isConstantExpression should return true for immuable bindings (#8122)

* isConstantExpression should return true for immuable bindings

* New test

* Don't return undefined

packages/babel-plugin-proposal-class-properties/src/index.js

@@ -319,14 +319,15 @@ export default declare((api, options) => {
         const instanceBody = [];
 
         for (const computedPath of computedPaths) {
+          computedPath.traverse(classFieldDefinitionEvaluationTDZVisitor, {
+            classRef: path.scope.getBinding(ref.name),
+            file: this.file,
+          });
+
           const computedNode = computedPath.node;
           // Make sure computed property names are only evaluated once (upon class definition)
           // and in the right order in combination with static properties
           if (!computedPath.get("key").isConstantExpression()) {
-            computedPath.traverse(classFieldDefinitionEvaluationTDZVisitor, {
-              classRef: path.scope.getBinding(ref.name),
-              file: this.file,
-            });
             const ident = path.scope.generateUidIdentifierBasedOnNode(
               computedNode.key,
             );

packages/babel-plugin-proposal-class-properties/test/fixtures/public-loose/computed/output.js

@@ -17,7 +17,6 @@ var _computed2 = computed();
 var _ref2 = "test" + one;
 
 var _ref3 = /regex/;
-var _bar = bar;
 var _baz = baz;
 var _ref4 = `template${expression}`;
 
@@ -33,7 +32,7 @@ function () {
     this[void 0] = "void 0";
     this[_ref3] = "regex";
     this[foo] = "foo";
-    this[_bar] = "bar";
+    this[bar] = "bar";
     this[_baz] = "baz";
     this[`template`] = "template";
     this[_ref4] = "template-with-expression";

packages/babel-plugin-proposal-class-properties/test/fixtures/public/computed/output.js

@@ -17,7 +17,6 @@ var _computed2 = computed();
 var _ref2 = "test" + one;
 
 var _ref3 = /regex/;
-var _bar = bar;
 var _baz = baz;
 var _ref4 = `template${expression}`;
 
@@ -33,7 +32,7 @@ function () {
     babelHelpers.defineProperty(this, void 0, "void 0");
     babelHelpers.defineProperty(this, _ref3, "regex");
     babelHelpers.defineProperty(this, foo, "foo");
-    babelHelpers.defineProperty(this, _bar, "bar");
+    babelHelpers.defineProperty(this, bar, "bar");
     babelHelpers.defineProperty(this, _baz, "baz");
     babelHelpers.defineProperty(this, `template`, "template");
     babelHelpers.defineProperty(this, _ref4, "template-with-expression");

packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8110/input.js

@@ -0,0 +1,5 @@
+const field = Symbol('field');
+
+class A {
+  [field] = 10;
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8110/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["external-helpers", "proposal-class-properties"]
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8110/output.js

@@ -0,0 +1,8 @@
+const field = Symbol('field');
+
+class A {
+  constructor() {
+    babelHelpers.defineProperty(this, field, 10);
+  }
+
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz-edgest-case/options.json

@@ -1,5 +0,0 @@
-{
-  "plugins": ["proposal-class-properties", "transform-classes"],
-  "minNodeVersion": "6.0.0",
-  "throws": "Class \"A\" cannot be referenced in computed property keys."
-}

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz-general/exec.js

@@ -1,3 +0,0 @@
-class C {
-  static [C + 3] = 3;
-}

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz-general/options.json

@@ -1,5 +0,0 @@
-{
-  "plugins": ["proposal-class-properties", "transform-classes"],
-  "minNodeVersion": "6.0.0",
-  "throws": "Class \"C\" cannot be referenced in computed property keys."
-}

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz-loose/exec.js

@@ -1,3 +0,0 @@
-class C {
-  static [C + 3] = 3;
-}

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz-loose/options.json

@@ -1,5 +0,0 @@
-{
-  "plugins": [["proposal-class-properties", {"loose": true}]],
-  "minNodeVersion": "6.0.0",
-  "throws": "Class \"C\" cannot be referenced in computed property keys."
-}

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz/edgest-case/exec.js

@@ -0,0 +1,5 @@
+expect(() => {
+  class A {
+    static [{ x: A || 0 }.x];
+  }
+}).toThrow();

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz/edgest-case/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["proposal-class-properties", "transform-classes"]
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz/edgest-case/output.js

@@ -0,0 +1,17 @@
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+
+function _classNameTDZError(name) { throw new Error("Class \"" + name + "\" cannot be referenced in computed property keys."); }
+
+var _x$x = {
+  x: (_classNameTDZError("A"), A) || 0
+}.x;
+
+let A = function A() {
+  "use strict";
+
+  _classCallCheck(this, A);
+};
+
+_defineProperty(A, _x$x, void 0);

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz/general/exec.js

@@ -0,0 +1,5 @@
+expect(() => {
+  class C {
+    static [C + 3] = 3;
+  }
+}).toThrow();

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz/general/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["proposal-class-properties", "transform-classes"]
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz/general/output.js

@@ -0,0 +1,15 @@
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+
+function _classNameTDZError(name) { throw new Error("Class \"" + name + "\" cannot be referenced in computed property keys."); }
+
+var _ref = (_classNameTDZError("C"), C) + 3;
+
+let C = function C() {
+  "use strict";
+
+  _classCallCheck(this, C);
+};
+
+_defineProperty(C, _ref, 3);

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz/loose/exec.js

@@ -0,0 +1,5 @@
+expect(() => {
+  class C {
+    static [C + 3] = 3;
+  }
+}).toThrow();

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz/loose/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": [["proposal-class-properties", { "loose": true }]]
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz/loose/output.js

@@ -0,0 +1,7 @@
+function _classNameTDZError(name) { throw new Error("Class \"" + name + "\" cannot be referenced in computed property keys."); }
+
+var _ref = (_classNameTDZError("C"), C) + 3;
+
+class C {}
+
+C[_ref] = 3;

packages/babel-traverse/src/path/introspection.js

@@ -402,10 +402,8 @@ export function _resolve(dangerous?, resolved?): ?NodePath {
 export function isConstantExpression() {
   if (this.isIdentifier()) {
     const binding = this.scope.getBinding(this.node.name);
-    if (!binding) {
-      return false;
-    }
-    return binding.constant && binding.path.get("init").isConstantExpression();
+    if (!binding) return false;
+    return binding.constant;
   }
 
   if (this.isLiteral()) {