add two way implicit for autorest deserialization

sdk/resourcemanager/Azure.ResourceManager.Core/src/Resources/ResourceType.cs

@@ -102,6 +102,18 @@ public static implicit operator ResourceType(string other)
             return new ResourceType(other);
         }
 
+        /// <summary>
+        /// Implicit operator for initializing a string from a <see cref="ResourceType"/>.
+        /// </summary>
+        /// <param name="other"> <see cref="ResourceType"/> to be converted into a string. </param>
+        public static implicit operator string(ResourceType other)
+        {
+            if (other is null)
+                return null;
+
+            return other.ToString();
+        }
+
         /// <summary>
         /// Compares two <see cref="ResourceType"/> objects.
         /// </summary>

sdk/resourcemanager/Azure.ResourceManager.Core/tests/Unit/ResourceTypeTests.cs

@@ -136,6 +136,15 @@ public void NullImplicitFromString()
             Assert.IsNull(to);
         }
 
+        [TestCase]
+        public void NullImplicitTotring()
+        {
+            ResourceType from = null;
+            string to = from;
+
+            Assert.IsNull(to);
+        }
+
         [TestCase(false, null, "Microsoft.Network1/VirtualNetworks2/subnets1")]
         [TestCase(false, "Microsoft.Network1/VirtualNetworks2/subnets1", null)]
         [TestCase(true, null, null)]
@@ -230,5 +239,18 @@ public void EqualsWithObjectString(bool expected, string left, string right)
             object rightObject = right;
             Assert.AreEqual(expected, rt.Equals(rightObject));
         }
+
+        [TestCase("Microsoft.classicStorage/storageAccounts")]
+        [TestCase("Microsoft.ClassicStorage/diffaccount")]
+        [TestCase("Microsoft.ClassicStorage/storageAccounts")]
+        [TestCase(null)]
+        [TestCase("Foo.Bar/puppies")]
+        public void ImplicitToString(string expected)
+        {
+            ResourceType type = expected;
+            string actual = type;
+
+            Assert.AreEqual(expected, actual);
+        }
     }
 }