Use .TryGetSpan on sequences instead of type checks to forward sequence comparison for arrays and lists (#97004)

neon-sunset · web-flow · commit 957ab2f239fa · 2024-01-17T22:40:02.000-05:00
diff --git a/src/libraries/System.Linq/src/System/Linq/SequenceEqual.cs b/src/libraries/System.Linq/src/System/Linq/SequenceEqual.cs
@@ -24,9 +24,9 @@ public static bool SequenceEqual<TSource>(this IEnumerable<TSource> first, IEnum
 
             if (first is ICollection<TSource> firstCol && second is ICollection<TSource> secondCol)
             {
-                if (first is TSource[] firstArray && second is TSource[] secondArray)
+                if (first.TryGetSpan(out ReadOnlySpan<TSource> firstSpan) && second.TryGetSpan(out ReadOnlySpan<TSource> secondSpan))
                 {
-                    return ((ReadOnlySpan<TSource>)firstArray).SequenceEqual(secondArray, comparer);
+                    return firstSpan.SequenceEqual(secondSpan, comparer);
                 }
 
                 if (firstCol.Count != secondCol.Count)

Original file line number	Diff line number	Diff line change
`@@ -24,9 +24,9 @@ public static bool SequenceEqual<TSource>(this IEnumerable<TSource> first, IEnum`
`24`	`24`
`25`	`25`	`if (first is ICollection<TSource> firstCol && second is ICollection<TSource> secondCol)`
`26`	`26`	`{`
`27`		`- if (first is TSource[] firstArray && second is TSource[] secondArray)`
	`27`	`+ if (first.TryGetSpan(out ReadOnlySpan<TSource> firstSpan) && second.TryGetSpan(out ReadOnlySpan<TSource> secondSpan))`
`28`	`28`	`{`
`29`		`- return ((ReadOnlySpan<TSource>)firstArray).SequenceEqual(secondArray, comparer);`
	`29`	`+ return firstSpan.SequenceEqual(secondSpan, comparer);`
`30`	`30`	`}`
`31`	`31`
`32`	`32`	`if (firstCol.Count != secondCol.Count)`