[stdlib] Small correction to UTF8 Iterator

Dave Abrahams · Dave Abrahams · commit dd3fb9b71dbc · 2017-07-07T06:15:25.000-07:00
This works either way I suppose, but the code is clearer now.
diff --git a/stdlib/public/core/StringUTF8.swift b/stdlib/public/core/StringUTF8.swift
@@ -455,7 +455,7 @@ extension String.UTF8View.Iterator : IteratorProtocol {
     while _sourceIndex != _source.endIndex && shift < _OutputBuffer.bitWidth {
       let u = _source[_sourceIndex]
       if u >= 0x80 { break }
-      _buffer |= _OutputBuffer(u &+ 1) &<< shift
+      _buffer |= _OutputBuffer(UInt8(extendingOrTruncating: u &+ 1)) &<< shift
       _sourceIndex += 1
       shift = shift &+ 8
     }

Original file line number	Diff line number	Diff line change
`@@ -455,7 +455,7 @@ extension String.UTF8View.Iterator : IteratorProtocol {`
`455`	`455`	`while _sourceIndex != _source.endIndex && shift < _OutputBuffer.bitWidth {`
`456`	`456`	`let u = _source[_sourceIndex]`
`457`	`457`	`if u >= 0x80 { break }`
`458`		`- _buffer \|= _OutputBuffer(u &+ 1) &<< shift`
	`458`	`+ _buffer \|= _OutputBuffer(UInt8(extendingOrTruncating: u &+ 1)) &<< shift`
`459`	`459`	`_sourceIndex += 1`
`460`	`460`	`shift = shift &+ 8`
`461`	`461`	`}`