Loosen restriction on requiring return expressions when a throw is used instead #1042
Description
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.