Coerce numeric types

[trans]

Take simple example:

def fib(n : Int64)
  ...
end
puts fib(42) 

Produces the error:

Error in ./ex.cr:11: no overload matches 'fib' with type Int32
Overloads are:
 - fib(n : Int64)

puts fib(42)
     ^~~

It must be possible for Crystal to coerce 42 into Int64 in cases like this. The error message makes it clear it knows what's up. Basically any IntX passed to an IntY parameter where X < Y, should be coercible by the compiler.

It would nice b/c it would let us remove a fair but of extra boilerplate in the form of _i64, and the like.

Although perhaps there is better/more appropriate way to remedy this?

[ozra]

Reads of interest: #567, #2995, #1778, etc.

[ysbaddaden]

Duplicate of #2995.

[refi64]

@trans Hey, you're back!

[trans]

@kirbyfan64 Hi! Yep, I've been heehawing about what new language to adopt for awhile. I narrowed it down just the other day when I decided I wanted a compiled language, nothing dynamic and no runtime VMs. That helped eliminated a few (otherwise good) choices like Clojure and Elixir, and left me with basically five options: Go, Rust, Julia, Swift and Crystal. The first two I decided are at a level a bit lower than I want to be working. For the moment Julia and Swift are still on my radar, but I need to get a project moving and I can leverage my Ruby skills, so Crystal.

P.S. Holy smokes, talk about serendipity. The project I just started working on (with Crystal) is a site/blog generator. One of the options I was thinking of adding was dynamic page generation from JSON (as an alternative to full static generation). Well bite my code, I just checked out your blog and the first post I see explains how that's exactly what you are doing!!!!!!!!! Hot damn. Could I get access to your source so I can use it in my project? With any luck that'll save me a lot of time. And in exchange I'll fix your RSS problem :-)

[refi64]

@trans

For the moment Julia and Swift are still on my radar

Uhh...doesn't Julia use a runtime VM?

P.S. Holy smokes, talk about serendipity. ...

:D FYI, we might want to discuss this off the issue tracker...

And in exchange I'll fix your RSS problem :-)

Wow, I just have to see this.

[trans]

Okay, email me (my address is listed on my github profile. I couldn't find yours.) I'm busy the rest of this week but should have time next week. And, oh yea, https://github.com/trans/brite.cr