Respect custom parserClass in methodSelectorFor:

[krono]

currently, MCFileTreeStCypressReader>>methodSelectorFor: does not take into account that a Class can have a custom compiler or parser. This is not an issue on GemStone, but Squeak and Pharo.

In Squeak it looks like that:

methodSelectorFor: source
    ^ Object parserClass new parseSelector: source

I propose:

methodSelectorFor: source in: className
    | cls |
    cls := Smalltalk at: className ifAbsent: [Object].
    ^ cls parserClass new parseSelector: source