Fix bad auto-possessification of certain types of class.

ChangeLog

@@ -160,6 +160,11 @@ fields (that is, all the fields that contain pointers) to zeros so that the
 result of serializing is always the same. These fields are re-set when the 
 pattern is deserialized.
 
+35. In a pattern such as /[^\x{100}-\x{ffff}]*[\x80-\xff]/ which has a repeated
+negative class with no characters less than 0x100 followed by a positive class
+with only characters less than 0x100, the first class was incorrectly being 
+auto-possessified, causing incorrect match failures.
+
 
 Version 10.31 12-February-2018
 ------------------------------

src/pcre2_auto_possess.c

@@ -505,7 +505,7 @@ Arguments:
   utf         TRUE in UTF mode
   cb          compile data block
   base_list   the data list of the base opcode
-  base_end    the end of the data list
+  base_end    the end of the base opcode
   rec_limit   points to recursion depth counter
 
 Returns:      TRUE if the auto-possessification is possible
@@ -730,7 +730,7 @@ for(;;)
       if ((*xclass_flags & XCL_MAP) == 0)
         {
         /* No bits are set for characters < 256. */
-        if (list[1] == 0) return TRUE;
+        if (list[1] == 0) return (*xclass_flags & XCL_NOT) == 0;
         /* Might be an empty repeat. */
         continue;
         }

testdata/testinput4

@@ -2309,4 +2309,13 @@
     
 # ------- 
 
+/[^\x{100}-\x{ffff}]*[\x80-\xff]/utf
+    \x{99}\x{99}\x{99}
+
+/[^\x{100}-\x{ffff}ABC]*[\x80-\xff]/utf
+    \x{99}\x{99}\x{99}
+
+/[^\x{100}-\x{ffff}]*[\x80-\xff]/i,utf
+    \x{99}\x{99}\x{99}
+
 # End of testinput4

testdata/testoutput4

@@ -3730,4 +3730,16 @@ No match
     
 # ------- 
 
+/[^\x{100}-\x{ffff}]*[\x80-\xff]/utf
+    \x{99}\x{99}\x{99}
+ 0: \x{99}\x{99}\x{99}
+
+/[^\x{100}-\x{ffff}ABC]*[\x80-\xff]/utf
+    \x{99}\x{99}\x{99}
+ 0: \x{99}\x{99}\x{99}
+
+/[^\x{100}-\x{ffff}]*[\x80-\xff]/i,utf
+    \x{99}\x{99}\x{99}
+ 0: \x{99}\x{99}\x{99}
+
 # End of testinput4