I think the original hesitation was uncertainty about whether the tokens should have their span or the span of the ‘SpannedValue`.

IIUC: SpannedValue would quote_spanned!(self.span() => #inner), so the span would apply to everything emitted unless something inside has its own span?

What is your T that needs the ‘SpannedValue` wrapper?

I'm parsing a struct with fields that have a #[dep(...)] attribute:

#[derive(Debug, darling::FromField)]
#[darling(attributes(dep), forward_attrs)]
pub struct DepsField {
    pub vis: Visibility,
    pub ident: Option<Ident>,
    pub ty: syn::Type,
    pub attrs: Vec<syn::Attribute>,

    // dep-attribute-specific fields here
}

In a later pass (analysis/validation), I'd like to refer to the entire field's span when emitting an error, so I wrapped this type in a SpannedValue to capture it.

... actually, that's not quite true. This was already a workaround: Originally, I wanted the span of just the entire dep attribute, but couldn't find a way to extract that, so I settled on the entire field instead.

If there's a better way of going about this please let me know 😅

Uh oh!

impl ToTokens for SpannedValue? #422

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impl `ToTokens` for `SpannedValue`? #422