[PATCH v2 11/20] rust: quote: import crate

Miguel Ojeda
2025-11-24T15:19:46Z

This is a subset of the Rust `quote` crate, version 1.0.40 (released
2025-03-12), licensed under "Apache-2.0 OR MIT", from:

https://github.com/dtolnay/quote/raw/1.0.40/src

The files are copied as-is, with no modifications whatsoever (not even
adding the SPDX identifiers).

For copyright details, please see:

https://github.com/dtolnay/quote/blob/1.0.40/README.md#license
https://github.com/dtolnay/quote/blob/1.0.40/LICENSE-APACHE
https://github.com/dtolnay/quote/blob/1.0.40/LICENSE-MIT

The next patch modifies these files as needed for use within the
kernel. This patch split allows reviewers to double-check the import
and to clearly see the differences introduced.

The following script may be used to verify the contents:

for path in $(cd rust/quote/ && find . -type f -name '*.rs'); do
curl --silent --show-error --location \
https://github.com/dtolnay/quote/raw/1.0.40/src/$path \
| diff --unified rust/quote/$path - && echo $path: OK
done

Reviewed-by: Gary Guo <gary@garyguo.net>
Tested-by: Gary Guo <gary@garyguo.net>
Tested-by: Jesung Yang <y.j3ms.n@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
rust/quote/ext.rs | 110 +++
rust/quote/format.rs | 168 ++++
rust/quote/ident_fragment.rs | 88 ++
rust/quote/lib.rs | 1454 ++++++++++++++++++++++++++++++++++
rust/quote/runtime.rs | 492 ++++++++++++
rust/quote/spanned.rs | 50 ++
rust/quote/to_tokens.rs | 271 +++++++
7 files changed, 2633 insertions(+)
create mode 100644 rust/quote/ext.rs
create mode 100644 rust/quote/format.rs
create mode 100644 rust/quote/ident_fragment.rs
create mode 100644 rust/quote/lib.rs
create mode 100644 rust/quote/runtime.rs
create mode 100644 rust/quote/spanned.rs
create mode 100644 rust/quote/to_tokens.rs

diff --git a/rust/quote/ext.rs b/rust/quote/ext.rs
new file mode 100644
index 000000000000..92c2315b182d
--- /dev/null
+++ b/rust/quote/ext.rs
@@ -0,0 +1,110 @@
+use super::ToTokens;
+use core::iter;
+use proc_macro2::{TokenStream, TokenTree};
+
+/// TokenStream extension trait with methods for appending tokens.
+///
+/// This trait is sealed and cannot be implemented outside of the `quote` crate.
+pub trait TokenStreamExt: private::Sealed {
+ /// For use by `ToTokens` implementations.
+ ///
+ /// Appends the token specified to this list of tokens.
+ fn append(&mut self, token: U)
+ where
+ U: Into<TokenTree>;
+
+ /// For use by `ToTokens` implementations.
+ ///
+ /// ```
+ /// # use quote::{quote, TokenStreamExt, ToTokens};
+ /// # use proc_macro2::TokenStream;
+ /// #
+ /// struct X;
+ ///
+ /// impl ToTokens for X {
+ /// fn to_tokens(&self, tokens: &mut TokenStream) {
+ /// tokens.append_all(&[true, false]);
+ /// }
+ /// }
+ ///
+ /// let tokens = quote!(#X);
+ /// assert_eq!(tokens.to_string(), "true false");
+ /// ```
+ fn append_all(&mut self, iter: I)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens;
+
+ /// For use by `ToTokens` implementations.
+ ///
+ /// Appends all of the items in the iterator `I`, separated by the tokens
+ /// `U`.
+ fn append_separated<I, U>(&mut self, iter: I, op: U)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens,
+ U: ToTokens;
+
+ /// For use by `ToTokens` implementations.
+ ///
+ /// Appends all tokens in the iterator `I`, appending `U` after each
+ /// element, including after the last element of the iterator.
+ fn append_terminated<I, U>(&mut self, iter: I, term: U)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens,
+ U: ToTokens;
+}
+
+impl TokenStreamExt for TokenStream {
+ fn append(&mut self, token: U)
+ where
+ U: Into<TokenTree>,
+ {
+ self.extend(iter::once(token.into()));
+ }
+
+ fn append_all(&mut self, iter: I)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens,
+ {
+ for token in iter {
+ token.to_tokens(self);
+ }
+ }
+
+ fn append_separated<I, U>(&mut self, iter: I, op: U)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens,
+ U: ToTokens,
+ {
+ for (i, token) in iter.into_iter().enumerate() {
+ if i > 0 {
+ op.to_tokens(self);
+ }
+ token.to_tokens(self);
+ }
+ }
+
+ fn append_terminated<I, U>(&mut self, iter: I, term: U)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens,
+ U: ToTokens,
+ {
+ for token in iter {
+ token.to_tokens(self);
+ term.to_tokens(self);
+ }
+ }
+}
+
+mod private {
+ use proc_macro2::TokenStream;
+
+ pub trait Sealed {}
+
+ impl Sealed for TokenStream {}
+}
diff --git a/rust/quote/format.rs b/rust/quote/format.rs
new file mode 100644
index 000000000000..ec0bbf38ba37
--- /dev/null
+++ b/rust/quote/format.rs
@@ -0,0 +1,168 @@
+/// Formatting macro for constructing `Ident`s.
+///
+///
+///
+/// # Syntax
+///
+/// Syntax is copied from the [`format!`] macro, supporting both positional and
+/// named arguments.
+///
+/// Only a limited set of formatting traits are supported. The current mapping
+/// of format types to traits is:
+///
+/// * `{}` ⇒ [`IdentFragment`]
+/// * `{:o}` ⇒ [`Octal`](std::fmt::Octal)
+/// * `{:x}` ⇒ [`LowerHex`](std::fmt::LowerHex)
+/// * `{:X}` ⇒ [`UpperHex`](std::fmt::UpperHex)
+/// * `{:b}` ⇒ [`Binary`](std::fmt::Binary)
+///
+/// See [`std::fmt`] for more information.
+///
+///
+///
+/// # IdentFragment
+///
+/// Unlike `format!`, this macro uses the [`IdentFragment`] formatting trait by
+/// default. This trait is like `Display`, with a few differences:
+///
+/// * `IdentFragment` is only implemented for a limited set of types, such as
+/// unsigned integers and strings.
+/// * [`Ident`] arguments will have their `r#` prefixes stripped, if present.
+///
+/// [`IdentFragment`]: crate::IdentFragment
+/// [`Ident`]: proc_macro2::Ident
+///
+///
+///
+/// # Hygiene
+///
+/// The [`Span`] of the first `Ident` argument is used as the span of the final
+/// identifier, falling back to [`Span::call_site`] when no identifiers are
+/// provided.
+///
+/// ```
+/// # use quote::format_ident;
+/// # let ident = format_ident!("Ident");
+/// // If `ident` is an Ident, the span of `my_ident` will be inherited from it.
+/// let my_ident = format_ident!("My{}{}", ident, "IsCool");
+/// assert_eq!(my_ident, "MyIdentIsCool");
+/// ```
+///
+/// Alternatively, the span can be overridden by passing the `span` named
+/// argument.
+///
+/// ```
+/// # use quote::format_ident;
+/// # const IGNORE_TOKENS: &'static str = stringify! {
+/// let my_span = /* ... */;
+/// # };
+/// # let my_span = proc_macro2::Span::call_site();
+/// format_ident!("MyIdent", span = my_span);
+/// ```
+///
+/// [`Span`]: proc_macro2::Span
+/// [`Span::call_site`]: proc_macro2::Span::call_site
+///
+///
+///
+/// # Panics
+///
+/// This method will panic if the resulting formatted string is not a valid
+/// identifier.
+///
+///
+///
+/// # Examples
+///
+/// Composing raw and non-raw identifiers:
+/// ```
+/// # use quote::format_ident;
+/// let my_ident = format_ident!("My{}", "Ident");
+/// assert_eq!(my_ident, "MyIdent");
+///
+/// let raw = format_ident!("r#Raw");
+/// assert_eq!(raw, "r#Raw");
+///
+/// let my_ident_raw = format_ident!("{}Is{}", my_ident, raw);
+/// assert_eq!(my_ident_raw, "MyIdentIsRaw");
+/// ```
+///
+/// Integer formatting options:
+/// ```
+/// # use quote::format_ident;
+/// let num: u32 = 10;
+///
+/// let decimal = format_ident!("Id_{}", num);
+/// assert_eq!(decimal, "Id_10");
+///
+/// let octal = format_ident!("Id_{:o}", num);
+/// assert_eq!(octal, "Id_12");
+///
+/// let binary = format_ident!("Id_{:b}", num);
+/// assert_eq!(binary, "Id_1010");
+///
+/// let lower_hex = format_ident!("Id_{:x}", num);
+/// assert_eq!(lower_hex, "Id_a");
+///
+/// let upper_hex = format_ident!("Id_{:X}", num);
+/// assert_eq!(upper_hex, "Id_A");
+/// ```
+#[macro_export]
+macro_rules! format_ident {
+ ($fmt:expr) => {
+ $crate::format_ident_impl!([
+ $crate::__private::Option::None,
+ $fmt
+ ])
+ };
+
+ ($fmt:expr, $($rest:tt)*) => {
+ $crate::format_ident_impl!([
+ $crate::__private::Option::None,
+ $fmt
+ ] $($rest)*)
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! format_ident_impl {
+ // Final state
+ ([$span:expr, $($fmt:tt)*]) => {
+ $crate::__private::mk_ident(
+ &$crate::__private::format!($($fmt)*),
+ $span,
+ )
+ };
+
+ // Span argument
+ ([$old:expr, $($fmt:tt)*] span = $span:expr) => {
+ $crate::format_ident_impl!([$old, $($fmt)*] span = $span,)
+ };
+ ([$old:expr, $($fmt:tt)*] span = $span:expr, $($rest:tt)*) => {
+ $crate::format_ident_impl!([
+ $crate::__private::Option::Some::<$crate::__private::Span>($span),
+ $($fmt)*
+ ] $($rest)*)
+ };
+
+ // Named argument
+ ([$span:expr, $($fmt:tt)*] $name:ident = $arg:expr) => {
+ $crate::format_ident_impl!([$span, $($fmt)*] $name = $arg,)
+ };
+ ([$span:expr, $($fmt:tt)*] $name:ident = $arg:expr, $($rest:tt)*) => {
+ match $crate::__private::IdentFragmentAdapter(&$arg) {
+ arg => $crate::format_ident_impl!([$span.or(arg.span()), $($fmt)*, $name = arg] $($rest)*),
+ }
+ };
+
+ // Positional argument
+ ([$span:expr, $($fmt:tt)*] $arg:expr) => {
+ $crate::format_ident_impl!([$span, $($fmt)*] $arg,)
+ };
+ ([$span:expr, $($fmt:tt)*] $arg:expr, $($rest:tt)*) => {
+ match $crate::__private::IdentFragmentAdapter(&$arg) {
+ arg => $crate::format_ident_impl!([$span.or(arg.span()), $($fmt)*, arg] $($rest)*),
+ }
+ };
+}
diff --git a/rust/quote/ident_fragment.rs b/rust/quote/ident_fragment.rs
new file mode 100644
index 000000000000..6c2a9a87acb4
--- /dev/null
+++ b/rust/quote/ident_fragment.rs
@@ -0,0 +1,88 @@
+use alloc::borrow::Cow;
+use core::fmt;
+use proc_macro2::{Ident, Span};
+
+/// Specialized formatting trait used by `format_ident!`.
