Warn about false ranges like \d-\w (see the change #4355).

The invalid ranges (b-a) warning message also enhanced.

p4raw-link: @4355 on //depot/cfgperl: 1209ba901e0b2880eea69ad70613848af5543517

p4raw-id: //depot/cfgperl@4374

5 files changed, 465 insertions, 319 deletions

diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index ed395be00e..b4d4d217de 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -15,8 +15,8 @@ This document describes differences between the 5.005 release and this one.
 
 =head2 Perl Source Incompatibilities
 
-Beware that any new warnings that have been added are B<not> considered
-incompatible changes.
+Beware that any new warnings that have been added or enhanced old
+warnings are B<not> considered incompatible changes.
 
 Since all new warnings must be explicitly requested via the C<-w>
 switch or the C<warnings> pragma, it is ultimately the programmer's
@@ -1012,7 +1012,7 @@ change#4052
 =item Data::Dumper
 
 A C<Maxdepth> setting can be specified to avoid venturing
-too deeply into depp data structures.  See L<Data::Dumper>.
+too deeply into deep data structures.  See L<Data::Dumper>.
 
 Dumping C<qr//> objects works correctly.
 
@@ -1342,7 +1342,7 @@ A tutorial on managing class data for object modules.
 
 =back
 
-=head1 New Diagnostics
+=head1 New or Changed Diagnostics
 
 =over 4
 
@@ -1561,6 +1561,13 @@ See Server error.
 (F) While under the C<use filetest> pragma, switching the real and
 effective uids or gids failed.
 
+=item false [] range "%s" in regexp
+
+(W) A character class range must start and end at a literal character, not
+another character class like C<\d> or C<[:alpha:]>.  The "-" in your false
+range is interpreted as a literal "-".  Consider quoting the "-",  "\-".
+See L<perlre>.
+
 =item Filehandle %s opened only for output
 
 (W) You tried to read from a filehandle opened only for writing.  If you
@@ -1624,6 +1631,10 @@ by Perl or by a user-supplied handler.  See L<attributes>.
 The indicated attributes for a subroutine or variable were not recognized
 by Perl or by a user-supplied handler.  See L<attributes>.
 
+=item invalid [] range "%s" in regexp
+
+The offending range is now explicitly displayed.
+
 =item Invalid separator character %s in attribute list
 
 (F) Something other than a comma or whitespace was seen between the
diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index 8988730c8d..11758e0e88 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -1380,6 +1380,13 @@ the effect of blessing the reference into the package main.  This is
 usually not what you want.  Consider providing a default target
 package, e.g. bless($ref, $p || 'MyPackage');
 
+=item false [] range "%s" in regexp
+
+(W) A character class range must start and end at a literal character, not
+another character class like C<\d> or C<[:alpha:]>.  The "-" in your false
+range is interpreted as a literal "-".  Consider quoting the "-",  "\-".
+See L<perlre>.
+
 =item Fatal VMS error at %s, line %d
 
 (P) An error peculiar to VMS.  Something untoward happened in a VMS system
@@ -1680,7 +1687,7 @@ by Perl or by a user-supplied handler.  See L<attributes>.
 The indicated attributes for a subroutine or variable were not recognized
 by Perl or by a user-supplied handler.  See L<attributes>.
 
-=item invalid [] range in regexp
+=item invalid [] range "%s" in regexp
 
 (F) The range specified in a character class had a minimum character
 greater than the maximum character.  See L<perlre>.
diff --git a/regcomp.c b/regcomp.c
index 02dca515a8..0dafdd0b9b 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -2300,6 +2300,7 @@ S_regclass(pTHX)
     register I32 def;
     I32 numlen;
     I32 namedclass;
+    char *rangebegin;
 
