[stdlib] CollectionOfOne.subscript: Replace setter with _modify

lorentey · lorentey · commit aedf2b91ad1e · 2018-10-19T11:32:43.000+01:00
diff --git a/stdlib/public/core/CollectionOfOne.swift b/stdlib/public/core/CollectionOfOne.swift
@@ -131,9 +131,9 @@ extension CollectionOfOne: RandomAccessCollection, MutableCollection {
       _precondition(position == 0, "Index out of range")
       return _element
     }
-    set {
+    _modify {
       _precondition(position == 0, "Index out of range")
-      _element = newValue
+      yield &_element
     }
   }
 

Original file line number	Diff line number	Diff line change
`@@ -131,9 +131,9 @@ extension CollectionOfOne: RandomAccessCollection, MutableCollection {`
`131`	`131`	`_precondition(position == 0, "Index out of range")`
`132`	`132`	`return _element`
`133`	`133`	`}`
`134`		`- set {`
	`134`	`+ _modify {`
`135`	`135`	`_precondition(position == 0, "Index out of range")`
`136`		`- _element = newValue`
	`136`	`+ yield &_element`
`137`	`137`	`}`
`138`	`138`	`}`
`139`	`139`