diff --git a/packages/babel-plugin-proposal-decorators/src/index.js b/packages/babel-plugin-proposal-decorators/src/index.js
index 84c627e6decd..be8e25403c04 100644
--- a/packages/babel-plugin-proposal-decorators/src/index.js
+++ b/packages/babel-plugin-proposal-decorators/src/index.js
@@ -6,16 +6,12 @@ import legacyVisitor from "./transformer-legacy";
 export default declare((api, options) => {
   api.assertVersion(7);
 
-  const {
-    legacy = false,
-    decoratorsBeforeExport,
-    automaticParentheses,
-  } = options;
-
+  const { legacy = false } = options;
   if (typeof legacy !== "boolean") {
     throw new Error("'legacy' must be a boolean.");
   }
 
+  let { decoratorsBeforeExport } = options;
   if (decoratorsBeforeExport !== undefined) {
     if (legacy) {
       throw new Error(
@@ -25,8 +21,11 @@ export default declare((api, options) => {
     if (typeof decoratorsBeforeExport !== "boolean") {
       throw new Error("'decoratorsBeforeExport' must be a boolean.");
     }
+  } else if (!legacy) {
+    decoratorsBeforeExport = true;
   }
 
+  const { automaticParentheses } = options;
   if (automaticParentheses !== undefined) {
     if (legacy) {
       throw new Error(
diff --git a/packages/babel-plugin-proposal-decorators/test/fixtures/transformation/export-default/input.mjs b/packages/babel-plugin-proposal-decorators/test/fixtures/transformation/export-default/input.mjs
index 99eb5ad60db3..97db46f8a830 100644
--- a/packages/babel-plugin-proposal-decorators/test/fixtures/transformation/export-default/input.mjs
+++ b/packages/babel-plugin-proposal-decorators/test/fixtures/transformation/export-default/input.mjs
@@ -1 +1,2 @@
-export default @dec() class {}
\ No newline at end of file
+@dec()
+export default class {}
diff --git a/packages/babel-plugin-syntax-decorators/src/index.js b/packages/babel-plugin-syntax-decorators/src/index.js
index 8f0c12fbc0d4..5a208d351566 100644
--- a/packages/babel-plugin-syntax-decorators/src/index.js
+++ b/packages/babel-plugin-syntax-decorators/src/index.js
@@ -8,14 +8,6 @@ export default declare((api, options) => {
     throw new Error("'legacy' must be a boolean.");
   }
 
-  if (legacy !== true) {
-    throw new Error(
-      "The new decorators proposal is not supported yet." +
-        ' You must pass the `"legacy": true` option to' +
-        " @babel/plugin-syntax-decorators",
-    );
-  }
-
   let { decoratorsBeforeExport } = options;
   if (decoratorsBeforeExport !== undefined) {
     if (legacy) {
diff --git a/packages/babel-plugin-syntax-decorators/test/index.js b/packages/babel-plugin-syntax-decorators/test/index.js
index 79e201fcc2e9..9242acad527c 100644
--- a/packages/babel-plugin-syntax-decorators/test/index.js
+++ b/packages/babel-plugin-syntax-decorators/test/index.js
@@ -15,7 +15,7 @@ describe("'legacy' option", function() {
     expect(makeParser("", { legacy: "legacy" })).toThrow();
   });
 
-  test.skip("'legacy': false", function() {
+  test("'legacy': false", function() {
     expect(makeParser("({ @dec fn() {} })", { legacy: false })).toThrow();
   });
 
@@ -23,17 +23,13 @@ describe("'legacy' option", function() {
     expect(makeParser("({ @dec fn() {} })", { legacy: true })).not.toThrow();
   });
 
-  test.skip("defaults to 'false'", function() {
+  test("defaults to 'false'", function() {
     expect(makeParser("({ @dec fn() {} })", {})).toThrow();
   });
-
-  test("it must be true", function() {
-    expect(makeParser("", { legacy: false })).toThrow();
-  });
 });
 
 describe("'decoratorsBeforeExport' option", function() {
-  test.skip("must be boolean", function() {
+  test("must be boolean", function() {
     expect(makeParser("", { decoratorsBeforeExport: "before" })).toThrow();
   });
 
