'" : "::");
                    len += morelen;
                    pkgname = 1;
@@ -7065,9 +7149,8 @@ Perl_yylex(pTHX)
                    if (ckWARN(WARN_BAREWORD)
                        && ! gv_fetchpvn_flags(PL_tokenbuf, len, UTF ? SVf_UTF8 : 0, SVt_PVHV))
                        Perl_warner(aTHX_ packWARN(WARN_BAREWORD),
-                           "Bareword \"%"SVf"\" refers to nonexistent package",
-                            SVfARG(newSVpvn_flags(PL_tokenbuf, len,
-                                        (UTF ? SVf_UTF8 : 0) | SVs_TEMP)));
+                         "Bareword \"%"UTF8f"\" refers to nonexistent package",
+                          UTF8fARG(UTF, len, PL_tokenbuf));
                    len -= 2;
                    PL_tokenbuf[len] = '\0';
                    gv = NULL;
@@ -7183,9 +7266,13 @@ Perl_yylex(pTHX)
                if (*s == '=' && s[1] == '>' && !pkgname) {
                    op_free(rv2cv_op);
                    CLINE;
+                   /* This is our own scalar, created a few lines above,
+                      so this is safe. */
+                   SvREADONLY_off(cSVOPx(pl_yylval.opval)->op_sv);
                    sv_setpv(((SVOP*)pl_yylval.opval)->op_sv, PL_tokenbuf);
                    if (UTF && !IN_BYTES && is_utf8_string((U8*)PL_tokenbuf, len))
                      SvUTF8_on(((SVOP*)pl_yylval.opval)->op_sv);
+                   SvREADONLY_on(cSVOPx(pl_yylval.opval)->op_sv);
                    TERM(WORD);
                }
 
@@ -7196,7 +7283,7 @@ Perl_yylex(pTHX)
                        d = s + 1;
                        while (SPACE_OR_TAB(*d))
                            d++;
-                       if (*d == ')' && (sv = cv_const_sv(cv))) {
+                       if (*d == ')' && (sv = cv_const_sv_or_av(cv))) {
                            s = d + 1;
                            goto its_constant;
                        }
@@ -7253,19 +7340,26 @@ Perl_yylex(pTHX)
 
                if (cv) {
                    if (lastchar == '-' && penultchar != '-') {
-                        const SV *tmpsv = newSVpvn_flags( PL_tokenbuf, len ? len : strlen(PL_tokenbuf), (UTF ? SVf_UTF8 : 0) | SVs_TEMP );
+                       const STRLEN l = len ? len : strlen(PL_tokenbuf);
                        Perl_ck_warner_d(aTHX_ packWARN(WARN_AMBIGUOUS),
-                               "Ambiguous use of -%"SVf" resolved as -&%"SVf"()",
-                               SVfARG(tmpsv), SVfARG(tmpsv));
+                           "Ambiguous use of -%"UTF8f" resolved as -&%"UTF8f"()",
+                            UTF8fARG(UTF, l, PL_tokenbuf),
+                            UTF8fARG(UTF, l, PL_tokenbuf));
                     }
                    /* Check for a constant sub */
-                   if ((sv = cv_const_sv(cv))) {
+                   if ((sv = cv_const_sv_or_av(cv))) {
                  its_constant:
                        op_free(rv2cv_op);
                        SvREFCNT_dec(((SVOP*)pl_yylval.opval)->op_sv);
                        ((SVOP*)pl_yylval.opval)->op_sv = SvREFCNT_inc_simple(sv);
-                       pl_yylval.opval->op_private = OPpCONST_FOLDED;
-                       pl_yylval.opval->op_flags |= OPf_SPECIAL;
+                       if (SvTYPE(sv) == SVt_PVAV)
+                           pl_yylval.opval = newUNOP(OP_RV2AV, OPf_PARENS,
+                                                     pl_yylval.opval);
+                       else {
+                           pl_yylval.opval->op_private = OPpCONST_FOLDED;
+                           pl_yylval.opval->op_folded = 1;
+                           pl_yylval.opval->op_flags |= OPf_SPECIAL;
+                       }
                        TOKEN(WORD);
                    }
 
