Remove helpersNamespace in favor of helperGenerator.

packages/babel-core/src/transformation/file/file.js

@@ -65,6 +65,16 @@ export default class File {
   }
 
   set(key: mixed, val: mixed) {
+    if (key === "helpersNamespace") {
+      throw new Error(
+        "Babel 7.0.0-beta.56 has dropped support for the 'helpersNamespace' utility." +
+          "If you are using @babel/plugin-external-helpers you will need to use a newer " +
+          "version than the one you currently have installed. " +
+          "If you have your own implementation, you'll want to explore using 'helperGenerator' " +
+          "alongside 'file.availableHelper()'.",
+      );
+    }
+
     this._map.set(key, val);
   }
 
@@ -166,12 +176,9 @@ export default class File {
     if (declar) return t.cloneNode(declar);
 
     const generator = this.get("helperGenerator");
-    const runtime = this.get("helpersNamespace");
     if (generator) {
       const res = generator(name);
       if (res) return res;
-    } else if (runtime) {
-      return t.memberExpression(t.cloneNode(runtime), t.identifier(name));
     }
 
     const uid = (this.declarations[name] = this.scope.generateUidIdentifier(

packages/babel-helper-module-imports/test/index.js

@@ -18,7 +18,12 @@ function test(sourceType, opts, initializer, expectedCode) {
       function({ types: t }) {
         return {
           pre(file) {
-            file.set("helpersNamespace", t.identifier("babelHelpers"));
+            file.set("helperGenerator", name =>
+              t.memberExpression(
+                t.identifier("babelHelpers"),
+                t.identifier(name),
+              ),
+            );
           },
           visitor: {
             Program(path) {

packages/babel-plugin-external-helpers/src/index.js

@@ -6,7 +6,12 @@ export default declare(api => {
 
   return {
     pre(file) {
-      file.set("helpersNamespace", t.identifier("babelHelpers"));
+      file.set("helperGenerator", name => {
+        return t.memberExpression(
+          t.identifier("babelHelpers"),
+          t.identifier(name),
+        );
+      });
     },
   };
 });