Remove "project_attr" feature and always enable #[project] attribute

Cargo.toml

@@ -18,8 +18,6 @@ all-features = true
 members = ["pin-project-internal"]
 
 [features]
-# Enable to use `project` attribute.
-project_attr = ["pin-project-internal/project_attr"]
 # Enable to allow using this crate as a renamed dependency
 renamed = ["pin-project-internal/renamed"]
 

pin-project-internal/Cargo.toml

@@ -17,15 +17,13 @@ all-features = true
 proc-macro = true
 
 [features]
-# Enable to use `project` attribute.
-project_attr = ["syn/visit-mut"]
 # Enable to allow using the crate with a renamed 'pin-project' dependency
 renamed = ["proc-macro-crate", "serde", "lazy_static"]
 
 [dependencies]
 proc-macro2 = "1.0"
 quote = "1.0"
-syn = { version = "1.0", features = ["full"] }
+syn = { version = "1.0", features = ["full", "visit-mut"] }
 
 proc-macro-crate = { version = "0.1.4", optional = true }
 # Required until a new toml-rs release is made with https://github.com/alexcrichton/toml-rs/pull/311,

pin-project-internal/src/lib.rs

@@ -19,7 +19,6 @@ mod utils;
 
 mod pin_project;
 mod pinned_drop;
-#[cfg(feature = "project_attr")]
 mod project;
 
 use proc_macro::TokenStream;
@@ -265,30 +264,23 @@ use syn::parse::Nothing;
 ///
 /// ### Enums
 ///
-/// `pin_project` also supports enums, but to use it ergonomically, you need
-/// to use the [`project`] attribute.
-///
-/// *This attribute is only available if pin-project is built
-/// with the `"project_attr"` feature.*
+/// `pin_project` also supports enums, but to use it, you need to use with the
+/// [`project`] attribute.
 ///
 /// The attribute at the expression position is not stable, so you need to use
 /// a dummy `#[project]` attribute for the function.
 ///
 /// ```rust
-/// # #[cfg(feature = "project_attr")]
 /// use pin_project::{project, pin_project};
-/// # #[cfg(feature = "project_attr")]
 /// use std::pin::Pin;
 ///
-/// # #[cfg(feature = "project_attr")]
 /// #[pin_project]
 /// enum Foo<A, B, C> {
 ///     Tuple(#[pin] A, B),
 ///     Struct { field: C },
 ///     Unit,
 /// }
 ///
-/// # #[cfg(feature = "project_attr")]
 /// impl<A, B, C> Foo<A, B, C> {
 ///     #[project] // Nightly does not need a dummy attribute to the function.
 ///     fn baz(self: Pin<&mut Self>) {
@@ -368,9 +360,6 @@ pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
 // TODO: Move this doc into pin-project crate when https://github.com/rust-lang/rust/pull/62855 merged.
 /// An attribute to provide way to refer to the projected type.
 ///
-/// *This attribute is available if pin-project is built with the
-/// `"project_attr"` feature.*
-///
 /// The following three syntaxes are supported.
 ///
 /// ## `impl` blocks
@@ -479,7 +468,6 @@ pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
 ///     }
 /// }
 /// ```
-#[cfg(feature = "project_attr")]
 #[proc_macro_attribute]
 pub fn project(args: TokenStream, input: TokenStream) -> TokenStream {
     let _: Nothing = syn::parse_macro_input!(args);

src/lib.rs

@@ -57,7 +57,6 @@ pub use pin_project_internal::pin_project;
 #[doc(hidden)]
 pub use pin_project_internal::pinned_drop;
 
-#[cfg(feature = "project_attr")]
 #[doc(hidden)]
 pub use pin_project_internal::project;
 

tests/compiletest.rs

@@ -1,6 +1,5 @@
 #![cfg(compiletest)]
 #![cfg(pin_project_show_unpin_struct)]
-#![cfg(feature = "project_attr")]
 #![warn(rust_2018_idioms, single_use_lifetimes)]
 
 use std::{env, path::PathBuf};

tests/project.rs

@@ -1,4 +1,3 @@
-#![cfg(feature = "project_attr")]
 #![warn(unsafe_code)]
 #![warn(rust_2018_idioms, single_use_lifetimes)]
 #![allow(dead_code)]