fix(es/compat): Fix generator (#5796)

**Description:**

- Merge `temp_vars` into `hoisted_vars`.
- Fix the context of the function call and new call.

**Related issue (if exists):**

 - vercel/next.js#40399

crates/swc/tests/exec/next/40399/1/exec.js

@@ -0,0 +1,7 @@
+(async () => {
+    // Blob is not defined
+    // const blob = new Blob();
+
+    new Uint8Array(await Promise.resolve(10));
+    console.log("Success");
+})();

crates/swc/tests/exec/next/40399/2/exec.js

@@ -0,0 +1,6 @@
+(async () => {
+    const a = await 1;
+    expect(a).toBe(1);
+    const b = ((x) => x + x)(await 2);
+    expect(b).toBe(4);
+})();

crates/swc/tests/exec/next/40399/3/exec.js

@@ -0,0 +1,25 @@
+class Foo {
+    constructor(v) {
+        this.value = v;
+    }
+
+    static klass = class {
+        constructor(v) {
+            this.value = v;
+        }
+    };
+}
+
+(async () => {
+    class Bar extends Foo {
+        async bar() {
+            const foo = new Foo(await Promise.resolve(1));
+            const foo2 = new Foo.klass(await Promise.resolve(2));
+
+            console.log(foo.value);
+            console.log(foo2.value);
+        }
+    }
+
+    await new Bar().bar();
+})();

crates/swc/tests/fixture/next.js/40399/1/input/index.js

@@ -0,0 +1,5 @@
+(async () => {
+    const blob = new Blob();
+    new Uint8Array(await blob.arrayBuffer());
+    console.log("Success");
+})();

crates/swc/tests/fixture/next.js/40399/1/output/index.js

@@ -0,0 +1,25 @@
+import _async_to_generator from "@swc/helpers/src/_async_to_generator.mjs";
+import _ts_generator from "@swc/helpers/src/_ts_generator.mjs";
+_async_to_generator(function() {
+    var blob, _;
+    return _ts_generator(this, function(_state) {
+        switch(_state.label){
+            case 0:
+                blob = new Blob();
+                _ = Uint8Array.bind;
+                return [
+                    4,
+                    blob.arrayBuffer()
+                ];
+            case 1:
+                new (_.apply(Uint8Array, [
+                    void 0,
+                    _state.sent()
+                ]));
+                console.log("Success");
+                return [
+                    2
+                ];
+        }
+    });
+})();

crates/swc/tests/fixture/next.js/40399/2/input/index.js

@@ -0,0 +1,6 @@
+(async () => {
+    const a = await 1;
+    expect(a).toBe(1);
+    const b = ((x) => x + x)(await 2);
+    expect(b).toBe(4);
+})();

crates/swc/tests/fixture/next.js/40399/2/output/index.js

@@ -0,0 +1,32 @@
+import _async_to_generator from "@swc/helpers/src/_async_to_generator.mjs";
+import _ts_generator from "@swc/helpers/src/_ts_generator.mjs";
+_async_to_generator(function() {
+    var a, b, _;
+    return _ts_generator(this, function(_state) {
+        switch(_state.label){
+            case 0:
+                return [
+                    4,
+                    1
+                ];
+            case 1:
+                a = _state.sent();
+                expect(a).toBe(1);
+                _ = function(x) {
+                    return x + x;
+                };
+                return [
+                    4,
+                    2
+                ];
+            case 2:
+                b = _.apply(void 0, [
+                    _state.sent()
+                ]);
+                expect(b).toBe(4);
+                return [
+                    2
+                ];
+        }
+    });
+})();

crates/swc/tests/fixture/next.js/40399/3/input/index.js

@@ -0,0 +1,25 @@
+class Foo {
+    constructor(v) {
+        this.value = v;
+    }
+
+    static klass = class {
+        constructor(v) {
+            this.value = v;
+        }
+    };
+}
+
+(async () => {
+    class Bar extends Foo {
+        async bar() {
+            const foo = new Foo(await Promise.resolve(1));
+            const foo2 = new Foo.klass(await Promise.resolve(2));
+
+            expect(foo.value).toBe(1);
+            expect(foo2.value).toBe(2);
+        }
+    }
+
+    await new Bar().bar();
+})();

