[DEPRECATION] Deprecates old browser support policy

lib/index.js

@@ -246,6 +246,12 @@ module.exports = {
     let ember;
     let targets = (this.project && this.project.targets && this.project.targets.browsers) || [];
 
+    if (targets.includes('ie 11')) {
+      this.ui.writeWarnLine(
+        'Internet Explorer 11 is listed in your compilation targets, but it will no longer be supported in the next major version of Ember. Please update your targets to remove IE 11 and include new targets that are within the updated support policy. For details on the new browser support policy, see:\n\n - The official documentation: http://emberjs.com/browser-support\n - the deprecation guide: https://emberjs.com/deprecations/v3.x#toc_3-0-browser-support-policy\n'
+      );
+    }
+
     const isProduction = process.env.EMBER_ENV === 'production';
 
     if (

packages/@ember/-internals/browser-environment/index.ts

@@ -3,6 +3,8 @@ import hasDom from './lib/has-dom';
 declare const InstallTrigger: unknown;
 declare const chrome: unknown;
 declare const opera: unknown;
+declare const MSInputMethodContext: unknown;
+declare const documentMode: unknown;
 
 export { default as hasDOM } from './lib/has-dom';
 export const window = hasDom ? self : null;
@@ -11,3 +13,6 @@ export const history = hasDom ? self.history : null;
 export const userAgent = hasDom ? self.navigator.userAgent : 'Lynx (textmode)';
 export const isChrome = hasDom ? typeof chrome === 'object' && !(typeof opera === 'object') : false;
 export const isFirefox = hasDom ? typeof InstallTrigger !== 'undefined' : false;
+export const isIE = hasDom
+  ? typeof MSInputMethodContext !== 'undefined' && typeof documentMode !== 'undefined'
+  : false;

packages/ember/index.js

@@ -170,6 +170,22 @@ import {
 
 const Ember = (typeof context.imports.Ember === 'object' && context.imports.Ember) || {};
 
+import { isIE } from '@ember/-internals/browser-environment';
+
+deprecate(
+  'Internet Explorer 11 will no longer be supported in the next major version of Ember. For details on the new browser support policy, see the official documentation: http://emberjs.com/browser-support',
+  !isIE,
+  {
+    id: '3-0-browser-support-policy',
+    url: 'https://emberjs.com/deprecations/v3.x#toc_3-0-browser-support-policy',
+    until: '4.0.0',
+    for: 'ember-source',
+    since: {
+      enabled: '3.26.0',
+    },
+  }
+);
+
 Ember.isNamespace = true;
 Ember.toString = function () {
   return 'Ember';

tests/index.html

@@ -66,7 +66,13 @@
           EmberENV.ENABLE_OPTIONAL_FEATURES = true;
         }
 
-        EmberENV['RAISE_ON_DEPRECATION'] = true;
+        var isIE = Boolean(window.MSInputMethodContext) && Boolean(document.documentMode);
+
+        // ignore deprecations for IE11 specifically (due to browser support
+        // policy deprecation, which happens before we can `expectDeprecation`)
+        if (!isIE) {
+          EmberENV['RAISE_ON_DEPRECATION'] = true;
+        }
 
         if (QUnit.urlParams.debugrendertree) {
           EmberENV['_DEBUG_RENDER_TREE'] = true;