bug: lowering block_builder "no entry found for key" in closure

[MagisterDallis]

Bug Report

Cairo version:
d44992f

Compiling the following code fails with

thread '<unnamed>' panicked at crates/cairo-lang-lowering/src/lower/block_builder.rs:178:54:
no entry found for key
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Rayon: detected unexpected panic; aborting

fn main(){
    let zero: ByteArray = "0";

    let format_string = |acc: ByteArray, x: u8| {
        format!("({acc} + {x})")
    };

    let result = format_string(zero, 1);
    assert_eq!(result, "(0 + 1)");
}