Fix address coder to prepare non-hexdatastring addresses as hexdatast…

…ring (ethers-io#1906).

packages/abi/src.ts/coders/address.ts

@@ -17,7 +17,7 @@ export class AddressCoder extends Coder {
 
     encode(writer: Writer, value: string): number {
         try {
-            getAddress(value);
+            value = getAddress(value)
         } catch (error) {
             this._throwError(error.message, value);
         }

packages/tests/src.ts/test-contract-interface.ts

@@ -659,3 +659,14 @@ describe('Test EIP-838 Error Codes', function() {
         }
     });
 });
+
+describe("Additional test cases", function() {
+    // See: #1906
+    it("allows addresses without the 0x", function() {
+        const iface = new ethers.utils.Interface([
+            "function test(address foo) view returns (bool)"
+        ]);
+        const tx = iface.encodeFunctionData("test", [ "c1912fee45d61c87cc5ea59dae31190fffff232d" ]);
+        console.log(tx);
+    });
+});