diff --git a/src/mixed.js b/src/mixed.js
index 99c4be041..2efacba5e 100644
--- a/src/mixed.js
+++ b/src/mixed.js
@@ -46,19 +46,21 @@ SchemaType.prototype = {
     if (!schema)
       return this
 
-    if( schema._type !== this._type )
+    if (schema._type !== this._type && this._type !== 'mixed')
       throw new TypeError(`You cannot \`concat()\` schema's of different types: ${this._type} and ${schema._type}`)
 
     var next = _.merge(this.clone(), schema.clone())
 
     // undefined isn't merged over, but is a valid value for default
-    if( schema._default === undefined && _.has(this, '_default') )
+    if (schema._default === undefined && _.has(this, '_default'))
       next._default = schema._default
 
     // trim exclusive tests, take the most recent ones
     next.tests = _.uniq(next.tests.reverse(),
       (fn, idx) => next[fn.VALIDATION_KEY] ? fn.VALIDATION_KEY : idx).reverse()
 
+    next._type = schema._type;
+
     return next
   },
 
@@ -68,7 +70,7 @@ SchemaType.prototype = {
   },
 
   cast(_value, _opts) {
-    var schema = this._resolve((_opts|| {}).context)
+    var schema = this._resolve((_opts || {}).context)
     return schema._cast(_value, _opts)
   },
 
@@ -212,7 +214,7 @@ SchemaType.prototype = {
   test(name, message, test, useCallback) {
     var opts = name
       , next = this.clone()
-      , errorMsg, isExclusive;
+      , isExclusive;
 
     if (typeof name === 'string') {
       if (typeof message === 'function')
diff --git a/src/util/condition.js b/src/util/condition.js
index e1b6c0f88..fbed00636 100644
--- a/src/util/condition.js
+++ b/src/util/condition.js
@@ -24,8 +24,8 @@ class Conditional {
       if( !options.then && !options.otherwise )
         throw new TypeError('either `then:` or `otherwise:` is required for `when()` conditions')
 
-      if(  options.then && options.then._type !== type || options.otherwise && options.otherwise._type !== type)
-        throw new TypeError(`cannot create polymorphic conditionals, \`then\` and \`otherwise\` must be the same type: ${type}`)
+      // if(  options.then && options.then._type !== type || options.otherwise && options.otherwise._type !== type)
+      //   throw new TypeError(`cannot create polymorphic conditionals, \`then\` and \`otherwise\` must be the same type: ${type}`)
 
       is = typeof is === 'function'
         ? is : ((is, value) => is === value).bind(null, is)
@@ -53,4 +53,4 @@ class Conditional {
   }
 }
 
-module.exports = Conditional;
\ No newline at end of file
+module.exports = Conditional;
diff --git a/test/mixed.js b/test/mixed.js
index 3f8087241..98ed2afc8 100644
--- a/test/mixed.js
+++ b/test/mixed.js
@@ -105,7 +105,7 @@ describe( 'Mixed Types ', function(){
   })
 
   it('exclusive tests should throw without a name', function(){
-    ;(function(){
+    (function(){
       mixed().test({ message: 'invalid', exclusive: true, test: function(){} })
     }).should.throw()
   })
@@ -133,7 +133,7 @@ describe( 'Mixed Types ', function(){
         message: 'invalid',
         exclusive: true,
         name: 'max',
-        test: function(v, path, context){
+        test: function(){
           this.path.should.equal('test')
           this.parent.should.eql({ other: 5, test : 'hi' })
           this.options.context.should.eql({ user: 'jason' })
@@ -149,7 +149,7 @@ describe( 'Mixed Types ', function(){
     var inst = mixed().test({
         message: 'invalid ${path}',
         name: 'max',
-        test: function(v){
+        test: function(){
           return this.createError({ path: 'my.path' })
         }
       })
@@ -166,7 +166,7 @@ describe( 'Mixed Types ', function(){
     var inst = mixed().test({
         message: 'invalid ${path}',
         name: 'max',
-        test: function(v){
+        test: function(){
           return this.createError({ message: '${path} nope!', path: 'my.path' })
         }
       })
@@ -254,13 +254,22 @@ describe( 'Mixed Types ', function(){
   })
 
   it('concat should fail on different types', function(){
-    var inst = string().default('hi')
+    var inst = string().default('hi');
 
-    ;(function(){
+    (function(){
       inst.concat(object())
     }).should.throw(TypeError)
   })
 
+  it('concat should allow mixed and other type', function(){
+    var inst = mixed().default('hi');
+
+    (function(){
+      inst.concat(string())._type.should.equal('string')
+
+    }).should.not.throw(TypeError)
+  })
+
   it('concat should maintain undefined defaults', function(){
     var inst = string().default('hi')
 
@@ -285,7 +294,7 @@ describe( 'Mixed Types ', function(){
       //parent
       inst._validate(undefined, {}, { parent: { prop: 5 }}).should.be.rejected,
       inst._validate(undefined, {}, { parent: { prop: 1 }}).should.be.fulfilled,
-      inst._validate('hello', {},   { parent: { prop: 5 }}).should.be.fulfilled,
+      inst._validate('hello', {},   { parent: { prop: 5 }}).should.be.fulfilled
     ])
     .then(function(){
 
@@ -336,6 +345,3 @@ describe( 'Mixed Types ', function(){
   })
 
 })
-
-
-