Report SyntaxError on Token::ILLEGAL in ParseTemplateLiteral

BUG=v8:3820, v8:3821
LOG=N
R=arv@chromium.org, dslomov@chromium.org, marja@chromium.org

Review URL: https://codereview.chromium.org/857433004

Cr-Commit-Position: refs/heads/master@{#26132}

src/preparser.h

@@ -2942,11 +2942,17 @@ ParserBase<Traits>::ParseTemplateLiteral(ExpressionT tag, int start, bool* ok) {
   do {
     CheckTemplateOctalLiteral(pos, peek_position(), CHECK_OK);
     next = peek();
-    if (!next) {
+    if (next == Token::EOS) {
       ReportMessageAt(Scanner::Location(start, peek_position()),
                       "unterminated_template");
       *ok = false;
       return Traits::EmptyExpression();
+    } else if (next == Token::ILLEGAL) {
+      Traits::ReportMessageAt(
+          Scanner::Location(position() + 1, peek_position()),
+          "unexpected_token", "ILLEGAL", false);
+      *ok = false;
+      return Traits::EmptyExpression();
     }
 
     int expr_pos = peek_position();
@@ -2966,10 +2972,16 @@ ParserBase<Traits>::ParseTemplateLiteral(ExpressionT tag, int start, bool* ok) {
     Next();
     pos = position();
 
-    if (!next) {
+    if (next == Token::EOS) {
       ReportMessageAt(Scanner::Location(start, pos), "unterminated_template");
       *ok = false;
       return Traits::EmptyExpression();
+    } else if (next == Token::ILLEGAL) {
+      Traits::ReportMessageAt(
+          Scanner::Location(position() + 1, peek_position()),
+          "unexpected_token", "ILLEGAL", false);
+      *ok = false;
+      return Traits::EmptyExpression();
     }
 
     Traits::AddTemplateSpan(&ts, next == Token::TEMPLATE_TAIL);

test/cctest/test-parsing.cc

@@ -4552,6 +4552,28 @@ TEST(ScanUnterminatedTemplateLiterals) {
 }
 
 
+TEST(TemplateLiteralsIllegalTokens) {
+  const char* context_data[][2] = {{"'use strict';", ""},
+                                   {"function foo(){ 'use strict';"
+                                    "  var a, b, c; return ", "}"},
+                                   {NULL, NULL}};
+  const char* data[] = {
+      "`hello\\x`",
+      "`hello\\x${1}`",
+      "`hello${1}\\x`",
+      "`hello${1}\\x${2}`",
+      "`hello\\x\n`",
+      "`hello\\x\n${1}`",
+      "`hello${1}\\x\n`",
+      "`hello${1}\\x\n${2}`",
+      NULL};
+
+  static const ParserFlag always_flags[] = {kAllowHarmonyTemplates};
+  RunParserSyncTest(context_data, data, kError, NULL, 0, always_flags,
+                    arraysize(always_flags));
+}
+
+
 TEST(LexicalScopingSloppyMode) {
   const char* context_data[][2] = {
       {"", ""},