// SPDX-License-Identifier: Apache-2.0 OR MIT use proc_macro2::TokenStream; use quote::quote; use syn::{parse::Nothing, parse_quote, spanned::Spanned, ImplItem, ItemImpl, Token}; use crate::diagnostics::{DiagCtxt, ErrorGuaranteed}; pub(crate) fn pinned_drop( _args: Nothing, mut input: ItemImpl, dcx: &mut DiagCtxt, ) -> Result<TokenStream, ErrorGuaranteed> { if let Some(unsafety) = input.unsafety { dcx.error(unsafety, "implementing `PinnedDrop` is safe"); } input.unsafety = Some(Token); match &mut input.trait_ { Some((not, path, _for)) => { if let Some(not) = not { dcx.error(not, "cannot implement `!PinnedDrop`"); } for (seg, expected) in path .segments .iter() .rev() .zip(["PinnedDrop", "pin_init", ""]) { if expected.is_empty() || seg.ident != expected { dcx.error(seg, "bad import path for `PinnedDrop`"); } if !seg.arguments.is_none() { dcx.error(&seg.arguments, "unexpected arguments for `PinnedDrop` path"); } } *path = parse_quote!(::pin_init::PinnedDrop); } None => { let span = input .impl_token .span .join(input.self_ty.span()) .unwrap_or(input.impl_token.span); dcx.error( span, "expected `impl ... PinnedDrop for ...`, got inherent impl", ); } } for item in &mut input.items { if let ImplItem::Fn(fn_item) = item { if fn_item.sig.ident == "drop" { fn_item .sig .inputs .push(parse_quote!(_: ::pin_init::__internal::OnlyCallFromDrop)); } } } Ok(quote!(#input)) }