Fixing an oversite in my first fix.

patches/rematch.patch

 Index: source/i18n/rematch.cpp
 ===================================================================
 --- source/i18n/rematch.cpp     (revision 98343)
 +++ source/i18n/rematch.cpp     (working copy)
 @@ -5598,6 +5598,7 @@
                      const UChar *foldChars = NULL;
                      int32_t foldOffset, foldLength;
                      UChar32 c;
 +                    UBool c_is_valid = FALSE;
                      
                      #ifdef REGEX_SMART_BACKTRACKING
                      int32_t originalInputIdx = fp->fInputIdx;
-@@ -5607,23 +5608,29 @@
+@@ -5607,23 +5608,31 @@
                      foldOffset = foldLength = 0;
  
                      while (patternChars < patternEnd && success) {
 -                        if(foldOffset < foldLength) {
 -                            U16_NEXT_UNSAFE(foldChars, foldOffset, c);
 -                        } else {
 -                            U16_NEXT(inputBuf, fp->fInputIdx, fActiveLimit, c);
 -                            foldLength = ucase_toFullFolding(csp, c, &foldChars, U_FOLD_CASE_DEFAULT);
 -                            if(foldLength >= 0) {
 -                                if(foldLength <= UCASE_MAX_STRING_LENGTH) {   // !!!: Does not correctly handle chars that fold to 0-length strings
@@ skipping 15 matching lines @@
 +                                if(foldLength >= 0) {
 +                                    if(foldLength <= UCASE_MAX_STRING_LENGTH) {   // !!!: Does not correctly handle chars that fold to 0-length strings
 +                                        foldOffset = 0;
 +                                        U16_NEXT_UNSAFE(foldChars, foldOffset, c);
 +                                    } else {
 +                                        c = foldLength;
 +                                        foldLength = foldOffset; // to avoid reading chars from the folding buffer
 +                                    }
                                  }
                              }
++                        } else {
++                          c_is_valid = FALSE;
                          }
                          
 -                        if (fp->fInputIdx <= fActiveLimit) {
 +                        if (fp->fInputIdx <= fActiveLimit && c_is_valid) {
                              if (U_IS_BMP(c)) {
                                  success = (*patternChars == c);
                                  patternChars += 1;
-@@ -6070,4 +6077,3 @@
+@@ -6070,4 +6079,3 @@
  U_NAMESPACE_END
  
  #endif  // !UCONFIG_NO_REGULAR_EXPRESSIONS
 -