+///
+/// [`Ident`] arguments formatted using this trait will have their `r#` prefix
+/// stripped, if present.
+///
+/// See [`format_ident!`] for more information.
+///
+/// [`format_ident!`]: crate::format_ident
+pub trait IdentFragment {
+ /// Format this value as an identifier fragment.
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result;
+
+ /// Span associated with this `IdentFragment`.
+ ///
+ /// If non-`None`, may be inherited by formatted identifiers.
+ fn span(&self) -> Option {
+ None
+ }
+}
+
+impl<T: IdentFragment + ?Sized> IdentFragment for &T {
+ fn span(&self) -> Option {
+ <T as IdentFragment>::span(*self)
+ }
+
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ IdentFragment::fmt(*self, f)
+ }
+}
+
+impl<T: IdentFragment + ?Sized> IdentFragment for &mut T {
+ fn span(&self) -> Option {
+ <T as IdentFragment>::span(*self)
+ }
+
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ IdentFragment::fmt(*self, f)
+ }
+}
+
+impl IdentFragment for Ident {
+ fn span(&self) -> Option {
+ Some(self.span())
+ }
+
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ let id = self.to_string();
+ if let Some(id) = id.strip_prefix("r#") {
+ fmt::Display::fmt(id, f)
+ } else {
+ fmt::Display::fmt(&id[..], f)
+ }
+ }
+}
+
+impl<T> IdentFragment for Cow<'_, T>
+where
+ T: IdentFragment + ToOwned + ?Sized,
+{
+ fn span(&self) -> Option {
+ T::span(self)
+ }
+
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ T::fmt(self, f)
+ }
+}
+
+// Limited set of types which this is implemented for, as we want to avoid types
+// which will often include non-identifier characters in their `Display` impl.
+macro_rules! ident_fragment_display {
+ ($($T:ty),*) => {
+ $(
+ impl IdentFragment for $T {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::Display::fmt(self, f)
+ }
+ }
+ )*
+ };
+}
+
+ident_fragment_display!(bool, str, String, char);
+ident_fragment_display!(u8, u16, u32, u64, u128, usize);
diff --git a/rust/quote/lib.rs b/rust/quote/lib.rs
new file mode 100644
index 000000000000..0a12d607f279
--- /dev/null
+++ b/rust/quote/lib.rs
@@ -0,0 +1,1454 @@
+//! [![github]](https://github.com/dtolnay/quote)&ensp;[![crates-io]](https://crates.io/crates/quote)&ensp;[![docs-rs]](https://docs.rs/quote)
+//!
+//! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github
+//! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust
+//! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs
+//!
+//!
+//!
+//! This crate provides the [`quote!`] macro for turning Rust syntax tree data
+//! structures into tokens of source code.
+//!
+//! Procedural macros in Rust receive a stream of tokens as input, execute
+//! arbitrary Rust code to determine how to manipulate those tokens, and produce
+//! a stream of tokens to hand back to the compiler to compile into the caller's
+//! crate. Quasi-quoting is a solution to one piece of that &mdash; producing
+//! tokens to return to the compiler.
+//!
+//! The idea of quasi-quoting is that we write *code* that we treat as *data*.
+//! Within the `quote!` macro, we can write what looks like code to our text
+//! editor or IDE. We get all the benefits of the editor's brace matching,
+//! syntax highlighting, indentation, and maybe autocompletion. But rather than
+//! compiling that as code into the current crate, we can treat it as data, pass
+//! it around, mutate it, and eventually hand it back to the compiler as tokens
+//! to compile into the macro caller's crate.
+//!
+//! This crate is motivated by the procedural macro use case, but is a
+//! general-purpose Rust quasi-quoting library and is not specific to procedural
+//! macros.
+//!
+//! ```toml
+//! [dependencies]
+//! quote = "1.0"
+//! ```
+//!
+//!
+//!
+//! # Example
+//!
+//! The following quasi-quoted block of code is something you might find in [a]
+//! procedural macro having to do with data structure serialization. The `#var`
+//! syntax performs interpolation of runtime variables into the quoted tokens.
+//! Check out the documentation of the [`quote!`] macro for more detail about
+//! the syntax. See also the [`quote_spanned!`] macro which is important for
+//! implementing hygienic procedural macros.
+//!
+//! [a]: https://serde.rs/
+//!
+//! ```
+//! # use quote::quote;
+//! #
+//! # let generics = "";
+//! # let where_clause = "";
+//! # let field_ty = "";
+//! # let item_ty = "";
+//! # let path = "";
+//! # let value = "";
+//! #
+//! let tokens = quote! {
+//! struct SerializeWith #generics #where_clause {
+//! value: &'a #field_ty,
+//! phantom: core::marker::PhantomData<#item_ty>,
+//! }
+//!
+//! impl #generics serde::Serialize for SerializeWith #generics #where_clause {
+//! fn serialize(&self, serializer: S) -> Result<S::Ok, S::Error>
+//! where
+//! S: serde::Serializer,
+//! {
+//! #path(self.value, serializer)
+//! }
+//! }
+//!
+//! SerializeWith {
+//! value: #value,
+//! phantom: core::marker::PhantomData::<#item_ty>,
+//! }
+//! };
+//! ```
+//!
+//!
+//!
+//! # Non-macro code generators
+//!
+//! When using `quote` in a build.rs or main.rs and writing the output out to a
+//! file, consider having the code generator pass the tokens through
+//! [prettyplease] before writing. This way if an error occurs in the generated
+//! code it is convenient for a human to read and debug.
+//!
+//! [prettyplease]: https://github.com/dtolnay/prettyplease
+
+// Quote types in rustdoc of other crates get linked to here.
+#![doc(html_root_url = "https://docs.rs/quote/1.0.40")]
+#![allow(
+ clippy::doc_markdown,
+ clippy::elidable_lifetime_names,
+ clippy::missing_errors_doc,
+ clippy::missing_panics_doc,
+ clippy::module_name_repetitions,
+ clippy::needless_lifetimes,
+ // false positive https://github.com/rust-lang/rust-clippy/issues/6983
+ clippy::wrong_self_convention,
+)]
+
+extern crate alloc;
+
+#[cfg(feature = "proc-macro")]
+extern crate proc_macro;
+
+mod ext;
+mod format;
+mod ident_fragment;
+mod to_tokens;
+
+// Not public API.
+#[doc(hidden)]
+#[path = "runtime.rs"]
+pub mod __private;
+
+pub use crate::ext::TokenStreamExt;
+pub use crate::ident_fragment::IdentFragment;
+pub use crate::to_tokens::ToTokens;
+
+// Not public API.
+#[doc(hidden)]
+pub mod spanned;
+
+macro_rules! __quote {
+ ($quote:item) => {
+ /// The whole point.
+ ///
+ /// Performs variable interpolation against the input and produces it as
+ /// [`proc_macro2::TokenStream`].
+ ///
+ /// Note: for returning tokens to the compiler in a procedural macro, use
+ /// `.into()` on the result to convert to [`proc_macro::TokenStream`].
+ ///
+ ///
+ ///
+ /// # Interpolation
+ ///
+ /// Variable interpolation is done with `#var` (similar to `$var` in
+ /// `macro_rules!` macros). This grabs the `var` variable that is currently in
+ /// scope and inserts it in that location in the output tokens. Any type
+ /// implementing the [`ToTokens`] trait can be interpolated. This includes most
+ /// Rust primitive types as well as most of the syntax tree types from the [Syn]
+ /// crate.
+ ///
+ /// [Syn]: https://github.com/dtolnay/syn
+ ///
+ /// Repetition is done using `#(...)*` or `#(...),*` again similar to
+ /// `macro_rules!`. This iterates through the elements of any variable
+ /// interpolated within the repetition and inserts a copy of the repetition body
+ /// for each one. The variables in an interpolation may be a `Vec`, slice,
+ /// `BTreeSet`, or any `Iterator`.
+ ///
+ /// - `#(#var)*` — no separators
+ /// - `#(#var),*` — the character before the asterisk is used as a separator
+ /// - `#( struct #var; )*` — the repetition can contain other tokens
+ /// - `#( #k => println!("{}", #v), )*` — even multiple interpolations
+ ///
+ ///
+ ///
+ /// # Hygiene
+ ///
+ /// Any interpolated tokens preserve the `Span` information provided by their
+ /// `ToTokens` implementation. Tokens that originate within the `quote!`
+ /// invocation are spanned with [`Span::call_site()`].
+ ///
+ /// [`Span::call_site()`]: proc_macro2::Span::call_site
+ ///
+ /// A different span can be provided through the [`quote_spanned!`] macro.
+ ///
+ ///
+ ///
+ /// # Return type
+ ///
+ /// The macro evaluates to an expression of type `proc_macro2::TokenStream`.
+ /// Meanwhile Rust procedural macros are expected to return the type
+ /// `proc_macro::TokenStream`.
+ ///
+ /// The difference between the two types is that `proc_macro` types are entirely
+ /// specific to procedural macros and cannot ever exist in code outside of a
+ /// procedural macro, while `proc_macro2` types may exist anywhere including
+ /// tests and non-macro code like main.rs and build.rs. This is why even the
+ /// procedural macro ecosystem is largely built around `proc_macro2`, because
+ /// that ensures the libraries are unit testable and accessible in non-macro
+ /// contexts.
+ ///
+ /// There is a [`From`]-conversion in both directions so returning the output of
+ /// `quote!` from a procedural macro usually looks like `tokens.into()` or
+ /// `proc_macro::TokenStream::from(tokens)`.
+ ///
+ ///
+ ///
+ /// # Examples
+ ///
+ /// ### Procedural macro
+ ///
+ /// The structure of a basic procedural macro is as follows. Refer to the [Syn]
+ /// crate for further useful guidance on using `quote!` as part of a procedural
+ /// macro.
+ ///
+ /// [Syn]: https://github.com/dtolnay/syn
+ ///
+ /// ```
+ /// # #[cfg(any())]
+ /// extern crate proc_macro;
+ /// # extern crate proc_macro2;
+ ///
+ /// # #[cfg(any())]
+ /// use proc_macro::TokenStream;
+ /// # use proc_macro2::TokenStream;
+ /// use quote::quote;
+ ///
+ /// # const IGNORE_TOKENS: &'static str = stringify! {
+ /// #[proc_macro_derive(HeapSize)]
+ /// # };
+ /// pub fn derive_heap_size(input: TokenStream) -> TokenStream {
+ /// // Parse the input and figure out what implementation to generate...
+ /// # const IGNORE_TOKENS: &'static str = stringify! {
+ /// let name = /* ... */;
+ /// let expr = /* ... */;
+ /// # };
+ /// #
+ /// # let name = 0;
+ /// # let expr = 0;
+ ///
+ /// let expanded = quote! {
+ /// // The generated impl.
+ /// impl heapsize::HeapSize for #name {
+ /// fn heap_size_of_children(&self) -> usize {
+ /// #expr
+ /// }
+ /// }
+ /// };
+ ///
+ /// // Hand the output tokens back to the compiler.
