unicase feature is not compilable without phf_macros dependency

[gootorov]

Hi, consider the following main.rs:

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

static MAP: phf::Map<UniCase<&'static str>, isize> = phf_map!(
   UniCase::ascii("FOO") => 10,
   UniCase::unicode("Bar") => 11,
);

fn main() {}

With Cargo.toml:

[package]
name = "rust_phf_issue"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
phf = { version = "0.10", features = ["macros", "unicase"] }
unicase = "2.6"

Then the code won't compile with the following error:

error: unsupported key expression
 --> src/main.rs:5:4
  |
5 |    UniCase::ascii("FOO") => 10,
  |    ^^^^^^^^^^^^^^^^^^^^^
  |
  = note: this error originates in the macro `proc_macro_call` (in Nightly builds, run with -Z macro-backtrace for more info)

error: could not compile `rust_phf_issue` due to previous error

Workaround: change dependencies in Cargo.toml to the following:

[dependencies]
phf = { version = "0.10", features = ["macros"] }
phf_macros = { version = "0.10", features = ["unicase"] }
unicase = "2.6"

and then it compiles just fine.
I'm not sure if this is intended or not. Perhaps some sub-feature in macros does not get activated when the unicase feature in phf is enabled?

[JohnTitor]

It was impossible to enable them without the phf_macros as we have to enable phf_macros/unicase feature if only we use unicase + macros features on phf. But 1.60 supports weak dependency and it's possible now. I've opened #251 to support that.