diff --git a/src/scope.js b/src/scope.js
index 1a6a796e1..a3a03fae7 100644
--- a/src/scope.js
+++ b/src/scope.js
@@ -30,7 +30,6 @@ var Scope = {
     })
   },
   push: function (ctx) {
-    assert(ctx, `trying to push ${ctx} into scopes`)
     this.scopes.push(ctx)
   },
   pop: function (ctx) {
diff --git a/tags/assign.js b/tags/assign.js
index 4cd6c50cb..c25119207 100644
--- a/tags/assign.js
+++ b/tags/assign.js
@@ -1,3 +1,4 @@
+'use strict'
 const Liquid = require('..')
 const lexical = Liquid.lexical
 const re = new RegExp(`(${lexical.identifier.source})\\s*=(.*)`)
@@ -6,13 +7,15 @@ const assert = require('../src/util/assert.js')
 module.exports = function (liquid) {
   liquid.registerTag('assign', {
     parse: function (token) {
-      var match = token.args.match(re)
+      let match = token.args.match(re)
       assert(match, `illegal token ${token.raw}`)
       this.key = match[1]
       this.value = match[2]
     },
     render: function (scope) {
-      scope.set(this.key, liquid.evalValue(this.value, scope))
+      let ctx = Object.create(null)
+      ctx[this.key] = liquid.evalValue(this.value, scope)
+      scope.push(ctx)
       return Promise.resolve('')
     }
   })
diff --git a/test/filters.js b/test/filters.js
index 4a2fc1c38..631b196c5 100644
--- a/test/filters.js
+++ b/test/filters.js
@@ -54,8 +54,7 @@ describe('filters', function () {
 
       {%- for item in everything -%}
       - {{ item }}
-      {% endfor -%}`,
-      `- apples
+      {% endfor -%}`, `- apples
       - oranges
       - peaches
       - carrots
@@ -70,8 +69,7 @@ describe('filters', function () {
 
       {%- for item in everything -%}
       - {{ item }}
-      {% endfor -%}`,
-      `- apples
+      {% endfor -%}`, `- apples
       - oranges
       - peaches
       - carrots
@@ -156,7 +154,7 @@ describe('filters', function () {
 
   it('should support join', function () {
     var src = '{% assign beatles = "John, Paul, George, Ringo" | split: ", " %}' +
-            '{{ beatles | join: " and " }}'
+      '{{ beatles | join: " and " }}'
     return test(src, 'John and Paul and George and Ringo')
   })
 
diff --git a/test/scope.js b/test/scope.js
index 6ecce7de1..889d61d93 100644
--- a/test/scope.js
+++ b/test/scope.js
@@ -187,11 +187,6 @@ describe('scope', function () {
   })
 
   describe('.push()', function () {
-    it('should throw when trying to push non-object', function () {
-      expect(function () {
-        scope.push(false)
-      }).to.throw()
-    })
     it('should push scope', function () {
       scope.set('bar', 'bar')
       scope.push({
diff --git a/test/tags/assign.js b/test/tags/assign.js
index d93f2831f..6a8e243cc 100644
--- a/test/tags/assign.js
+++ b/test/tags/assign.js
@@ -1,53 +1,67 @@
+'use strict'
 const Liquid = require('../..')
 const chai = require('chai')
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
 describe('tags/assign', function () {
-  var liquid = Liquid()
+  let liquid = Liquid()
   it('should throw when variable expression illegal', function () {
-    var src = '{% assign / %}'
-    var ctx = {}
+    let src = '{% assign / %}'
+    let ctx = {}
     return expect(liquid.parseAndRender(src, ctx)).to.be.rejectedWith(/illegal/)
   })
-
-  it('should assign as string', function () {
-    var src = '{% assign foo="bar" %}{{foo}}'
+  it('should support assign to a string', function () {
+    let src = '{% assign foo="bar" %}{{foo}}'
     return expect(liquid.parseAndRender(src))
       .to.eventually.equal('bar')
   })
+  it('should support assign to a number', function () {
+    let src = '{% assign foo=10086 %}{{foo}}'
+    return expect(liquid.parseAndRender(src))
+      .to.eventually.equal('10086')
+  })
+  it('should shading rather than overwriting', function () {
+    let ctx = {foo: 'foo'}
+    let src = '{% assign foo="FOO" %}{{foo}}'
+    return liquid.parseAndRender(src, ctx)
+      .then(x => {
+        expect(x).to.equal('FOO')
+        expect(ctx.foo).to.equal('foo')
+      })
+  })
   it('should assign as array', function () {
-    var src = '{% assign foo=(1..3) %}{{foo}}'
+    let src = '{% assign foo=(1..3) %}{{foo}}'
     return expect(liquid.parseAndRender(src))
       .to.eventually.equal('[1,2,3]')
   })
   it('should assign as filter result', function () {
-    var src = '{% assign foo="a b" | capitalize | split: " " | first %}{{foo}}'
+    let src = '{% assign foo="a b" | capitalize | split: " " | first %}{{foo}}'
     return expect(liquid.parseAndRender(src))
       .to.eventually.equal('A')
   })
   it('should assign var-1', function () {
-    var src = '{% assign var-1 = 5 %}{{ var-1 }}'
+    let src = '{% assign var-1 = 5 %}{{ var-1 }}'
     return expect(liquid.parseAndRender(src)).to.eventually.equal('5')
   })
   it('should assign var-', function () {
-    var src = '{% assign var- = 5 %}{{ var- }}'
+    let src = '{% assign var- = 5 %}{{ var- }}'
     return expect(liquid.parseAndRender(src)).to.eventually.equal('5')
   })
   it('should assign -var', function () {
-    var src = '{% assign -var = 5 %}{{ -var }}'
+    let src = '{% assign -let = 5 %}{{ -let }}'
     return expect(liquid.parseAndRender(src)).to.eventually.equal('5')
   })
   it('should assign -5-5', function () {
-    var src = '{% assign -5-5 = 5 %}{{ -5-5 }}'
+    let src = '{% assign -5-5 = 5 %}{{ -5-5 }}'
     return expect(liquid.parseAndRender(src)).to.eventually.equal('5')
   })
   it('should assign 4-3', function () {
-    var src = '{% assign 4-3 = 5 %}{{ 4-3 }}'
+    let src = '{% assign 4-3 = 5 %}{{ 4-3 }}'
     return expect(liquid.parseAndRender(src)).to.eventually.equal('5')
   })
   it('should not assign -6', function () {
-    var src = '{% assign -6 = 5 %}{{ -6 }}'
+    let src = '{% assign -6 = 5 %}{{ -6 }}'
     return expect(liquid.parseAndRender(src)).to.eventually.equal('-6')
   })
 })