[soareschen]

Overview

[deepseek-v4.1-flash] A #[cgp_fn] or #[cgp_impl] with an #[implicit] name: &str argument now reads any AsRef<str> field, and an Option<&str> argument reads any Option<U> whose U converts to &str, so neither needs an allocator. Every conversion and field read the macros emit is also a fully qualified trait call.

Motivation

The &str implicit argument required a String field, so a crate without an allocator failed with "cannot find type String". The Option<&str> form required an Option<String> field for the same reason. Both bounds tied the field to one concrete type, and the first one made the argument unusable in the no_std build that the previous change added.

Impact

The generated bound for &str changes from Value = String to Value: AsRef<str> + 'static, and the read from .as_str() to .as_ref(). A String field still satisfies it, so existing contexts keep compiling, and a Cow<str> or a Box<str> field now works too.

The generated bound for Option<&str> changes from Value = Option<String> to Value: OptionAsRef<str> + 'static, and the read from .as_deref() to .option_as_ref(). OptionAsRef<T> is a new trait in cgp-field, with a blanket impl for every Option<U> whose U implements AsRef<T>; its ?Sized bound is what lets T be str.

A getter keeps the String field, because its HasField bound is also used by the WithProvider adapter, which expects the field type itself. Applying AsRef<str> there broke chain_deeply_nested with a Value == str mismatch.

Every conversion and field read the macros emit is now a fully qualified trait call — ::core::convert::AsRef::as_ref, ::core::convert::AsMut::as_mut, ::core::clone::Clone::clone, ::core::option::Option::as_ref/as_mut/as_deref_mut, ::cgp::macro_prelude::OptionAsRef::option_as_ref, and ::cgp::macro_prelude::HasField::get_field — and the bounds name ::core::convert::AsRef and ::core::convert::AsMut, so a local trait of the same name cannot capture them. A probe crate that defines its own HasField and AsRef traits compiles, which it did not before.

Three tests cover #[cgp_impl] with a &str and an Option<&str> implicit, and run the provider against a String, a &str, and a Cow<str> field. cgp-no-std-tests uses both implicit forms and still builds for x86_64-unknown-none.