diff --git a/eng/Version.Details.xml b/eng/Version.Details.xml
index 44f37abdef19e..1e7bb566644a4 100644
--- a/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@ -380,17 +380,17 @@
       <Uri>https://github.com/dotnet/runtime-assets</Uri>
       <Sha>8254bfd574d0f7a89450a2e191d9e9f3dfb8ad59</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Net.Compilers.Toolset" Version="4.12.0-3.24523.10">
+    <Dependency Name="Microsoft.Net.Compilers.Toolset" Version="4.13.0-2.24531.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>16f58fa314e7deff4b3df36c862f157609ace2b4</Sha>
+      <Sha>9bb57bf3b4a88a3d3c1fabb95e7b34d03da1478c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis" Version="4.12.0-3.24523.10">
+    <Dependency Name="Microsoft.CodeAnalysis" Version="4.13.0-2.24531.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>16f58fa314e7deff4b3df36c862f157609ace2b4</Sha>
+      <Sha>9bb57bf3b4a88a3d3c1fabb95e7b34d03da1478c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.CSharp" Version="4.12.0-3.24523.10">
+    <Dependency Name="Microsoft.CodeAnalysis.CSharp" Version="4.13.0-2.24531.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>16f58fa314e7deff4b3df36c862f157609ace2b4</Sha>
+      <Sha>9bb57bf3b4a88a3d3c1fabb95e7b34d03da1478c</Sha>
     </Dependency>
     <Dependency Name="Microsoft.CodeAnalysis.Analyzers" Version="3.12.0-beta1.24516.1">
       <Uri>https://github.com/dotnet/roslyn-analyzers</Uri>
@@ -401,9 +401,9 @@
       <Sha>5dd0dd5db8fa79932517f153854c0f2c24ac98a3</Sha>
     </Dependency>
     <!-- Intermediate is necessary for source build. -->
-    <Dependency Name="Microsoft.SourceBuild.Intermediate.roslyn" Version="4.12.0-3.24523.10">
+    <Dependency Name="Microsoft.SourceBuild.Intermediate.roslyn" Version="4.13.0-2.24531.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>16f58fa314e7deff4b3df36c862f157609ace2b4</Sha>
+      <Sha>9bb57bf3b4a88a3d3c1fabb95e7b34d03da1478c</Sha>
       <SourceBuild RepoName="roslyn" ManagedOnly="true" />
     </Dependency>
     <Dependency Name="Microsoft.DotNet.ApiCompat.Task" Version="10.0.100-alpha.1.24480.5">
diff --git a/eng/Versions.props b/eng/Versions.props
index 54de087efb0f8..13213e9787df8 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -43,9 +43,9 @@
       Any tools that contribute to the design-time experience should use the MicrosoftCodeAnalysisVersion_LatestVS property above to ensure
       they do not break the local dev experience.
     -->
-    <MicrosoftCodeAnalysisCSharpVersion>4.12.0-3.24523.10</MicrosoftCodeAnalysisCSharpVersion>
-    <MicrosoftCodeAnalysisVersion>4.12.0-3.24523.10</MicrosoftCodeAnalysisVersion>
-    <MicrosoftNetCompilersToolsetVersion>4.12.0-3.24523.10</MicrosoftNetCompilersToolsetVersion>
+    <MicrosoftCodeAnalysisCSharpVersion>4.13.0-2.24531.4</MicrosoftCodeAnalysisCSharpVersion>
+    <MicrosoftCodeAnalysisVersion>4.13.0-2.24531.4</MicrosoftCodeAnalysisVersion>
+    <MicrosoftNetCompilersToolsetVersion>4.13.0-2.24531.4</MicrosoftNetCompilersToolsetVersion>
   </PropertyGroup>
   <!--
     For source generator support we need to target multiple versions of Roslyn in order to be able to run on older versions of Roslyn.
diff --git a/src/coreclr/tools/aot/ILCompiler.Trimming.Tests/TestCasesRunner/AssemblyChecker.cs b/src/coreclr/tools/aot/ILCompiler.Trimming.Tests/TestCasesRunner/AssemblyChecker.cs
index bbe9184c4d781..c62434f172dd2 100644
--- a/src/coreclr/tools/aot/ILCompiler.Trimming.Tests/TestCasesRunner/AssemblyChecker.cs
+++ b/src/coreclr/tools/aot/ILCompiler.Trimming.Tests/TestCasesRunner/AssemblyChecker.cs
@@ -977,7 +977,7 @@ private IEnumerable<string> VerifyReferences (AssemblyDefinition original, Assem
 				.Select (name => name.Name)
 				.ToArray ();
 
