Open Radar

 
Summary:
When calling a rethrowing function with an inline closure, it always assumes that the closure can throw.

Steps to Reproduce:
1. Create a method that takes in a closure and rethrows any errors from that closure.
2. Call that method with a simple inline closure that does not throw any errors.

Expected Results:
The code should compile and not require any error handling.

Actual Results:
The compiler requires that the call to the rethrowing method be enclosed in a do-catch block, or that the impossible errors be handled in some other way.

Regression:

Notes:
This only seems to affect inline closures. If you take the same closure code and store it in a local variable, and then pass that variable to the rethrowing function, it correctly determines that the call cannot throw.
I’ve attached a project that demonstrates the issue.