3 files changed, 24 insertions, 6 deletions
diff --git a/packages/utils/src/abi_encoder/calldata.ts b/packages/utils/src/abi_encoder/calldata.ts
index 078767c22..11288064e 100644
--- a/packages/utils/src/abi_encoder/calldata.ts
+++ b/packages/utils/src/abi_encoder/calldata.ts
@@ -248,7 +248,7 @@ export class Calldata {
     private selector: string;
     private rules: EncodingRules;
     private sizeInBytes: number;
-    private root: MemberCalldataBlock | undefined;
+    private root: CalldataBlock | undefined;
 
     constructor(rules: EncodingRules) {
         this.selector = '';
@@ -257,8 +257,17 @@ export class Calldata {
         this.root = undefined;
     }
 
-    private createQueue(memberBlock: MemberCalldataBlock): Queue<CalldataBlock> {
+    private createQueue(block: CalldataBlock): Queue<CalldataBlock> {
         const blockQueue = new Queue<CalldataBlock>();
+
+        // Base Case
+        if (block instanceof MemberCalldataBlock === false) {
+            blockQueue.push(block);
+            return blockQueue;
+        }
+
+        // This is a Member Block
+        const memberBlock = block as MemberCalldataBlock;
         _.eachRight(memberBlock.getMembers(), (member: CalldataBlock) => {
             if (member instanceof MemberCalldataBlock) {
                 blockQueue.mergeFront(this.createQueue(member));
@@ -429,7 +438,7 @@ export class Calldata {
         return "";
     }
 
-    public setRoot(block: MemberCalldataBlock) {
+    public setRoot(block: CalldataBlock) {
         this.root = block;
         this.sizeInBytes += block.getSizeInBytes();
     }
diff --git a/packages/utils/src/abi_encoder/data_type.ts b/packages/utils/src/abi_encoder/data_type.ts
index 022f5621f..0f3cecac5 100644
--- a/packages/utils/src/abi_encoder/data_type.ts
+++ b/packages/utils/src/abi_encoder/data_type.ts
@@ -35,7 +35,7 @@ export abstract class DataType {
         const calldata = new Calldata(rules_);
         if (selector) calldata.setSelector(selector);
         const block = this.generateCalldataBlock(value);
-        calldata.setRoot(block as MemberCalldataBlock); // @TODO CHANGE
+        calldata.setRoot(block); // @TODO CHANGE
         const calldataHex = calldata.toHexString();
         return calldataHex;
     }
diff --git a/packages/utils/src/abi_encoder/evm_data_types.ts b/packages/utils/src/abi_encoder/evm_data_types.ts
index bfb2808da..1ee95863b 100644
--- a/packages/utils/src/abi_encoder/evm_data_types.ts
+++ b/packages/utils/src/abi_encoder/evm_data_types.ts
@@ -20,6 +20,8 @@ export interface DataTypeStaticInterface {
 
 export class Address extends PayloadDataType {
     private static SIZE_KNOWN_AT_COMPILE_TIME: boolean = true;
+    public static ERROR_MESSAGE_ADDRESS_MUST_START_WITH_0X = "Address must start with '0x'";
+    public static ERROR_MESSAGE_ADDRESS_MUST_BE_20_BYTES = "Address must be 20 bytes";
 
     constructor(dataItem: DataItem) {
         super(dataItem, EvmDataTypeFactory.getInstance(), Address.SIZE_KNOWN_AT_COMPILE_TIME);
@@ -36,9 +38,16 @@ export class Address extends PayloadDataType {
         return type === 'address';
     }
 
-    public encodeValue(value: boolean): Buffer {
+    public encodeValue(value: string): Buffer {
+        if (value.startsWith('0x') === false) {
+            throw new Error(Address.ERROR_MESSAGE_ADDRESS_MUST_START_WITH_0X);
+        }
+        const valueAsBuffer = ethUtil.toBuffer(value);
+        if (valueAsBuffer.byteLength !== 20) {
+            throw new Error(Address.ERROR_MESSAGE_ADDRESS_MUST_BE_20_BYTES);
+        }
         const evmWordWidth = 32;
-        const encodedValueBuf = ethUtil.setLengthLeft(ethUtil.toBuffer(value), evmWordWidth);
+        const encodedValueBuf = ethUtil.setLengthLeft(valueAsBuffer, evmWordWidth);
         return encodedValueBuf;
     }