Changed extern crate foo as bar; error message

[gamazeps]

I did not put the crate name in the error note, if that's necessary I'll look into it.

Closes #17709

[huonw]

I think this should be an error (span_err).

[huonw]

Or, maybe it hits the expect below? In which case, doesn't this print something weird?

E.g.

extern crate foo as bar;

possibly prints something like:

note: expected `;`, found `as`; perhaps you meant to enclose the crate name in a string
...
error: expected `;`, found `bar`

(i.e. two messages)

Maybe you could adjust the branches a little more, which also allows for a nice error message:

let path = if self.eat(&token::EQ) {
    let path = self.parse_str();
    let span = self.span;
    self.obsolete(span, ObsoleteExternCrateRenaming);
    Some(path)
} else if self.eat_keyword(keywords::As) {
    // skip the ident if there is one
    if is_ident(&self.token) { self.bump(); }

    let last_span = self.last_span;
    self.span_err(last_span,
                  format!("expected `;`, found `as`; perhaps you meant \
                           to enclose the crate name (`{}`) in a string?",
                          the_ident.as_str())));
    None
} else {
    None
};
self.expect(&token::SEMI);
(path, the_ident)

[gamazeps]

Yes, it did hit two messages, but it didn't seem horrible to have both a note and an error (but it's my first diagnostic issue, so it may be why ^^).
On it, I'll commit you a new one in about an hour :)

[huonw]

Could you add a test for this? E.g. create src/test/compile-fail/extern-crate-as-no-string-help.rs

LICENSE

extern crate foo as bar;
//~^ ERROR expected `;`, found `as`; perhaps you meant to enclose the crate name (`foo`) in a string?

(where LICENSE can just be copied from one of the other compile-fail tests.)

[gamazeps]

Done :)

[huonw]

Oh, wait, this should move to be before the if statement above (we want the span to point at the original ident, not at the as keyword).

[huonw]

The space before ? will need to be removed.

[huonw]

It looks like the test src/test/compile-fail/extern-foreign-crate.rs needs to have it's ERROR directive updated, since = is no longer legal to follow extern crate foo.

[gamazeps]

on it :)

[gamazeps]

@huonw Done (sorry if it took so long for so few changes)