Loosen restriction on requiring return expressions when a throw is used instead

[danquirk]

Per #947, we currently require a return expression in a non-void returning function unless the first and only expression is a throw statement. This is basically an exemption to allow for throw new Exception('Not Yet Implemented'). It seems reasonable to allow throwing further along in a block if we're willing to try to track control flow, at which point we could likely also check for appropriate return expressions from all branches.

[vladima]

I have a branch with an implementation of simple control flow analysis that captures cases like this atop of new compiler. It is slightly out of date but I think it'll take less than a day to sync it

[RyanCavanaugh]

We should treat throw as equivalent to return for the purposes of this check

[Ptival]

Any update on this? I often use throw ...; and debugger; to close branches that should not happen and have no meaningful return values.

[RyanCavanaugh]

The new control analysis work should make this issue obsolete. Have you tried typescript@next ?

[Ptival]

No, I'm stuck on the npmjs version. (1.8.10?)

Good to know then! :-)

[NaridaL]

@RyanCavanaugh I think this can be closed?

[RyanCavanaugh]

Agree, thanks!