Merge branch 'master' into merge-master

# Conflicts:
#	lerna.json
#	packages/babel-cli/package.json
#	packages/babel-core/package.json
#	packages/babel-generator/package.json
#	packages/babel-helper-builder-react-jsx/package.json
#	packages/babel-helper-function-name/package.json
#	packages/babel-helper-optimise-call-expression/package.json
#	packages/babel-helper-replace-supers/package.json
#	packages/babel-helper-transform-fixture-test-runner/package.json
#	packages/babel-helpers/package.json
#	packages/babel-plugin-transform-class-properties/package.json
#	packages/babel-plugin-transform-es2015-block-scoping/package.json
#	packages/babel-plugin-transform-es2015-classes/package.json
#	packages/babel-plugin-transform-es2015-modules-commonjs/package.json
#	packages/babel-plugin-transform-es2015-modules-systemjs/package.json
#	packages/babel-plugin-transform-es2015-modules-umd/package.json
#	packages/babel-plugin-transform-es2015-parameters/package.json
#	packages/babel-plugin-transform-react-jsx/package.json
#	packages/babel-register/package.json
#	packages/babel-template/package.json
#	packages/babel-traverse/package.json
#	packages/babel/package.json

packages/babel-plugin-transform-react-constant-elements/package.json

@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-transform-react-constant-elements",
-  "version": "6.22.0",
+  "version": "6.23.0",
   "description": "Treat React JSX elements as value types and hoist them to the highest scope",
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-react-constant-elements",
   "license": "MIT",

packages/babel-plugin-transform-react-constant-elements/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function ({ types: t }) {
   const immutabilityVisitor = {
     enter(path, state) {
       const stop = () => {
@@ -11,15 +11,39 @@ export default function () {
         return;
       }
 
+      // Elements with refs are not safe to hoist.
       if (path.isJSXIdentifier({ name: "ref" }) && path.parentPath.isJSXAttribute({ name: path.node })) {
         return stop();
       }
 
+      // Ignore identifiers & JSX expressions.
       if (path.isJSXIdentifier() || path.isIdentifier() || path.isJSXMemberExpression()) {
         return;
       }
 
-      if (!path.isImmutable()) stop();
+      if (!path.isImmutable()) {
+        // If it's not immutable, it may still be a pure expression, such as string concatenation.
+        // It is still safe to hoist that, so long as its result is immutable.
+        // If not, it is not safe to replace as mutable values (like objects) could be mutated after render.
+        // https://github.com/facebook/react/issues/3226
+        if (path.isPure()) {
+          const expressionResult = path.evaluate();
+          if (expressionResult.confident) {
+            // We know the result; check its mutability.
+            const { value } = expressionResult;
+            const isMutable = (value && typeof value === "object") || (typeof value === "function");
+            if (!isMutable) {
+              // It evaluated to an immutable value, so we can hoist it.
+              return;
+            }
+          } else if (t.isIdentifier(expressionResult.deopt)) {
+            // It's safe to hoist here if the deopt reason is an identifier (e.g. func param).
+            // The hoister will take care of how high up it can be hoisted.
+            return;
+          }
+        }
+        stop();
+      }
     }
   };
 

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/append-to-end-when-declared-in-scope-3/expected.js

@@ -1,18 +1,19 @@
-var _ref = <p>Parent</p>;
-
 var _ref2 = <div>child</div>;
 
+var _ref3 = <p>Parent</p>;
+
 (function () {
   class App extends React.Component {
     render() {
-      return <div>
-          {_ref}
-          <AppItem />
-        </div>;
+      return _ref;
     }
   }
 
   const AppItem = () => {
     return _ref2;
-  };
-});
+  },
+        _ref = <div>
+          {_ref3}
+          <AppItem />
+        </div>;
+});

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/append-to-end-when-declared-in-scope/expected.js

@@ -1,16 +1,14 @@
-var _ref = <p>Parent</p>;
-
 export default class App extends React.Component {
   render() {
-    return <div>
-        {_ref}
-        <AppItem />
-      </div>;
+    return _ref;
   }
 }
 
-var _ref2 = <div>child</div>;
-
-const AppItem = () => {
+const _ref2 = <div>child</div>,
+      AppItem = () => {
   return _ref2;
-};
+},
+      _ref = <div>
+        <p>Parent</p>
+        <AppItem />
+      </div>;

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-class/actual.js

@@ -0,0 +1,15 @@
+import React from "react";
+
+const Parent = ({}) => (
+  <div className="parent">
+    <Child/>
+  </div>
+);
+
+export default Parent;
+
+let Child = () => (
+  <div className="child">
+    ChildTextContent
+  </div>
+);

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-class/expected.js

@@ -0,0 +1,13 @@
+import React from "react";
+
+const Parent = ({}) => _ref;
+
+export default Parent;
+
+let _ref2 = <div className="child">
+    ChildTextContent
+  </div>,
+    Child = () => _ref2,
+    _ref = <div className="parent">
+    <Child />
+  </div>;

