ES6 template literals should not use legacy octal strings

src/scanner.cc

Index: src/scanner.cc
diff --git a/src/scanner.cc b/src/scanner.cc
index 96459f3c6699ec07f5b3a73db6defd5665dc791e..6e2e67d328d81d90150ee1659710c2d79ae0e866 100644
--- a/src/scanner.cc
+++ b/src/scanner.cc
@@ -697,13 +697,13 @@ void Scanner::SeekForward(int pos) {
 }
 
 
-template <bool capture_raw>
+template <bool capture_raw, bool in_template_literal>
 bool Scanner::ScanEscape() {
   uc32 c = c0_;
   Advance<capture_raw>();
 
   // Skip escaped newlines.
-  if (c0_ >= 0 && unicode_cache_->IsLineTerminator(c)) {
+  if (!in_template_literal && c0_ >= 0 && unicode_cache_->IsLineTerminator(c)) {
     // Allow CR+LF newlines in multiline string literals.
     if (IsCarriageReturn(c) && IsLineFeed(c0_)) Advance<capture_raw>();
     // Allow LF+CR newlines in multiline string literals.
@@ -731,7 +731,21 @@ bool Scanner::ScanEscape() {
       if (c < 0) return false;
       break;
     }
-    case '0' :  // fall through
+    case '0':
+      if (in_template_literal) {
+        // \ 0 DecimalDigit is never allowed in templates.
+        if (IsDecimalDigit(c0_)) {
+          Advance<capture_raw>();
+          return false;

[caitp (gmail), 2014/12/17 19:35:56]

I feel like we should just let ScanOctalEscape do its thing and use
CheckOctalLiteral() in the preparser, instead of this (better error message).

I don't think that's a blocker though

+        }
+
+        // The TV of TemplateCharacter :: \ EscapeSequence is the CV of
+        //     EscapeSequence.
+        // The CV of EscapeSequence :: 0 is the code unit value 0.
+        c = 0;
+        break;
+      }
+    // Fall through.
     case '1' :  // fall through
     case '2' :  // fall through
     case '3' :  // fall through
@@ -739,7 +753,9 @@ bool Scanner::ScanEscape() {
     case '5' :  // fall through
     case '6' :  // fall through
     case '7':
-      c = ScanOctalEscape<capture_raw>(c, 2);
+      if (!in_template_literal) {
+        c = ScanOctalEscape<capture_raw>(c, 2);
+      }
       break;
   }
 
@@ -787,7 +803,7 @@ Token::Value Scanner::ScanString() {
     uc32 c = c0_;
     Advance();
     if (c == '\\') {
-      if (c0_ < 0 || !ScanEscape<false>()) return Token::ILLEGAL;
+      if (c0_ < 0 || !ScanEscape<false, false>()) return Token::ILLEGAL;
     } else {
       AddLiteralChar(c);
     }
@@ -818,6 +834,7 @@ Token::Value Scanner::ScanTemplateSpan() {
   LiteralScope literal(this);
   StartRawLiteral();
   const bool capture_raw = true;
+  const bool in_template_literal = true;
 
   while (true) {
     uc32 c = c0_;
@@ -844,11 +861,8 @@ Token::Value Scanner::ScanTemplateSpan() {
             AddRawLiteralChar('\n');
           }
         }
-      } else if (c0_ == '0') {
-        Advance<capture_raw>();
-        AddLiteralChar('0');
-      } else {
-        ScanEscape<true>();
+      } else if (!ScanEscape<capture_raw, in_template_literal>()) {
+        return Token::ILLEGAL;
       }
     } else if (c < 0) {
       // Unterminated template literal