Allow await expression at other than expression statement (#636)

Fixes #635

ecmascript/parser/src/parser/expr/ops.rs

@@ -305,7 +305,7 @@ impl<'a, I: Tokens> Parser<'a, I> {
             })));
         }
 
-        if self.ctx().in_async && is!("await") {
+        if (self.ctx().in_async || self.syntax().top_level_await()) && is!("await") {
             return self.parse_await_expr();
         }
 

tests/projects.rs

@@ -361,3 +361,12 @@ fn await_expr() {
     assert!(f.contains("await"));
     assert!(f.contains("test"));
 }
+
+#[test]
+fn await_expr_2() {
+    let f = file("tests/projects/await-expression-2/input.js").unwrap();
+    println!("{}", f);
+
+    assert!(f.contains("await"));
+    assert!(f.contains("test"));
+}

tests/projects/await-expression-2/.swcrc

@@ -0,0 +1,9 @@
+{
+  "jsc": {
+    "target": "es2017",
+    "parser": {
+        "syntax": "ecmascript",
+        "topLevelAwait": true
+    }
+  }
+}

tests/projects/await-expression-2/input.js

@@ -0,0 +1 @@
+const foo = await test;