Applicative partial application of curried functions with named parameters causes type mismatch

Originator:gordon
Number:rdar://20727035 Date Originated:28-Apr-2015 10:53 AM
Status:Open Resolved:
Product:Developer Tools Product Version:Swift 1.2
Classification:Serious Bug Reproducible:Always
 
Summary:
Partially applying a curried function (using concepts from Haskell’s Applicative typeclass) results in a type mismatch when the curried function has named parameters.

Steps to Reproduce:
1. Open the attached playground

Expected Results:
`baz` should be able to apply `f` on line 34

Actual Results:
`f` has a named parameter, causing a type mismatch, and so can’t be applied.

Notes:
1. This happens for our custom types, as well as with `Array`. It _doesn’t_ happen with `Optional`, however.
2. Ignoring the external labels in the curried function causes the error to go away:

```
func curried(_ foo: String)(_ bar: String)(_ baz: String) -> String
```

Comments

Gist of the submitted playground: https://gist.github.com/gfontenot/ffced0f07c2ce1fc2a23

By gordon at April 28, 2015, 2:54 p.m. (reply...)

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