1 files changed, 2 insertions, 2 deletions
diff --git a/src/Spv.Generator/TypeDeclarationKey.cs b/src/Spv.Generator/TypeDeclarationKey.cs
index e4fd5fd5..1f59331f 100644
--- a/src/Spv.Generator/TypeDeclarationKey.cs
+++ b/src/Spv.Generator/TypeDeclarationKey.cs
@@ -3,7 +3,7 @@ using System.Diagnostics.CodeAnalysis;
 
 namespace Spv.Generator
 {
-    internal struct TypeDeclarationKey : IEquatable<TypeDeclarationKey>
+    internal readonly struct TypeDeclarationKey : IEquatable<TypeDeclarationKey>
     {
         private readonly Instruction _typeDeclaration;
 
@@ -24,7 +24,7 @@ namespace Spv.Generator
 
         public override bool Equals([NotNullWhen(true)] object obj)
         {
-            return obj is TypeDeclarationKey && Equals((TypeDeclarationKey)obj);
+            return obj is TypeDeclarationKey key && Equals(key);
         }
     }
 }