# Pastebin J2IFVG2m
 Cool.pm
-    proto method index(|) {*}
-    multi method index(Cool:D: Str(Cool) $needle) {
-        self.Str.index($needle)
-    }
-    multi method index(Cool:D: Str(Cool) $needle, Int(Cool) $pos) {
-        self.Str.index($needle,$pos)
+    method index(Cool:D: |c) {
+        self.Str.index(|c)

Str.pm

-    multi method index(Str:D: Str:D $needle) {
+    proto method index(|) {*}
+    multi method index(Str:D: Str(Cool:D) $needle) {
         nqp::if(
           nqp::islt_i((my int $i =
             nqp::index($!value,nqp::getattr($needle,Str,'$!value'))),
@@ -229,7 +235,7 @@ my class Str does Stringy { # declared in BOOTSTRAP
           nqp::p6box_i($i)
         )
     }
-    multi method index(Str:D: Str:D $needle, Int:D $pos) {
+    multi method index(Str:D: Str(Cool:D) $needle, Int:D $pos) {
         nqp::if(
           nqp::isbig_I(nqp::decont($pos)),
           Failure.new(X::OutOfRange.new(
@@ -255,6 +261,7 @@ my class Str does Stringy { # declared in BOOTSTRAP
         )
     }