-			if (!actual.SequenceEqual(expected))
+			if (!actual!.SequenceEqual(expected))
 				yield return $"Expected references do not match actual references:\n\tExpected: {string.Join(", ", expected)}\n\tActual: {string.Join(", ", actual)}";
 		}
 
diff --git a/src/libraries/Microsoft.Extensions.DependencyInjection.Specification.Tests/src/DependencyInjectionSpecificationTests.cs b/src/libraries/Microsoft.Extensions.DependencyInjection.Specification.Tests/src/DependencyInjectionSpecificationTests.cs
index dd910d35e102e..46381662e03d0 100644
--- a/src/libraries/Microsoft.Extensions.DependencyInjection.Specification.Tests/src/DependencyInjectionSpecificationTests.cs
+++ b/src/libraries/Microsoft.Extensions.DependencyInjection.Specification.Tests/src/DependencyInjectionSpecificationTests.cs
@@ -900,7 +900,7 @@ public void DisposesInReverseOrderOfCreation()
 
             // Assert
             Assert.Equal(outer, callback.Disposed[0]);
-            Assert.Equal(multipleServices.Reverse(), callback.Disposed.Skip(1).Take(3).OfType<IFakeMultipleService>());
+            Assert.Equal(Enumerable.Reverse(multipleServices), callback.Disposed.Skip(1).Take(3).OfType<IFakeMultipleService>());
             Assert.Equal(outer.SingleService, callback.Disposed[4]);
         }
 
diff --git a/src/libraries/Microsoft.Extensions.Primitives/tests/StringValuesTests.cs b/src/libraries/Microsoft.Extensions.Primitives/tests/StringValuesTests.cs
index 5a0a0719ccc57..6cb9cb3c80849 100644
--- a/src/libraries/Microsoft.Extensions.Primitives/tests/StringValuesTests.cs
+++ b/src/libraries/Microsoft.Extensions.Primitives/tests/StringValuesTests.cs
@@ -453,19 +453,19 @@ public void DefaultNullOrEmpty_Concat(StringValues stringValues)
         {
             string[] expected = new[] { "abc", "bcd", "foo" };
             StringValues expectedStringValues = new StringValues(expected);
-            Assert.Equal(expected, StringValues.Concat(stringValues, expectedStringValues));
-            Assert.Equal(expected, StringValues.Concat(expectedStringValues, stringValues));
-            Assert.Equal(expected, StringValues.Concat((string)null, in expectedStringValues));
-            Assert.Equal(expected, StringValues.Concat(in expectedStringValues, (string)null));
+            Assert.Equal(expected, StringValues.Concat(stringValues, expectedStringValues).ToArray());
+            Assert.Equal(expected, StringValues.Concat(expectedStringValues, stringValues).ToArray());
+            Assert.Equal(expected, StringValues.Concat((string)null, in expectedStringValues).ToArray());
+            Assert.Equal(expected, StringValues.Concat(in expectedStringValues, (string)null).ToArray());
 
             string[] empty = new string[0];
             StringValues emptyStringValues = new StringValues(empty);
-            Assert.Equal(empty, StringValues.Concat(stringValues, StringValues.Empty));
-            Assert.Equal(empty, StringValues.Concat(StringValues.Empty, stringValues));
-            Assert.Equal(empty, StringValues.Concat(stringValues, new StringValues()));
-            Assert.Equal(empty, StringValues.Concat(new StringValues(), stringValues));
-            Assert.Equal(empty, StringValues.Concat((string)null, in emptyStringValues));
-            Assert.Equal(empty, StringValues.Concat(in emptyStringValues, (string)null));
+            Assert.Equal(empty, StringValues.Concat(stringValues, StringValues.Empty).ToArray());
+            Assert.Equal(empty, StringValues.Concat(StringValues.Empty, stringValues).ToArray());
+            Assert.Equal(empty, StringValues.Concat(stringValues, new StringValues()).ToArray());
+            Assert.Equal(empty, StringValues.Concat(new StringValues(), stringValues).ToArray());
+            Assert.Equal(empty, StringValues.Concat((string)null, in emptyStringValues).ToArray());
+            Assert.Equal(empty, StringValues.Concat(in emptyStringValues, (string)null).ToArray());
         }
 
