Why and where (which idioms) is this the case? Is this due to type erasure on generics or something else? I ask this as this is the sort of knowledge that remai

Why and where (which idioms) is this the case? Is this due to type erasure on generics or something else? I ask this as this is the sort of knowledge that remains implicit amongst the experienced. p.s. i'm new to scala (and using it on app engine and android) but have extensive F# and decent haskell and ocaml experience and have found stuff like hyperpolyglot useful but this type of knowledge is not readily found.