Fix incorrect compiling when [Aa] etc. are quantified

ChangeLog

@@ -86,6 +86,12 @@ Clarke PR#72.
 21. A user discovered that the library names in CMakeLists.txt for MSVC 
 debugger (PDB) files were incorrect - perhaps never tried for PCRE2?
 
+22. An item such as [Aa] is optimized into a caseless single character match.
+When this was quantified (e.g. [Aa]{2}) and was also the last literal item in a
+pattern, the optimizing "must be present for a match" character check was not
+being flagged as caseless, causing some matches that should have succeeded to
+fail.
+
 
 Version 10.39 29-October-2021
 -----------------------------

src/pcre2_compile.c

@@ -7023,14 +7023,19 @@ for (;; pptr++)
 #endif  /* MAYBE_UTF_MULTI */
 
       /* Handle the case of a single code unit - either with no UTF support, or
-      with UTF disabled, or for a single-code-unit UTF character. */
+      with UTF disabled, or for a single-code-unit UTF character. In the latter
+      case, for a repeated positive match, get the caseless flag for the
+      required code unit from the previous character, because a class like [Aa]
+      sets a caseless A but by now the req_caseopt flag has been reset. */
+
         {
         mcbuffer[0] = code[-1];
         mclength = 1;
         if (op_previous <= OP_CHARI && repeat_min > 1)
           {
           reqcu = mcbuffer[0];
-          reqcuflags = req_caseopt | cb->req_varyopt;
+          reqcuflags = cb->req_varyopt;
+          if (op_previous == OP_CHARI) reqcuflags |= REQ_CASELESS;
           }
         }
       goto OUTPUT_SINGLE_REPEAT;  /* Code shared with single character types */

testdata/testinput2

@@ -5923,4 +5923,13 @@ a)"xI
 
 # --------- 
 
+/[Aa]{2}/BI
+    aabcd
+
+/A{2}/iBI
+    aabcd
+
+/[Aa]{2,3}/BI
+    aabcd
+
 # End of testinput2

testdata/testoutput2

@@ -17702,6 +17702,50 @@ Failed: error -51: NULL argument passed with non-zero length
 
 # --------- 
 
+/[Aa]{2}/BI
+------------------------------------------------------------------
+        Bra
+     /i A{2}
+        Ket
+        End
+------------------------------------------------------------------
+Capture group count = 0
+First code unit = 'A' (caseless)
+Last code unit = 'A' (caseless)
+Subject length lower bound = 2
+    aabcd
+ 0: aa
+
+/A{2}/iBI
+------------------------------------------------------------------
+        Bra
+     /i A{2}
+        Ket
+        End
+------------------------------------------------------------------
+Capture group count = 0
+Options: caseless
+First code unit = 'A' (caseless)
+Last code unit = 'A' (caseless)
+Subject length lower bound = 2
+    aabcd
+ 0: aa
+
+/[Aa]{2,3}/BI
+------------------------------------------------------------------
+        Bra
+     /i A{2}
+     /i A?+
+        Ket
+        End
+------------------------------------------------------------------
+Capture group count = 0
+First code unit = 'A' (caseless)
+Last code unit = 'A' (caseless)
+Subject length lower bound = 2
+    aabcd
+ 0: aa
+
 # End of testinput2
 Error -70: PCRE2_ERROR_BADDATA (unknown error number)
 Error -62: bad serialized data