Derived constructors should not be allowed to return primitives

packages/babel-helpers/src/helpers.js

@@ -615,9 +615,14 @@ helpers.possibleConstructorReturn = helper("7.0.0-beta.0")`
   import assertThisInitialized from "assertThisInitialized";
 
   export default function _possibleConstructorReturn(self, call) {
-    if (call && (typeof call === "object" || typeof call === "function")) {
-      return call;
+    if (call) {
+      if(typeof call === "object" || typeof call === "function"){
+        return call;
+      }else{
+        throw new TypeError("Invalid attempt to return primitive value");
+      }
     }
+
     return assertThisInitialized(self);
   }
 `;

packages/babel-plugin-transform-classes/test/fixtures/spec/derived-constructor-must-call-super-5/exec.js

@@ -0,0 +1,10 @@
+class Bar {}
+
+class Foo extends Bar {
+    constructor() {
+      super();
+      return 3;
+    }
+  }
+
+expect(() => new Foo()).toThrow("Invalid attempt to return primitive value");

packages/babel-plugin-transform-classes/test/fixtures/spec/derived-constructor-must-call-super-5/index.js

@@ -0,0 +1,6 @@
+class Foo extends Bar {
+  constructor() {
+    super();
+    return 3;
+  }
+}