internal: remove proc-macro[2] and quote workarounds

The kernel only had the `proc-macro` library available, whereas the
user-space version also used `proc-macro2` and `quote`. Now both are
available to the kernel, making it possible to remove the workarounds.

Signed-off-by: Benno Lossin <lossin@kernel.org>

Author: BennoLossin

internal/src/helpers.rs

@@ -1,9 +1,6 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
-#[cfg(not(kernel))]
-use proc_macro2 as proc_macro;
-
-use proc_macro::{TokenStream, TokenTree};
+use proc_macro2::{TokenStream, TokenTree};
 
 /// Parsed generics.
 ///

internal/src/lib.rs

@@ -7,27 +7,11 @@
 //! `pin-init` proc macros.
 
 #![cfg_attr(not(RUSTC_LINT_REASONS_IS_STABLE), feature(lint_reasons))]
-// Allow `.into()` to convert
-// - `proc_macro2::TokenStream` into `proc_macro::TokenStream` in the user-space version.
-// - `proc_macro::TokenStream` into `proc_macro::TokenStream` in the kernel version.
-//   Clippy warns on this conversion, but it's required by the user-space version.
-//
-// Remove once we have `proc_macro2` in the kernel.
-#![allow(clippy::useless_conversion)]
 // Documentation is done in the pin-init crate instead.
 #![allow(missing_docs)]
 
 use proc_macro::TokenStream;
 
-#[cfg(kernel)]
-#[path = "../../../macros/quote.rs"]
-#[macro_use]
-#[cfg_attr(not(kernel), rustfmt::skip)]
-mod quote;
-#[cfg(not(kernel))]
-#[macro_use]
-extern crate quote;
-
 mod helpers;
 mod pin_data;
 mod pinned_drop;

internal/src/pin_data.rs

@@ -1,10 +1,8 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
-#[cfg(not(kernel))]
-use proc_macro2 as proc_macro;
-
 use crate::helpers::{parse_generics, Generics};
-use proc_macro::{Group, Punct, Spacing, TokenStream, TokenTree};
+use proc_macro2::{Group, Punct, Spacing, TokenStream, TokenTree};
+use quote::quote;
 
 pub(crate) fn pin_data(args: TokenStream, input: TokenStream) -> TokenStream {
     // This proc-macro only does some pre-parsing and then delegates the actual parsing to

internal/src/pinned_drop.rs

@@ -1,9 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
-#[cfg(not(kernel))]
-use proc_macro2 as proc_macro;
-
-use proc_macro::{TokenStream, TokenTree};
+use proc_macro2::{TokenStream, TokenTree};
+use quote::quote;
 
 pub(crate) fn pinned_drop(_args: TokenStream, input: TokenStream) -> TokenStream {
     let mut toks = input.into_iter().collect::<Vec<_>>();

internal/src/zeroable.rs

@@ -1,10 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
 
-#[cfg(not(kernel))]
-use proc_macro2 as proc_macro;
-
 use crate::helpers::{parse_generics, Generics};
-use proc_macro::{TokenStream, TokenTree};
+use proc_macro2::{TokenStream, TokenTree};
+use quote::quote;
 
 pub(crate) fn parse_zeroable_derive_input(
     input: TokenStream,