Parse new.target.

Summary:
Add parsing for the "MetaProperty" `new.target`, which is a `MemberExpression`.
We detect the `.` and create the `MetaPropertyNode` from that.

Reviewed By: tmikov

Differential Revision: D16421942

fbshipit-source-id: 9daf3151bbc04073c34f3a9cea7731e0f191b74e

lib/Parser/JSParserImpl.cpp

@@ -79,6 +79,8 @@ void JSParserImpl::initializeIdentifiers() {
   methodIdent_ = lexer_.getIdentifier("method");
   constructorIdent_ = lexer_.getIdentifier("constructor");
   yieldIdent_ = lexer_.getIdentifier("yield");
+  newIdent_ = lexer_.getIdentifier("new");
+  targetIdent_ = lexer_.getIdentifier("target");
 
   // Generate the string representation of all tokens.
   for (unsigned i = 0; i != NUM_JS_TOKENS; ++i)
@@ -2544,7 +2546,30 @@ Optional<ESTree::Node *> JSParserImpl::parseNewExpressionOrMemberExpression() {
   if (!check(TokenKind::rw_new))
     return parseMemberExpressionExceptNew();
 
-  SMLoc startLoc = advance().Start;
+  SMRange newRange = advance();
+  SMLoc startLoc = newRange.Start;
+
+  if (checkAndEat(TokenKind::period)) {
+    // NewTarget: new . target
+    //                  ^
+    if (!check(targetIdent_)) {
+      sm_.error(
+          tok_->getSourceRange(), "'target' expected in member expression");
+      sm_.note(startLoc, "start of member expression");
+      return None;
+    }
+    auto *meta = setLocation(
+        newRange,
+        newRange,
+        new (context_) ESTree::IdentifierNode(newIdent_, nullptr));
+    auto *prop = setLocation(
+        tok_,
+        tok_,
+        new (context_) ESTree::IdentifierNode(targetIdent_, nullptr));
+    advance();
+    return setLocation(
+        meta, prop, new (context_) ESTree::MetaPropertyNode(meta, prop));
+  }
 
   auto optExpr = parseNewExpressionOrMemberExpression();
   if (!optExpr)

lib/Parser/JSParserImpl.h

@@ -199,6 +199,8 @@ class JSParserImpl {
   UniqueString *methodIdent_;
   UniqueString *constructorIdent_;
   UniqueString *yieldIdent_;
+  UniqueString *newIdent_;
+  UniqueString *targetIdent_;
   /// String representation of all tokens.
   UniqueString *tokenIdent_[NUM_JS_TOKENS];
 

test/BCGen/HBC/es6/function-kinds.js

@@ -3,8 +3,7 @@
 // This source code is licensed under the MIT license found in the LICENSE
 // file in the root directory of this source tree.
 //
-// RUN: %hermes -Xflow-parser -target=HBC -dump-bytecode %s | %FileCheck --match-full-lines %s
-// REQUIRES: flowparser
+// RUN: %hermes -target=HBC -dump-bytecode %s | %FileCheck --match-full-lines %s
 
 function normal() {}
 //CHECK-LABEL:Function<normal>(1 params, {{.*}}):

test/IRGen/es6/new-target.js

@@ -3,8 +3,7 @@
 // This source code is licensed under the MIT license found in the LICENSE
 // file in the root directory of this source tree.
 //
-// RUN: %hermesc -Xflow-parser -dump-ir %s | %FileCheck --match-full-lines %s
-// REQUIRES: flowparser
+// RUN: %hermesc -dump-ir %s | %FileCheck --match-full-lines %s
 
 function func1() {
     return new.target;

test/Parser/es6/new-target-error.js

@@ -3,8 +3,7 @@
 // This source code is licensed under the MIT license found in the LICENSE
 // file in the root directory of this source tree.
 //
-// RUN: (! %hermesc -Xflow-parser -dump-ast -pretty-json %s 2>&1 ) | %FileCheck --match-full-lines %s
-// REQUIRES: flowparser
+// RUN: (! %hermesc -dump-ast -pretty-json %s 2>&1 ) | %FileCheck --match-full-lines %s
 
 new.target;
 // CHECK: {{.*}}:8:1: error: 'new.target' not in a function

test/Parser/es6/new-target.js

@@ -0,0 +1,49 @@
+// Copyright (c) Facebook, Inc. and its affiliates.
+//
+// This source code is licensed under the MIT license found in the LICENSE
+// file in the root directory of this source tree.
+//
+// RUN: %hermesc -dump-ast -pretty-json %s | %FileCheck %s --match-full-lines
+
+// CHECK: {
+// CHECK-NEXT:   "type": "Program",
+// CHECK-NEXT:   "body": [
+
+function foo() {
+  return new.target;
+}
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "type": "FunctionDeclaration",
+// CHECK-NEXT:       "id": {
+// CHECK-NEXT:         "type": "Identifier",
+// CHECK-NEXT:         "name": "foo",
+// CHECK-NEXT:         "typeAnnotation": null
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "params": [],
+// CHECK-NEXT:       "body": {
+// CHECK-NEXT:         "type": "BlockStatement",
+// CHECK-NEXT:         "body": [
+// CHECK-NEXT:           {
+// CHECK-NEXT:             "type": "ReturnStatement",
+// CHECK-NEXT:             "argument": {
+// CHECK-NEXT:               "type": "MetaProperty",
+// CHECK-NEXT:               "meta": {
+// CHECK-NEXT:                 "type": "Identifier",
+// CHECK-NEXT:                 "name": "new",
+// CHECK-NEXT:                 "typeAnnotation": null
+// CHECK-NEXT:               },
+// CHECK-NEXT:               "property": {
+// CHECK-NEXT:                 "type": "Identifier",
+// CHECK-NEXT:                 "name": "target",
+// CHECK-NEXT:                 "typeAnnotation": null
+// CHECK-NEXT:               }
+// CHECK-NEXT:             }
+// CHECK-NEXT:           }
+// CHECK-NEXT:         ]
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "returnType": null,
+// CHECK-NEXT:       "generator": false
+// CHECK-NEXT:     }
+
+// CHECK-NEXT:   ]
+// CHECK-NEXT: }

test/hermes/es6/new-target.js

@@ -3,9 +3,8 @@
 // This source code is licensed under the MIT license found in the LICENSE
 // file in the root directory of this source tree.
 //
-// RUN: %hermes -Xflow-parser %s | %FileCheck --match-full-lines %s
-// RUN: %hermes -Xflow-parser -O %s | %FileCheck --match-full-lines %s
-// REQUIRES: flowparser
+// RUN: %hermes %s | %FileCheck --match-full-lines %s
+// RUN: %hermes -O %s | %FileCheck --match-full-lines %s
 
 function foo() {
     print(typeof new.target, new.target === foo);