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-declaration/expected.js

@@ -8,8 +8,9 @@ function render() {
 
 function render() {
   const bar = "bar",
-        renderFoo = () => <foo bar={bar} baz={baz} />,
-        baz = "baz";
+        renderFoo = () => _ref2,
+        baz = "baz",
+        _ref2 = <foo bar={bar} baz={baz} />;
 
   return renderFoo();
 }

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-hoc/actual.js

@@ -0,0 +1,18 @@
+import React from "react";
+
+const HOC = component => component;
+
+const Parent = ({}) => (
+  <div className="parent">
+    <Child/>
+  </div>
+);
+
+export default Parent;
+
+let Child = () => (
+  <div className="child">
+    ChildTextContent
+  </div>
+);
+Child = HOC(Child);

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-before-hoc/expected.js

@@ -0,0 +1,18 @@
+import React from "react";
+
+const HOC = component => component;
+
+const Parent = ({}) => _ref;
+
+export default Parent;
+
+var _ref2 = <div className="child">
+    ChildTextContent
+  </div>;
+
+let Child = () => _ref2;
+Child = HOC(Child);
+
+var _ref = <div className="parent">
+    <Child />
+  </div>;

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/dont-hoist-block-scoped-variables/expected.js

@@ -1,17 +1,11 @@
 function render(flag) {
   if (flag) {
-    var _ret = function () {
-      var bar = "bar";
+    var bar = "bar";
 
-      [].map(() => bar);
+    [].map(() => bar);
 
-      return {
-        v: <foo bar={bar} />
-      };
-    }();
-
-    if (typeof _ret === "object") return _ret.v;
+    return <foo bar={bar} />;
   }
 
   return null;
-}
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-constant/actual.js

@@ -0,0 +1,4 @@
+function render() {
+  this.component = "div";
+  return () => <this.component />;
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-constant/expected.js

@@ -0,0 +1,7 @@
+function render() {
+  this.component = "div";
+
+  var _ref = <this.component />;
+
+  return () => _ref;
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/actual.js

@@ -0,0 +1,5 @@
+class Component extends React.Component {
+  subComponent = () => <span>Sub Component</span>
+
+  render = () => <this.subComponent />
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/expected.js

@@ -0,0 +1,12 @@
+var _ref = <span>Sub Component</span>;
+
+class Component extends React.Component {
+  constructor(...args) {
+    var _temp;
+
+    var _ref2 = <this.subComponent />;
+
+    return _temp = super(...args), this.subComponent = () => _ref, this.render = () => _ref2, _temp;
+  }
+
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression-this/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["syntax-jsx", "transform-react-constant-elements", "transform-class-properties"]
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/actual.js

@@ -0,0 +1,6 @@
+const els = {
+  subComponent: () => <span>Sub Component</span>
+};
+class Component extends React.Component {
+  render = () => <els.subComponent />
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/expected.js

@@ -0,0 +1,16 @@
+var _ref = <span>Sub Component</span>;
+
+const els = {
+  subComponent: () => _ref
+};
+
+var _ref2 = <els.subComponent />;
+
+class Component extends React.Component {
+  constructor(...args) {
+    var _temp;
+
+    return _temp = super(...args), this.render = () => _ref2, _temp;
+  }
+
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/member-expression/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["syntax-jsx", "transform-react-constant-elements", "transform-class-properties"]
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-deopt/actual.js

@@ -0,0 +1,5 @@
+// https://github.com/facebook/react/issues/3226
+// Not safe to reuse because it is mutable
+function render() {
+  return <div style={{ width: 100 }} />;
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-deopt/expected.js

@@ -0,0 +1,5 @@
+// https://github.com/facebook/react/issues/3226
+// Not safe to reuse because it is mutable
+function render() {
+  return <div style={{ width: 100 }} />;
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-2/actual.js

@@ -0,0 +1,5 @@
+function render(offset) {
+  return function () {
+    return <div tabIndex={offset + 1} />;
+  };
+}

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-2/expected.js

@@ -0,0 +1,8 @@
+function render(offset) {
+  var _ref = <div tabIndex={offset + 1} />;
+
+  return function () {
+    return _ref;
+  };
+}
+

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-3/actual.js

@@ -0,0 +1,10 @@
+const OFFSET = 3;
+
+var Foo = React.createClass({
+  render: function () {
+    return (
+      <div tabIndex={OFFSET + 1} />
+    );
+  }
+});
+

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression-3/expected.js

@@ -0,0 +1,10 @@
+const OFFSET = 3;
+
+var _ref = <div tabIndex={OFFSET + 1} />;
+
+var Foo = React.createClass({
+  render: function () {
+    return _ref;
+  }
+});
+

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression/actual.js

@@ -0,0 +1,11 @@
+var Foo = React.createClass({
+  render: function () {
+    return (
+      <div data-text={
+        "Some text, " +
+        "and some more too."
+      } />
+    );
+  }
+});
+

packages/babel-plugin-transform-react-constant-elements/test/fixtures/constant-elements/pure-expression/expected.js

@@ -0,0 +1,8 @@
+var _ref = <div data-text={"Some text, " + "and some more too."} />;
+
+var Foo = React.createClass({
+  render: function () {
+    return _ref;
+  }
+});
+