crates/swc/tests/fixture/next.js/40399/3/output/index.js

@@ -0,0 +1,84 @@
+import _async_to_generator from "@swc/helpers/src/_async_to_generator.mjs";
+import _class_call_check from "@swc/helpers/src/_class_call_check.mjs";
+import _create_class from "@swc/helpers/src/_create_class.mjs";
+import _define_property from "@swc/helpers/src/_define_property.mjs";
+import _inherits from "@swc/helpers/src/_inherits.mjs";
+import _create_super from "@swc/helpers/src/_create_super.mjs";
+import _ts_generator from "@swc/helpers/src/_ts_generator.mjs";
+var Foo = function Foo(v) {
+    "use strict";
+    _class_call_check(this, Foo);
+    this.value = v;
+};
+_define_property(Foo, "klass", function _class(v) {
+    "use strict";
+    _class_call_check(this, _class);
+    this.value = v;
+});
+_async_to_generator(function() {
+    var Bar;
+    return _ts_generator(this, function(_state) {
+        switch(_state.label){
+            case 0:
+                Bar = /*#__PURE__*/ function(Foo1) {
+                    "use strict";
+                    _inherits(Bar, Foo1);
+                    var _super = _create_super(Bar);
+                    function Bar() {
+                        _class_call_check(this, Bar);
+                        return _super.apply(this, arguments);
+                    }
+                    _create_class(Bar, [
+                        {
+                            key: "bar",
+                            value: function bar() {
+                                return _async_to_generator(function() {
+                                    var foo, _, foo2, _1, _2;
+                                    return _ts_generator(this, function(_state) {
+                                        switch(_state.label){
+                                            case 0:
+                                                _ = Foo.bind;
+                                                return [
+                                                    4,
+                                                    Promise.resolve(1)
+                                                ];
+                                            case 1:
+                                                foo = new (_.apply(Foo, [
+                                                    void 0,
+                                                    _state.sent()
+                                                ]));
+                                                _2 = (_1 = Foo.klass).bind;
+                                                return [
+                                                    4,
+                                                    Promise.resolve(2)
+                                                ];
+                                            case 2:
+                                                foo2 = new (_2.apply(_1, [
+                                                    void 0,
+                                                    _state.sent()
+                                                ]));
+                                                expect(foo.value).toBe(1);
+                                                expect(foo2.value).toBe(2);
+                                                return [
+                                                    2
+                                                ];
+                                        }
+                                    });
+                                })();
+                            }
+                        }
+                    ]);
+                    return Bar;
+                }(Foo);
+                return [
+                    4,
+                    new Bar().bar()
+                ];
+            case 1:
+                _state.sent();
+                return [
+                    2
+                ];
+        }
+    });
+})();

crates/swc/tests/tsc-references/awaitCallExpression6_es5.1.normal.js

@@ -6,7 +6,7 @@ function func() {
 }
 function _func() {
     _func = _async_to_generator(function() {
-        var b;
+        var b, _;
         return _ts_generator(this, function(_state) {
             switch(_state.label){
                 case 0:
@@ -17,7 +17,7 @@ function _func() {
                         p
                     ];
                 case 1:
-                    b = _.apply(void 0, [
+                    b = _.apply(o, [
                         _state.sent(),
                         a,
                         a

crates/swc/tests/tsc-references/awaitCallExpression7_es5.1.normal.js

@@ -6,7 +6,7 @@ function func() {
 }
 function _func() {
     _func = _async_to_generator(function() {
-        var b, _tmp;
+        var b, _, _tmp;
         return _ts_generator(this, function(_state) {
             switch(_state.label){
                 case 0:
@@ -20,7 +20,7 @@ function _func() {
                         p
                     ];
                 case 1:
-                    b = _.apply(void 0, _tmp.concat(_state.sent(), a));
+                    b = _.apply(o, _tmp.concat(_state.sent(), a));
                     after();
                     return [
                         2

crates/swc/tests/tsc-references/awaitClassExpression_es5.1.normal.js

@@ -9,7 +9,7 @@ function func() {
 }
 function _func() {
     _func = _async_to_generator(function() {
-        var D;
+        var D, _;
         return _ts_generator(this, function(_state) {
             switch(_state.label){
                 case 0:

crates/swc_ecma_transforms_compat/src/es2015/generator.rs

@@ -338,7 +338,6 @@ struct Generator {
     /// Index to `blocks`
     with_block_stack: Option<Vec<Ptr<CodeBlock>>>,
 
