Generic function signatures are not differentiated on their ability to throw

Number:rdar://23147654 Date Originated:16-Oct-2015 11:52 AM
Status:Open Resolved:
Product:Developer Tools Product Version:Swift 2.0
Classification:UI/Usability Reproducible:Always

Generic functions that return type `T` or `T?` are not differentiated by
the compiler based on their ability to `throws`. Meaning that if you
have a function that does not throw and returns `T?`, and a function
with the same signature that throws and returns type `T`, you get a
ambiguous function error.

Steps to reproduce:

1. Create a function that returns `T` and throws
2. Create a function that returns `T?` and doesn't throw
3. Attempt to call the function that returns `T?` and assign it to an
   optional `T`


1. See the attached playground

Expected results:

The ability to throw should be take into account to choose which
function to call.

Actual results:

The compiler produces an "Ambiguous use of X()" error.


By keithbsmiley at Oct. 16, 2015, 6:54 p.m. (reply...)

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