diff --git a/ChangeLog b/ChangeLog
index 6156b24..d276feb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -255,6 +255,10 @@ This lifts a restriction on the number of branches in a group (more than about
 38. Add the "-ac" command line option to pcre2test as a synonym for "-pattern
 auto_callout".
 
+39. In a library with Unicode support, incorrect data was compiled for a
+pattern with PCRE2_UCP set without PCRE2_UTF if a class required all wide
+characters to match (for example, /[\s[:^ascii:]]/).
+
 
 Version 10.22 29-July-2016
 --------------------------
diff --git a/src/pcre2_compile.c b/src/pcre2_compile.c
index 9dc9c98..fce226b 100644
--- a/src/pcre2_compile.c
+++ b/src/pcre2_compile.c
@@ -4927,9 +4927,13 @@ for (;; pptr++)
           automatically handled by the use of OP_CLASS or OP_NCLASS, but an
           explicit range is needed for OP_XCLASS. Setting a flag here
           causes the range to be generated later when it is known that
-          OP_XCLASS is required. */
+          OP_XCLASS is required. In the 8-bit library this is relevant only in 
+          utf mode, since no wide characters can exist otherwise. */
 
           default:
+#if PCRE2_CODE_UNIT_WIDTH == 8
+          if (utf)
+#endif 
           match_all_or_no_wide_chars |= local_negate;
           break;
           }
@@ -5217,6 +5221,8 @@ for (;; pptr++)
     all wide characters (depending on whether the whole class is or is not
     negated). This requirement is indicated by match_all_or_no_wide_chars being
     true. We do this by including an explicit range, which works in both cases.
+    This applies only in UTF and 16-bit and 32-bit non-UTF modes, since there
+    cannot be any wide characters in 8-bit non-UTF mode.
 
     When there *are* properties in a positive UTF-8 or any 16-bit or 32_bit
     class where \S etc is present without PCRE2_UCP, causing an extended class
diff --git a/testdata/testinput10 b/testdata/testinput10
index a1806ae..85d2005 100644
--- a/testdata/testinput10
+++ b/testdata/testinput10
@@ -456,4 +456,6 @@
 
 /(*:*++++++++++++''''''''''''''''''''+''+++'+++x+++++++++++++++++++++++++++++++++++(++++++++++++++++++++:++++++%++:''''''''''''''''''''''''+++++++++++++++++++++++++++++++++++++++++++++++++++++-++++++++k+++++++''''+++'+++++++++++++++++++++++''''++++++++++++':ƿ)/utf
 
+/[\s[:^ascii:]]/B,ucp
+
 # End of testinput10
diff --git a/testdata/testinput12 b/testdata/testinput12
index 5b29f41..c3b2bfc 100644
--- a/testdata/testinput12
+++ b/testdata/testinput12
@@ -358,4 +358,6 @@
 \= Expect no match
     123     
 
+/[\s[:^ascii:]]/B,ucp
+
 # End of testinput12
diff --git a/testdata/testoutput10 b/testdata/testoutput10
index 3c35f0b..31b7d00 100644
--- a/testdata/testoutput10
+++ b/testdata/testoutput10
@@ -1567,4 +1567,12 @@ No match
 /(*:*++++++++++++''''''''''''''''''''+''+++'+++x+++++++++++++++++++++++++++++++++++(++++++++++++++++++++:++++++%++:''''''''''''''''''''''''+++++++++++++++++++++++++++++++++++++++++++++++++++++-++++++++k+++++++''''+++'+++++++++++++++++++++++''''++++++++++++':ƿ)/utf
 Failed: error 176 at offset 259: name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN)
 
+/[\s[:^ascii:]]/B,ucp
+------------------------------------------------------------------
+        Bra
+        [\x80-\xff\p{Xsp}]
+        Ket
+        End
+------------------------------------------------------------------
+
 # End of testinput10
diff --git a/testdata/testoutput12-16 b/testdata/testoutput12-16
index f0f2230..3b5a0cd 100644
--- a/testdata/testoutput12-16
+++ b/testdata/testoutput12-16
@@ -1407,4 +1407,12 @@ Subject length lower bound = 2
     123     
 No match
 
+/[\s[:^ascii:]]/B,ucp
+------------------------------------------------------------------
+        Bra
+        [\x80-\xff\p{Xsp}\x{100}-\x{ffff}]
+        Ket
+        End
+------------------------------------------------------------------
+
 # End of testinput12
diff --git a/testdata/testoutput12-32 b/testdata/testoutput12-32
index 3718b27..1496159 100644
--- a/testdata/testoutput12-32
+++ b/testdata/testoutput12-32
@@ -1401,4 +1401,12 @@ Failed: error -28: UTF-32 error: code points greater than 0x10ffff are not defin
     123     
 No match
 
+/[\s[:^ascii:]]/B,ucp
+------------------------------------------------------------------
+        Bra
+        [\x80-\xff\p{Xsp}\x{100}-\x{ffffffff}]
+        Ket
+        End
+------------------------------------------------------------------
+
 # End of testinput12