If you look at the GopherCon talk I gave (linked at the beginning of the post), it is about reading the spec. So yes, I did read the spec, and I realize that this is not syntactically valid (it would be a very basic compiler bug if this were valid syntax and it was diagnosed as a syntax error).

However, the spec only states what _is_ but not _why_ it is that way. Sure, I could look at the git blame of the spec for every odd thing I run into, but there is only so much time in the day...