# System.Reflection.Emit

``` diff
 namespace System.Reflection.Emit {
     public abstract class TypeBuilder : TypeInfo {
-        public PropertyBuilder DefineProperty(string name, PropertyAttributes attributes, CallingConventions callingConvention, Type returnType, Type[]? parameterTypes);
+        public PropertyBuilder DefineProperty(string name, PropertyAttributes attributes, CallingConventions callingConvention, Type? returnType, Type[]? parameterTypes);
-        public PropertyBuilder DefineProperty(string name, PropertyAttributes attributes, CallingConventions callingConvention, Type returnType, Type[]? returnTypeRequiredCustomModifiers, Type[]? returnTypeOptionalCustomModifiers, Type[]? parameterTypes, Type[][]? parameterTypeRequiredCustomModifiers, Type[][]? parameterTypeOptionalCustomModifiers);
+        public PropertyBuilder DefineProperty(string name, PropertyAttributes attributes, CallingConventions callingConvention, Type? returnType, Type[]? returnTypeRequiredCustomModifiers, Type[]? returnTypeOptionalCustomModifiers, Type[]? parameterTypes, Type[][]? parameterTypeRequiredCustomModifiers, Type[][]? parameterTypeOptionalCustomModifiers);
-        public PropertyBuilder DefineProperty(string name, PropertyAttributes attributes, Type returnType, Type[]? parameterTypes);
+        public PropertyBuilder DefineProperty(string name, PropertyAttributes attributes, Type? returnType, Type[]? parameterTypes);
-        public PropertyBuilder DefineProperty(string name, PropertyAttributes attributes, Type returnType, Type[]? returnTypeRequiredCustomModifiers, Type[]? returnTypeOptionalCustomModifiers, Type[]? parameterTypes, Type[][]? parameterTypeRequiredCustomModifiers, Type[][]? parameterTypeOptionalCustomModifiers);
+        public PropertyBuilder DefineProperty(string name, PropertyAttributes attributes, Type? returnType, Type[]? returnTypeRequiredCustomModifiers, Type[]? returnTypeOptionalCustomModifiers, Type[]? parameterTypes, Type[][]? parameterTypeRequiredCustomModifiers, Type[][]? parameterTypeOptionalCustomModifiers);
-        protected abstract PropertyBuilder DefinePropertyCore(string name, PropertyAttributes attributes, CallingConventions callingConvention, Type returnType, Type[]? returnTypeRequiredCustomModifiers, Type[]? returnTypeOptionalCustomModifiers, Type[]? parameterTypes, Type[][]? parameterTypeRequiredCustomModifiers, Type[][]? parameterTypeOptionalCustomModifiers);
+        protected abstract PropertyBuilder DefinePropertyCore(string name, PropertyAttributes attributes, CallingConventions callingConvention, Type? returnType, Type[]? returnTypeRequiredCustomModifiers, Type[]? returnTypeOptionalCustomModifiers, Type[]? parameterTypes, Type[][]? parameterTypeRequiredCustomModifiers, Type[][]? parameterTypeOptionalCustomModifiers);
     }
 }
```

