Simplify SelectArrayIterator method (#85695)

stephentoub · web-flow · commit caaab8a30583 · 2023-05-03T13:51:32.000-07:00
diff --git a/src/libraries/System.Linq/src/System/Linq/Select.cs b/src/libraries/System.Linq/src/System/Linq/Select.cs
@@ -178,15 +178,17 @@ public SelectArrayIterator(TSource[] source, Func<TSource, TResult> selector)
 
             public override bool MoveNext()
             {
-                if (_state < 1 | _state == _source.Length + 1)
+                TSource[] source = _source;
+                int index = _state - 1;
+                if ((uint)index < (uint)source.Length)
                 {
-                    Dispose();
-                    return false;
+                    _state++;
+                    _current = _selector(source[index]);
+                    return true;
                 }
 
-                int index = _state++ - 1;
-                _current = _selector(_source[index]);
-                return true;
+                Dispose();
+                return false;
             }
 
             public override IEnumerable<TResult2> Select<TResult2>(Func<TResult, TResult2> selector) =>

Original file line number	Diff line number	Diff line change
`@@ -178,15 +178,17 @@ public SelectArrayIterator(TSource[] source, Func<TSource, TResult> selector)`
`178`	`178`
`179`	`179`	`public override bool MoveNext()`
`180`	`180`	`{`
`181`		`- if (_state < 1 \| _state == _source.Length + 1)`
	`181`	`+ TSource[] source = _source;`
	`182`	`+ int index = _state - 1;`
	`183`	`+ if ((uint)index < (uint)source.Length)`
`182`	`184`	`{`
`183`		`- Dispose();`
`184`		`- return false;`
	`185`	`+ _state++;`
	`186`	`+ _current = _selector(source[index]);`
	`187`	`+ return true;`
`185`	`188`	`}`
`186`	`189`
`187`		`- int index = _state++ - 1;`
`188`		`- _current = _selector(_source[index]);`
`189`		`- return true;`
	`190`	`+ Dispose();`
	`191`	`+ return false;`
`190`	`192`	`}`
`191`	`193`
`192`	`194`	`public override IEnumerable<TResult2> Select<TResult2>(Func<TResult, TResult2> selector) =>`