Trait bound of type declared in a trait

help
1

Hello, I would like to access the trait bound of a type that is defined in a trait from rustc's HIR (or THIR).
Example:

pub trait A {
type B: C
}

I went down to the TraitItemRef but I cannot find how to get the trait bound (C) from there. I guess I could find this information somewhere in the THIR but I don't know where. I would be thankful if someone could show me where to look :slight_smile:

2

You might have better luck asking in Zulip, or perhaps on IRLO. If you ask on the latter, please drop a link here so people know.

1 Like
3

Posted the question on Zulip as well

4

After getting lost in the compiler's docs I found out that to explore further a TraitItemRef, the solution is to use expect_trait_item and call it as in the following example:

pub fn print_trait_item(tcx: &TyCtxt, trait_item_ref: &rustc_hir::TraitItemRef) {
    let rustc_hir::TraitItemRef {
        id,
        ..
        } = trait_item_ref;
    let trait_item: &rustc_hir::TraitItem = tcx.hir().expect_trait_item(id.def_id);
    println!("{:?}", trait_item);
}
5

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