     s = opnd = MASK(PL_regcode);
     ret = reg_node(ANYOF);
@@ -2329,6 +2330,8 @@ S_regclass(pTHX)
     while (PL_regcomp_parse < PL_regxend && *PL_regcomp_parse != ']') {
        skipcond:
 	namedclass = OOB_NAMEDCLASS;
+	if (!range)
+	    rangebegin = PL_regcomp_parse;
 	value = UCHARAT(PL_regcomp_parse++);
 	if (value == '[')
 	    namedclass = regpposixcc(value);
@@ -2363,258 +2366,274 @@ S_regclass(pTHX)
 		break;
 	    }
 	}
-	if (!SIZE_ONLY && namedclass > OOB_NAMEDCLASS) {
-	    if (range) {
-		ANYOF_BITMAP_SET(opnd, lastvalue);
-		ANYOF_BITMAP_SET(opnd, '-');
-	    }
-	    switch (namedclass) {
-	    case ANYOF_ALNUM:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_ALNUM);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isALNUM(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NALNUM:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NALNUM);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isALNUM(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_SPACE:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_SPACE);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isSPACE(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NSPACE:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NSPACE);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isSPACE(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_DIGIT:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_DIGIT);
-		else {
-		    for (value = '0'; value <= '9'; value++)
-			ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NDIGIT:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NDIGIT);
-		else {
-		    for (value = 0; value < '0'; value++)
-			ANYOF_BITMAP_SET(opnd, value);
-		    for (value = '9' + 1; value < 256; value++)
-			ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NALNUMC:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NALNUMC);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isALNUMC(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_ALNUMC:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_ALNUMC);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isALNUMC(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_ALPHA:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_ALPHA);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isALPHA(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NALPHA:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NALPHA);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isALPHA(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_ASCII:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_ASCII);
-		else {
-		    for (value = 0; value < 128; value++)
-			ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NASCII:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NASCII);
-		else {
-		    for (value = 128; value < 256; value++)
-			ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_CNTRL:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_CNTRL);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isCNTRL(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		lastvalue = OOB_CHAR8;
-		break;
-	    case ANYOF_NCNTRL:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NCNTRL);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isCNTRL(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_GRAPH:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_GRAPH);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isGRAPH(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NGRAPH:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NGRAPH);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isGRAPH(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_LOWER:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_LOWER);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isLOWER(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NLOWER:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NLOWER);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isLOWER(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_PRINT:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_PRINT);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isPRINT(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NPRINT:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NPRINT);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isPRINT(value))
-			    ANYOF_BITMAP_SET(opnd, value);
+	if (namedclass > OOB_NAMEDCLASS) {
+	    if (range) { /* a-\d, a-[:digit:] */
+		if (!SIZE_ONLY) {
+		    if (ckWARN(WARN_UNSAFE))
+			Perl_warner(aTHX_ WARN_UNSAFE,
+				    "/%.127s/: false [] range \"%*.*s\" in regexp",
+				    PL_regprecomp,
+				    PL_regcomp_parse - rangebegin,
+				    PL_regcomp_parse - rangebegin,
+				    rangebegin);
+		    ANYOF_BITMAP_SET(opnd, lastvalue);
+		    ANYOF_BITMAP_SET(opnd, '-');
 		}
-		break;
-	    case ANYOF_PUNCT:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_PUNCT);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isPUNCT(value))
+		range = 0; /* this is not a true range */
+	    }
+	    if (!SIZE_ONLY) {
+		switch (namedclass) {
+		case ANYOF_ALNUM:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_ALNUM);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isALNUM(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_NALNUM:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NALNUM);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isALNUM(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_SPACE:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_SPACE);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isSPACE(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_NSPACE:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NSPACE);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isSPACE(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_DIGIT:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_DIGIT);
+		    else {
+			for (value = '0'; value <= '9'; value++)
 			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NPUNCT:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NPUNCT);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isPUNCT(value))
+		    }
+		    break;
+		case ANYOF_NDIGIT:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NDIGIT);
