Esteban Küber c6c243ae1e Move check only relevant in error case out of critical path
Move the check for potentially forgotten `return` in a tail expression
of arbitrary expressions into the coercion error branch to avoid
computing unncessary coercion checks on successful code.

Follow up to .
2021-03-03 18:28:53 -08:00
..

For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.