Fix getobj

src/ambiguities.jl

@@ -150,7 +150,7 @@ struct _NoValue end
 # FIXME: This does not support non-singleton callables.
 function getobj(m::Method)
     ty = try
-        Base.tuple_type_head(m.sig)
+        fieldtype(m.sig, 1)
     catch err
         @error(
             "Failed to obtain a function from `Method`.",
@@ -160,6 +160,7 @@ function getobj(m::Method)
         # too much compared to what it is now.  So, bailing out.
         return _NoValue()
     end
+    ty = Base.unwrap_unionall(ty)
     try
         return ty.instance  # this should work for singletons (e.g., functions)
     catch

src/piracy.jl

@@ -144,10 +144,7 @@ end
 function is_pirate(meth::Method)
     method_pkg = Base.PkgId(meth.module)
 
-    signature = meth.sig
-    while signature isa UnionAll
-        signature = signature.body
-    end
+    signature = Base.unwrap_unionall(meth.sig)
 
     # the first parameter in the signature is the function type, and it
     # follows slightly other rules if it happens to be a Union type