The spec simply wants a string literal there, so both string forms are permitted.

It's fine to have gofmt produce only double-quoted strings.

Maybe keep raw strings if the import has double quotes in it already. (which will be approximately 0% of programs in the wild)

According to http://golang.org/ref/spec#Import_declarations,
It's ok to reject " or ` in import paths, so I think we'd just reject
those paths and always use import "foo".

@minux The implementation restriction in http://golang.org/ref/spec#Import_declarations is already implemented (in gc I think, and in go/types for sure) and is applied to the runes of the string, but not the string's quotes. That is, both math and "math" are permitted.

It's trivial to do this in gofmt and there's no need to be overly restrictive in the compiler.

Right, so there is really no reason not to always rewrite import foo into
import "foo".

btw, my point about import path restrictions was replying to Brad's comment
about
import path containing double-quotes.