@@ -7285,6 +7379,7 @@ Perl_yylex(pTHX)
                        STRLEN protolen = CvPROTOLEN(cv);
                        const char *proto = CvPROTO(cv);
                        bool optional;
+                       proto = S_strip_spaces(aTHX_ proto, &protolen);
                        if (!protolen)
                            TERM(FUNC0SUB);
                        if ((optional = *proto == ';'))
@@ -7429,12 +7524,13 @@ Perl_yylex(pTHX)
                op_free(rv2cv_op);
 
            safe_bareword:
-               if ((lastchar == '*' || lastchar == '%' || lastchar == '&')) {
+               if ((lastchar == '*' || lastchar == '%' || lastchar == '&')
+                && saw_infix_sigil) {
                    Perl_ck_warner_d(aTHX_ packWARN(WARN_AMBIGUOUS),
-                                    "Operator or semicolon missing before %c%"SVf,
-                                    lastchar, SVfARG(newSVpvn_flags(PL_tokenbuf,
-                                                    strlen(PL_tokenbuf),
-                                                    SVs_TEMP | (UTF ? SVf_UTF8 : 0))));
+                                    "Operator or semicolon missing before %c%"UTF8f,
+                                    lastchar,
+                                    UTF8fARG(UTF, strlen(PL_tokenbuf),
+                                             PL_tokenbuf));
                    Perl_ck_warner_d(aTHX_ packWARN(WARN_AMBIGUOUS),
                                     "Ambiguous use of %c resolved as operator %c",
                                     lastchar, lastchar);
@@ -7465,21 +7561,12 @@ Perl_yylex(pTHX)
        case KEY___END__: {
            GV *gv;
            if (PL_rsfp && (!PL_in_eval || PL_tokenbuf[2] == 'D')) {
-               const char *pname = "main";
-               STRLEN plen = 4;
-               U32 putf8 = 0;
-               if (PL_tokenbuf[2] == 'D')
-               {
-                   HV * const stash =
-                       PL_curstash ? PL_curstash : PL_defstash;
-                   pname = HvNAME_get(stash);
-                   plen  = HvNAMELEN (stash);
-                   if(HvNAMEUTF8(stash)) putf8 = SVf_UTF8;
-               }
-               gv = gv_fetchpvn_flags(
-                       Perl_form(aTHX_ "%*s::DATA", (int)plen, pname),
-                       plen+6, GV_ADD|putf8, SVt_PVIO
-               );
+               HV * const stash = PL_tokenbuf[2] == 'D' && PL_curstash
+                                       ? PL_curstash
+                                       : PL_defstash;
+               gv = (GV *)*hv_fetchs(stash, "DATA", 1);
+               if (!isGV(gv))
+                   gv_init(gv,stash,"DATA",4,0);
                GvMULTI_on(gv);
                if (!GvIO(gv))
                    GvIOp(gv) = newIO();
@@ -7594,9 +7681,8 @@ Perl_yylex(pTHX)
                    goto just_a_word;
                }
                if (!tmp)
-                   Perl_croak(aTHX_ "CORE::%"SVf" is not a keyword",
-                                    SVfARG(newSVpvn_flags(PL_tokenbuf, len,
-                                                (UTF ? SVf_UTF8 : 0) | SVs_TEMP)));
+                   Perl_croak(aTHX_ "CORE::%"UTF8f" is not a keyword",
+                                     UTF8fARG(UTF, len, PL_tokenbuf));
                if (tmp < 0)
                    tmp = -tmp;
                else if (tmp == KEY_require || tmp == KEY_do
@@ -7749,7 +7835,7 @@ Perl_yylex(pTHX)
 
        case KEY_dump:
            PL_expect = XOPERATOR;
-           s = force_word(s,WORD,TRUE,FALSE,FALSE);
+           s = force_word(s,WORD,TRUE,FALSE);
            LOOPX(OP_DUMP);
 
        case KEY_else:
@@ -7882,7 +7968,7 @@ Perl_yylex(pTHX)
 
        case KEY_goto:
            PL_expect = XOPERATOR;
-           s = force_word(s,WORD,TRUE,FALSE,FALSE);
+           s = force_word(s,WORD,TRUE,FALSE);
            LOOPX(OP_GOTO);
 
        case KEY_gmtime:
@@ -8008,7 +8094,7 @@ Perl_yylex(pTHX)
 
        case KEY_last:
            PL_expect = XOPERATOR;
-           s = force_word(s,WORD,TRUE,FALSE,FALSE);
+           s = force_word(s,WORD,TRUE,FALSE);
            LOOPX(OP_LAST);
        
        case KEY_lc:
@@ -8116,7 +8202,7 @@ Perl_yylex(pTHX)
 
