improve error message for missing return type

[emekoi]

when the return type is missing for a function, i get the error expected token '{', found 'fn'. could someone point me towards the code that handles parsing of functions, so i could fix this?

[thejoshwolfe]

I actually think we should disallow return type expressions starting with {. That would solve this problem.

Here's the real question: why would you ever want a return expression to legitimately begin with {? I believe it's never going to work semantically, since the only value a {...} block could possibly evaluate to is the void value {}, and that's not a type. You would have to put a label on the block to get any other value, and in that case the expression doesn't start with { anymore.

[ghost]

I would make this a priority... It's something that newcomers are going to run into again and again. (As well as people who frequently switch between Zig and another language like JS.) The error message still initially confuses me after the tenth time running into it.

And if there was a reason to allow return types to start with {, I think it would be worth adding a new symbol to the syntax introducing the return type.

For me, this issue ranks right up there with the 'copying fieldParentPtr thing out of a struct' footgun.

[winksaville]

I too run frequently forget the return type and stumble into this all the time. So I look forward to seeing a better error message.

…

On Sun, Oct 21, 2018, 10:46 AM dbandstra ***@***.***> wrote: I would make this a priority... It's something that newcomers are going to run into again and again. (As well as people who frequently switch between Zig and another language like JS.) The error message still initially confuses me after the tenth time running into it. And if there was a reason to allow return types to start with {, I think it would be worth adding a new symbol to the syntax introducing the return type. For me, this issue ranks right up there with the 'copying fieldParentPtr thing out of a struct' footgun. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1672 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA-hHCIA4Oys6VVoi-tPAJ2Um7NRba89ks5unLLtgaJpZM4XyJ31> .

[emekoi]

@thejoshwolfe i think we're talking about two different things here. i'm talking about the error message you get from code like this:

fn foo() {

}

fn bar() void {

}

[thejoshwolfe]

@emekoi that is what I'm talking about too. Once the parser sees:

fn foo() {

there's no possible way that the program could compile successfully. We can have the parser report an error pointing to that { saying that you need a return type.

[Hejsil]

This is related to #760, and I'm currently working on a solution.

[Hejsil]

After #1685 we now get this error:

/home/jhc/repo/zig/test.zig:1:8: error: invalid token: '{'
fn a() {}
       ^

Not perfect, but we get the error earlier, which should help alot.

[andrewrk]

I would consider this solved, with a low priority further improvement being to special case this error and add something like "expected return type"

[nektro]

with Zig master this now works as expected

pub fn main() {
}

test.zig:1:15: error: expected return type expression, found '{'
pub fn main() {
              ^