React to compiler and ref readonly changes

Author: MihaZupan

src/libraries/System.Private.CoreLib/src/System/SearchValues/Strings/Helpers/AhoCorasick.cs

@@ -101,7 +101,7 @@ private readonly int IndexOfAnyCore<TCaseSensitivity, TFastScanVariant>(ReadOnly
                     int offset = IndexOfAnyAsciiSearcher.IndexOfAnyVectorized<IndexOfAnyAsciiSearcher.DontNegate, IndexOfAnyAsciiSearcher.Default>(
                         ref Unsafe.As<char, short>(ref Unsafe.Add(ref MemoryMarshal.GetReference(span), i)),
                         remainingLength,
-                        ref Unsafe.AsRef(_startingCharsAsciiBitmap));
+                        ref Unsafe.AsRef(in _startingCharsAsciiBitmap));
 
                     if (offset < 0)
                     {
@@ -210,7 +210,7 @@ private readonly int IndexOfAnyCaseInsensitiveUnicode<TFastScanVariant>(ReadOnly
                     int offset = IndexOfAnyAsciiSearcher.IndexOfAnyVectorized<IndexOfAnyAsciiSearcher.DontNegate, IndexOfAnyAsciiSearcher.Default>(
                         ref Unsafe.As<char, short>(ref Unsafe.Add(ref MemoryMarshal.GetReference(span), i)),
                         remainingLength,
-                        ref Unsafe.AsRef(_startingCharsAsciiBitmap));
+                        ref Unsafe.AsRef(in _startingCharsAsciiBitmap));
 
                     if (offset < 0)
                     {

src/libraries/System.Private.CoreLib/src/System/SearchValues/Strings/Helpers/EightPackedReferences.cs

@@ -7,10 +7,10 @@
 namespace System.Buffers
 {
     [InlineArray(8)]
-    internal readonly struct EightPackedReferences
+    internal struct EightPackedReferences
     {
 #pragma warning disable CA1823 // Unused field -- https://github.com/dotnet/roslyn-analyzers/issues/6788
-        private readonly object? _ref0;
+        private object? _ref0;
 #pragma warning restore CA1823
 
         public EightPackedReferences(ReadOnlySpan<object> values)

src/libraries/System.Private.CoreLib/src/System/SearchValues/Strings/StringSearchValues.cs

@@ -34,7 +34,7 @@ public static SearchValues<string> Create(ReadOnlySpan<string> values, bool igno
                 ArgumentNullException.ThrowIfNull(value, nameof(values));
                 string normalizedValue = NormalizeIfNeeded(value, ignoreCase);
 
-                AnalyzeValues(new ReadOnlySpan<string>(normalizedValue), ref ignoreCase, out bool ascii, out bool asciiLettersOnly, out _, out _);
+                AnalyzeValues(new ReadOnlySpan<string>(ref normalizedValue), ref ignoreCase, out bool ascii, out bool asciiLettersOnly, out _, out _);
                 return CreateForSingleValue(normalizedValue, uniqueValues: null, ignoreCase, ascii, asciiLettersOnly);
             }