         [Theory]
@@ -475,24 +475,24 @@ public void Concat(StringValues stringValues, string[] array)
             string[] filled = new[] { "abc", "bcd", "foo" };
 
             string[] expectedPrepended = array.Concat(filled).ToArray();
-            Assert.Equal(expectedPrepended, StringValues.Concat(stringValues, new StringValues(filled)));
+            Assert.Equal(expectedPrepended, StringValues.Concat(stringValues, new StringValues(filled)).ToArray());
 
             string[] expectedAppended = filled.Concat(array).ToArray();
-            Assert.Equal(expectedAppended, StringValues.Concat(new StringValues(filled), stringValues));
+            Assert.Equal(expectedAppended, StringValues.Concat(new StringValues(filled), stringValues).ToArray());
 
             StringValues values = stringValues;
             foreach (string s in filled)
             {
                 values = StringValues.Concat(in values, s);
             }
-            Assert.Equal(expectedPrepended, values);
+            Assert.Equal(expectedPrepended, (string[])values);
 
             values = stringValues;
-            foreach (string s in filled.Reverse())
+            foreach (string s in Enumerable.Reverse(filled))
             {
                 values = StringValues.Concat(s, in values);
             }
-            Assert.Equal(expectedAppended, values);
+            Assert.Equal(expectedAppended, (string[])values);
         }
 
         [Fact]
diff --git a/src/libraries/System.Collections.Immutable/tests/ImmutableStackTest.cs b/src/libraries/System.Collections.Immutable/tests/ImmutableStackTest.cs
index 4abd031ed43b2..397990ee49497 100644
--- a/src/libraries/System.Collections.Immutable/tests/ImmutableStackTest.cs
+++ b/src/libraries/System.Collections.Immutable/tests/ImmutableStackTest.cs
@@ -305,7 +305,7 @@ public void PeekRef_Empty()
         protected override IEnumerable<T> GetEnumerableOf<T>(params T[] contents)
         {
             ImmutableStack<T> stack = ImmutableStack<T>.Empty;
-            foreach (T value in contents.Reverse())
+            foreach (T value in Enumerable.Reverse(contents))
             {
                 stack = stack.Push(value);
             }
diff --git a/src/libraries/System.Collections.Specialized/tests/ListDictionaryTests.cs b/src/libraries/System.Collections.Specialized/tests/ListDictionaryTests.cs
index e1e2d9da040da..abbecf3bd18c1 100644
--- a/src/libraries/System.Collections.Specialized/tests/ListDictionaryTests.cs
+++ b/src/libraries/System.Collections.Specialized/tests/ListDictionaryTests.cs
@@ -137,7 +137,7 @@ public static void Set_CustomComparerTest()
 
             int visited = s_dictionaryData.Length;
 
-            Assert.All(s_dictionaryData.Reverse(), element =>
+            Assert.All(Enumerable.Reverse(s_dictionaryData), element =>
             {
                 string newValue = "new" + element.Value;
                 Assert.True(ld.Contains(element.Key));
@@ -154,7 +154,7 @@ public static void Remove_CustomComparerTest()
             ObservableStringComparer comparer = new ObservableStringComparer();
             ListDictionary ld = Fill(new ListDictionary(comparer), s_dictionaryData);
 
-            Assert.All(s_dictionaryData.Reverse(), element =>
+            Assert.All(Enumerable.Reverse(s_dictionaryData), element =>
             {
                 int originalSize = ld.Count;
                 Assert.True(ld.Contains(element.Key));
diff --git a/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
index 7c900d4c6ef32..e5adef0e878d7 100644
--- a/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
@@ -181,7 +181,6 @@ public void Queue_Generic_ToArray_NonWrappedQueue(int count)
             Queue<T> collection = new Queue<T>(count + 1);
             AddToCollection(collection, count);
             T[] elements = collection.ToArray();
-            elements.Reverse();
             Assert.True(Enumerable.SequenceEqual(elements, collection.ToArray<T>()));
         }
 
