geraldalewis/coffee-script — comment on commit ef34002cb4467e186dbb7a8ef8a44d85c39c21db
File: src/lexer.coffee line 138
By michaelficarra:

Well browsers allow it because it's not an octal literal. It's a valid decimal literal. But if we disallow numbers of the form `0[0-7]+` and allow numbers of the form `0[0-9]*[89][0-9]*`, it seems to defeat the purpose of disallowing octal literals that are not very explicit (`0o` being *more* explicit than `0`).