+ /// TokenStream::from(expanded)
+ /// }
+ /// ```
+ ///
+ ///
+ ///
+ /// ### Combining quoted fragments
+ ///
+ /// Usually you don't end up constructing an entire final `TokenStream` in one
+ /// piece. Different parts may come from different helper functions. The tokens
+ /// produced by `quote!` themselves implement `ToTokens` and so can be
+ /// interpolated into later `quote!` invocations to build up a final result.
+ ///
+ /// ```
+ /// # use quote::quote;
+ /// #
+ /// let type_definition = quote! {...};
+ /// let methods = quote! {...};
+ ///
+ /// let tokens = quote! {
+ /// #type_definition
+ /// #methods
+ /// };
+ /// ```
+ ///
+ ///
+ ///
+ /// ### Constructing identifiers
+ ///
+ /// Suppose we have an identifier `ident` which came from somewhere in a macro
+ /// input and we need to modify it in some way for the macro output. Let's
+ /// consider prepending the identifier with an underscore.
+ ///
+ /// Simply interpolating the identifier next to an underscore will not have the
+ /// behavior of concatenating them. The underscore and the identifier will
+ /// continue to be two separate tokens as if you had written `_ x`.
+ ///
+ /// ```
+ /// # use proc_macro2::{self as syn, Span};
+ /// # use quote::quote;
+ /// #
+ /// # let ident = syn::Ident::new("i", Span::call_site());
+ /// #
+ /// // incorrect
+ /// quote! {
+ /// let mut _#ident = 0;
+ /// }
+ /// # ;
+ /// ```
+ ///
+ /// The solution is to build a new identifier token with the correct value. As
+ /// this is such a common case, the [`format_ident!`] macro provides a
+ /// convenient utility for doing so correctly.
+ ///
+ /// ```
+ /// # use proc_macro2::{Ident, Span};
+ /// # use quote::{format_ident, quote};
+ /// #
+ /// # let ident = Ident::new("i", Span::call_site());
+ /// #
+ /// let varname = format_ident!("_{}", ident);
+ /// quote! {
+ /// let mut #varname = 0;
+ /// }
+ /// # ;
+ /// ```
+ ///
+ /// Alternatively, the APIs provided by Syn and proc-macro2 can be used to
+ /// directly build the identifier. This is roughly equivalent to the above, but
+ /// will not handle `ident` being a raw identifier.
+ ///
+ /// ```
+ /// # use proc_macro2::{self as syn, Span};
+ /// # use quote::quote;
+ /// #
+ /// # let ident = syn::Ident::new("i", Span::call_site());
+ /// #
+ /// let concatenated = format!("_{}", ident);
+ /// let varname = syn::Ident::new(&concatenated, ident.span());
+ /// quote! {
+ /// let mut #varname = 0;
+ /// }
+ /// # ;
+ /// ```
+ ///
+ ///
+ ///
+ /// ### Making method calls
+ ///
+ /// Let's say our macro requires some type specified in the macro input to have
+ /// a constructor called `new`. We have the type in a variable called
+ /// `field_type` of type `syn::Type` and want to invoke the constructor.
+ ///
+ /// ```
+ /// # use quote::quote;
+ /// #
+ /// # let field_type = quote!(...);
+ /// #
+ /// // incorrect
+ /// quote! {
+ /// let value = #field_type::new();
+ /// }
+ /// # ;
+ /// ```
+ ///
+ /// This works only sometimes. If `field_type` is `String`, the expanded code
+ /// contains `String::new()` which is fine. But if `field_type` is something
+ /// like `Vec<i32>` then the expanded code is `Vec<i32>::new()` which is invalid
+ /// syntax. Ordinarily in handwritten Rust we would write `Vec::<i32>::new()`
+ /// but for macros often the following is more convenient.
+ ///
+ /// ```
+ /// # use quote::quote;
+ /// #
+ /// # let field_type = quote!(...);
+ /// #
+ /// quote! {
+ /// let value = <#field_type>::new();
+ /// }
+ /// # ;
+ /// ```
+ ///
+ /// This expands to `<Vec<i32>>::new()` which behaves correctly.
+ ///
+ /// A similar pattern is appropriate for trait methods.
+ ///
+ /// ```
+ /// # use quote::quote;
+ /// #
+ /// # let field_type = quote!(...);
+ /// #
+ /// quote! {
+ /// let value = <#field_type as core::default::Default>::default();
+ /// }
+ /// # ;
+ /// ```
+ ///
+ ///
+ ///
+ /// ### Interpolating text inside of doc comments
+ ///
+ /// Neither doc comments nor string literals get interpolation behavior in
+ /// quote:
+ ///
+ /// ```compile_fail
+ /// quote! {
+ /// /// try to interpolate: #ident
+ /// ///
+ /// /// ...
+ /// }
+ /// ```
+ ///
+ /// ```compile_fail
+ /// quote! {
+ /// #[doc = "try to interpolate: #ident"]
+ /// }
+ /// ```
+ ///
+ /// Instead the best way to build doc comments that involve variables is by
+ /// formatting the doc string literal outside of quote.
+ ///
+ /// ```rust
+ /// # use proc_macro2::{Ident, Span};
+ /// # use quote::quote;
+ /// #
+ /// # const IGNORE: &str = stringify! {
+ /// let msg = format!(...);
+ /// # };
+ /// #
+ /// # let ident = Ident::new("var", Span::call_site());
+ /// # let msg = format!("try to interpolate: {}", ident);
+ /// quote! {
+ /// #[doc = #msg]
+ /// ///
+ /// /// ...
+ /// }
+ /// # ;
+ /// ```
+ ///
+ ///
+ ///
+ /// ### Indexing into a tuple struct
+ ///
+ /// When interpolating indices of a tuple or tuple struct, we need them not to
+ /// appears suffixed as integer literals by interpolating them as [`syn::Index`]
+ /// instead.
+ ///
+ /// [`syn::Index`]: https://docs.rs/syn/2.0/syn/struct.Index.html
+ ///
+ /// ```compile_fail
+ /// let i = 0usize..self.fields.len();
+ ///
+ /// // expands to 0 + self.0usize.heap_size() + self.1usize.heap_size() + ...
+ /// // which is not valid syntax
+ /// quote! {
+ /// 0 #( + self.#i.heap_size() )*
+ /// }
+ /// ```
+ ///
+ /// ```
+ /// # use proc_macro2::{Ident, TokenStream};
+ /// # use quote::quote;
+ /// #
+ /// # mod syn {
+ /// # use proc_macro2::{Literal, TokenStream};
+ /// # use quote::{ToTokens, TokenStreamExt};
+ /// #
+ /// # pub struct Index(usize);
+ /// #
+ /// # impl From<usize> for Index {
+ /// # fn from(i: usize) -> Self {
+ /// # Index(i)
+ /// # }
+ /// # }
+ /// #
+ /// # impl ToTokens for Index {
+ /// # fn to_tokens(&self, tokens: &mut TokenStream) {
+ /// # tokens.append(Literal::usize_unsuffixed(self.0));
+ /// # }
+ /// # }
+ /// # }
+ /// #
+ /// # struct Struct {
+ /// # fields: Vec<Ident>,
+ /// # }
+ /// #
+ /// # impl Struct {
+ /// # fn example(&self) -> TokenStream {
+ /// let i = (0..self.fields.len()).map(syn::Index::from);
+ ///
+ /// // expands to 0 + self.0.heap_size() + self.1.heap_size() + ...
+ /// quote! {
+ /// 0 #( + self.#i.heap_size() )*
+ /// }
+ /// # }
+ /// # }
+ /// ```
+ $quote
+ };
+}
+
+#[cfg(doc)]
+__quote![
+ #[macro_export]
+ macro_rules! quote {
+ ($($tt:tt)*) => {
+ ...
+ };
+ }
+];
+
+#[cfg(not(doc))]
+__quote![
+ #[macro_export]
+ macro_rules! quote {
+ () => {
+ $crate::__private::TokenStream::new()
+ };
+
+ // Special case rule for a single tt, for performance.
+ ($tt:tt) => {{
+ let mut _s = $crate::__private::TokenStream::new();
+ $crate::quote_token!{$tt _s}
+ _s
+ }};
+
+ // Special case rules for two tts, for performance.
+ (# $var:ident) => {{
+ let mut _s = $crate::__private::TokenStream::new();
+ $crate::ToTokens::to_tokens(&$var, &mut _s);
+ _s
+ }};
+ ($tt1:tt $tt2:tt) => {{
+ let mut _s = $crate::__private::TokenStream::new();
+ $crate::quote_token!{$tt1 _s}
+ $crate::quote_token!{$tt2 _s}
+ _s
+ }};
+
+ // Rule for any other number of tokens.
+ ($($tt:tt)*) => {{
+ let mut _s = $crate::__private::TokenStream::new();
+ $crate::quote_each_token!{_s $($tt)*}
+ _s
+ }};
+ }
+];
+
+macro_rules! __quote_spanned {
+ ($quote_spanned:item) => {
+ /// Same as `quote!`, but applies a given span to all tokens originating within
+ /// the macro invocation.
+ ///
+ ///
+ ///
+ /// # Syntax
+ ///
+ /// A span expression of type [`Span`], followed by `=>`, followed by the tokens
+ /// to quote. The span expression should be brief &mdash; use a variable for
+ /// anything more than a few characters. There should be no space before the
+ /// `=>` token.
+ ///
+ /// [`Span`]: proc_macro2::Span
+ ///
+ /// ```
+ /// # use proc_macro2::Span;
+ /// # use quote::quote_spanned;
+ /// #
+ /// # const IGNORE_TOKENS: &'static str = stringify! {
+ /// let span = /* ... */;
+ /// # };
+ /// # let span = Span::call_site();
+ /// # let init = 0;
+ ///
+ /// // On one line, use parentheses.
+ /// let tokens = quote_spanned!(span=> Box::into_raw(Box::new(#init)));
+ ///
+ /// // On multiple lines, place the span at the top and use braces.
+ /// let tokens = quote_spanned! {span=>
+ /// Box::into_raw(Box::new(#init))
+ /// };
+ /// ```
+ ///
+ /// The lack of space before the `=>` should look jarring to Rust programmers
+ /// and this is intentional. The formatting is designed to be visibly
+ /// off-balance and draw the eye a particular way, due to the span expression
+ /// being evaluated in the context of the procedural macro and the remaining
+ /// tokens being evaluated in the generated code.
+ ///
+ ///
+ ///
+ /// # Hygiene
+ ///
+ /// Any interpolated tokens preserve the `Span` information provided by their
+ /// `ToTokens` implementation. Tokens that originate within the `quote_spanned!`
+ /// invocation are spanned with the given span argument.
+ ///
+ ///
+ ///
+ /// # Example
+ ///
+ /// The following procedural macro code uses `quote_spanned!` to assert that a
+ /// particular Rust type implements the [`Sync`] trait so that references can be
+ /// safely shared between threads.
+ ///
+ /// ```
+ /// # use quote::{quote_spanned, TokenStreamExt, ToTokens};
+ /// # use proc_macro2::{Span, TokenStream};
+ /// #
+ /// # struct Type;
+ /// #
+ /// # impl Type {
+ /// # fn span(&self) -> Span {
+ /// # Span::call_site()
+ /// # }
+ /// # }
+ /// #
+ /// # impl ToTokens for Type {
+ /// # fn to_tokens(&self, _tokens: &mut TokenStream) {}
+ /// # }
+ /// #
+ /// # let ty = Type;
+ /// # let call_site = Span::call_site();
+ /// #
+ /// let ty_span = ty.span();
+ /// let assert_sync = quote_spanned! {ty_span=>
+ /// struct _AssertSync where #ty: Sync;
+ /// };
+ /// ```
+ ///
+ /// If the assertion fails, the user will see an error like the following. The
+ /// input span of their type is highlighted in the error.
