diff --git a/packages/babel-plugin-proposal-partial-application/src/index.js b/packages/babel-plugin-proposal-partial-application/src/index.js
index d9b18598b3..9b10ac7357 100644
--- a/packages/babel-plugin-proposal-partial-application/src/index.js
+++ b/packages/babel-plugin-proposal-partial-application/src/index.js
@@ -99,8 +99,6 @@ export default declare(api => {
               t.memberExpression(
                 t.cloneNode(receiverLVal),
                 node.callee.property,
-                false,
-                false,
               ),
             ),
             ...argsInitializers,
@@ -114,8 +112,6 @@ export default declare(api => {
                       t.memberExpression(
                         t.cloneNode(functionLVal),
                         t.identifier("call"),
-                        false,
-                        false,
                       ),
                       [t.cloneNode(receiverLVal), ...args],
                     ),
diff --git a/packages/babel-types/src/definitions/core.ts b/packages/babel-types/src/definitions/core.ts
index a7fa02ba25..c6ec727eb3 100644
--- a/packages/babel-types/src/definitions/core.ts
+++ b/packages/babel-types/src/definitions/core.ts
@@ -641,7 +641,12 @@ defineType("LogicalExpression", {
 });
 
 defineType("MemberExpression", {
-  builder: ["object", "property", "computed", "optional"],
+  builder: [
+    "object",
+    "property",
+    "computed",
+    ...(!process.env.BABEL_TYPES_8_BREAKING ? ["optional"] : []),
+  ],
   visitor: ["object", "property"],
   aliases: ["Expression", "LVal"],
   fields: {