diff --git a/packages/core/src/util/ng_dev_mode.ts b/packages/core/src/util/ng_dev_mode.ts
index 119c391f96..16bc5f4477 100644
--- a/packages/core/src/util/ng_dev_mode.ts
+++ b/packages/core/src/util/ng_dev_mode.ts
@@ -8,9 +8,6 @@
 
 import {global} from './global';
 
-// Do not remove: needed for closure to be able to properly tree-shake ngDevMode.
-// goog.define
-
 declare global {
   /**
    * Values of ngDevMode
diff --git a/packages/core/src/util/ng_i18n_closure_mode.ts b/packages/core/src/util/ng_i18n_closure_mode.ts
index 5e784defdf..a966565819 100644
--- a/packages/core/src/util/ng_i18n_closure_mode.ts
+++ b/packages/core/src/util/ng_i18n_closure_mode.ts
@@ -8,9 +8,6 @@
 
 import {global} from './global';
 
-// Do not remove: needed for closure to be able to properly tree-shake ngI18nClosureMode.
-// goog.define
-
 declare global {
   const ngI18nClosureMode: boolean;
 }