pin_init_internal/
diagnostics.rs

1// SPDX-License-Identifier: Apache-2.0 OR MIT
2
3use std::fmt::Display;
4
5use proc_macro2::TokenStream;
6use quote::quote_spanned;
7use syn::{spanned::Spanned, Error};
8
9pub(crate) struct DiagCtxt(TokenStream);
10pub(crate) struct ErrorGuaranteed(());
11
12impl DiagCtxt {
13    pub(crate) fn error(&mut self, span: impl Spanned, msg: impl Display) -> ErrorGuaranteed {
14        let error = Error::new(span.span(), msg);
15        self.0.extend(error.into_compile_error());
16        ErrorGuaranteed(())
17    }
18
19    pub(crate) fn warn(&mut self, span: impl Spanned, msg: impl Display) {
20        // Have the message start on a new line for visual clarity.
21        let msg = format!("\n{}", msg);
22        self.0.extend(quote_spanned!(span.span() =>
23            // Approximate using deprecated warning while `proc_macro_diagnostic` is unstable.
24            const _: () = {
25                #[deprecated = #msg]
26                const fn warn() {}
27                warn();
28            };
29        ));
30    }
31
32    pub(crate) fn with(
33        fun: impl FnOnce(&mut DiagCtxt) -> Result<TokenStream, ErrorGuaranteed>,
34    ) -> TokenStream {
35        let mut dcx = Self(TokenStream::new());
36        match fun(&mut dcx) {
37            Ok(mut stream) => {
38                stream.extend(dcx.0);
39                stream
40            }
41            Err(ErrorGuaranteed(())) => dcx.0,
42        }
43    }
44}
pin_init_internal/diagnostics.rs

pin_init_internal/
diagnostics.rs