@@ -46,7 +42,6 @@ describe("'decoratorsBeforeExport' option", function() {
   const BEFORE = "@dec export class Foo {}";
   const AFTER = "export @dec class Foo {}";
 
-  // These are skipped
   run(BEFORE, undefined, false);
   run(AFTER, undefined, true);
   run(BEFORE, true, false);
@@ -61,7 +56,7 @@ describe("'decoratorsBeforeExport' option", function() {
       (code === BEFORE ? "before" : "after") +
       "export";
 
-    test.skip(name, function() {
+    test(name, function() {
       const expectTheParser = expect(
         makeParser(code, { decoratorsBeforeExport: before }),
       );
diff --git a/packages/babel-types/src/asserts/generated/index.js b/packages/babel-types/src/asserts/generated/index.js
index 5feffa76e445..4fc988f4fd7d 100644
--- a/packages/babel-types/src/asserts/generated/index.js
+++ b/packages/babel-types/src/asserts/generated/index.js
@@ -468,6 +468,12 @@ export function assertObjectTypeAnnotation(
 ): void {
   assert("ObjectTypeAnnotation", node, opts);
 }
+export function assertObjectTypeInternalSlot(
+  node: Object,
+  opts?: Object = {},
+): void {
+  assert("ObjectTypeInternalSlot", node, opts);
+}
 export function assertObjectTypeCallProperty(
   node: Object,
   opts?: Object = {},
diff --git a/packages/babel-types/src/builders/generated/index.js b/packages/babel-types/src/builders/generated/index.js
index fdb9bde25685..eda7514c11fe 100644
--- a/packages/babel-types/src/builders/generated/index.js
+++ b/packages/babel-types/src/builders/generated/index.js
@@ -429,6 +429,10 @@ export function ObjectTypeAnnotation(...args: Array<any>): Object {
   return builder("ObjectTypeAnnotation", ...args);
 }
 export { ObjectTypeAnnotation as objectTypeAnnotation };
+export function ObjectTypeInternalSlot(...args: Array<any>): Object {
+  return builder("ObjectTypeInternalSlot", ...args);
+}
+export { ObjectTypeInternalSlot as objectTypeInternalSlot };
 export function ObjectTypeCallProperty(...args: Array<any>): Object {
   return builder("ObjectTypeCallProperty", ...args);
 }
diff --git a/packages/babel-types/src/validators/generated/index.js b/packages/babel-types/src/validators/generated/index.js
index 1171e9a55711..42de2ad2e8da 100644
--- a/packages/babel-types/src/validators/generated/index.js
+++ b/packages/babel-types/src/validators/generated/index.js
@@ -1522,6 +1522,20 @@ export function isObjectTypeAnnotation(node: Object, opts?: Object): boolean {
 
   return false;
 }
+export function isObjectTypeInternalSlot(node: Object, opts?: Object): boolean {
+  if (!node) return false;
+
+  const nodeType = node.type;
+  if (nodeType === "ObjectTypeInternalSlot") {
+    if (typeof opts === "undefined") {
+      return true;
+    } else {
+      return shallowEqual(node, opts);
+    }
+  }
+
+  return false;
+}
 export function isObjectTypeCallProperty(node: Object, opts?: Object): boolean {
   if (!node) return false;
 
@@ -3659,6 +3673,7 @@ export function isUserWhitespacable(node: Object, opts?: Object): boolean {
     nodeType === "UserWhitespacable" ||
     "ObjectMethod" === nodeType ||
     "ObjectProperty" === nodeType ||
+    "ObjectTypeInternalSlot" === nodeType ||
     "ObjectTypeCallProperty" === nodeType ||
     "ObjectTypeIndexer" === nodeType ||
     "ObjectTypeProperty" === nodeType ||
@@ -3882,6 +3897,7 @@ export function isFlow(node: Object, opts?: Object): boolean {
     "NumberLiteralTypeAnnotation" === nodeType ||
     "NumberTypeAnnotation" === nodeType ||
     "ObjectTypeAnnotation" === nodeType ||
+    "ObjectTypeInternalSlot" === nodeType ||
     "ObjectTypeCallProperty" === nodeType ||
     "ObjectTypeIndexer" === nodeType ||
     "ObjectTypeProperty" === nodeType ||