diff --git a/package.json b/package.json
index 9e56fef2e..8b78097b2 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ethers",
-  "version": "3.0.22",
+  "version": "3.0.23",
   "description": "Ethereum wallet library.",
   "main": "index.js",
   "scripts": {
diff --git a/tests/test-contract-interface.js b/tests/test-contract-interface.js
index 17fcc40c8..3e51cdb7c 100644
--- a/tests/test-contract-interface.js
+++ b/tests/test-contract-interface.js
@@ -173,6 +173,26 @@ describe('ABI Coder ABIv2 Decoding', function() {
         it(('decodes ABIv2 parameters - ' + test.name + ' - ' + test.types), function() {
             var decoded = coder.decode(types, result);
             assert.ok(equals(decoded, values), 'decoded positional parameters - ' + title);
+
+            // Test for mutation
+            // https://github.com/ethers-io/ethers.js/issues/200
+            // https://github.com/ethers-io/ethers.js/issues/201
+
+            // @TODO: Expose parseParameter
+            // Check that it works with objects as well as strings
+            var expandedTypes = [];
+            types.forEach(function(type) {
+                var sig = 'function foo(' + type + ' foo)';
+                var abi = ethers.utils.AbiCoder.parseSignature(sig);
+                expandedTypes.push(abi.inputs[0]);
+            });
+
+            var typesBefore = JSON.stringify(expandedTypes);
+
+            decoded = coder.decode(expandedTypes, result);
+            assert.ok(equals(decoded, values), 'decoded positional parameters - ' + title);
+
+            assert.equal(typesBefore, JSON.stringify(expandedTypes), 'decoding does not modify the types');
         });
     });
 });
diff --git a/utils/abi-coder.js b/utils/abi-coder.js
index 6b1134713..8c9a6571f 100644
--- a/utils/abi-coder.js
+++ b/utils/abi-coder.js
@@ -382,7 +382,7 @@ var coderBoolean = function(coerceFunc, localName) {
         encode: function(value) {
            return uint256Coder.encode(!!value ? 1: 0);
         },
-       decode: function(data, offset) {
+        decode: function(data, offset) {
             try {
                 var result = uint256Coder.decode(data, offset);
             } catch (error) {
@@ -758,8 +758,17 @@ function coderArray(coerceFunc, coder, length, localName) {
                  offset += decodedLength.consumed;
             }
 
+            // We don't want the children to have a localName
+            var subCoder = {
+                name: coder.name,
+                type: coder.type,
+                encode: coder.encode,
+                decode: coder.decode,
+                dynamic: coder.dynamic
+            };
+
             var coders = [];
-            for (var i = 0; i < count; i++) { coders.push(coder); }
+            for (var i = 0; i < count; i++) { coders.push(subCoder); }
 
             var result = unpack(coders, data, offset);
             result.consumed += consumed;