1f58e0efd0
* executor-macros: don't parse function bodies. * executor-macros: refactor for better recovery and ide-friendliness on errors. * executor-macros: disallow `impl Trait` in task arguments. Fixes #3420 * Fix example using `impl Trait` in tasks.
75 lines
2.3 KiB
Rust
75 lines
2.3 KiB
Rust
use std::fmt::Display;
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use proc_macro2::{TokenStream, TokenTree};
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use quote::{ToTokens, TokenStreamExt};
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use syn::parse::{Parse, ParseStream};
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use syn::{braced, bracketed, token, AttrStyle, Attribute, Signature, Token, Visibility};
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pub fn token_stream_with_error(mut tokens: TokenStream, error: syn::Error) -> TokenStream {
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tokens.extend(error.into_compile_error());
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tokens
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}
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pub fn error<A: ToTokens, T: Display>(s: &mut TokenStream, obj: A, msg: T) {
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s.extend(syn::Error::new_spanned(obj.into_token_stream(), msg).into_compile_error())
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}
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/// Function signature and body.
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///
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/// Same as `syn`'s `ItemFn` except we keep the body as a TokenStream instead of
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/// parsing it. This makes the macro not error if there's a syntax error in the body,
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/// which helps IDE autocomplete work better.
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#[derive(Debug, Clone)]
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pub struct ItemFn {
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pub attrs: Vec<Attribute>,
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pub vis: Visibility,
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pub sig: Signature,
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pub brace_token: token::Brace,
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pub body: TokenStream,
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}
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impl Parse for ItemFn {
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fn parse(input: ParseStream) -> syn::Result<Self> {
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let mut attrs = input.call(Attribute::parse_outer)?;
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let vis: Visibility = input.parse()?;
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let sig: Signature = input.parse()?;
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let content;
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let brace_token = braced!(content in input);
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while content.peek(Token![#]) && content.peek2(Token![!]) {
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let content2;
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attrs.push(Attribute {
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pound_token: content.parse()?,
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style: AttrStyle::Inner(content.parse()?),
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bracket_token: bracketed!(content2 in content),
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meta: content2.parse()?,
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});
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}
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let mut body = Vec::new();
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while !content.is_empty() {
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body.push(content.parse::<TokenTree>()?);
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}
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let body = body.into_iter().collect();
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Ok(ItemFn {
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attrs,
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vis,
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sig,
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brace_token,
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body,
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})
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}
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}
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impl ToTokens for ItemFn {
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fn to_tokens(&self, tokens: &mut TokenStream) {
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tokens.append_all(self.attrs.iter().filter(|a| matches!(a.style, AttrStyle::Outer)));
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self.vis.to_tokens(tokens);
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self.sig.to_tokens(tokens);
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self.brace_token.surround(tokens, |tokens| {
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tokens.append_all(self.body.clone());
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});
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}
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}
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