        case KEY_next:
            PL_expect = XOPERATOR;
-           s = force_word(s,WORD,TRUE,FALSE,FALSE);
+           s = force_word(s,WORD,TRUE,FALSE);
            LOOPX(OP_NEXT);
 
        case KEY_ne:
@@ -8152,11 +8238,9 @@ Perl_yylex(pTHX)
                    && !(t[0] == ':' && t[1] == ':')
                    && !keyword(s, d-s, 0)
                ) {
-                   SV *tmpsv = newSVpvn_flags(s, (STRLEN)(d-s),
-                                                SVs_TEMP | (UTF ? SVf_UTF8 : 0));
                    Perl_warner(aTHX_ packWARN(WARN_PRECEDENCE),
-                          "Precedence problem: open %"SVf" should be open(%"SVf")",
-                           SVfARG(tmpsv), SVfARG(tmpsv));
+                      "Precedence problem: open %"UTF8f" should be open(%"UTF8f")",
+                       UTF8fARG(UTF, d-s, s), UTF8fARG(UTF, d-s, s));
                }
            }
            LOP(OP_OPEN,XTERM);
@@ -8200,7 +8284,7 @@ Perl_yylex(pTHX)
            LOP(OP_PACK,XTERM);
 
        case KEY_package:
-           s = force_word(s,WORD,FALSE,TRUE,FALSE);
+           s = force_word(s,WORD,FALSE,TRUE);
            s = SKIPSPACE1(s);
            s = force_strict_version(s);
            PL_lex_expect = XBLOCK;
@@ -8303,7 +8387,7 @@ Perl_yylex(pTHX)
                    || (s = force_version(s, TRUE), *s == 'v'))
            {
                *PL_tokenbuf = '\0';
-               s = force_word(s,WORD,TRUE,TRUE,FALSE);
+               s = force_word(s,WORD,TRUE,TRUE);
                if (isIDFIRST_lazy_if(PL_tokenbuf,UTF))
                    gv_stashpvn(PL_tokenbuf, strlen(PL_tokenbuf),
                                 GV_ADD | (UTF ? SVf_UTF8 : 0));
@@ -8328,7 +8412,7 @@ Perl_yylex(pTHX)
 
        case KEY_redo:
            PL_expect = XOPERATOR;
-           s = force_word(s,WORD,TRUE,FALSE,FALSE);
+           s = force_word(s,WORD,TRUE,FALSE);
            LOOPX(OP_REDO);
 
        case KEY_rename:
@@ -8469,7 +8553,7 @@ Perl_yylex(pTHX)
            checkcomma(s,PL_tokenbuf,"subroutine name");
            s = SKIPSPACE1(s);
            PL_expect = XTERM;
-           s = force_word(s,WORD,TRUE,TRUE,FALSE);
+           s = force_word(s,WORD,TRUE,TRUE);
            LOP(OP_SORT,XREF);
 
        case KEY_split:
@@ -8501,10 +8585,12 @@ Perl_yylex(pTHX)
          really_sub:
            {
                char * const tmpbuf = PL_tokenbuf + 1;
-               SSize_t tboffset = 0;
                expectation attrful;
                bool have_name, have_proto;
                const int key = tmp;
+#ifndef PERL_MAD
+                SV *format_name = NULL;
+#endif
 
 #ifdef PERL_MAD
                SV *tmpwhite = 0;
@@ -8531,13 +8617,14 @@ Perl_yylex(pTHX)
 
                    PL_expect = XBLOCK;
                    attrful = XATTRBLOCK;
-                   /* remember buffer pos'n for later force_word */
-                   tboffset = s - PL_oldbufptr;
                    d = scan_word(s, tmpbuf, sizeof PL_tokenbuf - 1, TRUE,
                                  &len);
 #ifdef PERL_MAD
                    if (PL_madskills)
                        nametoke = newSVpvn_flags(s, d - s, SvUTF8(PL_linestr));
+#else
+                    if (key == KEY_format)
+                       format_name = S_newSV_maybe_utf8(aTHX_ s, d - s);
 #endif
                    *PL_tokenbuf = '&';
                    if (memchr(tmpbuf, ':', len) || key != KEY_sub
@@ -8584,89 +8671,24 @@ Perl_yylex(pTHX)
 #ifdef PERL_MAD
                    PL_thistoken = subtoken;
                    s = d;
-                    PERL_UNUSED_VAR(tboffset);
 #else
-                   if (have_name)
-                       (void) force_word(PL_oldbufptr + tboffset, WORD,
-                                         FALSE, TRUE, TRUE);
+                   if (format_name) {
+                        start_force(PL_curforce);
+                        NEXTVAL_NEXTTOKE.opval
+                            = (OP*)newSVOP(OP_CONST,0, format_name);
+                        NEXTVAL_NEXTTOKE.opval->op_private |= OPpCONST_BARE;
+                        force_next(WORD);
+                    }
 #endif
                    PREBLOCK(FORMAT);
                }
 
