LibJS: Allow methods in classes named 'async'

Also add tests for all static, setter and getter cases.

Userland/Libraries/LibJS/Parser.cpp

@@ -1086,7 +1086,9 @@ NonnullRefPtr<ClassExpression> Parser::parse_class_expression(bool expect_class_
 
         if (match(TokenType::Async)) {
             auto lookahead_token = next_token();
-            if (lookahead_token.type() != TokenType::Semicolon && lookahead_token.type() != TokenType::CurlyClose
+            // If async is followed by a Semicolon or CurlyClose it is a field (CurlyClose indicates end of class)
+            // Otherwise if it is followed by a ParenOpen it is a function named async
+            if (lookahead_token.type() != TokenType::Semicolon && lookahead_token.type() != TokenType::CurlyClose && lookahead_token.type() != TokenType::ParenOpen
                 && !lookahead_token.trivia_contains_line_terminator()) {
                 consume();
                 is_async = true;

Userland/Libraries/LibJS/Tests/classes/class-constructor.js

@@ -65,3 +65,10 @@ test("implicit constructor", () => {
 
     expect(new A()).toBeInstanceOf(A);
 });
+
+test("can call constructor without parentheses", () => {
+    class A {}
+
+    // prettier-ignore
+    expect(new A).toBeInstanceOf(A);
+});

Userland/Libraries/LibJS/Tests/classes/class-getters.js

@@ -73,3 +73,15 @@ test("inherited getter overriding", () => {
 
     expect(new Child().x).toBe(10);
 });
+
+test("static getter named 'async'", () => {
+    class A {
+        get async() {
+            return "getter named async";
+        }
+    }
+
+    const a = new A();
+    expect("async" in a).toBeTrue();
+    expect(a.async).toBe("getter named async");
+});

Userland/Libraries/LibJS/Tests/classes/class-methods.js

@@ -49,3 +49,15 @@ test("extended name syntax", () => {
     expect(a[12]()).toBe(2);
     expect(a.hello()).toBe(3);
 });
+
+test("method named 'async'", () => {
+    class A {
+        async() {
+            return "function named async";
+        }
+    }
+
+    const a = new A();
+    expect("async" in a).toBeTrue();
+    expect(a.async()).toBe("function named async");
+});

Userland/Libraries/LibJS/Tests/classes/class-setters.js

@@ -106,3 +106,18 @@ test("inherited static setter overriding", () => {
     c.x = 10;
     expect(c.x).toBe(30);
 });
+
+test("static setter named 'async'", () => {
+    let called = false;
+    class A {
+        set async(value) {
+            called = true;
+            expect(value).toBe("value set on setter named async");
+        }
+    }
+
+    const a = new A();
+    expect("async" in a).toBeTrue();
+    a.async = "value set on setter named async";
+    expect(called).toBeTrue();
+});

Userland/Libraries/LibJS/Tests/classes/class-static-getters.js

@@ -85,3 +85,14 @@ describe("errors", () => {
     }`).not.toEval();
     });
 });
+
+test("static getter named 'async'", () => {
+    class A {
+        static get async() {
+            return "static getter named async";
+        }
+    }
+
+    expect("async" in A).toBeTrue();
+    expect(A.async).toBe("static getter named async");
+});

Userland/Libraries/LibJS/Tests/classes/class-static-setters.js

@@ -110,3 +110,17 @@ describe("errors", () => {
     }`).not.toEval();
     });
 });
+
+test("static setter named 'async'", () => {
+    let called = false;
+    class A {
+        static set async(value) {
+            called = true;
+            expect(value).toBe("value set on static setter named async");
+        }
+    }
+
+    expect("async" in A).toBeTrue();
+    A.async = "value set on static setter named async";
+    expect(called).toBeTrue();
+});

Userland/Libraries/LibJS/Tests/classes/class-static.js

@@ -70,3 +70,14 @@ test("static method overriding", () => {
     expect(Parent.method()).toBe(3);
     expect(Child.method()).toBe(10);
 });
+
+test("static function named 'async'", () => {
+    class A {
+        static async() {
+            return "static function named async";
+        }
+    }
+
+    expect("async" in A).toBeTrue();
+    expect(A.async()).toBe("static function named async");
+});