Support union types in the typechecker

[polybuildr]

Instead of falling back to plain old Any, the typechecker should support union types in cases where inference cannot settle on just one type (and in the future when explicit type annotations are supported).

Therefore, in cases like:

var x = 5;
if foo {
    x = true;
}

The typechecker should not give up and use Any, but instead have a Number | Bool type. This might need to happen after #26.

[bollu]

This can lead to exponential blowup. Also, I think you need to be somewhat careful and handle things like recursion carefully.

On Sat 10 Jun, 2017, 21:38 Vivek Ghaisas, ***@***.***> wrote: Instead of falling back to plain old Any, the typechecker should support union types in cases where inference cannot settle on just one type (and in the future when explicit type annotations are supported). Therefore, in cases like: var x = 5; if foo { x = true; } The typechecker should not give up and use Any, but instead have a Number | Bool type. This might need to happen after #26 <#26>. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#44>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABncjTs-RqlcEGNf-_IQPxdvE1KxdHNzks5sCvClgaJpZM4N2NAA> .

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