Remove redundant UnderlyingSystemType calls (#24000)

UnderlyingSystemType is virtual

diff --git a/src/System.Private.CoreLib/shared/System/Type.cs b/src/System.Private.CoreLib/shared/System/Type.cs
index 8b19fbc..d2a31cb 100644 (file)
--- a/src/System.Private.CoreLib/shared/System/Type.cs
+++ b/src/System.Private.CoreLib/shared/System/Type.cs
@@ -281,8 +281,9 @@ namespace System
         }
         protected virtual TypeCode GetTypeCodeImpl()
         {
-            if (this != UnderlyingSystemType && UnderlyingSystemType != null)
-                return Type.GetTypeCode(UnderlyingSystemType);
+            Type systemType = UnderlyingSystemType;
+            if (this != systemType && systemType != null)
+                return Type.GetTypeCode(systemType);
 
             return TypeCode.Object;
         }