                /* Look for a prototype */
                if (*s == '(') {
-                   char *p;
-                   bool bad_proto = FALSE;
-                   bool in_brackets = FALSE;
-                   char greedy_proto = ' ';
-                   bool proto_after_greedy_proto = FALSE;
-                   bool must_be_last = FALSE;
-                   bool underscore = FALSE;
-                   bool seen_underscore = FALSE;
-                   const bool warnillegalproto = ckWARN(WARN_ILLEGALPROTO);
-                    STRLEN tmplen;
-
                    s = scan_str(s,!!PL_madskills,FALSE,FALSE, FALSE);
                    if (!s)
                        Perl_croak(aTHX_ "Prototype not terminated");
-                   /* strip spaces and check for bad characters */
-                   d = SvPV(PL_lex_stuff, tmplen);
-                   tmp = 0;
-                   for (p = d; tmplen; tmplen--, ++p) {
-                       if (!isSPACE(*p)) {
-                            d[tmp++] = *p;
-
-                           if (warnillegalproto) {
-                               if (must_be_last)
-                                   proto_after_greedy_proto = TRUE;
-                               if (!strchr("$@%*;[]&\\_+", *p) || *p == '\0') {
-                                   bad_proto = TRUE;
-                               }
-                               else {
-                                   if ( underscore ) {
-                                       if ( !strchr(";@%", *p) )
-                                           bad_proto = TRUE;
-                                       underscore = FALSE;
-                                   }
-                                   if ( *p == '[' ) {
-                                       in_brackets = TRUE;
-                                   }
-                                   else if ( *p == ']' ) {
-                                       in_brackets = FALSE;
-                                   }
-                                   else if ( (*p == '@' || *p == '%') &&
-                                        ( tmp < 2 || d[tmp-2] != '\\' ) &&
-                                        !in_brackets ) {
-                                       must_be_last = TRUE;
-                                       greedy_proto = *p;
-                                   }
-                                   else if ( *p == '_' ) {
-                                       underscore = seen_underscore = TRUE;
-                                   }
-                               }
-                           }
-                       }
-                   }
-                    d[tmp] = '\0';
-                   if (proto_after_greedy_proto)
-                       Perl_warner(aTHX_ packWARN(WARN_ILLEGALPROTO),
-                                   "Prototype after '%c' for %"SVf" : %s",
-                                   greedy_proto, SVfARG(PL_subname), d);
-                   if (bad_proto) {
-                        SV *dsv = newSVpvs_flags("", SVs_TEMP);
-                       Perl_warner(aTHX_ packWARN(WARN_ILLEGALPROTO),
-                                   "Illegal character %sin prototype for %"SVf" : %s",
-                                   seen_underscore ? "after '_' " : "",
-                                   SVfARG(PL_subname),
-                                    SvUTF8(PL_lex_stuff)
-                                        ? sv_uni_display(dsv,
-                                            newSVpvn_flags(d, tmp, SVs_TEMP | SVf_UTF8),
-                                            tmp,
-                                            UNI_DISPLAY_ISPRINT)
-                                        : pv_pretty(dsv, d, tmp, 60, NULL, NULL,
-                                            PERL_PV_ESCAPE_NONASCII));
-                    }
-                    SvCUR_set(PL_lex_stuff, tmp);
+                   (void)validate_proto(PL_subname, PL_lex_stuff, ckWARN(WARN_ILLEGALPROTO));
                    have_proto = TRUE;
 
 #ifdef PERL_MAD
@@ -9003,9 +9025,9 @@ S_pending_ident(pTHX)
         {
             /* Downgraded from fatal to warning 20000522 mjd */
             Perl_warner(aTHX_ packWARN(WARN_AMBIGUOUS),
-                       "Possible unintended interpolation of %"SVf" in string",
-                       SVfARG(newSVpvn_flags(PL_tokenbuf, tokenbuf_len,
-                                        SVs_TEMP | ( UTF ? SVf_UTF8 : 0 ))));
+                       "Possible unintended interpolation of %"UTF8f
+                       " in string",
+                       UTF8fARG(UTF, tokenbuf_len, PL_tokenbuf));
         }
     }
 