+ ///
+ /// ```text
+ /// error[E0277]: the trait bound `*const (): std::marker::Sync` is not satisfied
+ /// --> src/main.rs:10:21
+ /// |
+ /// 10 | static ref PTR: *const () = &();
+ /// | ^^^^^^^^^ `*const ()` cannot be shared between threads safely
+ /// ```
+ ///
+ /// In this example it is important for the where-clause to be spanned with the
+ /// line/column information of the user's input type so that error messages are
+ /// placed appropriately by the compiler.
+ $quote_spanned
+ };
+}
+
+#[cfg(doc)]
+__quote_spanned![
+ #[macro_export]
+ macro_rules! quote_spanned {
+ ($span:expr=> $($tt:tt)*) => {
+ ...
+ };
+ }
+];
+
+#[cfg(not(doc))]
+__quote_spanned![
+ #[macro_export]
+ macro_rules! quote_spanned {
+ ($span:expr=>) => {{
+ let _: $crate::__private::Span = $crate::__private::get_span($span).__into_span();
+ $crate::__private::TokenStream::new()
+ }};
+
+ // Special case rule for a single tt, for performance.
+ ($span:expr=> $tt:tt) => {{
+ let mut _s = $crate::__private::TokenStream::new();
+ let _span: $crate::__private::Span = $crate::__private::get_span($span).__into_span();
+ $crate::quote_token_spanned!{$tt _s _span}
+ _s
+ }};
+
+ // Special case rules for two tts, for performance.
+ ($span:expr=> # $var:ident) => {{
+ let mut _s = $crate::__private::TokenStream::new();
+ let _: $crate::__private::Span = $crate::__private::get_span($span).__into_span();
+ $crate::ToTokens::to_tokens(&$var, &mut _s);
+ _s
+ }};
+ ($span:expr=> $tt1:tt $tt2:tt) => {{
+ let mut _s = $crate::__private::TokenStream::new();
+ let _span: $crate::__private::Span = $crate::__private::get_span($span).__into_span();
+ $crate::quote_token_spanned!{$tt1 _s _span}
+ $crate::quote_token_spanned!{$tt2 _s _span}
+ _s
+ }};
+
+ // Rule for any other number of tokens.
+ ($span:expr=> $($tt:tt)*) => {{
+ let mut _s = $crate::__private::TokenStream::new();
+ let _span: $crate::__private::Span = $crate::__private::get_span($span).__into_span();
+ $crate::quote_each_token_spanned!{_s _span $($tt)*}
+ _s
+ }};
+ }
+];
+
+// Extract the names of all #metavariables and pass them to the $call macro.
+//
+// in: pounded_var_names!(then!(...) a #b c #( #d )* #e)
+// out: then!(... b);
+// then!(... d);
+// then!(... e);
+#[macro_export]
+#[doc(hidden)]
+macro_rules! pounded_var_names {
+ ($call:ident! $extra:tt $($tts:tt)*) => {
+ $crate::pounded_var_names_with_context!{$call! $extra
+ (@ $($tts)*)
+ ($($tts)* @)
+ }
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! pounded_var_names_with_context {
+ ($call:ident! $extra:tt ($($b1:tt)*) ($($curr:tt)*)) => {
+ $(
+ $crate::pounded_var_with_context!{$call! $extra $b1 $curr}
+ )*
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! pounded_var_with_context {
+ ($call:ident! $extra:tt $b1:tt ( $($inner:tt)* )) => {
+ $crate::pounded_var_names!{$call! $extra $($inner)*}
+ };
+
+ ($call:ident! $extra:tt $b1:tt [ $($inner:tt)* ]) => {
+ $crate::pounded_var_names!{$call! $extra $($inner)*}
+ };
+
+ ($call:ident! $extra:tt $b1:tt { $($inner:tt)* }) => {
+ $crate::pounded_var_names!{$call! $extra $($inner)*}
+ };
+
+ ($call:ident!($($extra:tt)*) # $var:ident) => {
+ $crate::$call!($($extra)* $var);
+ };
+
+ ($call:ident! $extra:tt $b1:tt $curr:tt) => {};
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_bind_into_iter {
+ ($has_iter:ident $var:ident) => {
+ // `mut` may be unused if $var occurs multiple times in the list.
+ #[allow(unused_mut)]
+ let (mut $var, i) = $var.quote_into_iter();
+ let $has_iter = $has_iter | i;
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_bind_next_or_break {
+ ($var:ident) => {
+ let $var = match $var.next() {
+ Some(_x) => $crate::__private::RepInterp(_x),
+ None => break,
+ };
+ };
+}
+
+// The obvious way to write this macro is as a tt muncher. This implementation
+// does something more complex for two reasons.
+//
+// - With a tt muncher it's easy to hit Rust's built-in recursion_limit, which
+// this implementation avoids because it isn't tail recursive.
+//
+// - Compile times for a tt muncher are quadratic relative to the length of
+// the input. This implementation is linear, so it will be faster
+// (potentially much faster) for big inputs. However, the constant factors
+// of this implementation are higher than that of a tt muncher, so it is
+// somewhat slower than a tt muncher if there are many invocations with
+// short inputs.
+//
+// An invocation like this:
+//
+// quote_each_token!(_s a b c d e f g h i j);
+//
+// expands to this:
+//
+// quote_tokens_with_context!(_s
+// (@ @ @ @ @ @ a b c d e f g h i j)
+// (@ @ @ @ @ a b c d e f g h i j @)
+// (@ @ @ @ a b c d e f g h i j @ @)
+// (@ @ @ (a) (b) (c) (d) (e) (f) (g) (h) (i) (j) @ @ @)
+// (@ @ a b c d e f g h i j @ @ @ @)
+// (@ a b c d e f g h i j @ @ @ @ @)
+// (a b c d e f g h i j @ @ @ @ @ @)
+// );
+//
+// which gets transposed and expanded to this:
+//
+// quote_token_with_context!(_s @ @ @ @ @ @ a);
+// quote_token_with_context!(_s @ @ @ @ @ a b);
+// quote_token_with_context!(_s @ @ @ @ a b c);
+// quote_token_with_context!(_s @ @ @ (a) b c d);
+// quote_token_with_context!(_s @ @ a (b) c d e);
+// quote_token_with_context!(_s @ a b (c) d e f);
+// quote_token_with_context!(_s a b c (d) e f g);
+// quote_token_with_context!(_s b c d (e) f g h);
+// quote_token_with_context!(_s c d e (f) g h i);
+// quote_token_with_context!(_s d e f (g) h i j);
+// quote_token_with_context!(_s e f g (h) i j @);
+// quote_token_with_context!(_s f g h (i) j @ @);
+// quote_token_with_context!(_s g h i (j) @ @ @);
+// quote_token_with_context!(_s h i j @ @ @ @);
+// quote_token_with_context!(_s i j @ @ @ @ @);
+// quote_token_with_context!(_s j @ @ @ @ @ @);
+//
+// Without having used muncher-style recursion, we get one invocation of
+// quote_token_with_context for each original tt, with three tts of context on
+// either side. This is enough for the longest possible interpolation form (a
+// repetition with separator, as in `# (#var) , *`) to be fully represented with
+// the first or last tt in the middle.
+//
+// The middle tt (surrounded by parentheses) is the tt being processed.
+//
+// - When it is a `#`, quote_token_with_context can do an interpolation. The
+// interpolation kind will depend on the three subsequent tts.
+//
+// - When it is within a later part of an interpolation, it can be ignored
+// because the interpolation has already been done.
+//
+// - When it is not part of an interpolation it can be pushed as a single
+// token into the output.
+//
+// - When the middle token is an unparenthesized `@`, that call is one of the
+// first 3 or last 3 calls of quote_token_with_context and does not
+// correspond to one of the original input tokens, so turns into nothing.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_each_token {
+ ($tokens:ident $($tts:tt)*) => {
+ $crate::quote_tokens_with_context!{$tokens
+ (@ @ @ @ @ @ $($tts)*)
+ (@ @ @ @ @ $($tts)* @)
+ (@ @ @ @ $($tts)* @ @)
+ (@ @ @ $(($tts))* @ @ @)
+ (@ @ $($tts)* @ @ @ @)
+ (@ $($tts)* @ @ @ @ @)
+ ($($tts)* @ @ @ @ @ @)
+ }
+ };
+}
+
+// See the explanation on quote_each_token.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_each_token_spanned {
+ ($tokens:ident $span:ident $($tts:tt)*) => {
+ $crate::quote_tokens_with_context_spanned!{$tokens $span
+ (@ @ @ @ @ @ $($tts)*)
+ (@ @ @ @ @ $($tts)* @)
+ (@ @ @ @ $($tts)* @ @)
+ (@ @ @ $(($tts))* @ @ @)
+ (@ @ $($tts)* @ @ @ @)
+ (@ $($tts)* @ @ @ @ @)
+ ($($tts)* @ @ @ @ @ @)
+ }
+ };
+}
+
+// See the explanation on quote_each_token.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_tokens_with_context {
+ ($tokens:ident
+ ($($b3:tt)*) ($($b2:tt)*) ($($b1:tt)*)
+ ($($curr:tt)*)
+ ($($a1:tt)*) ($($a2:tt)*) ($($a3:tt)*)
+ ) => {
+ $(
+ $crate::quote_token_with_context!{$tokens $b3 $b2 $b1 $curr $a1 $a2 $a3}
+ )*
+ };
+}
+
+// See the explanation on quote_each_token.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_tokens_with_context_spanned {
+ ($tokens:ident $span:ident
+ ($($b3:tt)*) ($($b2:tt)*) ($($b1:tt)*)
+ ($($curr:tt)*)
+ ($($a1:tt)*) ($($a2:tt)*) ($($a3:tt)*)
+ ) => {
+ $(
+ $crate::quote_token_with_context_spanned!{$tokens $span $b3 $b2 $b1 $curr $a1 $a2 $a3}
+ )*
+ };
+}
+
+// See the explanation on quote_each_token.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_token_with_context {
+ // Unparenthesized `@` indicates this call does not correspond to one of the
+ // original input tokens. Ignore it.
+ ($tokens:ident $b3:tt $b2:tt $b1:tt @ $a1:tt $a2:tt $a3:tt) => {};
+
+ // A repetition with no separator.
+ ($tokens:ident $b3:tt $b2:tt $b1:tt (#) ( $($inner:tt)* ) * $a3:tt) => {{
+ use $crate::__private::ext::*;
+ let has_iter = $crate::__private::ThereIsNoIteratorInRepetition;
+ $crate::pounded_var_names!{quote_bind_into_iter!(has_iter) () $($inner)*}
+ let _: $crate::__private::HasIterator = has_iter;
+ // This is `while true` instead of `loop` because if there are no
+ // iterators used inside of this repetition then the body would not
+ // contain any `break`, so the compiler would emit unreachable code
+ // warnings on anything below the loop. We use has_iter to detect and
+ // fail to compile when there are no iterators, so here we just work
+ // around the unneeded extra warning.
