diff --git a/src/libraries/System.ComponentModel.Composition/ref/System.ComponentModel.Composition.cs b/src/libraries/System.ComponentModel.Composition/ref/System.ComponentModel.Composition.cs
index f55f6b216d37f9..43dd8ad0b82de0 100644
--- a/src/libraries/System.ComponentModel.Composition/ref/System.ComponentModel.Composition.cs
+++ b/src/libraries/System.ComponentModel.Composition/ref/System.ComponentModel.Composition.cs
@@ -615,10 +615,10 @@ public partial struct LazyMemberInfo
         public LazyMemberInfo(System.Reflection.MemberInfo member) { throw null; }
         public LazyMemberInfo(System.Reflection.MemberTypes memberType, System.Func<System.Reflection.MemberInfo[]> accessorsCreator) { throw null; }
         public LazyMemberInfo(System.Reflection.MemberTypes memberType, params System.Reflection.MemberInfo[] accessors) { throw null; }
-        public System.Reflection.MemberTypes MemberType { get { throw null; } }
-        public override bool Equals(object? obj) { throw null; }
+        public readonly System.Reflection.MemberTypes MemberType { get { throw null; } }
+        public override readonly bool Equals(object? obj) { throw null; }
         public System.Reflection.MemberInfo[] GetAccessors() { throw null; }
-        public override int GetHashCode() { throw null; }
+        public override readonly int GetHashCode() { throw null; }
         public static bool operator ==(System.ComponentModel.Composition.ReflectionModel.LazyMemberInfo left, System.ComponentModel.Composition.ReflectionModel.LazyMemberInfo right) { throw null; }
         public static bool operator !=(System.ComponentModel.Composition.ReflectionModel.LazyMemberInfo left, System.ComponentModel.Composition.ReflectionModel.LazyMemberInfo right) { throw null; }
     }
diff --git a/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/CompositionResult.cs b/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/CompositionResult.cs
index 2d0bee2f608a43..d40981328705db 100644
--- a/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/CompositionResult.cs
+++ b/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/CompositionResult.cs
@@ -23,17 +23,17 @@ public CompositionResult(IEnumerable<CompositionError>? errors)
             _errors = errors;
         }
 
-        public bool Succeeded
+        public readonly bool Succeeded
         {
             get { return _errors == null || !_errors.Any(); }
         }
 
-        public IEnumerable<CompositionError> Errors
+        public readonly IEnumerable<CompositionError> Errors
         {
             get { return _errors ?? Enumerable.Empty<CompositionError>(); }
         }
 
-        public CompositionResult MergeResult(CompositionResult result)
+        public readonly CompositionResult MergeResult(CompositionResult result)
         {
             if (Succeeded)
             {
@@ -46,27 +46,27 @@ public CompositionResult MergeResult(CompositionResult result)
             return MergeErrors(result._errors);
         }
 
-        public CompositionResult MergeError(CompositionError error)
+        public readonly CompositionResult MergeError(CompositionError error)
         {
             return MergeErrors(new CompositionError[] { error });
         }
 
-        public CompositionResult MergeErrors(IEnumerable<CompositionError>? errors)
+        public readonly CompositionResult MergeErrors(IEnumerable<CompositionError>? errors)
         {
             return new CompositionResult(_errors.ConcatAllowingNull(errors));
         }
 
-        public CompositionResult<T> ToResult<T>(T value)
+        public readonly CompositionResult<T> ToResult<T>(T value)
         {
             return new CompositionResult<T>(value, _errors);
         }
 
-        public void ThrowOnErrors()
+        public readonly void ThrowOnErrors()
         {
             ThrowOnErrors(null);
         }
 
-        public void ThrowOnErrors(AtomicComposition? atomicComposition)
+        public readonly void ThrowOnErrors(AtomicComposition? atomicComposition)
         {
             if (!Succeeded)
             {
diff --git a/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/CompositionResultOfT.cs b/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/CompositionResultOfT.cs
index 9c66e1817b8956..3c658c0b98ce82 100644
--- a/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/CompositionResultOfT.cs
+++ b/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/CompositionResultOfT.cs
@@ -34,12 +34,12 @@ internal CompositionResult(T? value, IEnumerable<CompositionError>? errors)
             _value = value;
         }
 
-        public bool Succeeded
+        public readonly bool Succeeded
         {
             get { return _errors == null || !_errors.Any(); }
         }
 
-        public IEnumerable<CompositionError> Errors
+        public readonly IEnumerable<CompositionError> Errors
         {
             get { return _errors ?? Enumerable.Empty<CompositionError>(); }
         }
@@ -47,7 +47,7 @@ public IEnumerable<CompositionError> Errors
         /// <summary>
         ///     Gets the value from the result, throwing a CompositionException if there are any errors.
         /// </summary>
-        public T Value
+        public readonly T Value
         {
             get
             {
@@ -57,17 +57,17 @@ public T Value
             }
         }
 
-        internal CompositionResult<TValue> ToResult<TValue>()
+        internal readonly CompositionResult<TValue> ToResult<TValue>()
         {
             return new CompositionResult<TValue>(_errors);
         }
 
-        internal CompositionResult ToResult()
+        internal readonly CompositionResult ToResult()
         {
             return new CompositionResult(_errors);
         }
 
-        private void ThrowOnErrors()
+        private readonly void ThrowOnErrors()
         {
             if (!Succeeded)
             {
diff --git a/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/ReflectionModel/LazyMemberInfo.cs b/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/ReflectionModel/LazyMemberInfo.cs
index cbfc3cdda8afa0..21be260253f488 100644
--- a/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/ReflectionModel/LazyMemberInfo.cs
+++ b/src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/ReflectionModel/LazyMemberInfo.cs
@@ -68,7 +68,7 @@ public LazyMemberInfo(MemberTypes memberType, Func<MemberInfo[]> accessorsCreato
             _accessorsCreator = accessorsCreator;
         }
 
-        public MemberTypes MemberType
+        public readonly MemberTypes MemberType
         {
             get { return _memberType; }
         }
@@ -91,7 +91,7 @@ public MemberInfo[] GetAccessors()
             return _accessors!;
         }
 
-        public override int GetHashCode()
+        public override readonly int GetHashCode()
         {
             if (_accessorsCreator != null)
             {
@@ -106,7 +106,7 @@ public override int GetHashCode()
             throw new Exception(SR.Diagnostic_InternalExceptionMessage);
         }
 
-        public override bool Equals(object? obj)
+        public override readonly bool Equals(object? obj)
         {
             LazyMemberInfo that = (LazyMemberInfo)obj!;