fix: preserve this for super.* template tags

packages/babel-preset-env/test/fixtures/plugins-integration/class-arrow-super-tagged-expr/exec.js

@@ -0,0 +1,13 @@
+async function test() {
+  class Foo { foo() { return this } }
+  class Bar extends Foo {
+    a = async () => super.foo``
+    b = async () => super['foo']``
+    c = async (foo) => super[foo]``
+  }
+  const bar = new Bar
+  expect(await bar.a()).toEqual(bar);
+  expect(await bar.b()).toEqual(bar);
+  expect(await bar.c('foo')).toEqual(bar);
+}
+test()

packages/babel-preset-env/test/fixtures/plugins-integration/class-arrow-super-tagged-expr/input.js

@@ -0,0 +1,16 @@
+// This should print "true true true"
+async function test() {
+  class Foo { foo() { return this } }
+  class Bar extends Foo {
+    a = async () => super.foo``
+    b = async () => super['foo']``
+    c = async (foo) => super[foo]``
+  }
+  const bar = new Bar
+  console.log(
+    (await bar.a()) === bar,
+    (await bar.b()) === bar,
+    (await bar.c('foo')) === bar,
+  )
+}
+test()

packages/babel-preset-env/test/fixtures/plugins-integration/class-arrow-super-tagged-expr/options.json

@@ -0,0 +1,4 @@
+{
+  "targets": "chrome 50",
+  "presets": ["env"]
+}

packages/babel-preset-env/test/fixtures/plugins-integration/class-arrow-super-tagged-expr/output.js

@@ -0,0 +1,40 @@
+// This should print "true true true"
+function test() {
+  return _test.apply(this, arguments);
+}
+function _test() {
+  _test = babelHelpers.asyncToGenerator(function* () {
+    class Foo {
+      foo() {
+        return this;
+      }
+    }
+    class Bar extends Foo {
+      constructor(...args) {
+        var _superprop_getFoo = () => super.foo,
+          _this,
+          _superprop_get = _prop => super[_prop];
+        super(...args);
+        _this = this;
+        babelHelpers.defineProperty(this, "a", /*#__PURE__*/babelHelpers.asyncToGenerator(function* () {
+          return _superprop_getFoo().bind(_this)``;
+        }));
+        babelHelpers.defineProperty(this, "b", /*#__PURE__*/babelHelpers.asyncToGenerator(function* () {
+          return _superprop_get('foo').bind(_this)``;
+        }));
+        babelHelpers.defineProperty(this, "c", /*#__PURE__*/function () {
+          var _ref3 = babelHelpers.asyncToGenerator(function* (foo) {
+            return _superprop_get(foo).bind(_this)``;
+          });
+          return function (_x) {
+            return _ref3.apply(this, arguments);
+          };
+        }());
+      }
+    }
+    const bar = new Bar();
+    console.log((yield bar.a()) === bar, (yield bar.b()) === bar, (yield bar.c('foo')) === bar);
+  });
+  return _test.apply(this, arguments);
+}
+test();

packages/babel-traverse/src/path/conversion.ts

@@ -368,6 +368,9 @@ function hoistFunctionEnvironment(
       const isCall = superParentPath.isCallExpression({
         callee: superProp.node,
       });
+      const isTaggedTemplate = superParentPath.isTaggedTemplateExpression({
+        tag: superProp.node,
+      });
       const superBinding = getSuperPropBinding(thisEnvFn, isAssignment, key);
 
       const args: t.Expression[] = [];
@@ -393,6 +396,16 @@ function hoistFunctionEnvironment(
       } else if (isAssignment) {
         // Replace not only the super.prop, but the whole assignment
         superParentPath.replaceWith(call);
+      } else if (isTaggedTemplate) {
+        superProp.replaceWith(
+          callExpression(memberExpression(call, identifier("bind"), false), [
+            thisExpression(),
+          ]),
+        );
+
+        thisPaths.push(
+          superProp.get("arguments.0") as NodePath<t.ThisExpression>,
+        );
       } else {
         superProp.replaceWith(call);
       }