+		    else {
+			for (value = 0; value < '0'; value++)
 			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_UPPER:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_UPPER);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isUPPER(value))
+			for (value = '9' + 1; value < 256; value++)
 			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_NUPPER:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NUPPER);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isUPPER(value))
+		    }
+		    break;
+		case ANYOF_NALNUMC:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NALNUMC);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isALNUMC(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_ALNUMC:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_ALNUMC);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isALNUMC(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_ALPHA:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_ALPHA);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isALPHA(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_NALPHA:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NALPHA);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isALPHA(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_ASCII:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_ASCII);
+		    else {
+			for (value = 0; value < 128; value++)
 			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    case ANYOF_XDIGIT:
-		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_XDIGIT);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (isXDIGIT(value))
+		    }
+		    break;
+		case ANYOF_NASCII:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NASCII);
+		    else {
+			for (value = 128; value < 256; value++)
 			    ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_CNTRL:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_CNTRL);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isCNTRL(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    lastvalue = OOB_CHAR8;
+		    break;
+		case ANYOF_NCNTRL:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NCNTRL);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isCNTRL(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_GRAPH:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_GRAPH);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isGRAPH(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_NGRAPH:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NGRAPH);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isGRAPH(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_LOWER:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_LOWER);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isLOWER(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_NLOWER:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NLOWER);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isLOWER(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_PRINT:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_PRINT);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isPRINT(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_NPRINT:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NPRINT);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isPRINT(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_PUNCT:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_PUNCT);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isPUNCT(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_NPUNCT:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NPUNCT);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isPUNCT(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_UPPER:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_UPPER);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isUPPER(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_NUPPER:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NUPPER);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isUPPER(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_XDIGIT:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_XDIGIT);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (isXDIGIT(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		case ANYOF_NXDIGIT:
+		    if (LOC)
+			ANYOF_CLASS_SET(opnd, ANYOF_NXDIGIT);
+		    else {
+			for (value = 0; value < 256; value++)
+			    if (!isXDIGIT(value))
+				ANYOF_BITMAP_SET(opnd, value);
+		    }
+		    break;
+		default:
+		    FAIL("invalid [::] class in regexp");
+		    break;
 		}
-		break;
-	    case ANYOF_NXDIGIT:
 		if (LOC)
-		    ANYOF_CLASS_SET(opnd, ANYOF_NXDIGIT);
-		else {
-		    for (value = 0; value < 256; value++)
-			if (!isXDIGIT(value))
-			    ANYOF_BITMAP_SET(opnd, value);
-		}
-		break;
-	    default:
-		FAIL("invalid [::] class in regexp");
-		break;
+		    ANYOF_FLAGS(opnd) |= ANYOF_CLASS;
+		continue;
 	    }
-	    if (LOC)
-		ANYOF_FLAGS(opnd) |= ANYOF_CLASS;
-	    continue;
 	}
-	if (range && namedclass > OOB_NAMEDCLASS)
-	    range = 0; /* [a-\d], [a-[:digit:]], not a true range. */
 	if (range) {
-	    if (lastvalue > value)
-		FAIL("invalid [] range in regexp"); /* [b-a] */
+	    if (lastvalue > value) /* b-a */ {
+		Perl_croak(aTHX_
+			   "/%.127s/: invalid [] range \"%*.*s\" in regexp",
+			   PL_regprecomp,
+			   PL_regcomp_parse - rangebegin,
+			   PL_regcomp_parse - rangebegin,
+			   rangebegin);
+	    }
 	    range = 0;
 	}
 	else {
@@ -2622,7 +2641,18 @@ S_regclass(pTHX)
 	    if (*PL_regcomp_parse == '-' && PL_regcomp_parse+1 < PL_regxend &&
 		PL_regcomp_parse[1] != ']') {
 		PL_regcomp_parse++;
-		range = 1;
+		if (namedclass > OOB_NAMEDCLASS) { /* \w-, [:word:]- */
+		    if (ckWARN(WARN_UNSAFE))
+			Perl_warner(aTHX_ WARN_UNSAFE,
+				    "/%.127s/: false [] range \"%*.*s\" in regexp",
+				    PL_regprecomp,
+				    PL_regcomp_parse - rangebegin,
+				    PL_regcomp_parse - rangebegin,
+				    rangebegin);
+		    if (!SIZE_ONLY)
+			ANYOF_BITMAP_SET(opnd, '-');
+		} else
+		    range = 1;
 		continue;	/* do it next time */
 	    }
 	}
@@ -2684,6 +2714,7 @@ S_regclassutf8(pTHX)
     SV *listsv;
     U8 flags = 0;
     I32 namedclass;
+    char *rangebegin;
 
