Reland "[parser] Forbid \08 in strict strings"

test/cctest/test-parsing.cc

Index: test/cctest/test-parsing.cc
diff --git a/test/cctest/test-parsing.cc b/test/cctest/test-parsing.cc
index 7f2a072e21fe6523dda8dc95048f11106807e22e..fa98a2b455ab9fafe0ec4442b932c4da3b6352ea 100644
--- a/test/cctest/test-parsing.cc
+++ b/test/cctest/test-parsing.cc
@@ -5901,6 +5901,33 @@ TEST(UnicodeEscapes) {
   RunParserSyncTest(context_data, data, kSuccess);
 }
 
+TEST(OctalEscapes) {
+  const char* sloppy_context_data[][2] = {{"", ""},    // as a directive
+                                          {"0;", ""},  // as a string literal
+                                          {NULL, NULL}};
+
+  const char* strict_context_data[][2] = {
+      {"'use strict';", ""},     // as a directive before 'use strict'
+      {"", ";'use strict';"},    // as a directive after 'use strict'
+      {"'use strict'; 0;", ""},  // as a string literal
+      {NULL, NULL}};
+
+  // clang-format off
+  const char* data[] = {
+    "'\\1'",
+    "'\\01'",
+    "'\\001'",
+    "'\\08'",
+    "'\\09'",
+    NULL};
+  // clang-format on
+
+  // Permitted in sloppy mode
+  RunParserSyncTest(sloppy_context_data, data, kSuccess);
+
+  // Error in strict mode
+  RunParserSyncTest(strict_context_data, data, kError);
+}
 
 TEST(ScanTemplateLiterals) {
   const char* context_data[][2] = {{"'use strict';", ""},
@@ -7112,6 +7139,7 @@ TEST(TemplateEscapesPositiveTests) {
 
   // clang-format off
   const char* data[] = {
+    "tag`\\08`",
     "tag`\\01`",
     "tag`\\01${0}right`",
     "tag`left${0}\\01`",
@@ -7195,6 +7223,7 @@ TEST(TemplateEscapesNegativeTests) {
 
   // clang-format off
   const char* data[] = {
+    "`\\08`",
     "`\\01`",
     "`\\01${0}right`",
     "`left${0}\\01`",