[SR-6305] Cannot initialise Dictionary from an EnumeratedSequence

[karwa]

Previous ID	SR-6305
Radar	rdar://problem/37159993
Original Reporter	@karwa
Type	Bug

Environment

Apple Swift version 4.0.3 (swiftlang-900.0.71 clang-900.0.38)

Target: x86_64-apple-macosx10.9

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, TypeChecker
Assignee	@xedin
Priority	Medium

md5: a219796b79b304ec98d478ac6a4adc11

is duplicated by:

• SR-6905 Dictionary(uniqueKeysWithValues:) does not accept sequence of labeled tuples

Issue Description:

The following snippet fails to compile:

let test = Dictionary(uniqueKeysWithValues: ["a", "b", "c"].enumerated())

With the message:

Cannot invoke initializer for type 'Dictionary<_, _>' with an argument list of type '(uniqueKeysWithValues: EnumeratedSequence<[String]>)'

The only way I was able to get it to work was to add a pass-through call to "map" on the end:

let test = Dictionary(uniqueKeysWithValues: ["a", "b", "c"].enumerated().map { $0 })

[belkadan]

cc @xedin

[belkadan]

(thanks, Karl!)

[belkadan]

@swift-ci create

[swift-ci]

Comment by Manuel Martín Benítez (JIRA)

You are just passing a Sequence to the initializer with the keys, and it needs a sequence with key-value pairs.

let test = Dictionary(uniqueKeysWithValues: zip(["a", "b", "c"], [1, 2, 3]))