     if (*PL_regcomp_parse == '^') {	/* Complement of range. */
 	PL_regnaughty++;
@@ -2707,9 +2738,10 @@ S_regclassutf8(pTHX)
     while (PL_regcomp_parse < PL_regxend && *PL_regcomp_parse != ']') {
        skipcond:
 	namedclass = OOB_NAMEDCLASS;
+	if (!range)
+	    rangebegin = PL_regcomp_parse;
 	value = utf8_to_uv((U8*)PL_regcomp_parse, &numlen);
 	PL_regcomp_parse += numlen;
-
 	if (value == '[')
 	    namedclass = regpposixcc(value);
 	else if (value == '\\') {
@@ -2778,73 +2810,89 @@ S_regclassutf8(pTHX)
 		break;
 	    }
 	}
-	if (!SIZE_ONLY && namedclass > OOB_NAMEDCLASS) {
-	    if (range) /* [a-\d], [a-[:digit:]] */
-                Perl_sv_catpvf(aTHX_ listsv, /* 0x002D is Unicode for '-' */
-			       "%04"UVxf"\n%002D\n", (UV)lastvalue);
- 	    switch (namedclass) {
-	    case ANYOF_ALNUM:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsWord\n");	break;
-	    case ANYOF_NALNUM:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsWord\n");	break;
-	    case ANYOF_ALNUMC:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsAlnum\n");	break;
-	    case ANYOF_NALNUMC:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsAlnum\n");	break;
-	    case ANYOF_ALPHA:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsAlpha\n");	break;
-	    case ANYOF_NALPHA:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsAlpha\n");	break;
-	    case ANYOF_ASCII:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsASCII\n");	break;
-	    case ANYOF_NASCII:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsASCII\n");	break;
-	    case ANYOF_CNTRL:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsCntrl\n");	break;
-	    case ANYOF_NCNTRL:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsCntrl\n");	break;
-	    case ANYOF_GRAPH:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsGraph\n");	break;
-	    case ANYOF_NGRAPH:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsGraph\n");	break;
-	    case ANYOF_DIGIT:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsDigit\n");	break;
-	    case ANYOF_NDIGIT:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsDigit\n");	break;
-	    case ANYOF_LOWER:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsLower\n");	break;
-	    case ANYOF_NLOWER:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsLower\n");	break;
-	    case ANYOF_PRINT:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsPrint\n");	break;
-	    case ANYOF_NPRINT:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsPrint\n");	break;
-	    case ANYOF_PUNCT:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsPunct\n");	break;
-	    case ANYOF_NPUNCT:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsPunct\n");	break;
-	    case ANYOF_SPACE:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsSpace\n");	break;
-	    case ANYOF_NSPACE:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsSpace\n");	break;
-	    case ANYOF_UPPER:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsUpper\n");	break;
-	    case ANYOF_NUPPER:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsUpper\n");	break;
-	    case ANYOF_XDIGIT:
-		Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsXDigit\n");	break;
-	    case ANYOF_NXDIGIT:
-		Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsXDigit\n");	break;
+	if (namedclass > OOB_NAMEDCLASS) {
+	    if (range) { /* a-\d, a-[:digit:] */
+		if (!SIZE_ONLY) {
+		    if (ckWARN(WARN_UNSAFE))
+			Perl_warner(aTHX_ WARN_UNSAFE,
+				    "/%.127s/: false [] range \"%*.*s\" in regexp",
+				    PL_regprecomp,
+				    PL_regcomp_parse - rangebegin,
+				    PL_regcomp_parse - rangebegin,
+				    rangebegin);
+		    Perl_sv_catpvf(aTHX_ listsv,
+				   /* 0x002D is Unicode for '-' */
+				   "%04"UVxf"\n002D\n", (UV)lastvalue);
+		}
+		range = 0;
+	    }
+	    if (!SIZE_ONLY) {
+		switch (namedclass) {
+		case ANYOF_ALNUM:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsWord\n");	break;
+		case ANYOF_NALNUM:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsWord\n");	break;
+		case ANYOF_ALNUMC:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsAlnum\n");	break;
+		case ANYOF_NALNUMC:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsAlnum\n");	break;
+		case ANYOF_ALPHA:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsAlpha\n");	break;
+		case ANYOF_NALPHA:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsAlpha\n");	break;
+		case ANYOF_ASCII:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsASCII\n");	break;
+		case ANYOF_NASCII:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsASCII\n");	break;
+		case ANYOF_CNTRL:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsCntrl\n");	break;
+		case ANYOF_NCNTRL:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsCntrl\n");	break;
+		case ANYOF_GRAPH:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsGraph\n");	break;
+		case ANYOF_NGRAPH:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsGraph\n");	break;
+		case ANYOF_DIGIT:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsDigit\n");	break;
+		case ANYOF_NDIGIT:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsDigit\n");	break;
+		case ANYOF_LOWER:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsLower\n");	break;
+		case ANYOF_NLOWER:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsLower\n");	break;
+		case ANYOF_PRINT:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsPrint\n");	break;
+		case ANYOF_NPRINT:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsPrint\n");	break;
+		case ANYOF_PUNCT:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsPunct\n");	break;
+		case ANYOF_NPUNCT:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsPunct\n");	break;
+		case ANYOF_SPACE:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsSpace\n");	break;
+		case ANYOF_NSPACE:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsSpace\n");	break;
+		case ANYOF_UPPER:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsUpper\n");	break;
+		case ANYOF_NUPPER:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsUpper\n");	break;
+		case ANYOF_XDIGIT:
+		    Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsXDigit\n");	break;
+		case ANYOF_NXDIGIT:
+		    Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsXDigit\n");	break;
+		}
+		continue;
 	    }
-	    continue;
 	}
-	if (range && namedclass > OOB_NAMEDCLASS)
-	    range = 0; /* [a-\d], [a-[:digit:]], not a true range. */
         if (range) {
-	    if (lastvalue > value)
-		FAIL("invalid [] range in regexp"); /* [b-a] */
-	    if (!SIZE_ONLY)
-                Perl_sv_catpvf(aTHX_ listsv, "%04"UVxf"\t%04"UVxf"\n", (UV)lastvalue, (UV)value);
+	    if (lastvalue > value) { /* b-a */
+		Perl_croak(aTHX_
+			   "/%.127s/: invalid [] range \"%*.*s\" in regexp",
+			   PL_regprecomp,
+			   PL_regcomp_parse - rangebegin,
+			   PL_regcomp_parse - rangebegin,
+			   rangebegin);
+	    }
 	    range = 0;
 	}
 	else {
@@ -2852,13 +2900,27 @@ S_regclassutf8(pTHX)
 	    if (*PL_regcomp_parse == '-' && PL_regcomp_parse+1 < PL_regxend &&
 		PL_regcomp_parse[1] != ']') {
 		PL_regcomp_parse++;
-		range = 1;
+		if (namedclass > OOB_NAMEDCLASS) { /* \w-, [:word:]- */
+		    if (ckWARN(WARN_UNSAFE))
+			Perl_warner(aTHX_ WARN_UNSAFE,
+				    "/%.127s/: false [] range \"%*.*s\" in regexp",
+				    PL_regprecomp,
+				    PL_regcomp_parse - rangebegin,
+				    PL_regcomp_parse - rangebegin,
+				    rangebegin);
+		    if (!SIZE_ONLY)
+			Perl_sv_catpvf(aTHX_ listsv,
+				       /* 0x002D is Unicode for '-' */
+				       "002D\n");
+		} else
+		    range = 1;
 		continue;	/* do it next time */
 	    }
 	}
 	/* now is the next time */
 	if (!SIZE_ONLY)
-	    Perl_sv_catpvf(aTHX_ listsv, "%04"UVxf"\n", (UV)value);
+	    Perl_sv_catpvf(aTHX_ listsv, "%04"UVxf"\t%04"UVxf"\n",
+			   (UV)lastvalue, (UV)value);
 	range = 0;
     }
 
