[parser] report illegal token error in ParseMemberExpressionContinuation()

Report correct error message when a scanner error occurs while parsing a tagged
template within an expression context.

BUG=v8:4829, v8:3230
LOG=N
R=adamk@chromium.org, littledan@chromium.org

Review URL: https://codereview.chromium.org/1806063002

Cr-Commit-Position: refs/heads/master@{#34839}

src/parsing/parser-base.h

@@ -2616,6 +2616,11 @@ ParserBase<Traits>::ParseMemberExpressionContinuation(
             ParseTemplateLiteral(expression, pos, classifier, CHECK_OK);
         break;
       }
+      case Token::ILLEGAL: {
+        ReportUnexpectedTokenAt(scanner()->peek_location(), Token::ILLEGAL);
+        *ok = false;
+        return this->EmptyExpression();
+      }
       default:
         return expression;
     }

test/cctest/test-parsing.cc

@@ -7189,6 +7189,36 @@ TEST(MiscSyntaxErrors) {
   RunParserSyncTest(context_data, error_data, kError, NULL, 0, NULL, 0);
 }
 
+
+TEST(EscapeSequenceErrors) {
+  // clang-format off
+  const char* context_data[][2] = {
+    { "'", "'" },
+    { "\"", "\"" },
+    { "`", "`" },
+    { "`${'", "'}`" },
+    { "`${\"", "\"}`" },
+    { "`${`", "`}`" },
+    { "f(tag`", "`);" },
+    { NULL, NULL }
+  };
+  const char* error_data[] = {
+    "\\uABCG",
+    "\\u{ZZ}",
+    "\\u{FFZ}",
+    "\\u{FFFFFFFFFF }",
+    "\\u{110000}",
+    "\\u{110000",
+    "\\u{FFFD }",
+    "\\xZF",
+    NULL
+  };
+  // clang-format on
+
+  RunParserSyncTest(context_data, error_data, kError, NULL, 0, NULL, 0);
+}
+
+
 TEST(FunctionSentErrors) {
   // clang-format off
   const char* context_data[][2] = {

test/message/regress/regress-4829-1.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function tag() {}
+
+tag(tag`\xyy`);

test/message/regress/regress-4829-1.out

+# Copyright 2016 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+*%(basename)s:7: SyntaxError: Invalid or unexpected token
+tag(tag`\xyy`);
+       ^^^
+SyntaxError: Invalid or unexpected token
\ No newline at end of file

test/message/regress/regress-4829-2.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function tag() {}
+
+`${tag`\xyy`}`;

test/message/regress/regress-4829-2.out

+# Copyright 2016 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+*%(basename)s:7: SyntaxError: Invalid or unexpected token
+`${tag`\xyy`}`;
+      ^^^
+SyntaxError: Invalid or unexpected token
\ No newline at end of file