render macro panics with index out of bounds error

[abhijeetbhagat]

Problem

i am trying to do this:

...
div {
        class: "flex flex-col",
        for group in my_vec.iter().as_slice().group_by(|a, b| a.from_id == b.from_id) {

         }
}
...

with #![feature(slice_group_by)] add to the top in a mod.rs file and i get this:

message: index out of bounds: the len is 0 but the index is 0

removing the for loop doesn't cause panic.
the for loop works fine on the rust playground: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=e8878294d72f9a525a8ed2cf2291ed28

Expected behavior

should not panic

Environment:

• dioxus = "0.4.3"
• dioxus-web = "0.4.3"
• Rust version: 1.77 nightly
• OS info: MacOS
• App platform: web

Questionnaire

• I'm interested in fixing this myself but don't know where to start
• I would like to fix and I have a solution
• I don't have time to fix this right now, but maybe later

[ealmloff]

The body of the for loop is rsx. You run into the same error if you try to use an empty rsx macro: rsx!{}

If you are interested in fixing this issue, I would start in the rsx macro. We are indexing into an empty array somewhere. Maybe here?

dioxus/packages/rsx/src/lib.rs

Line 207 in 0166eaf

let spndbg = format!("{:?}", self.roots[0].span());

[abhijeetbhagat]

@ealmloff thanks for pointing out the source location. i shall look into this.