[swift-dev] Help with SR-1052: Handling generic return values

Trent Nadeau tanadeau at gmail.com
Fri Apr 22 17:43:27 CDT 2016

Could someone who knows the generics system better than I give me a pointer
for my question in https://bugs.swift.org/browse/SR-1052 (support for
@discardableResult attribute)?


I'm starting to look at Part 5 (having the compiler use the new attr). What
I have so far appears to be working with the exception of signatures like

public mutating func withMutableCharacters<R>(_ body: (inout CharacterView)
-> R) -> R

where the return type is generic.

For regular functions, I can skip the warning if the result type in the
decl is Void.

Any ideas on how to tell if a call to a generic function like
withMutableCharacters has a return type of Void in context?

My branch with the work for Part 5 so far is at

Trent Nadeau
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