@@ -10002,7 +10024,7 @@ S_scan_heredoc(pTHX_ char *s)
            /* shared is only null if we have gone beyond the outermost
               lexing scope.  In a file, we will have broken out of the
               loop in the previous iteration.  In an eval, the string buf-
-              fer ends with "\n;", so the while condition below will have
+              fer ends with "\n;", so the while condition above will have
               evaluated to false.  So shared can never be null. */
            assert(shared);
            /* A LEXSHARED struct with a null ls_prev pointer is the outer-
@@ -10106,8 +10128,11 @@ S_scan_heredoc(pTHX_ char *s)
        }
        CopLINE_set(PL_curcop, (line_t)PL_multi_start - 1);
        if (!SvCUR(PL_linestr) || PL_bufend[-1] != '\n') {
-           lex_grow_linestr(SvCUR(PL_linestr) + 2);
+            s = lex_grow_linestr(SvLEN(PL_linestr) + 3);
+            /* ^That should be enough to avoid this needing to grow:  */
            sv_catpvs(PL_linestr, "\n\0");
+            assert(s == SvPVX(PL_linestr));
+            PL_bufend = SvEND(PL_linestr);
        }
        s = PL_bufptr;
 #ifdef PERL_MAD
@@ -10325,11 +10350,15 @@ intro_sym:
 
 
 /* scan_str
-   takes: start position in buffer
-         keep_quoted preserve \ on the embedded delimiter(s)
-         keep_delims preserve the delimiters around the string
-         re_reparse  compiling a run-time /(?{})/:
-                       collapse // to /,  and skip encoding src
+   takes:
+       start                   position in buffer
+       keep_quoted             preserve \ on the embedded delimiter(s)
+       keep_delims             preserve the delimiters around the string
+       re_reparse              compiling a run-time /(?{})/:
+                                  collapse // to /,  and skip encoding src
+       deprecate_escaped_meta  issue a deprecation warning for cer-
+                               tain paired metacharacters that appear
+                               escaped within it
    returns: position to continue reading from buffer
    side-effects: multi_start, multi_close, lex_repl or lex_stuff, and
        updates the read buffer.
@@ -10371,9 +10400,7 @@ intro_sym:
 
 STATIC char *
 S_scan_str(pTHX_ char *start, int keep_quoted, int keep_delims, int re_reparse,
-        bool deprecate_escaped_meta /* Should we issue a deprecation warning
-                                       for certain paired metacharacters that
-                                       appear escaped within it */
+                bool deprecate_escaped_meta
     )
 {
     dVAR;
@@ -10473,8 +10500,49 @@ S_scan_str(pTHX_ char *start, int keep_quoted, int keep_delims, int re_reparse,
                int offset = s - SvPVX_const(PL_linestr);
                const bool found = sv_cat_decode(sv, PL_encoding, PL_linestr,
                                           &offset, (char*)termstr, termlen);
-               const char * const ns = SvPVX_const(PL_linestr) + offset;
-               char * const svlast = SvEND(sv) - 1;
+               const char *ns;
+               char *svlast;
+
+               if (SvIsCOW(PL_linestr)) {
+                   STRLEN bufend_pos, bufptr_pos, oldbufptr_pos;
+                   STRLEN oldoldbufptr_pos, linestart_pos, last_uni_pos;
+                   STRLEN last_lop_pos, re_eval_start_pos, s_pos;
+                   char *buf = SvPVX(PL_linestr);
+                   bufend_pos = PL_parser->bufend - buf;
+                   bufptr_pos = PL_parser->bufptr - buf;
+                   oldbufptr_pos = PL_parser->oldbufptr - buf;
+                   oldoldbufptr_pos = PL_parser->oldoldbufptr - buf;
+                   linestart_pos = PL_parser->linestart - buf;
+                   last_uni_pos = PL_parser->last_uni
+                       ? PL_parser->last_uni - buf
+                       : 0;
+                   last_lop_pos = PL_parser->last_lop
+                       ? PL_parser->last_lop - buf
+                       : 0;
+                   re_eval_start_pos =
+                       PL_parser->lex_shared->re_eval_start ?
+                            PL_parser->lex_shared->re_eval_start - buf : 0;
+                   s_pos = s - buf;
+
+                   sv_force_normal(PL_linestr);
+
+                   buf = SvPVX(PL_linestr);
+                   PL_parser->bufend = buf + bufend_pos;
+                   PL_parser->bufptr = buf + bufptr_pos;
+                   PL_parser->oldbufptr = buf + oldbufptr_pos;
+                   PL_parser->oldoldbufptr = buf + oldoldbufptr_pos;
+                   PL_parser->linestart = buf + linestart_pos;
+                   if (PL_parser->last_uni)
+                       PL_parser->last_uni = buf + last_uni_pos;
+                   if (PL_parser->last_lop)
+                       PL_parser->last_lop = buf + last_lop_pos;
+                   if (PL_parser->lex_shared->re_eval_start)
+                       PL_parser->lex_shared->re_eval_start  =
+                           buf + re_eval_start_pos;
+                   s = buf + s_pos;
+               }
+               ns = SvPVX_const(PL_linestr) + offset;
+               svlast = SvEND(sv) - 1;
 
