Fair point, but I disagree with you - fulled specced out designed languages generally specify how exactly the implementation should handle these cases. How references should be retained, when references fall out of scope, etc.

eg:

http://clang.llvm.org/docs/Block-ABI-Apple.html

http://download.oracle.com/otndocs/jcp/lambda-0_5_1-edr2-spe...

http://www.microsoft.com/en-us/download/details.aspx?id=7029

etc etc. I also don't believe I'm attacking javascript here, merely repeating what people have always known about evolved languages. Evolved languages have a lot of pros (mainly speed of new features and practical application), and they have cons too. What I'm saying is very simple: this type of bug in javascript should not be a surprise - it should be expected. There will be more.

EDIT: Laughably enough, while the ObjC and Java specifications both specifically address this issue, the C# specification actually formalizes this exact bug into the language specification. So I concede your point, C# - a designed language - simply designed the exact same bug into the language itself. See section 7.15.5.1 Captured outer variables.

Feel free to downvote this post - I now concede that designed languages are just as likely to design stupid bugs into the language as evolved languages are to create them by mistake. ;)