-    temp_vars: Vec<VarDeclarator>,
     hoisted_vars: Vec<VarDeclarator>,
     hoisted_fns: Vec<FnDecl>,
 }
@@ -370,7 +369,6 @@ impl Default for Generator {
             exception_block_stack: Default::default(),
             current_exception_block: Default::default(),
             with_block_stack: Default::default(),
-            temp_vars: Default::default(),
             hoisted_vars: Default::default(),
             hoisted_fns: Default::default(),
         }
@@ -751,10 +749,11 @@ impl VisitMut for Generator {
             //  .mark resumeLabel
             //      _b.apply(_a, _c.concat([%sent%, 2]));
 
-            let (mut target, this_arg) =
-                self.create_call_binding(node.callee.take().expect_expr(), true);
+            node.callee.visit_mut_with(self);
+
+            let (target, this_arg) =
+                self.create_call_binding(node.callee.take().expect_expr(), false);
 
-            target.visit_mut_with(self);
             let callee = self.cache_expression(target);
 
             let mut args = node.args.take().into_iter().map(Some).collect::<Vec<_>>();
@@ -787,13 +786,11 @@ impl VisitMut for Generator {
             //  .mark resumeLabel
             //      new (_b.apply(_a, _c.concat([%sent%, 2])));
 
-            let (mut target, this_arg) = self.create_call_binding(
-                Box::new(node.callee.take().make_member(quote_ident!("bind"))),
-                true,
-            );
+            node.callee.visit_mut_with(self);
 
-            target.visit_mut_with(self);
-            let callee = self.cache_expression(target);
+            let (target, this_arg) = self.create_call_binding(node.callee.take(), true);
+
+            let callee = self.cache_expression(Box::new(target.make_member(quote_ident!("bind"))));
 
             let mut arg = if let Some(args) = node.args.take() {
                 let mut args = args.into_iter().map(Some).collect::<Vec<_>>();
@@ -809,16 +806,16 @@ impl VisitMut for Generator {
                 None
             };
 
-            let apply = callee.make_member(Ident::new(js_word!("apply"), node.span));
+            let apply = Expr::Ident(callee).apply(
+                node.span,
+                this_arg,
+                arg.take().map(|v| v.as_arg()).into_iter().collect(),
+            );
 
             *node = NewExpr {
                 span: node.span,
                 callee: Box::new(apply),
-                args: Some(
-                    once(this_arg.as_arg())
-                        .chain(arg.take().map(|v| v.as_arg()).into_iter())
-                        .collect(),
-                ),
+                args: None,
                 type_args: None,
             };
             return;
@@ -3392,7 +3389,7 @@ impl Generator {
     fn create_temp_variable(&mut self) -> Ident {
         let i = private_ident!("_");
 
-        self.temp_vars.push(VarDeclarator {
+        self.hoisted_vars.push(VarDeclarator {
             span: DUMMY_SP,
             name: i.clone().into(),
             init: None,
@@ -3404,16 +3401,43 @@ impl Generator {
 
     /// Returns `(target, this_arg)`
     fn create_call_binding(
-        &self,
+        &mut self,
         expr: Box<Expr>,
-        _cache_identifier: bool,
+        is_new_call: bool,
     ) -> (Box<Expr>, Box<Expr>) {
-        let callee = expr;
+        let mut callee = expr;
 
-        match &*callee {
-            Expr::SuperProp(..) => (callee, Box::new(Expr::This(ThisExpr { span: DUMMY_SP }))),
+        match &mut *callee {
+            Expr::Ident(..) => (
+                callee.clone(),
+                if is_new_call {
+                    callee
+                } else {
+                    undefined(DUMMY_SP)
+                },
+            ),
+
+            Expr::Member(MemberExpr { obj, .. }) if !is_new_call => {
+                if obj.is_ident() {
+                    let this_arg = obj.clone();
+                    return (callee, this_arg);
+                }
+
+                let this_arg = self.create_temp_variable();
+                *obj = Box::new(obj.take().make_assign_to(op!("="), this_arg.clone().into()));
+
+                (callee, Box::new(Expr::Ident(this_arg)))
+            }
 
-            _ => (callee, undefined(DUMMY_SP)),
+            _ => {
+                if !is_new_call {
+                    (callee, undefined(DUMMY_SP))
+                } else {
+                    let this_arg = self.create_temp_variable();
+                    let target = callee.make_assign_to(op!("="), this_arg.clone().into());
+                    (Box::new(target), Box::new(Expr::Ident(this_arg)))
+                }
+            }
         }
     }
 }