Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

vendor/syn/src/parse_quote.rs

@@ -0,0 +1,209 @@
+/// Quasi-quotation macro that accepts input like the [`quote!`] macro but uses
+/// type inference to figure out a return type for those tokens.
+///
+/// [`quote!`]: https://docs.rs/quote/1.0/quote/index.html
+///
+/// The return type can be any syntax tree node that implements the [`Parse`]
+/// trait.
+///
+/// [`Parse`]: crate::parse::Parse
+///
+/// ```
+/// use quote::quote;
+/// use syn::{parse_quote, Stmt};
+///
+/// fn main() {
+///     let name = quote!(v);
+///     let ty = quote!(u8);
+///
+///     let stmt: Stmt = parse_quote! {
+///         let #name: #ty = Default::default();
+///     };
+///
+///     println!("{:#?}", stmt);
+/// }
+/// ```
+///
+/// *This macro is available only if Syn is built with both the `"parsing"` and
+/// `"printing"` features.*
+///
+/// # Example
+///
+/// The following helper function adds a bound `T: HeapSize` to every type
+/// parameter `T` in the input generics.
+///
+/// ```
+/// use syn::{parse_quote, Generics, GenericParam};
+///
+/// // Add a bound `T: HeapSize` to every type parameter T.
+/// fn add_trait_bounds(mut generics: Generics) -> Generics {
+///     for param in &mut generics.params {
+///         if let GenericParam::Type(type_param) = param {
+///             type_param.bounds.push(parse_quote!(HeapSize));
+///         }
+///     }
+///     generics
+/// }
+/// ```
+///
+/// # Special cases
+///
+/// This macro can parse the following additional types as a special case even
+/// though they do not implement the `Parse` trait.
+///
+/// - [`Attribute`] — parses one attribute, allowing either outer like `#[...]`
+///   or inner like `#![...]`
+/// - [`Punctuated<T, P>`] — parses zero or more `T` separated by punctuation
+///   `P` with optional trailing punctuation
+/// - [`Vec<Stmt>`] — parses the same as `Block::parse_within`
+///
+/// [`Vec<Stmt>`]: Block::parse_within
+///
+/// # Panics
+///
+/// Panics if the tokens fail to parse as the expected syntax tree type. The
+/// caller is responsible for ensuring that the input tokens are syntactically
+/// valid.
+#[cfg_attr(doc_cfg, doc(cfg(all(feature = "parsing", feature = "printing"))))]
+#[macro_export]
+macro_rules! parse_quote {
+    ($($tt:tt)*) => {
+        $crate::__private::parse_quote($crate::__private::quote::quote!($($tt)*))
+    };
+}
+
+/// This macro is [`parse_quote!`] + [`quote_spanned!`][quote::quote_spanned].
+///
+/// Please refer to each of their documentation.
+///
+/// # Example
+///
+/// ```
+/// use quote::{quote, quote_spanned};
+/// use syn::spanned::Spanned;
+/// use syn::{parse_quote_spanned, ReturnType, Signature};
+///
+/// // Changes `fn()` to `fn() -> Pin<Box<dyn Future<Output = ()>>>`,
+/// // and `fn() -> T` to `fn() -> Pin<Box<dyn Future<Output = T>>>`,
+/// // without introducing any call_site() spans.
+/// fn make_ret_pinned_future(sig: &mut Signature) {
+///     let ret = match &sig.output {
+///         ReturnType::Default => quote_spanned!(sig.paren_token.span=> ()),
+///         ReturnType::Type(_, ret) => quote!(#ret),
+///     };
+///     sig.output = parse_quote_spanned! {ret.span()=>
+///         -> ::std::pin::Pin<::std::boxed::Box<dyn ::std::future::Future<Output = #ret>>>
+///     };
+/// }
+/// ```
+#[cfg_attr(doc_cfg, doc(cfg(all(feature = "parsing", feature = "printing"))))]
+#[macro_export]
+macro_rules! parse_quote_spanned {
+    ($span:expr=> $($tt:tt)*) => {
+        $crate::__private::parse_quote($crate::__private::quote::quote_spanned!($span=> $($tt)*))
+    };
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Can parse any type that implements Parse.
+
+use crate::parse::{Parse, ParseStream, Parser, Result};
+use proc_macro2::TokenStream;
+
+// Not public API.
+#[doc(hidden)]
+pub fn parse<T: ParseQuote>(token_stream: TokenStream) -> T {
+    let parser = T::parse;
+    match parser.parse2(token_stream) {
+        Ok(t) => t,
+        Err(err) => panic!("{}", err),
+    }
+}
+
+#[doc(hidden)]
+pub trait ParseQuote: Sized {
+    fn parse(input: ParseStream) -> Result<Self>;
+}
+
+impl<T: Parse> ParseQuote for T {
+    fn parse(input: ParseStream) -> Result<Self> {
+        <T as Parse>::parse(input)
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Any other types that we want `parse_quote!` to be able to parse.
+
+use crate::punctuated::Punctuated;
+#[cfg(any(feature = "full", feature = "derive"))]
+use crate::{attr, Attribute, Field, FieldMutability, Ident, Type, Visibility};
+#[cfg(feature = "full")]
+use crate::{Block, Pat, Stmt};
+
+#[cfg(any(feature = "full", feature = "derive"))]
+impl ParseQuote for Attribute {
+    fn parse(input: ParseStream) -> Result<Self> {
+        if input.peek(Token![#]) && input.peek2(Token![!]) {
+            attr::parsing::single_parse_inner(input)
+        } else {
+            attr::parsing::single_parse_outer(input)
+        }
+    }
+}
+
+#[cfg(any(feature = "full", feature = "derive"))]
+impl ParseQuote for Field {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let attrs = input.call(Attribute::parse_outer)?;
+        let vis: Visibility = input.parse()?;
+
+        let ident: Option<Ident>;
+        let colon_token: Option<Token![:]>;
+        let is_named = input.peek(Ident) && input.peek2(Token![:]) && !input.peek2(Token![::]);
+        if is_named {
+            ident = Some(input.parse()?);
+            colon_token = Some(input.parse()?);
+        } else {
+            ident = None;
+            colon_token = None;
+        }
+
+        let ty: Type = input.parse()?;
+
+        Ok(Field {
+            attrs,
+            vis,
+            mutability: FieldMutability::None,
+            ident,
+            colon_token,
+            ty,
+        })
+    }
+}
+
+#[cfg(feature = "full")]
+impl ParseQuote for Pat {
+    fn parse(input: ParseStream) -> Result<Self> {
+        Pat::parse_multi_with_leading_vert(input)
+    }
+}
+
+#[cfg(feature = "full")]
+impl ParseQuote for Box<Pat> {
+    fn parse(input: ParseStream) -> Result<Self> {
+        <Pat as ParseQuote>::parse(input).map(Box::new)
+    }
+}
+
+impl<T: Parse, P: Parse> ParseQuote for Punctuated<T, P> {
+    fn parse(input: ParseStream) -> Result<Self> {
+        Self::parse_terminated(input)
+    }
+}
+
+#[cfg(feature = "full")]
+impl ParseQuote for Vec<Stmt> {
+    fn parse(input: ParseStream) -> Result<Self> {
+        Block::parse_within(input)
+    }
+}