A decimal integer literal with a leading 0 is now an error in strict mode.

src/messages.h

Index: src/messages.h
diff --git a/src/messages.h b/src/messages.h
index 3a03de9ce2a2eb76c666736bbd044cbc34944625..055f44eaa5ce26f502077331d18ad37c1a6b3500 100644
--- a/src/messages.h
+++ b/src/messages.h
@@ -594,10 +594,13 @@ class ErrorUtils : public AllStatic {
   T(StrictFunction,                                                            \
     "In strict mode code, functions can only be declared at top level or "     \
     "inside a block.")                                                         \
-  T(StrictOctalLiteral, "Octal literals are not allowed in strict mode.")      \
+  T(StrictOctalLiteral,                                                        \
+    "Number literals must not have a '0' prefix in strict mode.")              \

[Dan Ehrenberg, 2016/11/18 17:13:51]

This isn't quite right. 0b1 is a number literal allowed in strict mode, for
example...

+  T(StrictOctalEscape,                                                         \
+    "Octal escape sequences are not allowed in strict mode.")                  \
   T(StrictWith, "Strict mode code may not include a with statement")           \
   T(TemplateOctalLiteral,                                                      \
-    "Octal literals are not allowed in template strings.")                     \
+    "Octal escape sequences are not allowed in template strings.")             \
   T(ThisFormalParameter, "'this' is not a valid formal parameter name")        \
   T(AwaitBindingIdentifier,                                                    \
     "'await' is not a valid identifier name in an async function")             \