Macro codegen hangs forever when trying to mix Unicase and normal strings

[DelSkayn]

When trying to use the proc macro to build a map, whenever you try to mix strings and unicase strings the macro generates a compile error.

However when a unicase string matches a normal string the macro just runs forever without progressing.

I know what I tried to do is probably not supported but because the macro kept running forever it prevented the code from compiling and it took me quite a while to figure out what was happening. So it would be nice if this was fixed.

Below a minimal reproduction.

use phf::phf_map;
use unicase::UniCase;

pub(crate) static KEYWORDS: phf::Map<UniCase<&'static str>, usize> = phf_map! {
    "foo" => 0,
    UniCase::ascii("FOO") => 0
};

fn main(){
    KEYWORDS.get("foo").unwap();
}