#1676 compiler: Non-nullable field 'mytext' must be assigned in constructor 'make' fault

jessevdam Tue 25 Oct 2011

When I have the following code

using fwt

class Test : EdgePane
  private Text mytext

  new make()
    center = EdgePane
      it.center = mytext = Text
        it.text = "hallo world"

It gives an compile error Non-nullable field mytext must be assigned in constructor make. While it is assigned in the constructor, it seems the compiler does not look inside the it blocks for initializations

brian Tue 25 Oct 2011

Promoted to ticket #1676 and assigned to brian

Looks like a hole in the definite assignment checks. Good timing because I also detected this other definite assignment bug:

if (days <= 1)       interval = 1min
else if (days <= 8)  interval = 10min
else if (days <= 32) interval = 1hr
else throw ArgErr()

brian Mon 14 Nov 2011

Ticket resolved in 1.0.61

I fixed a bunch of issues related to definite assignment checks.

If you assign a non-nullable field in a closure, then the compiler no longer reports an error. However, we don't actually have any guarantee that the closure will be run, so we still generate a runtime check. For example:

class Foo
  new make(Bool c) 
    f := |->| { x = "ok" }
    if (c) f() 
  Str x

This code above will now compile (previously would have given you a compiler error). However if you try to run Foo(false), then it will correctly raise a FieldNotSetErr.

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