Report an error if a class is inherited from before it is defined

[bsr203]

Hello,

I am having the same issue, which had lot of activity on codeplex.
https://typescript.codeplex.com/workitem/627

class A extends B {
  // ...
}

class B {
  // ...
}

Compiles without error but obviously fails at runtime.

[danquirk]

Edited the original issue for clarity. We've had this request for awhile but have generally avoided trying to handle ordering issues, instead leaving it up to the user because in the general case we can't really give you all the errors you'd want. We would need a more structured look at the various use cases and how we might give an error in some or all of them.

[mhegazy]

more details can be found at: #21

[RyanCavanaugh]

We do this now