+ while true {
+ $crate::pounded_var_names!{quote_bind_next_or_break!() () $($inner)*}
+ $crate::quote_each_token!{$tokens $($inner)*}
+ }
+ }};
+ // ... and one step later.
+ ($tokens:ident $b3:tt $b2:tt # (( $($inner:tt)* )) * $a2:tt $a3:tt) => {};
+ // ... and one step later.
+ ($tokens:ident $b3:tt # ( $($inner:tt)* ) (*) $a1:tt $a2:tt $a3:tt) => {};
+
+ // A repetition with separator.
+ ($tokens:ident $b3:tt $b2:tt $b1:tt (#) ( $($inner:tt)* ) $sep:tt *) => {{
+ use $crate::__private::ext::*;
+ let mut _i = 0usize;
+ let has_iter = $crate::__private::ThereIsNoIteratorInRepetition;
+ $crate::pounded_var_names!{quote_bind_into_iter!(has_iter) () $($inner)*}
+ let _: $crate::__private::HasIterator = has_iter;
+ while true {
+ $crate::pounded_var_names!{quote_bind_next_or_break!() () $($inner)*}
+ if _i > 0 {
+ $crate::quote_token!{$sep $tokens}
+ }
+ _i += 1;
+ $crate::quote_each_token!{$tokens $($inner)*}
+ }
+ }};
+ // ... and one step later.
+ ($tokens:ident $b3:tt $b2:tt # (( $($inner:tt)* )) $sep:tt * $a3:tt) => {};
+ // ... and one step later.
+ ($tokens:ident $b3:tt # ( $($inner:tt)* ) ($sep:tt) * $a2:tt $a3:tt) => {};
+ // (A special case for `#(var)**`, where the first `*` is treated as the
+ // repetition symbol and the second `*` is treated as an ordinary token.)
+ ($tokens:ident # ( $($inner:tt)* ) * (*) $a1:tt $a2:tt $a3:tt) => {
+ // https://github.com/dtolnay/quote/issues/130
+ $crate::quote_token!{* $tokens}
+ };
+ // ... and one step later.
+ ($tokens:ident # ( $($inner:tt)* ) $sep:tt (*) $a1:tt $a2:tt $a3:tt) => {};
+
+ // A non-repetition interpolation.
+ ($tokens:ident $b3:tt $b2:tt $b1:tt (#) $var:ident $a2:tt $a3:tt) => {
+ $crate::ToTokens::to_tokens(&$var, &mut $tokens);
+ };
+ // ... and one step later.
+ ($tokens:ident $b3:tt $b2:tt # ($var:ident) $a1:tt $a2:tt $a3:tt) => {};
+
+ // An ordinary token, not part of any interpolation.
+ ($tokens:ident $b3:tt $b2:tt $b1:tt ($curr:tt) $a1:tt $a2:tt $a3:tt) => {
+ $crate::quote_token!{$curr $tokens}
+ };
+}
+
+// See the explanation on quote_each_token, and on the individual rules of
+// quote_token_with_context.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_token_with_context_spanned {
+ ($tokens:ident $span:ident $b3:tt $b2:tt $b1:tt @ $a1:tt $a2:tt $a3:tt) => {};
+
+ ($tokens:ident $span:ident $b3:tt $b2:tt $b1:tt (#) ( $($inner:tt)* ) * $a3:tt) => {{
+ use $crate::__private::ext::*;
+ let has_iter = $crate::__private::ThereIsNoIteratorInRepetition;
+ $crate::pounded_var_names!{quote_bind_into_iter!(has_iter) () $($inner)*}
+ let _: $crate::__private::HasIterator = has_iter;
+ while true {
+ $crate::pounded_var_names!{quote_bind_next_or_break!() () $($inner)*}
+ $crate::quote_each_token_spanned!{$tokens $span $($inner)*}
+ }
+ }};
+ ($tokens:ident $span:ident $b3:tt $b2:tt # (( $($inner:tt)* )) * $a2:tt $a3:tt) => {};
+ ($tokens:ident $span:ident $b3:tt # ( $($inner:tt)* ) (*) $a1:tt $a2:tt $a3:tt) => {};
+
+ ($tokens:ident $span:ident $b3:tt $b2:tt $b1:tt (#) ( $($inner:tt)* ) $sep:tt *) => {{
+ use $crate::__private::ext::*;
+ let mut _i = 0usize;
+ let has_iter = $crate::__private::ThereIsNoIteratorInRepetition;
+ $crate::pounded_var_names!{quote_bind_into_iter!(has_iter) () $($inner)*}
+ let _: $crate::__private::HasIterator = has_iter;
+ while true {
+ $crate::pounded_var_names!{quote_bind_next_or_break!() () $($inner)*}
+ if _i > 0 {
+ $crate::quote_token_spanned!{$sep $tokens $span}
+ }
+ _i += 1;
+ $crate::quote_each_token_spanned!{$tokens $span $($inner)*}
+ }
+ }};
+ ($tokens:ident $span:ident $b3:tt $b2:tt # (( $($inner:tt)* )) $sep:tt * $a3:tt) => {};
+ ($tokens:ident $span:ident $b3:tt # ( $($inner:tt)* ) ($sep:tt) * $a2:tt $a3:tt) => {};
+ ($tokens:ident $span:ident # ( $($inner:tt)* ) * (*) $a1:tt $a2:tt $a3:tt) => {
+ // https://github.com/dtolnay/quote/issues/130
+ $crate::quote_token_spanned!{* $tokens $span}
+ };
+ ($tokens:ident $span:ident # ( $($inner:tt)* ) $sep:tt (*) $a1:tt $a2:tt $a3:tt) => {};
+
+ ($tokens:ident $span:ident $b3:tt $b2:tt $b1:tt (#) $var:ident $a2:tt $a3:tt) => {
+ $crate::ToTokens::to_tokens(&$var, &mut $tokens);
+ };
+ ($tokens:ident $span:ident $b3:tt $b2:tt # ($var:ident) $a1:tt $a2:tt $a3:tt) => {};
+
+ ($tokens:ident $span:ident $b3:tt $b2:tt $b1:tt ($curr:tt) $a1:tt $a2:tt $a3:tt) => {
+ $crate::quote_token_spanned!{$curr $tokens $span}
+ };
+}
+
+// These rules are ordered by approximate token frequency, at least for the
+// first 10 or so, to improve compile times. Having `ident` first is by far the
+// most important because it's typically 2-3x more common than the next most
+// common token.
+//
+// Separately, we put the token being matched in the very front so that failing
+// rules may fail to match as quickly as possible.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_token {
+ ($ident:ident $tokens:ident) => {
+ $crate::__private::push_ident(&mut $tokens, stringify!($ident));
+ };
+
+ (:: $tokens:ident) => {
+ $crate::__private::push_colon2(&mut $tokens);
+ };
+
+ (( $($inner:tt)* ) $tokens:ident) => {
+ $crate::__private::push_group(
+ &mut $tokens,
+ $crate::__private::Delimiter::Parenthesis,
+ $crate::quote!($($inner)*),
+ );
+ };
+
+ ([ $($inner:tt)* ] $tokens:ident) => {
+ $crate::__private::push_group(
+ &mut $tokens,
+ $crate::__private::Delimiter::Bracket,
+ $crate::quote!($($inner)*),
+ );
+ };
+
+ ({ $($inner:tt)* } $tokens:ident) => {
+ $crate::__private::push_group(
+ &mut $tokens,
+ $crate::__private::Delimiter::Brace,
+ $crate::quote!($($inner)*),
+ );
+ };
+
+ (# $tokens:ident) => {
+ $crate::__private::push_pound(&mut $tokens);
+ };
+
+ (, $tokens:ident) => {
+ $crate::__private::push_comma(&mut $tokens);
+ };
+
+ (. $tokens:ident) => {
+ $crate::__private::push_dot(&mut $tokens);
+ };
+
+ (; $tokens:ident) => {
+ $crate::__private::push_semi(&mut $tokens);
+ };
+
+ (: $tokens:ident) => {
+ $crate::__private::push_colon(&mut $tokens);
+ };
+
+ (+ $tokens:ident) => {
+ $crate::__private::push_add(&mut $tokens);
+ };
+
+ (+= $tokens:ident) => {
+ $crate::__private::push_add_eq(&mut $tokens);
+ };
+
+ (& $tokens:ident) => {
+ $crate::__private::push_and(&mut $tokens);
+ };
+
+ (&& $tokens:ident) => {
+ $crate::__private::push_and_and(&mut $tokens);
+ };
+
+ (&= $tokens:ident) => {
+ $crate::__private::push_and_eq(&mut $tokens);
+ };
+
+ (@ $tokens:ident) => {
+ $crate::__private::push_at(&mut $tokens);
+ };
+
+ (! $tokens:ident) => {
+ $crate::__private::push_bang(&mut $tokens);
+ };
+
+ (^ $tokens:ident) => {
+ $crate::__private::push_caret(&mut $tokens);
+ };
+
+ (^= $tokens:ident) => {
+ $crate::__private::push_caret_eq(&mut $tokens);
+ };
+
+ (/ $tokens:ident) => {
+ $crate::__private::push_div(&mut $tokens);
+ };
+
+ (/= $tokens:ident) => {
+ $crate::__private::push_div_eq(&mut $tokens);
+ };
+
+ (.. $tokens:ident) => {
+ $crate::__private::push_dot2(&mut $tokens);
+ };
+
+ (... $tokens:ident) => {
+ $crate::__private::push_dot3(&mut $tokens);
+ };
+
+ (..= $tokens:ident) => {
+ $crate::__private::push_dot_dot_eq(&mut $tokens);
+ };
+
+ (= $tokens:ident) => {
+ $crate::__private::push_eq(&mut $tokens);
+ };
+
+ (== $tokens:ident) => {
+ $crate::__private::push_eq_eq(&mut $tokens);
+ };
+
+ (>= $tokens:ident) => {
+ $crate::__private::push_ge(&mut $tokens);
+ };
+
+ (> $tokens:ident) => {
+ $crate::__private::push_gt(&mut $tokens);
+ };
+
+ (<= $tokens:ident) => {
+ $crate::__private::push_le(&mut $tokens);
+ };
+
+ (< $tokens:ident) => {
+ $crate::__private::push_lt(&mut $tokens);
+ };
+
+ (*= $tokens:ident) => {
+ $crate::__private::push_mul_eq(&mut $tokens);
+ };
+
+ (!= $tokens:ident) => {
+ $crate::__private::push_ne(&mut $tokens);
+ };
+
+ (| $tokens:ident) => {
+ $crate::__private::push_or(&mut $tokens);
+ };
+
+ (|= $tokens:ident) => {
+ $crate::__private::push_or_eq(&mut $tokens);
+ };
+
+ (|| $tokens:ident) => {
+ $crate::__private::push_or_or(&mut $tokens);
+ };
+
+ (? $tokens:ident) => {
+ $crate::__private::push_question(&mut $tokens);
+ };
+
+ (-> $tokens:ident) => {
+ $crate::__private::push_rarrow(&mut $tokens);
+ };
+
+ (<- $tokens:ident) => {
+ $crate::__private::push_larrow(&mut $tokens);
+ };
+
+ (% $tokens:ident) => {
+ $crate::__private::push_rem(&mut $tokens);
+ };
+
+ (%= $tokens:ident) => {
+ $crate::__private::push_rem_eq(&mut $tokens);
+ };
+
+ (=> $tokens:ident) => {
+ $crate::__private::push_fat_arrow(&mut $tokens);
+ };
+
+ (<< $tokens:ident) => {
+ $crate::__private::push_shl(&mut $tokens);
+ };
+
+ (<<= $tokens:ident) => {
