Louis-Vincent

This PR introduces callref without receiver. Here's an example : ~~~nit import functional class A var x: Int fun toto: Int do return x + 1 end var a =...

Here's the minimal code to reproduce the error : ~~~~nit class A var x: Int end class B var a: nullable A = null end var b = new B...

Here's the use case when compiling with `--global`: ``` class C[E] var x: E redef fun to_s do if x != null then return "x is {x.as(not null)}" end return...