Test chaining of !before/!after

RT#125575: https://rt.perl.org/Ticket/Display.html?id=125575

Includes fudges for mixed combinations, pending resolution of
R#1304: rakudo/rakudo#1304

S03-metaops/not.t

@@ -1,7 +1,7 @@
 use v6;
 use Test;
 
-plan 46;
+plan 47;
 
 =begin pod
 
@@ -71,4 +71,27 @@ is &infix:<![!%%]>(3,2), False, "Meta not can autogen (![!%%])";
 is infix:<!===>(1,2), True, "Meta not can autogen (!===) without &";
 is &[!===](1,2), True, "Meta not can autogen (!===) with &[]";
 
+# RT #125575
+subtest 'chaining of !before/!after' => {
+    plan 12;
+
+    is-deeply ("a" !after  "b" !after  "c"), True,  '!after/!after (Str)';
+    is-deeply ("a" !before "b" !before "c"), False, '!before/!before (Str)';
+
+    #?rakudo 4 skip 'Should this work? https://github.com/rakudo/rakudo/issues/1304'
+    is-deeply ("a" !before "b" !after  "c"), False, '!before/!after (Str) (1)';
+    is-deeply ("a" !after  "b" !before "c"), False, '!after/!before (Str) (1)';
+    is-deeply ("c" !before "a" !after  "b"), True,  '!before/!after (Str) (2)';
+    is-deeply ("a" !after  "c" !before "b"), False, '!after/!before (Str) (2)';
+
+    is-deeply (1 !after  2 !after  3), True,  '!after/!after (Int)';
+    is-deeply (1 !before 2 !before 3), False, '!before/!before (Int)';
+
+    #?rakudo 4 skip 'Should this work? https://github.com/rakudo/rakudo/issues/1304'
+    is-deeply (1 !before 2 !after  3), False, '!before/!after (Int) (1)';
+    is-deeply (1 !after  2 !before 3), False, '!after/!before (Int) (1)';
+    is-deeply (3 !before 1 !after  2), True,  '!before/!after (Int) (2)';
+    is-deeply (1 !after  3 !before 2), False, '!after/!before (Int) (2)';
+}
+
 # vim: ft=perl6