+ $crate::__private::push_shl_eq(&mut $tokens);
+ };
+
+ (>> $tokens:ident) => {
+ $crate::__private::push_shr(&mut $tokens);
+ };
+
+ (>>= $tokens:ident) => {
+ $crate::__private::push_shr_eq(&mut $tokens);
+ };
+
+ (* $tokens:ident) => {
+ $crate::__private::push_star(&mut $tokens);
+ };
+
+ (- $tokens:ident) => {
+ $crate::__private::push_sub(&mut $tokens);
+ };
+
+ (-= $tokens:ident) => {
+ $crate::__private::push_sub_eq(&mut $tokens);
+ };
+
+ ($lifetime:lifetime $tokens:ident) => {
+ $crate::__private::push_lifetime(&mut $tokens, stringify!($lifetime));
+ };
+
+ (_ $tokens:ident) => {
+ $crate::__private::push_underscore(&mut $tokens);
+ };
+
+ ($other:tt $tokens:ident) => {
+ $crate::__private::parse(&mut $tokens, stringify!($other));
+ };
+}
+
+// See the comment above `quote_token!` about the rule ordering.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_token_spanned {
+ ($ident:ident $tokens:ident $span:ident) => {
+ $crate::__private::push_ident_spanned(&mut $tokens, $span, stringify!($ident));
+ };
+
+ (:: $tokens:ident $span:ident) => {
+ $crate::__private::push_colon2_spanned(&mut $tokens, $span);
+ };
+
+ (( $($inner:tt)* ) $tokens:ident $span:ident) => {
+ $crate::__private::push_group_spanned(
+ &mut $tokens,
+ $span,
+ $crate::__private::Delimiter::Parenthesis,
+ $crate::quote_spanned!($span=> $($inner)*),
+ );
+ };
+
+ ([ $($inner:tt)* ] $tokens:ident $span:ident) => {
+ $crate::__private::push_group_spanned(
+ &mut $tokens,
+ $span,
+ $crate::__private::Delimiter::Bracket,
+ $crate::quote_spanned!($span=> $($inner)*),
+ );
+ };
+
+ ({ $($inner:tt)* } $tokens:ident $span:ident) => {
+ $crate::__private::push_group_spanned(
+ &mut $tokens,
+ $span,
+ $crate::__private::Delimiter::Brace,
+ $crate::quote_spanned!($span=> $($inner)*),
+ );
+ };
+
+ (# $tokens:ident $span:ident) => {
+ $crate::__private::push_pound_spanned(&mut $tokens, $span);
+ };
+
+ (, $tokens:ident $span:ident) => {
+ $crate::__private::push_comma_spanned(&mut $tokens, $span);
+ };
+
+ (. $tokens:ident $span:ident) => {
+ $crate::__private::push_dot_spanned(&mut $tokens, $span);
+ };
+
+ (; $tokens:ident $span:ident) => {
+ $crate::__private::push_semi_spanned(&mut $tokens, $span);
+ };
+
+ (: $tokens:ident $span:ident) => {
+ $crate::__private::push_colon_spanned(&mut $tokens, $span);
+ };
+
+ (+ $tokens:ident $span:ident) => {
+ $crate::__private::push_add_spanned(&mut $tokens, $span);
+ };
+
+ (+= $tokens:ident $span:ident) => {
+ $crate::__private::push_add_eq_spanned(&mut $tokens, $span);
+ };
+
+ (& $tokens:ident $span:ident) => {
+ $crate::__private::push_and_spanned(&mut $tokens, $span);
+ };
+
+ (&& $tokens:ident $span:ident) => {
+ $crate::__private::push_and_and_spanned(&mut $tokens, $span);
+ };
+
+ (&= $tokens:ident $span:ident) => {
+ $crate::__private::push_and_eq_spanned(&mut $tokens, $span);
+ };
+
+ (@ $tokens:ident $span:ident) => {
+ $crate::__private::push_at_spanned(&mut $tokens, $span);
+ };
+
+ (! $tokens:ident $span:ident) => {
+ $crate::__private::push_bang_spanned(&mut $tokens, $span);
+ };
+
+ (^ $tokens:ident $span:ident) => {
+ $crate::__private::push_caret_spanned(&mut $tokens, $span);
+ };
+
+ (^= $tokens:ident $span:ident) => {
+ $crate::__private::push_caret_eq_spanned(&mut $tokens, $span);
+ };
+
+ (/ $tokens:ident $span:ident) => {
+ $crate::__private::push_div_spanned(&mut $tokens, $span);
+ };
+
+ (/= $tokens:ident $span:ident) => {
+ $crate::__private::push_div_eq_spanned(&mut $tokens, $span);
+ };
+
+ (.. $tokens:ident $span:ident) => {
+ $crate::__private::push_dot2_spanned(&mut $tokens, $span);
+ };
+
+ (... $tokens:ident $span:ident) => {
+ $crate::__private::push_dot3_spanned(&mut $tokens, $span);
+ };
+
+ (..= $tokens:ident $span:ident) => {
+ $crate::__private::push_dot_dot_eq_spanned(&mut $tokens, $span);
+ };
+
+ (= $tokens:ident $span:ident) => {
+ $crate::__private::push_eq_spanned(&mut $tokens, $span);
+ };
+
+ (== $tokens:ident $span:ident) => {
+ $crate::__private::push_eq_eq_spanned(&mut $tokens, $span);
+ };
+
+ (>= $tokens:ident $span:ident) => {
+ $crate::__private::push_ge_spanned(&mut $tokens, $span);
+ };
+
+ (> $tokens:ident $span:ident) => {
+ $crate::__private::push_gt_spanned(&mut $tokens, $span);
+ };
+
+ (<= $tokens:ident $span:ident) => {
+ $crate::__private::push_le_spanned(&mut $tokens, $span);
+ };
+
+ (< $tokens:ident $span:ident) => {
+ $crate::__private::push_lt_spanned(&mut $tokens, $span);
+ };
+
+ (*= $tokens:ident $span:ident) => {
+ $crate::__private::push_mul_eq_spanned(&mut $tokens, $span);
+ };
+
+ (!= $tokens:ident $span:ident) => {
+ $crate::__private::push_ne_spanned(&mut $tokens, $span);
+ };
+
+ (| $tokens:ident $span:ident) => {
+ $crate::__private::push_or_spanned(&mut $tokens, $span);
+ };
+
+ (|= $tokens:ident $span:ident) => {
+ $crate::__private::push_or_eq_spanned(&mut $tokens, $span);
+ };
+
+ (|| $tokens:ident $span:ident) => {
+ $crate::__private::push_or_or_spanned(&mut $tokens, $span);
+ };
+
+ (? $tokens:ident $span:ident) => {
+ $crate::__private::push_question_spanned(&mut $tokens, $span);
+ };
+
+ (-> $tokens:ident $span:ident) => {
+ $crate::__private::push_rarrow_spanned(&mut $tokens, $span);
+ };
+
+ (<- $tokens:ident $span:ident) => {
+ $crate::__private::push_larrow_spanned(&mut $tokens, $span);
+ };
+
+ (% $tokens:ident $span:ident) => {
+ $crate::__private::push_rem_spanned(&mut $tokens, $span);
+ };
+
+ (%= $tokens:ident $span:ident) => {
+ $crate::__private::push_rem_eq_spanned(&mut $tokens, $span);
+ };
+
+ (=> $tokens:ident $span:ident) => {
+ $crate::__private::push_fat_arrow_spanned(&mut $tokens, $span);
+ };
+
+ (<< $tokens:ident $span:ident) => {
+ $crate::__private::push_shl_spanned(&mut $tokens, $span);
+ };
+
+ (<<= $tokens:ident $span:ident) => {
+ $crate::__private::push_shl_eq_spanned(&mut $tokens, $span);
+ };
+
+ (>> $tokens:ident $span:ident) => {
+ $crate::__private::push_shr_spanned(&mut $tokens, $span);
+ };
+
+ (>>= $tokens:ident $span:ident) => {
+ $crate::__private::push_shr_eq_spanned(&mut $tokens, $span);
+ };
+
+ (* $tokens:ident $span:ident) => {
+ $crate::__private::push_star_spanned(&mut $tokens, $span);
+ };
+
+ (- $tokens:ident $span:ident) => {
+ $crate::__private::push_sub_spanned(&mut $tokens, $span);
+ };
+
+ (-= $tokens:ident $span:ident) => {
+ $crate::__private::push_sub_eq_spanned(&mut $tokens, $span);
+ };
+
+ ($lifetime:lifetime $tokens:ident $span:ident) => {
+ $crate::__private::push_lifetime_spanned(&mut $tokens, $span, stringify!($lifetime));
+ };
+
+ (_ $tokens:ident $span:ident) => {
+ $crate::__private::push_underscore_spanned(&mut $tokens, $span);
+ };
+
+ ($other:tt $tokens:ident $span:ident) => {
+ $crate::__private::parse_spanned(&mut $tokens, $span, stringify!($other));
+ };
+}
diff --git a/rust/quote/runtime.rs b/rust/quote/runtime.rs
new file mode 100644
index 000000000000..c704ca89411f
--- /dev/null
+++ b/rust/quote/runtime.rs
@@ -0,0 +1,492 @@
+use self::get_span::{GetSpan, GetSpanBase, GetSpanInner};
+use crate::{IdentFragment, ToTokens, TokenStreamExt};
+use core::fmt;
+use core::iter;
+use core::ops::BitOr;
+use proc_macro2::{Group, Ident, Punct, Spacing, TokenTree};
+
+#[doc(hidden)]
+pub use alloc::format;
+#[doc(hidden)]
+pub use core::option::Option;
+
+#[doc(hidden)]
+pub type Delimiter = proc_macro2::Delimiter;
+#[doc(hidden)]
+pub type Span = proc_macro2::Span;
+#[doc(hidden)]
+pub type TokenStream = proc_macro2::TokenStream;
+
+#[doc(hidden)]
+pub struct HasIterator; // True
+#[doc(hidden)]
+pub struct ThereIsNoIteratorInRepetition; // False
+
+impl BitOr<ThereIsNoIteratorInRepetition> for ThereIsNoIteratorInRepetition {
+ type Output = ThereIsNoIteratorInRepetition;
+ fn bitor(self, _rhs: ThereIsNoIteratorInRepetition) -> ThereIsNoIteratorInRepetition {
+ ThereIsNoIteratorInRepetition
+ }
+}
+
+impl BitOr<ThereIsNoIteratorInRepetition> for HasIterator {
+ type Output = HasIterator;
+ fn bitor(self, _rhs: ThereIsNoIteratorInRepetition) -> HasIterator {
+ HasIterator
+ }
+}
+
+impl BitOr<HasIterator> for ThereIsNoIteratorInRepetition {
+ type Output = HasIterator;
+ fn bitor(self, _rhs: HasIterator) -> HasIterator {
+ HasIterator
+ }
+}
+
+impl BitOr<HasIterator> for HasIterator {
+ type Output = HasIterator;
+ fn bitor(self, _rhs: HasIterator) -> HasIterator {
+ HasIterator
+ }
+}
+
+/// Extension traits used by the implementation of `quote!`. These are defined
+/// in separate traits, rather than as a single trait due to ambiguity issues.
