On HEAD Rakudo, there are many warnings about a probable mis-use of contains #2
Description
They look like this:
Calling '.contains' on a Array[Java::Generate::Utils::Modifier], did you mean 'needle (elem) list'?
in method generate at /home/jnthn/dev/MoarVM/install/share/perl6/site/sources/27F248180A0A9997A8D087A4DF643A33103124C5 (Java::Generate::JavaMethod) line 43
Calling contains on an Array stringifies it and then looks within that, which can work, but is slow and risks false positives in general.