Don't insert the same node into the AST multiple times (fixes babel/m…

…inify#556)

packages/babel-plugin-transform-es2015-modules-commonjs/src/index.js

@@ -73,7 +73,11 @@ export default function() {
  ),
  );
  } else {
- path.replaceWith(remap);
+ path.replaceWith(
+ // Clone the node before inserting it to ensure that different nodes in the AST are represented
+ // by different objects.
+ t.cloneWithoutLoc(remap),
+ );
  }
  this.requeueInParent(path);
  },

packages/babel-plugin-transform-es2015-modules-commonjs/test/copied-nodes.js

@@ -0,0 +1,19 @@
+const assert = require("assert");
+const babel = require("babel-core");
+
+test("Doesn't use the same object for two different nodes in the AST", function() {
+ const code = 'import Foo from "bar"; Foo; Foo;';
+
+ const ast = babel.transform(code, {
+ plugins: [[require("../"), { loose: true }]],
+ }).ast;
+
+ assert.equal(ast.program.body[3].expression.type, "MemberExpression");
+ assert.equal(ast.program.body[4].expression.type, "MemberExpression");
+
+ assert.notEqual(
+ ast.program.body[3].expression,
+ ast.program.body[4].expression,
+ "Expected different nodes in the AST to not be the same object",
+ );
+});