+///
+/// These traits expose a `quote_into_iter` method which should allow calling
+/// whichever impl happens to be applicable. Calling that method repeatedly on
+/// the returned value should be idempotent.
+#[doc(hidden)]
+pub mod ext {
+ use super::RepInterp;
+ use super::{HasIterator as HasIter, ThereIsNoIteratorInRepetition as DoesNotHaveIter};
+ use crate::ToTokens;
+ use alloc::collections::btree_set::{self, BTreeSet};
+ use core::slice;
+
+ /// Extension trait providing the `quote_into_iter` method on iterators.
+ #[doc(hidden)]
+ pub trait RepIteratorExt: Iterator + Sized {
+ fn quote_into_iter(self) -> (Self, HasIter) {
+ (self, HasIter)
+ }
+ }
+
+ impl<T: Iterator> RepIteratorExt for T {}
+
+ /// Extension trait providing the `quote_into_iter` method for
+ /// non-iterable types. These types interpolate the same value in each
+ /// iteration of the repetition.
+ #[doc(hidden)]
+ pub trait RepToTokensExt {
+ /// Pretend to be an iterator for the purposes of `quote_into_iter`.
+ /// This allows repeated calls to `quote_into_iter` to continue
+ /// correctly returning DoesNotHaveIter.
+ fn next(&self) -> Option<&Self> {
+ Some(self)
+ }
+
+ fn quote_into_iter(&self) -> (&Self, DoesNotHaveIter) {
+ (self, DoesNotHaveIter)
+ }
+ }
+
+ impl<T: ToTokens + ?Sized> RepToTokensExt for T {}
+
+ /// Extension trait providing the `quote_into_iter` method for types that
+ /// can be referenced as an iterator.
+ #[doc(hidden)]
+ pub trait RepAsIteratorExt<'q> {
+ type Iter: Iterator;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter);
+ }
+
+ impl<'q, T: RepAsIteratorExt<'q> + ?Sized> RepAsIteratorExt<'q> for &T {
+ type Iter = T::Iter;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ <T as RepAsIteratorExt>::quote_into_iter(*self)
+ }
+ }
+
+ impl<'q, T: RepAsIteratorExt<'q> + ?Sized> RepAsIteratorExt<'q> for &mut T {
+ type Iter = T::Iter;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ <T as RepAsIteratorExt>::quote_into_iter(*self)
+ }
+ }
+
+ impl<'q, T: 'q> RepAsIteratorExt<'q> for [T] {
+ type Iter = slice::Iter<'q, T>;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ (self.iter(), HasIter)
+ }
+ }
+
+ impl<'q, T: 'q, const N: usize> RepAsIteratorExt<'q> for [T; N] {
+ type Iter = slice::Iter<'q, T>;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ (self.iter(), HasIter)
+ }
+ }
+
+ impl<'q, T: 'q> RepAsIteratorExt<'q> for Vec<T> {
+ type Iter = slice::Iter<'q, T>;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ (self.iter(), HasIter)
+ }
+ }
+
+ impl<'q, T: 'q> RepAsIteratorExt<'q> for BTreeSet<T> {
+ type Iter = btree_set::Iter<'q, T>;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ (self.iter(), HasIter)
+ }
+ }
+
+ impl<'q, T: RepAsIteratorExt<'q>> RepAsIteratorExt<'q> for RepInterp<T> {
+ type Iter = T::Iter;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ self.0.quote_into_iter()
+ }
+ }
+}
+
+// Helper type used within interpolations to allow for repeated binding names.
+// Implements the relevant traits, and exports a dummy `next()` method.
+#[derive(Copy, Clone)]
+#[doc(hidden)]
+pub struct RepInterp<T>(pub T);
+
+impl<T> RepInterp<T> {
+ // This method is intended to look like `Iterator::next`, and is called when
+ // a name is bound multiple times, as the previous binding will shadow the
+ // original `Iterator` object. This allows us to avoid advancing the
+ // iterator multiple times per iteration.
+ pub fn next(self) -> Option<T> {
+ Some(self.0)
+ }
+}
+
+impl<T: Iterator> Iterator for RepInterp<T> {
+ type Item = T::Item;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.0.next()
+ }
+}
+
+impl<T: ToTokens> ToTokens for RepInterp<T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ self.0.to_tokens(tokens);
+ }
+}
+
+#[doc(hidden)]
+#[inline]
+pub fn get_span<T>(span: T) -> GetSpan<T> {
+ GetSpan(GetSpanInner(GetSpanBase(span)))
+}
+
+mod get_span {
+ use core::ops::Deref;
+ use proc_macro2::extra::DelimSpan;
+ use proc_macro2::Span;
+
+ pub struct GetSpan<T>(pub(crate) GetSpanInner<T>);
+
+ pub struct GetSpanInner<T>(pub(crate) GetSpanBase<T>);
+
+ pub struct GetSpanBase<T>(pub(crate) T);
+
+ impl GetSpan {
+ #[inline]
+ pub fn __into_span(self) -> Span {
+ ((self.0).0).0
+ }
+ }
+
+ impl GetSpanInner<DelimSpan> {
+ #[inline]
+ pub fn __into_span(&self) -> Span {
+ (self.0).0.join()
+ }
+ }
+
+ impl<T> GetSpanBase<T> {
+ #[allow(clippy::unused_self)]
+ pub fn __into_span(&self) -> T {
+ unreachable!()
+ }
+ }
+
+ impl<T> Deref for GetSpan<T> {
+ type Target = GetSpanInner<T>;
+
+ #[inline]
+ fn deref(&self) -> &Self::Target {
+ &self.0
+ }
+ }
+
+ impl<T> Deref for GetSpanInner<T> {
+ type Target = GetSpanBase<T>;
+
+ #[inline]
+ fn deref(&self) -> &Self::Target {
+ &self.0
+ }
+ }
+}
+
+#[doc(hidden)]
+pub fn push_group(tokens: &mut TokenStream, delimiter: Delimiter, inner: TokenStream) {
+ tokens.append(Group::new(delimiter, inner));
+}
+
+#[doc(hidden)]
+pub fn push_group_spanned(
+ tokens: &mut TokenStream,
+ span: Span,
+ delimiter: Delimiter,
+ inner: TokenStream,
+) {
+ let mut g = Group::new(delimiter, inner);
+ g.set_span(span);
+ tokens.append(g);
+}
+
+#[doc(hidden)]
+pub fn parse(tokens: &mut TokenStream, s: &str) {
+ let s: TokenStream = s.parse().expect("invalid token stream");
+ tokens.extend(iter::once(s));
+}
+
+#[doc(hidden)]
+pub fn parse_spanned(tokens: &mut TokenStream, span: Span, s: &str) {
+ let s: TokenStream = s.parse().expect("invalid token stream");
+ tokens.extend(s.into_iter().map(|t| respan_token_tree(t, span)));
+}
+
+// Token tree with every span replaced by the given one.
+fn respan_token_tree(mut token: TokenTree, span: Span) -> TokenTree {
+ match &mut token {
+ TokenTree::Group(g) => {
+ let stream = g
+ .stream()
+ .into_iter()
+ .map(|token| respan_token_tree(token, span))
+ .collect();
+ *g = Group::new(g.delimiter(), stream);
+ g.set_span(span);
+ }
+ other => other.set_span(span),
+ }
+ token
+}
+
+#[doc(hidden)]
+pub fn push_ident(tokens: &mut TokenStream, s: &str) {
+ let span = Span::call_site();
+ push_ident_spanned(tokens, span, s);
+}
+
+#[doc(hidden)]
+pub fn push_ident_spanned(tokens: &mut TokenStream, span: Span, s: &str) {
+ tokens.append(ident_maybe_raw(s, span));
+}
+
+#[doc(hidden)]
+pub fn push_lifetime(tokens: &mut TokenStream, lifetime: &str) {
+ tokens.extend([
+ TokenTree::Punct(Punct::new('\'', Spacing::Joint)),
+ TokenTree::Ident(Ident::new(&lifetime[1..], Span::call_site())),
+ ]);
+}
+
+#[doc(hidden)]
+pub fn push_lifetime_spanned(tokens: &mut TokenStream, span: Span, lifetime: &str) {
+ tokens.extend([
+ TokenTree::Punct({
+ let mut apostrophe = Punct::new('\'', Spacing::Joint);
+ apostrophe.set_span(span);
+ apostrophe
+ }),
+ TokenTree::Ident(Ident::new(&lifetime[1..], span)),
+ ]);
+}
+
+macro_rules! push_punct {
+ ($name:ident $spanned:ident $char1:tt) => {
+ #[doc(hidden)]
+ pub fn $name(tokens: &mut TokenStream) {
+ tokens.append(Punct::new($char1, Spacing::Alone));
+ }
+ #[doc(hidden)]
+ pub fn $spanned(tokens: &mut TokenStream, span: Span) {
+ let mut punct = Punct::new($char1, Spacing::Alone);
+ punct.set_span(span);
+ tokens.append(punct);
+ }
+ };
+ ($name:ident $spanned:ident $char1:tt $char2:tt) => {
+ #[doc(hidden)]
+ pub fn $name(tokens: &mut TokenStream) {
+ tokens.append(Punct::new($char1, Spacing::Joint));
+ tokens.append(Punct::new($char2, Spacing::Alone));
+ }
+ #[doc(hidden)]
+ pub fn $spanned(tokens: &mut TokenStream, span: Span) {
+ let mut punct = Punct::new($char1, Spacing::Joint);
+ punct.set_span(span);
+ tokens.append(punct);
+ let mut punct = Punct::new($char2, Spacing::Alone);
+ punct.set_span(span);
+ tokens.append(punct);
+ }
+ };
+ ($name:ident $spanned:ident $char1:tt $char2:tt $char3:tt) => {
+ #[doc(hidden)]
+ pub fn $name(tokens: &mut TokenStream) {
+ tokens.append(Punct::new($char1, Spacing::Joint));
+ tokens.append(Punct::new($char2, Spacing::Joint));
+ tokens.append(Punct::new($char3, Spacing::Alone));
+ }
+ #[doc(hidden)]
+ pub fn $spanned(tokens: &mut TokenStream, span: Span) {
+ let mut punct = Punct::new($char1, Spacing::Joint);
+ punct.set_span(span);
+ tokens.append(punct);
+ let mut punct = Punct::new($char2, Spacing::Joint);
+ punct.set_span(span);
+ tokens.append(punct);
+ let mut punct = Punct::new($char3, Spacing::Alone);
+ punct.set_span(span);
+ tokens.append(punct);
+ }
+ };
+}
+
+push_punct!(push_add push_add_spanned '+');
+push_punct!(push_add_eq push_add_eq_spanned '+' '=');
+push_punct!(push_and push_and_spanned '&');
+push_punct!(push_and_and push_and_and_spanned '&' '&');
+push_punct!(push_and_eq push_and_eq_spanned '&' '=');
+push_punct!(push_at push_at_spanned '@');
+push_punct!(push_bang push_bang_spanned '!');
+push_punct!(push_caret push_caret_spanned '^');
+push_punct!(push_caret_eq push_caret_eq_spanned '^' '=');
+push_punct!(push_colon push_colon_spanned ':');
+push_punct!(push_colon2 push_colon2_spanned ':' ':');
+push_punct!(push_comma push_comma_spanned ',');
+push_punct!(push_div push_div_spanned '/');
+push_punct!(push_div_eq push_div_eq_spanned '/' '=');
+push_punct!(push_dot push_dot_spanned '.');
+push_punct!(push_dot2 push_dot2_spanned '.' '.');
+push_punct!(push_dot3 push_dot3_spanned '.' '.' '.');
+push_punct!(push_dot_dot_eq push_dot_dot_eq_spanned '.' '.' '=');
+push_punct!(push_eq push_eq_spanned '=');
+push_punct!(push_eq_eq push_eq_eq_spanned '=' '=');
+push_punct!(push_ge push_ge_spanned '>' '=');
+push_punct!(push_gt push_gt_spanned '>');
+push_punct!(push_le push_le_spanned '<' '=');
+push_punct!(push_lt push_lt_spanned '<');
+push_punct!(push_mul_eq push_mul_eq_spanned '*' '=');
+push_punct!(push_ne push_ne_spanned '!' '=');
+push_punct!(push_or push_or_spanned '|');
+push_punct!(push_or_eq push_or_eq_spanned '|' '=');
+push_punct!(push_or_or push_or_or_spanned '|' '|');
+push_punct!(push_pound push_pound_spanned '#');
+push_punct!(push_question push_question_spanned '?');
+push_punct!(push_rarrow push_rarrow_spanned '-' '>');
+push_punct!(push_larrow push_larrow_spanned '<' '-');
+push_punct!(push_rem push_rem_spanned '%');
+push_punct!(push_rem_eq push_rem_eq_spanned '%' '=');
+push_punct!(push_fat_arrow push_fat_arrow_spanned '=' '>');
+push_punct!(push_semi push_semi_spanned ';');
+push_punct!(push_shl push_shl_spanned '<' '<');
+push_punct!(push_shl_eq push_shl_eq_spanned '<' '<' '=');
+push_punct!(push_shr push_shr_spanned '>' '>');
+push_punct!(push_shr_eq push_shr_eq_spanned '>' '>' '=');
+push_punct!(push_star push_star_spanned '*');
+push_punct!(push_sub push_sub_spanned '-');
+push_punct!(push_sub_eq push_sub_eq_spanned '-' '=');
+
+#[doc(hidden)]
+pub fn push_underscore(tokens: &mut TokenStream) {
+ push_underscore_spanned(tokens, Span::call_site());
+}
+
+#[doc(hidden)]
+pub fn push_underscore_spanned(tokens: &mut TokenStream, span: Span) {
+ tokens.append(Ident::new("_", span));
+}
+
+// Helper method for constructing identifiers from the `format_ident!` macro,
+// handling `r#` prefixes.