diff --git a/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs
index a3e04713f1d6a..8c032eff8f7de 100644
--- a/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs
@@ -80,7 +80,7 @@ public void Stack_Generic_Constructor_IEnumerable(EnumerableType enumerableType,
             _ = numberOfMatchingElements;
             IEnumerable<T> enumerable = CreateEnumerable(enumerableType, null, enumerableLength, 0, numberOfDuplicateElements);
             Stack<T> stack = new Stack<T>(enumerable);
-            Assert.Equal(enumerable.ToArray().Reverse(), stack.ToArray());
+            Assert.Equal(Enumerable.Reverse(enumerable.ToArray()), stack.ToArray());
         }
 
         [Fact]
diff --git a/src/libraries/System.ComponentModel.Composition/tests/System/ComponentModel/Composition/CompositionErrorTests.cs b/src/libraries/System.ComponentModel.Composition/tests/System/ComponentModel/Composition/CompositionErrorTests.cs
index 4dbd14618a316..0a0b4e7ed09a6 100644
--- a/src/libraries/System.ComponentModel.Composition/tests/System/ComponentModel/Composition/CompositionErrorTests.cs
+++ b/src/libraries/System.ComponentModel.Composition/tests/System/ComponentModel/Composition/CompositionErrorTests.cs
@@ -416,7 +416,7 @@ private static CompositionError CreateCompositionError(CompositionErrorId id, st
         private static CompositionError CreateCompositionError(params string[] messages)
         {
             CompositionError error = null;
-            foreach (string message in messages.Reverse())
+            foreach (string message in Enumerable.Reverse(messages))
             {
                 CompositionException exception = null;
                 if (error != null)
diff --git a/src/libraries/System.Diagnostics.TraceSource/tests/System.Diagnostics.TraceSource.Tests/TraceListenerClassTests.cs b/src/libraries/System.Diagnostics.TraceSource/tests/System.Diagnostics.TraceSource.Tests/TraceListenerClassTests.cs
index a2e60be485933..095bfac1763b7 100644
--- a/src/libraries/System.Diagnostics.TraceSource/tests/System.Diagnostics.TraceSource.Tests/TraceListenerClassTests.cs
+++ b/src/libraries/System.Diagnostics.TraceSource/tests/System.Diagnostics.TraceSource.Tests/TraceListenerClassTests.cs
@@ -358,7 +358,7 @@ public void WriteFooterTest_LogicalOperationStack()
                     listener.Flush();
 
                     Assert.Contains("LogicalOperationStack=", listener.Output);
-                    Assert.Contains(string.Join(", ", items.Reverse()), listener.Output);
+                    Assert.Contains(string.Join(", ", Enumerable.Reverse(items)), listener.Output);
                 }
                 finally
                 {
diff --git a/src/libraries/System.Memory/tests/Memory/CopyTo.cs b/src/libraries/System.Memory/tests/Memory/CopyTo.cs
index 69f9f1fd2a442..c88fd64d52e5d 100644
--- a/src/libraries/System.Memory/tests/Memory/CopyTo.cs
+++ b/src/libraries/System.Memory/tests/Memory/CopyTo.cs
@@ -41,7 +41,7 @@ public static void TryCopyToArraySegmentImplicit()
             Memory<int> srcMemory = src;
             bool success = srcMemory.TryCopyTo(segment);
             Assert.True(success);
-            Assert.Equal(src, segment);
+            Assert.Equal(src.AsSpan(), segment);
         }
 
         [Fact]
diff --git a/src/libraries/System.Memory/tests/ReadOnlySpan/CopyTo.cs b/src/libraries/System.Memory/tests/ReadOnlySpan/CopyTo.cs
index 578f7867ac96c..0d297485f7a40 100644
--- a/src/libraries/System.Memory/tests/ReadOnlySpan/CopyTo.cs
+++ b/src/libraries/System.Memory/tests/ReadOnlySpan/CopyTo.cs
@@ -42,7 +42,7 @@ public static void TryCopyToArraySegmentImplicit()
             ReadOnlySpan<int> srcSpan = new ReadOnlySpan<int>(src);
             bool success = srcSpan.TryCopyTo(segment);
             Assert.True(success);
-            Assert.Equal(src, segment);
+            Assert.Equal(src.AsSpan(), segment);
         }
 
