Issue To Be Solved

We currently determine if a failable cast can succeed (in sema.FailableCastCanSucceed), and report an error it can never succeed.

Extend this check to also handle primitive types, e.g. the following examples should be static errors:

let s = ""
let i = s as! Int

struct S {}
let s = S()
let i = s as! Int

Suggested Solution

• Extend sema.FailableCastCanSucceed
• Tests