                for (; s < ns; s++) {
                    if (*s == '\n' && !PL_rsfp && !PL_parser->filtered)
@@ -10595,26 +10663,39 @@ S_scan_str(pTHX_ char *start, int keep_quoted, int keep_delims, int re_reparse,
                          * context where the delimiter is also a metacharacter,
                          * the backslash is useless, and deprecated.  () and []
                          * are meta in any context. {} are meta only when
-                         * appearing in a quantifier or in things like '\p{'.
-                         * They also aren't meta unless there is a matching
-                         * closed, escaped char later on within the string.
-                         * If 's' points to an open, set a flag; if to a close,
-                         * test that flag, and raise a warning if it was set */
+                         * appearing in a quantifier or in things like '\p{'
+                         * (but '\\p{' isn't meta).  They also aren't meta
+                         * unless there is a matching closed, escaped char
+                         * later on within the string.  If 's' points to an
+                         * open, set a flag; if to a close, test that flag, and
+                         * raise a warning if it was set */
 
                        if (deprecate_escaped_meta) {
                             if (*s == PL_multi_open) {
                                 if (*s != '{') {
                                     escaped_open = s;
                                 }
-                                else if (regcurly(s,
-                                                  TRUE /* Look for a closing
-                                                          '\}' */)
-                                         || (s - start > 2  /* Look for e.g.
-                                                               '\x{' */
-                                             && _generic_isCC(*(s-2), _CC_BACKSLASH_FOO_LBRACE_IS_META)))
-                                {
+                                     /* Look for a closing '\}' */
+                                else if (regcurly(s, TRUE)) {
                                     escaped_open = s;
                                 }
+                                     /* Look for e.g.  '\x{' */
+                                else if (s - start > 2
+                                         && _generic_isCC(*(s-2),
+                                             _CC_BACKSLASH_FOO_LBRACE_IS_META))
+                                { /* Exclude '\\x', '\\\\x', etc. */
+                                    char *lookbehind = s - 4;
+                                    bool is_meta = TRUE;
+                                    while (lookbehind >= start
+                                           && *lookbehind == '\\')
+                                    {
+                                        is_meta = ! is_meta;
+                                        lookbehind--;
+                                    }
+                                    if (is_meta) {
+                                        escaped_open = s;
+                                    }
+                                }
                             }
                             else if (escaped_open) {
                                 Perl_warner(aTHX_ packWARN(WARN_DEPRECATED),
@@ -11396,9 +11477,8 @@ Perl_yyerror_pvn(pTHX_ const char *const s, STRLEN len, U32 flags)
     Perl_sv_catpvf(aTHX_ msg, " at %s line %"IVdf", ",
         OutCopFILE(PL_curcop), (IV)CopLINE(PL_curcop));
     if (context)
-       Perl_sv_catpvf(aTHX_ msg, "near \"%"SVf"\"\n",
-                            SVfARG(newSVpvn_flags(context, contlen,
-                                        SVs_TEMP | (UTF ? SVf_UTF8 : 0))));
+       Perl_sv_catpvf(aTHX_ msg, "near \"%"UTF8f"\"\n",
+                            UTF8fARG(UTF, contlen, context));
     else
        Perl_sv_catpvf(aTHX_ msg, "%"SVf"\n", SVfARG(where_sv));
     if (PL_multi_start < PL_multi_end && (U32)(CopLINE(PL_curcop) - PL_multi_end) <= 1) {