         [Fact]
diff --git a/src/libraries/System.Memory/tests/Span/CopyTo.cs b/src/libraries/System.Memory/tests/Span/CopyTo.cs
index 0e87eea54c61f..4b10f5d00bdb1 100644
--- a/src/libraries/System.Memory/tests/Span/CopyTo.cs
+++ b/src/libraries/System.Memory/tests/Span/CopyTo.cs
@@ -42,7 +42,7 @@ public static void TryCopyToArraySegmentImplicit()
             Span<int> srcSpan = new Span<int>(src);
             bool success = srcSpan.TryCopyTo(segment);
             Assert.True(success);
-            Assert.Equal(src, segment);
+            Assert.Equal(src.AsSpan(), segment);
         }
 
         [Fact]
diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/Headers/HttpHeaders.cs b/src/libraries/System.Net.Http/src/System/Net/Http/Headers/HttpHeaders.cs
index 03b5934ea38dc..ef8b5f0628846 100644
--- a/src/libraries/System.Net.Http/src/System/Net/Http/Headers/HttpHeaders.cs
+++ b/src/libraries/System.Net.Http/src/System/Net/Http/Headers/HttpHeaders.cs
@@ -1165,7 +1165,7 @@ internal static void GetStoreValuesAsStringOrStringArray(HeaderDescriptor descri
                 else
                 {
                     Debug.Assert(length > 1, "The header should have been removed when it became empty");
-                    values = multiValue = new string[length];
+                    values = (multiValue = new string[length])!;
                 }
 
                 int currentIndex = 0;
@@ -1205,8 +1205,8 @@ internal static int GetStoreValuesIntoStringArray(HeaderDescriptor descriptor, o
                 }
 
                 int currentIndex = 0;
-                ReadStoreValues<object?>(values, info.ParsedAndInvalidValues, descriptor.Parser, ref currentIndex);
-                ReadStoreValues<string?>(values, info.RawValue, null, ref currentIndex);
+                ReadStoreValues<object?>(values!, info.ParsedAndInvalidValues, descriptor.Parser, ref currentIndex);
+                ReadStoreValues<string?>(values!, info.RawValue, null, ref currentIndex);
                 Debug.Assert(currentIndex == length);
 
                 return length;
diff --git a/src/libraries/System.Numerics.Tensors/tests/TensorTests.cs b/src/libraries/System.Numerics.Tensors/tests/TensorTests.cs
index f1886069e056c..7191519e826de 100644
--- a/src/libraries/System.Numerics.Tensors/tests/TensorTests.cs
+++ b/src/libraries/System.Numerics.Tensors/tests/TensorTests.cs
@@ -684,7 +684,7 @@ public static void TensorMultiplyTests()
             Tensor<int> t1 = Tensor.Create(Enumerable.Range(0, 3), [3, 1]);
             Tensor<int> t2 = Tensor.Multiply(t0.AsReadOnlyTensorSpan(), t1);
 
-            Assert.Equal([3,3], t2.Lengths.ToArray());
+            Assert.Equal([3,3], t2.Lengths);
             Assert.Equal(0, t2[0, 0]);
             Assert.Equal(0, t2[0, 1]);
             Assert.Equal(0, t2[0, 2]);
@@ -697,7 +697,7 @@ public static void TensorMultiplyTests()
 
             t2 = Tensor.Multiply(t1.AsReadOnlyTensorSpan(), t0);
 
-            Assert.Equal([3, 3], t2.Lengths.ToArray());
+            Assert.Equal([3, 3], t2.Lengths);
             Assert.Equal(0, t2[0, 0]);
             Assert.Equal(0, t2[0, 1]);
             Assert.Equal(0, t2[0, 2]);
@@ -711,7 +711,7 @@ public static void TensorMultiplyTests()
             t1 = Tensor.Create(Enumerable.Range(0, 9), [3, 3]);
             t2 = Tensor.Multiply(t0.AsReadOnlyTensorSpan(), t1);
 
-            Assert.Equal([3, 3], t2.Lengths.ToArray());
+            Assert.Equal([3, 3], t2.Lengths);
             Assert.Equal(0, t2[0, 0]);
             Assert.Equal(1, t2[0, 1]);
             Assert.Equal(4, t2[0, 2]);
@@ -729,7 +729,7 @@ public static void TensorBroadcastTests()
             Tensor<int> t0 = Tensor.Create(Enumerable.Range(0, 3), [1, 3, 1, 1, 1]);
             Tensor<int> t1 = Tensor.Broadcast<int>(t0, [1, 3, 1, 2, 1]);
 
