Fix for older julias

src/piracy.jl

@@ -1,5 +1,7 @@
 module Piracy
 
+using ..Aqua: is_kwcall
+
 if VERSION >= v"1.6-"
     using Test: is_in_mods
 else
@@ -163,7 +165,7 @@ function is_pirate(meth::Method; treat_as_own = Union{Function,Type}[])
     signature = Base.unwrap_unionall(meth.sig)
 
     function_type_index = 1
-    if signature.parameters[1] === typeof(Core.kwcall)
+    if is_kwcall(signature)
         # kwcall is a special case, since it is not a real function
         # but a wrapper around a function, the third parameter is the original
         # function, its positional arguments follow.

src/utils.jl

@@ -157,3 +157,22 @@ function format_diff(
     $text_b
     """
 end
+
+function is_kwcall(signature::DataType)
+    @static if VERSION < v"1.9"
+        try
+            return length(signature.parameters) >= 3 &&
+                   signature <: Tuple{Function,Any,Any,Vararg} &&
+                   (
+                       signature.parameters[3] <: Type ||
+                       isconcretetype(signature.parameters[3])
+                   ) &&
+                   signature.parameters[1] === Core.kwftype(signature.parameters[3])
+        catch err
+            @warn "Please open an issue on JuliaTesting/Aqua.jl for \"is_kwcall\" and the following data:" signature err
+            return false
+        end
+    else
+        return signature.parameters[1] === typeof(Core.kwcall)
+    end
+end