Test all regex blocks update $/

RT#126249: https://rt.perl.org/Public/Bug/Display.html?id=126249

S05-match/positions.t

@@ -8,7 +8,7 @@ version 0.3 (12 Apr 2004), file t/pos.t.
 
 =end pod
 
-plan 12;
+plan 13;
 
 my $str = "abrAcadAbbra";
 
@@ -33,4 +33,17 @@ is ('abc' ~~ /\d+/), Nil, 'Failed match returns Nil';
     is-deeply $/.to,   6, 'List.to';
 }
 
+# RT #126249
+subtest '$/ is constructed in all blocks inside regexes' => {
+    plan 2;
+    my @res;
+    my token foo {
+            { @res.push: $/.to }
+        abc { @res.push: $/.to }
+        123 { @res.push: $/.to }
+    };
+    ok "abc123" ~~ /<foo>/, 'regex matched';
+    is-deeply @res, [0, 3, 6], 'blocks returned correct $/.to values';
+}
+
 # vim: ft=perl6