-            Assert.Equal([1, 3, 1, 2, 1], t1.Lengths.ToArray());
+            Assert.Equal([1, 3, 1, 2, 1], t1.Lengths);
 
             Assert.Equal(0, t1[0, 0, 0, 0, 0]);
             Assert.Equal(0, t1[0, 0, 0, 1, 0]);
@@ -739,7 +739,7 @@ public static void TensorBroadcastTests()
             Assert.Equal(2, t1[0, 2, 0, 1, 0]);
 
             t1 = Tensor.Broadcast<int>(t0, [1, 3, 2, 1, 1]);
-            Assert.Equal([1, 3, 2, 1, 1], t1.Lengths.ToArray());
+            Assert.Equal([1, 3, 2, 1, 1], t1.Lengths);
 
             Assert.Equal(0, t1[0, 0, 0, 0, 0]);
             Assert.Equal(0, t1[0, 0, 1, 0, 0]);
@@ -751,7 +751,7 @@ public static void TensorBroadcastTests()
             t0 = Tensor.Create(Enumerable.Range(0, 3), [1, 3]);
             t1 = Tensor.Create(Enumerable.Range(0, 3), [3, 1]);
             var t2 = Tensor.Broadcast<int>(t0, [3, 3]);
-            Assert.Equal([3, 3], t2.Lengths.ToArray());
+            Assert.Equal([3, 3], t2.Lengths);
 
             Assert.Equal(0, t2[0, 0]);
             Assert.Equal(1, t2[0, 1]);
@@ -765,7 +765,7 @@ public static void TensorBroadcastTests()
 
             t1 = Tensor.Create(Enumerable.Range(0, 3), [3, 1]);
             t2 = Tensor.Broadcast<int>(t1, [3, 3]);
-            Assert.Equal([3, 3], t2.Lengths.ToArray());
+            Assert.Equal([3, 3], t2.Lengths);
 
             Assert.Equal(0, t2[0, 0]);
             Assert.Equal(0, t2[0, 1]);
@@ -789,11 +789,11 @@ public static void TensorBroadcastTests()
             Assert.Equal(2, s1[2, 2]);
 
             var t3 = t2.Slice(0..1, ..);
-            Assert.Equal([1, 3], t3.Lengths.ToArray());
+            Assert.Equal([1, 3], t3.Lengths);
 
             t1 = Tensor.Create(Enumerable.Range(0, 3), default);
             t2 = Tensor.Broadcast<int>(t1, [3, 3]);
-            Assert.Equal([3, 3], t2.Lengths.ToArray());
+            Assert.Equal([3, 3], t2.Lengths);
 
             Assert.Equal(0, t2[0, 0]);
             Assert.Equal(1, t2[0, 1]);
@@ -811,15 +811,15 @@ public static void TensorResizeTests()
         {
             Tensor<int> t0 = Tensor.Create(Enumerable.Range(0, 8), [2, 2, 2]);
             var t1 = Tensor.Resize(t0, [1]);
-            Assert.Equal([1], t1.Lengths.ToArray());
+            Assert.Equal([1], t1.Lengths);
             Assert.Equal(0, t1[0]);
 
             t1 = Tensor.Resize(t0, [1, 1]);
-            Assert.Equal([1, 1], t1.Lengths.ToArray());
+            Assert.Equal([1, 1], t1.Lengths);
             Assert.Equal(0, t1[0, 0]);
 
             t1 = Tensor.Resize(t0, [6]);
-            Assert.Equal([6], t1.Lengths.ToArray());
+            Assert.Equal([6], t1.Lengths);
             Assert.Equal(0, t1[0]);
             Assert.Equal(1, t1[1]);
             Assert.Equal(2, t1[2]);
@@ -828,7 +828,7 @@ public static void TensorResizeTests()
             Assert.Equal(5, t1[5]);
 
