Try/finally not counted as definite assignment

[floitsch]

The following program yields an error:

class A:
  foo/int

  constructor:
    try:
      foo = 499
    finally:
      print "done"

ᐅ toit analyze /tmp/t.toit
/tmp/t.toit:4:3: error: Field 'foo' not initialized on all paths in constructor
  constructor:
  ^~~~~~~~~~~

[kasperl]

I guess you have to be a little bit careful with ways to get out of the finally block without unwinding, thus continuing to construct the object without necessarily having run through the entire try block.

class A:
  foo/int
  constructor:
    while true:
      woops := : break
      try:
        [0,1,2][3]
        foo = 87
      finally:
        woops.call

[floitsch]

Agreed.
For field-initialization that's fortunately not a problem. If we exit the constructor without an exception, then we must have gone through all statements in the try-block. And the finally doesn't have a way to change an exception into a "normal" return, as that would change the constructor into a factory.

[kasperl]

Have you tried to run my example? It does not throw an exception, constructs the objects, and does not set the field to 87. You may need to set the field to something before the try-block to work around the compiler error.

[floitsch]

Have you tried to run my example?

Not correctly :)