diff --git a/t/op/re_tests b/t/op/re_tests
index 974bec5988..d72a0f73b2 100644
--- a/t/op/re_tests
+++ b/t/op/re_tests
@@ -45,7 +45,7 @@ a[b-d]e	ace	y	$&	ace
 a[b-d]	aac	y	$&	ac
 a[-b]	a-	y	$&	a-
 a[b-]	a-	y	$&	a-
-a[b-a]	-	c	-	/a[b-a]/: invalid [] range in regexp
+a[b-a]	-	c	-	/a[b-a]/: invalid [] range "b-a" in regexp
 a[]b	-	c	-	/a[]b/: unmatched [] in regexp
 a[	-	c	-	/a[/: unmatched [] in regexp
 a]	a]	y	$&	a]
@@ -218,7 +218,7 @@ a[-]?c	ac	y	$&	ac
 'a[b-d]'i	AAC	y	$&	AC
 'a[-b]'i	A-	y	$&	A-
 'a[b-]'i	A-	y	$&	A-
-'a[b-a]'i	-	c	-	/a[b-a]/: invalid [] range in regexp
+'a[b-a]'i	-	c	-	/a[b-a]/: invalid [] range "b-a" in regexp
 'a[]b'i	-	c	-	/a[]b/: unmatched [] in regexp
 'a['i	-	c	-	/a[/: unmatched [] in regexp
 'a]'i	A]	y	$&	A]
@@ -736,9 +736,9 @@ foo.bart	foo.bart	y	-	-
 .[X][X](.+)+[X]	bbbbXXXaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa	n	-	-
 tt+$	xxxtt	y	-	-
 ([a-\d]+)	za-9z	y	$1	a-9
-([\d-\s]+)	a0- z	y	$1	0- 
 ([\d-z]+)	a0-za	y	$1	0-z
+([\d-\s]+)	a0- z	y	$1	0- 
 ([a-[:digit:]]+)	za-9z	y	$1	a-9
-([[:digit:]-[:alpha:]]+)	=0-z=	y	$1	0-z
 ([[:digit:]-z]+)	=0-z=	y	$1	0-z
+([[:digit:]-[:alpha:]]+)	=0-z=	y	$1	0-z
 \GX.*X	aaaXbX	n	-	-
diff --git a/t/pragma/warn/regcomp b/t/pragma/warn/regcomp
index 9c3677ee10..88909626db 100644
--- a/t/pragma/warn/regcomp
+++ b/t/pragma/warn/regcomp
@@ -15,8 +15,9 @@
 