             t1 = Tensor.Resize(t0, [10]);
-            Assert.Equal([10], t1.Lengths.ToArray());
+            Assert.Equal([10], t1.Lengths);
             Assert.Equal(0, t1[0]);
             Assert.Equal(1, t1[1]);
             Assert.Equal(2, t1[2]);
@@ -841,7 +841,7 @@ public static void TensorResizeTests()
             Assert.Equal(0, t1[9]);
 
             t1 = Tensor.Resize(t0, [2, 5]);
-            Assert.Equal([2, 5], t1.Lengths.ToArray());
+            Assert.Equal([2, 5], t1.Lengths);
             Assert.Equal(0, t1[0, 0]);
             Assert.Equal(1, t1[0, 1]);
             Assert.Equal(2, t1[0, 2]);
@@ -859,8 +859,8 @@ public static void TensorSplitTests()
         {
             Tensor<int> t0 = Tensor.Create(Enumerable.Range(0, 8), [2, 2, 2]);
             var t1 = Tensor.Split<int>(t0, 2, 0);
-            Assert.Equal([1, 2, 2], t1[0].Lengths.ToArray());
-            Assert.Equal([1, 2, 2], t1[1].Lengths.ToArray());
+            Assert.Equal([1, 2, 2], t1[0].Lengths);
+            Assert.Equal([1, 2, 2], t1[1].Lengths);
             Assert.Equal(0, t1[0][0, 0, 0]);
             Assert.Equal(1, t1[0][0, 0, 1]);
             Assert.Equal(2, t1[0][0, 1, 0]);
@@ -871,8 +871,8 @@ public static void TensorSplitTests()
             Assert.Equal(7, t1[1][0, 1, 1]);
 
             t1 = Tensor.Split<int>(t0, 2, 1);
-            Assert.Equal([2, 1, 2], t1[0].Lengths.ToArray());
-            Assert.Equal([2, 1, 2], t1[1].Lengths.ToArray());
+            Assert.Equal([2, 1, 2], t1[0].Lengths);
+            Assert.Equal([2, 1, 2], t1[1].Lengths);
             Assert.Equal(0, t1[0][0, 0, 0]);
             Assert.Equal(1, t1[0][0, 0, 1]);
             Assert.Equal(4, t1[0][1, 0, 0]);
@@ -883,8 +883,8 @@ public static void TensorSplitTests()
             Assert.Equal(7, t1[1][1, 0, 1]);
 
             t1 = Tensor.Split<int>(t0, 2, 2);
-            Assert.Equal([2, 2, 1], t1[0].Lengths.ToArray());
-            Assert.Equal([2, 2, 1], t1[1].Lengths.ToArray());
+            Assert.Equal([2, 2, 1], t1[0].Lengths);
+            Assert.Equal([2, 2, 1], t1[1].Lengths);
             Assert.Equal(0, t1[0][0, 0, 0]);
             Assert.Equal(2, t1[0][0, 1, 0]);
             Assert.Equal(4, t1[0][1, 0, 0]);
diff --git a/src/libraries/System.Private.CoreLib/src/System/Runtime/CompilerServices/QCallHandles.cs b/src/libraries/System.Private.CoreLib/src/System/Runtime/CompilerServices/QCallHandles.cs
index ea2e95f6d8b29..10b955478ecd3 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Runtime/CompilerServices/QCallHandles.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Runtime/CompilerServices/QCallHandles.cs
@@ -37,6 +37,12 @@ internal static ObjectHandleOnStack Create<T>(ref T o) where T : class?
     internal ref struct ByteRef
     {
         private ref byte _ref;
+
+        internal ByteRef(ref byte byteReference)
+        {
+            _ref = ref byteReference;
+        }
+
         internal ref byte Get()
         {
             return ref _ref;
diff --git a/src/libraries/System.Runtime/tests/System.Diagnostics.Debug.Tests/System.Diagnostics.Debug.Tests.csproj b/src/libraries/System.Runtime/tests/System.Diagnostics.Debug.Tests/System.Diagnostics.Debug.Tests.csproj
index f27284e29a907..8cd911f50213d 100644
--- a/src/libraries/System.Runtime/tests/System.Diagnostics.Debug.Tests/System.Diagnostics.Debug.Tests.csproj
+++ b/src/libraries/System.Runtime/tests/System.Diagnostics.Debug.Tests/System.Diagnostics.Debug.Tests.csproj
@@ -13,6 +13,7 @@
     <ProjectReference Include="$(CoreLibProject)" />
     <ProjectReference Include="$(LibrariesProjectRoot)System.Runtime\src\System.Runtime.csproj" />
     <ProjectReference Include="$(LibrariesProjectRoot)System.Collections\src\System.Collections.csproj" />
+    <ProjectReference Include="$(LibrariesProjectRoot)System.Memory\src\System.Memory.csproj" />
     <ProjectReference Include="$(LibrariesProjectRoot)System.Threading\src\System.Threading.csproj" />
   </ItemGroup>
   <ItemGroup>
diff --git a/src/libraries/System.Runtime/tests/System.Globalization.Tests/System/Globalization/GraphemeBreakTest.cs b/src/libraries/System.Runtime/tests/System.Globalization.Tests/System/Globalization/GraphemeBreakTest.cs
index c741edd882966..e7edba854fae7 100644
--- a/src/libraries/System.Runtime/tests/System.Globalization.Tests/System/Globalization/GraphemeBreakTest.cs
+++ b/src/libraries/System.Runtime/tests/System.Globalization.Tests/System/Globalization/GraphemeBreakTest.cs
@@ -141,7 +141,7 @@ public void VisualBasicReverseString()
                 // Arrange
 
