[asterite]

I can't seem to reply to your reply to this, but the error message has nothing to do with where a class is defined.

You can't compile a part of your application in crystal, there are no linked crystal libraries. You compile your whole app, will all class definitions. The compiler then will have all the type information to know if a method is missing in a subclass, when that method is used from a parent class.

[catnaroek]

Well, that's even worse. Whole-program compilation has positive aspects to it, like enabling more aggressive optimizations, but it should be strictly opt-in.

For future reference: The easiest way to reply to a message that doesn't have a “reply” link below, is to click on the “X minutes ago” link above.

[asterite]

Thank you! I didn't know that easy way to reply.

The compiler does some incremental compilation for the generated object files, so compile times are kept relatively small. Other than that, I don't think it makes a big difference for a developer except saving compile times. On the other hand, in this way you can't have a compiled library conflict so you have to "clean and rebuild" when this happens.

For example in Ruby there's no such thing as pre-compiling a gem, and every time you run an app the whole app is "analyzed" (parsed and converted to VM instructions), and so you can think in Crystal it's the same (except that it's compiled to native code)

[catnaroek]

Incremental compilation isn't a good alternative to actually separate compilation. If I implement a module Foo that depends on another module Bar, the only information I need is the interface Bar exposes, so I shouldn't have to wait until Bar is actually implemented to begin implementing Foo.