Revert one optimization

IDisposable · IDisposable · commit c8c880158ca2 · 2023-07-29T02:16:27.000-05:00
Subtle bug in that the entire string is being placed in the set, not the span.
diff --git a/src/libraries/System.Collections.Immutable/src/System/Collections/Frozen/String/KeyAnalyzer.cs b/src/libraries/System.Collections.Immutable/src/System/Collections/Frozen/String/KeyAnalyzer.cs
@@ -109,7 +109,7 @@ private static AnalysisResults CreateAnalysisResults(
                 foreach (string s in uniqueStrings)
                 {
                     // Get the span for the substring.
-                    ReadOnlySpan<char> substring = s.AsSpan();
+                    ReadOnlySpan<char> substring = count == 0 ? s.AsSpan() : Slicer(s, index, count);
 
                     // If the substring isn't ASCII, bail out to return the results.
                     if (!IsAllAscii(substring))

Original file line number	Diff line number	Diff line change
`@@ -109,7 +109,7 @@ private static AnalysisResults CreateAnalysisResults(`
`109`	`109`	`foreach (string s in uniqueStrings)`
`110`	`110`	`{`
`111`	`111`	`// Get the span for the substring.`
`112`		`- ReadOnlySpan<char> substring = s.AsSpan();`
	`112`	`+ ReadOnlySpan<char> substring = count == 0 ? s.AsSpan() : Slicer(s, index, count);`
`113`	`113`
`114`	`114`	`// If the substring isn't ASCII, bail out to return the results.`
`115`	`115`	`if (!IsAllAscii(substring))`