let! doesn't infer return types

[andriusch]

require "spectator"

def four
  2 + 2
end

Spectator.describe Int32 do
  let!(:x) { four }
  it("returns 4") { expect(x).to eq(4) }
end

Does not compile because crystal can't infer what type four returns. Strangely though if I replace let! with let it works fine and passes as it should. While I get why it doesn't compile with naive implementation of let!, you seem to have solved it with let, so it would be nice if it worked with let! too.

[icy-arctic-fox]

Yeah, sadly this fails because Crystal doesn't allow the following:

def four
  2 + 2
end

class Foo
  @var = four
end

There's actually a TODO in the code where this is a problem. I'll see what I can do to work around it.

[icy-arctic-fox]

Didn't mean to close this, but can you confirm that this is fixed in the latest version on master (0.9.2)? The code in your example works now. Hopefully that fixes any other issues with it that are non-trivial.

[andriusch]

Yup it works now, very interesting way to bypass restrictions of crystal 🙂