   Character class syntax [%c %c] belongs inside character classes [S_checkposixcc] 
   
+  /%.127s/: false [] range \"%*.*s\" in regexp [S_regclass]
 
-  
+  /%.127s/: false [] range \"%*.*s\" in regexp [S_regclassutf8]
 
 __END__
 # regcomp.c [S_regpiece]
@@ -73,3 +74,68 @@ Character class syntax [. .] is reserved for future extensions at - line 8.
 Character class syntax [= =] is reserved for future extensions at - line 9.
 Character class syntax [: :] belongs inside character classes at - line 10.
 Character class [:zog:] unknown at - line 19.
+########
+# regcomp.c [S_regclass]
+$_ = "";
+use warnings 'unsafe' ;
+/[a-b]/;
+/[a-\d]/;
+/[\d-b]/;
+/[\s-\d]/;
+/[\d-\s]/;
+/[a-[:digit:]]/;
+/[[:digit:]-b]/;
+/[[:alpha:]-[:digit:]]/;
+/[[:digit:]-[:alpha:]]/;
+no warnings 'unsafe' ;
+/[a-b]/;
+/[a-\d]/;
+/[\d-b]/;
+/[\s-\d]/;
+/[\d-\s]/;
+/[a-[:digit:]]/;
+/[[:digit:]-b]/;
+/[[:alpha:]-[:digit:]]/;
+/[[:digit:]-[:alpha:]]/;
+EXPECT
+/[a-\d]/: false [] range "a-\d" in regexp at - line 5.
+/[\d-b]/: false [] range "\d-" in regexp at - line 6.
+/[\s-\d]/: false [] range "\s-" in regexp at - line 7.
+/[\d-\s]/: false [] range "\d-" in regexp at - line 8.
+/[a-[:digit:]]/: false [] range "a-[:digit:]" in regexp at - line 9.
+/[[:digit:]-b]/: false [] range "[:digit:]-" in regexp at - line 10.
+/[[:alpha:]-[:digit:]]/: false [] range "[:alpha:]-" in regexp at - line 11.
+/[[:digit:]-[:alpha:]]/: false [] range "[:digit:]-" in regexp at - line 12.
+########
+# regcomp.c [S_regclassutf8]
+use utf8;
+$_ = "";
+use warnings 'unsafe' ;
+/[a-b]/;
+/[a-\d]/;
+/[\d-b]/;
+/[\s-\d]/;
+/[\d-\s]/;
+/[a-[:digit:]]/;
+/[[:digit:]-b]/;
+/[[:alpha:]-[:digit:]]/;
+/[[:digit:]-[:alpha:]]/;
+no warnings 'unsafe' ;
+/[a-b]/;
+/[a-\d]/;
+/[\d-b]/;
+/[\s-\d]/;
+/[\d-\s]/;
+/[a-[:digit:]]/;
+/[[:digit:]-b]/;
+/[[:alpha:]-[:digit:]]/;
+/[[:digit:]-[:alpha:]]/;
+EXPECT
+/[a-\d]/: false [] range "a-\d" in regexp at - line 6.
+/[\d-b]/: false [] range "\d-" in regexp at - line 7.
+/[\s-\d]/: false [] range "\s-" in regexp at - line 8.
+/[\d-\s]/: false [] range "\d-" in regexp at - line 9.
+/[a-[:digit:]]/: false [] range "a-[:digit:]" in regexp at - line 10.
+/[[:digit:]-b]/: false [] range "[:digit:]-" in regexp at - line 11.
+/[[:alpha:]-[:digit:]]/: false [] range "[:alpha:]-" in regexp at - line 12.
+/[[:digit:]-[:alpha:]]/: false [] range "[:digit:]-" in regexp at - line 13.