Unhelpful tracing macro error

blah.rs

use tracing::{info_span, Span};

pub struct Blah {
    pub span: Span,
}

impl Blah {
    pub fn new(name: &str) -> Self {
        Blah {
            span: info_span!(name),
        }
    }
}

output.txt

   Compiling ice v0.1.0 (/Users/martin/dev/str0m/ice)
error[E0435]: attempt to use a non-constant value in a constant
  --> ice/tests/blah.rs:10:30
   |
10 |             span: info_span!(name),
   |                   -----------^^^^-
   |                   |          |
   |                   |          non-constant value
   |                   help: consider using `let` instead of `static`: `let CALLSITE`

For more information about this error, try `rustc --explain E0435`.