Opening this as @eladb has suggested it is a bug.

Currently the any type is being detected as optional, so a method signature like foo(myArg: any, otherArg: boolean) is detecting that myArg is optional. This (might?) extend to function signatures like foo(myArg?: boolean, otherArg: boolean).

Generally some languages (Python, .NET) can't support a mandatory parameter after an optional parameter has been emitted. So we need to make sure that:

(1) We're not erroneously detecting the any type as optional.
(2) We're not emitting mandatory parameters after optional parameters.