Handle foo && yield bar (#218)

Fix #216.

ecmascript/transforms/src/compat/es2017/async_to_generator/mod.rs

@@ -582,12 +582,19 @@ impl Actual {
 fn make_fn_ref(mut expr: FnExpr) -> Expr {
     struct AwaitToYield;
 
-    impl Fold<Function> for AwaitToYield {
+    macro_rules! noop {
+        ($T:path) => {
+            impl Fold<$T> for AwaitToYield {
                 /// Don't recurse into function.
-        fn fold(&mut self, f: Function) -> Function {
+                fn fold(&mut self, f: $T) -> $T {
                     f
                 }
             }
+        };
+    }
+    noop!(Function);
+    noop!(Constructor);
+    noop!(ArrowExpr);
 
     impl Fold<Expr> for AwaitToYield {
         fn fold(&mut self, expr: Expr) -> Expr {

ecmascript/transforms/src/compat/es2017/async_to_generator/tests.rs

@@ -27,6 +27,28 @@ fn tr() -> impl Fold<Module> {
     )
 }
 
+test!(
+    ::swc_ecma_parser::Syntax::default(),
+    |_| tr(),
+    issue_216,
+    r#"
+async function foo(bar) {
+  bar && await bar();
+}
+"#,
+    r#"
+function _foo() {
+    _foo = _asyncToGenerator(function*(bar) {
+        bar && (yield bar());
+    });
+    return _foo.apply(this, arguments);
+}
+function foo(bar) {
+    return _foo.apply(this, arguments);
+}
+"#
+);
+
 test!(
     ::swc_ecma_parser::Syntax::default(),
     |_| tr(),

ecmascript/transforms/src/fixer.rs

@@ -309,7 +309,9 @@ impl Fold<Expr> for Fixer {
 
             Expr::Bin(mut expr) => {
                 expr.right = match *expr.right {
-                    e @ Expr::Assign(..) | e @ Expr::Seq(..) => box e.wrap_with_paren(),
+                    e @ Expr::Assign(..) | e @ Expr::Seq(..) | e @ Expr::Yield(..) => {
+                        box e.wrap_with_paren()
+                    }
                     _ => expr.right,
                 };