fix(mangle): handle inferred names for functions

packages/babel-plugin-minify-mangle-names/src/index.js

@@ -139,6 +139,29 @@ module.exports = babel => {
           });
         },
 
+        /**
+         * This is required because after function name transformation
+         * plugin (part of es2015), the function name is NOT added to the
+         * scope's bindings. So to fix this issue, we simply add a hack to
+         * handle that case - fix it to the scope tree.
+         *
+         * Related:
+         * - https://github.com/babel/minify/issues/829
+         */
+        BindingIdentifier(path) {
+          const { scope } = path;
+
+          if (
+            // the parent has this id as the name
+            (path.parentPath.isFunctionExpression({ id: path.node }) ||
+              path.parentPath.isClassExpression({ id: path.node })) &&
+            // and the id isn't yet added to the scope
+            !hop.call(path.parentPath.scope.bindings, path.node.name)
+          ) {
+            path.parentPath.scope.registerBinding("local", path.parentPath);
+          }
+        },
+
         /**
          * This is necessary because, in Babel, the scope.references
          * does NOT contain the references in that scope. Only the program

packages/babel-preset-minify/__tests__/minify-env-tests.js

@@ -196,4 +196,59 @@ describe("preset along with env", () => {
       console.log(foo);
     `
   );
+
+  thePlugin(
+    "should fix issue#829 mangling after function name",
+    `
+      function foo() {
+        let con = console;
+
+        return {
+          a(bar) {
+            con.log(bar);
+          }
+        };
+      }
+    `,
+    `
+      function foo() {
+        var b = console;
+        return {
+          a: function d(c) {
+            b.log(c);
+          }
+        };
+      }
+    `
+  );
+
+  thePlugin(
+    "should fix issue#829 mangling after function name 2",
+    `
+      function bar() {
+        var b = console;
+        return {
+          a: class {
+            constructor(bar) {
+              b.log(bar);
+            }
+          }
+        };
+      }
+    `,
+    `
+      function _classCallCheck(a, b) { if (!(a instanceof b)) throw new TypeError(\"Cannot call a class as a function\"); }
+
+      function bar() {
+        var c = console;
+        return {
+          a: function b(a) {
+            "use strict";
+
+            _classCallCheck(this, b), c.log(a);
+          }
+        };
+      }
+    `
+  );
 });