                 string forwardActual = string.Concat(clusters.SelectMany(cluster => cluster).Select(rune => rune.ToString()));
-                string reverseExpected = string.Concat(clusters.Reverse().SelectMany(cluster => cluster).Select(rune => rune.ToString()));
+                string reverseExpected = string.Concat(Enumerable.Reverse(clusters).SelectMany(cluster => cluster).Select(rune => rune.ToString()));
 
                 // Act
 
diff --git a/src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Runtime/CompilerServices/RuntimeHelpersTests.cs b/src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Runtime/CompilerServices/RuntimeHelpersTests.cs
index 13ce28e4f233c..8c9f6ea247c58 100644
--- a/src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Runtime/CompilerServices/RuntimeHelpersTests.cs
+++ b/src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Runtime/CompilerServices/RuntimeHelpersTests.cs
@@ -391,10 +391,10 @@ public static void ArrayGetSubArrayTest()
             Assert.Equal(a, RuntimeHelpers.GetSubArray(a, range));
 
             range = new Range(Index.FromStart(1), Index.FromEnd(5));
-            Assert.Equal(new int [] { 2, 3, 4, 5}, RuntimeHelpers.GetSubArray(a, range));
+            Assert.Equal(new int[] { 2, 3, 4, 5 }, RuntimeHelpers.GetSubArray(a, range));
 
             range = new Range(Index.FromStart(0), Index.FromStart(a.Length + 1));
-            Assert.Throws<ArgumentOutOfRangeException>(() => { int [] array = RuntimeHelpers.GetSubArray(a, range); });
+            Assert.Throws<ArgumentOutOfRangeException>(() => { int[] array = RuntimeHelpers.GetSubArray(a, range); });
         }
 
         [Fact]
@@ -454,6 +454,11 @@ private ref struct RefStructWithReferences
         private ref struct RefStructWithRef
         {
             public ref int a;
+
+            internal RefStructWithRef(ref int aVal)
+            {
+                a = ref aVal;
+            }
         }
 
         private ref struct RefStructWithNestedRef
@@ -499,7 +504,7 @@ public static unsafe void SizeOf()
             Assert.Equal(8, RuntimeHelpers.SizeOf(typeof(double).TypeHandle));
             Assert.Equal(3, RuntimeHelpers.SizeOf(typeof(Byte3).TypeHandle));
             Assert.Equal(nint.Size, RuntimeHelpers.SizeOf(typeof(void*).TypeHandle));
-            Assert.Equal(nint.Size, RuntimeHelpers.SizeOf(typeof(delegate* <void>).TypeHandle));
+            Assert.Equal(nint.Size, RuntimeHelpers.SizeOf(typeof(delegate*<void>).TypeHandle));
             Assert.Equal(nint.Size, RuntimeHelpers.SizeOf(typeof(int).MakeByRefType().TypeHandle));
             Assert.Throws<ArgumentNullException>(() => RuntimeHelpers.SizeOf(default));
             Assert.ThrowsAny<ArgumentException>(() => RuntimeHelpers.SizeOf(typeof(List<>).TypeHandle));