Refactoring RegExp parsing and modifying SyntaxError message

Author: Kenji Fukuda

lib/Parser/RegexParser.cpp

@@ -2157,16 +2157,19 @@ namespace UnifiedRegex
 
                 if (returnedNode->tag == Node::MatchSet)
                 {
-                    if (unicodeFlagPresent && pendingRangeStart != INVALID_CODEPOINT)
-                    {
-                        Fail(JSERR_UnicodeRegExpRangeContainsCharClass);
-                    }
-
-                    pendingCodePoint = INVALID_CODEPOINT;
                     if (pendingRangeStart != INVALID_CODEPOINT)
                     {
+                        if (unicodeFlagPresent)
+                        {
+                            //We a range containing a character class and the unicode flag is present, thus we end up having to throw a "Syntax" error here
+                            //This breaks the notion of Pass0 check for valid syntax, because during that time, the unicode flag is unknown.
+                            Fail(JSERR_UnicodeRegExpRangeContainsCharClass); //From #sec-patterns-static-semantics-early-errors-annexb
+                        }
+
                         codePointSet.Set(ctAllocator, '-');
                     }
+
+                    pendingCodePoint = INVALID_CODEPOINT;
                     pendingRangeStart = INVALID_CODEPOINT;
                     codePointSet.UnionInPlace(ctAllocator, deferredSetNode.set);
                     currIsACharSet = true;
@@ -2201,18 +2204,21 @@ namespace UnifiedRegex
 
             if (codePointToSet != INVALID_CODEPOINT || prevprevWasACharSetAndPartOfRange)
             {
-                if (unicodeFlagPresent && prevprevWasACharSetAndPartOfRange)
-                {
-                    Fail(JSERR_UnicodeRegExpRangeContainsCharClass);
-                }
-                else if (prevprevWasACharSetAndPartOfRange)
+                if (prevprevWasACharSetAndPartOfRange)
                 {
+                    //We a range containing a character class and the unicode flag is present, thus we end up having to throw a "Syntax" error here
+                    //This breaks the notion of Pass0 check for valid syntax, because during that time, the unicode flag is unknown.
+                    if (unicodeFlagPresent)
+                    {
+                        Fail(JSERR_UnicodeRegExpRangeContainsCharClass);
+                    }
+
                     if (pendingCodePoint != INVALID_CODEPOINT)
                     {
                         codePointSet.Set(ctAllocator, pendingCodePoint);
                     }
 
-                    codePointSet.Set(ctAllocator, '-');
+                    codePointSet.Set(ctAllocator, '-'); //Add '-' to set because a range was detected but turned out to be a union of character set with '-' and another atom.
                     pendingRangeStart = pendingCodePoint = INVALID_CODEPOINT;
                 }
                 else if (pendingRangeStart != INVALID_CODEPOINT)

lib/Parser/rterrors.h

@@ -366,7 +366,7 @@ RT_ERROR_MSG(JSERR_NoAccessors, 5673, "Invalid property descriptor: accessors no
 RT_ERROR_MSG(JSERR_RegExpInvalidEscape, 5674, "", "Invalid regular expression: invalid escape in unicode pattern", kjstSyntaxError, 0)
 RT_ERROR_MSG(JSERR_RegExpTooManyCapturingGroups, 5675, "", "Regular expression cannot have more than 32,767 capturing groups", kjstRangeError, 0)
 RT_ERROR_MSG(JSERR_ProxyHandlerReturnedFalse, 5676, "Proxy %s handler returned false", "Proxy handler returned false", kjstTypeError, 0)
-RT_ERROR_MSG(JSERR_UnicodeRegExpRangeContainsCharClass, 5677, "", "Character classes not allowed in class ranges", kjstSyntaxError, 0)
+RT_ERROR_MSG(JSERR_UnicodeRegExpRangeContainsCharClass, 5677, "%s", "Character classes not allowed in a RegExp class range.", kjstSyntaxError, 0)
 
 //Host errors
 RT_ERROR_MSG(JSERR_HostMaybeMissingPromiseContinuationCallback, 5700, "", "Host may not have set any promise continuation callback. Promises may not be executed.", kjstTypeError, 0)

test/Regex/characterclass_with_range.js

@@ -58,7 +58,9 @@ var tests = [
             matchRegExp("g", reUnicode, null);
             matchRegExp("\u2028", reUnicode, null);
             matchRegExp("\u2009", reUnicode, null);
-            assert.throws(() => eval("/^[\\s-z]$/u.exec(\"-\")"), SyntaxError, "Expected an error due to character sets not being allowed in ranges when unicode flag is set.", "Character classes not allowed in class ranges");
+            assert.throws(() => eval("/^[\\s-z]$/u.exec(\"-\")"), SyntaxError, "Expected an error due to character sets not being allowed in ranges when unicode flag is set.", "Character classes not allowed in a RegExp class range.");
+            assert.throws(() => eval("/^[z-\\s]$/u.exec(\"-\")"), SyntaxError, "Expected an error due to character sets not being allowed in ranges when unicode flag is set.", "Character classes not allowed in a RegExp class range.");
+        
         }
     },
     {
@@ -95,6 +97,7 @@ var tests = [
                 matchRegExp('--', re, '--');
                 matchRegExp('-9', re, '-9');
                 matchRegExp('  ', re, null);
+                matchRegExp('-\\', re, null);
         }
     },
     {