+#[doc(hidden)]
+pub fn mk_ident(id: &str, span: Option) -> Ident {
+ let span = span.unwrap_or_else(Span::call_site);
+ ident_maybe_raw(id, span)
+}
+
+fn ident_maybe_raw(id: &str, span: Span) -> Ident {
+ if let Some(id) = id.strip_prefix("r#") {
+ Ident::new_raw(id, span)
+ } else {
+ Ident::new(id, span)
+ }
+}
+
+// Adapts from `IdentFragment` to `fmt::Display` for use by the `format_ident!`
+// macro, and exposes span information from these fragments.
+//
+// This struct also has forwarding implementations of the formatting traits
+// `Octal`, `LowerHex`, `UpperHex`, and `Binary` to allow for their use within
+// `format_ident!`.
+#[derive(Copy, Clone)]
+#[doc(hidden)]
+pub struct IdentFragmentAdapter<T: IdentFragment>(pub T);
+
+impl<T: IdentFragment> IdentFragmentAdapter<T> {
+ pub fn span(&self) -> Option {
+ self.0.span()
+ }
+}
+
+impl<T: IdentFragment> fmt::Display for IdentFragmentAdapter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ IdentFragment::fmt(&self.0, f)
+ }
+}
+
+impl<T: IdentFragment + fmt::Octal> fmt::Octal for IdentFragmentAdapter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::Octal::fmt(&self.0, f)
+ }
+}
+
+impl<T: IdentFragment + fmt::LowerHex> fmt::LowerHex for IdentFragmentAdapter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::LowerHex::fmt(&self.0, f)
+ }
+}
+
+impl<T: IdentFragment + fmt::UpperHex> fmt::UpperHex for IdentFragmentAdapter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::UpperHex::fmt(&self.0, f)
+ }
+}
+
+impl<T: IdentFragment + fmt::Binary> fmt::Binary for IdentFragmentAdapter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::Binary::fmt(&self.0, f)
+ }
+}
diff --git a/rust/quote/spanned.rs b/rust/quote/spanned.rs
new file mode 100644
index 000000000000..6eba64445d89
--- /dev/null
+++ b/rust/quote/spanned.rs
@@ -0,0 +1,50 @@
+use crate::ToTokens;
+use proc_macro2::extra::DelimSpan;
+use proc_macro2::{Span, TokenStream};
+
+// Not public API other than via the syn crate. Use syn::spanned::Spanned.
+pub trait Spanned: private::Sealed {
+ fn __span(&self) -> Span;
+}
+
+impl Spanned for Span {
+ fn __span(&self) -> Span {
+ *self
+ }
+}
+
+impl Spanned for DelimSpan {
+ fn __span(&self) -> Span {
+ self.join()
+ }
+}
+
+impl<T: ?Sized + ToTokens> Spanned for T {
+ fn __span(&self) -> Span {
+ join_spans(self.into_token_stream())
+ }
+}
+
+fn join_spans(tokens: TokenStream) -> Span {
+ let mut iter = tokens.into_iter().map(|tt| tt.span());
+
+ let first = match iter.next() {
+ Some(span) => span,
+ None => return Span::call_site(),
+ };
+
+ iter.fold(None, |_prev, next| Some(next))
+ .and_then(|last| first.join(last))
+ .unwrap_or(first)
+}
+
+mod private {
+ use crate::ToTokens;
+ use proc_macro2::extra::DelimSpan;
+ use proc_macro2::Span;
+
+ pub trait Sealed {}
+ impl Sealed for Span {}
+ impl Sealed for DelimSpan {}
+ impl<T: ?Sized + ToTokens> Sealed for T {}
+}
diff --git a/rust/quote/to_tokens.rs b/rust/quote/to_tokens.rs
new file mode 100644
index 000000000000..f373092b650f
--- /dev/null
+++ b/rust/quote/to_tokens.rs
@@ -0,0 +1,271 @@
+use super::TokenStreamExt;
+use alloc::borrow::Cow;
+use alloc::rc::Rc;
+use core::iter;
+use proc_macro2::{Group, Ident, Literal, Punct, Span, TokenStream, TokenTree};
+use std::ffi::{CStr, CString};
+
+/// Types that can be interpolated inside a `quote!` invocation.
+pub trait ToTokens {
+ /// Write `self` to the given `TokenStream`.
+ ///
+ /// The token append methods provided by the [`TokenStreamExt`] extension
+ /// trait may be useful for implementing `ToTokens`.
+ ///
+ /// # Example
+ ///
+ /// Example implementation for a struct representing Rust paths like
+ /// `std::cmp::PartialEq`:
+ ///
+ /// ```
+ /// use proc_macro2::{TokenTree, Spacing, Span, Punct, TokenStream};
+ /// use quote::{TokenStreamExt, ToTokens};
+ ///
+ /// pub struct Path {
+ /// pub global: bool,
+ /// pub segments: Vec<PathSegment>,
+ /// }
+ ///
+ /// impl ToTokens for Path {
+ /// fn to_tokens(&self, tokens: &mut TokenStream) {
+ /// for (i, segment) in self.segments.iter().enumerate() {
+ /// if i > 0 || self.global {
+ /// // Double colon `::`
+ /// tokens.append(Punct::new(':', Spacing::Joint));
+ /// tokens.append(Punct::new(':', Spacing::Alone));
+ /// }
+ /// segment.to_tokens(tokens);
+ /// }
+ /// }
+ /// }
+ /// #
+ /// # pub struct PathSegment;
+ /// #
+ /// # impl ToTokens for PathSegment {
+ /// # fn to_tokens(&self, tokens: &mut TokenStream) {
+ /// # unimplemented!()
+ /// # }
+ /// # }
+ /// ```
+ fn to_tokens(&self, tokens: &mut TokenStream);
+
+ /// Convert `self` directly into a `TokenStream` object.
+ ///
+ /// This method is implicitly implemented using `to_tokens`, and acts as a
+ /// convenience method for consumers of the `ToTokens` trait.
+ fn to_token_stream(&self) -> TokenStream {
+ let mut tokens = TokenStream::new();
+ self.to_tokens(&mut tokens);
+ tokens
+ }
+
+ /// Convert `self` directly into a `TokenStream` object.
+ ///
+ /// This method is implicitly implemented using `to_tokens`, and acts as a
+ /// convenience method for consumers of the `ToTokens` trait.
+ fn into_token_stream(self) -> TokenStream
+ where
+ Self: Sized,
+ {
+ self.to_token_stream()
+ }
+}
+
+impl<T: ?Sized + ToTokens> ToTokens for &T {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ (**self).to_tokens(tokens);
+ }
+}
+
+impl<T: ?Sized + ToTokens> ToTokens for &mut T {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ (**self).to_tokens(tokens);
+ }
+}
+
+impl<'a, T: ?Sized + ToOwned + ToTokens> ToTokens for Cow<'a, T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ (**self).to_tokens(tokens);
+ }
+}
+
+impl<T: ?Sized + ToTokens> ToTokens for Box<T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ (**self).to_tokens(tokens);
+ }
+}
+
+impl<T: ?Sized + ToTokens> ToTokens for Rc<T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ (**self).to_tokens(tokens);
+ }
+}
+
+impl<T: ToTokens> ToTokens for Option<T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ if let Some(t) = self {
+ t.to_tokens(tokens);
+ }
+ }
+}
+
+impl ToTokens for str {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::string(self));
+ }
+}
+
+impl ToTokens for String {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ self.as_str().to_tokens(tokens);
+ }
+}
+
+impl ToTokens for i8 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::i8_suffixed(*self));
+ }
+}
+
+impl ToTokens for i16 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::i16_suffixed(*self));
+ }
+}
+
+impl ToTokens for i32 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::i32_suffixed(*self));
+ }
+}
+
+impl ToTokens for i64 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::i64_suffixed(*self));
+ }
+}
+
+impl ToTokens for i128 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::i128_suffixed(*self));
+ }
+}
+
+impl ToTokens for isize {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::isize_suffixed(*self));
+ }
+}
+
+impl ToTokens for u8 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::u8_suffixed(*self));
+ }
+}
+
+impl ToTokens for u16 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::u16_suffixed(*self));
+ }
+}
+
+impl ToTokens for u32 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::u32_suffixed(*self));
+ }
+}
+
+impl ToTokens for u64 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::u64_suffixed(*self));
+ }
+}
+
+impl ToTokens for u128 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::u128_suffixed(*self));
+ }
+}
+
+impl ToTokens for usize {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::usize_suffixed(*self));
+ }
+}
+
+impl ToTokens for f32 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::f32_suffixed(*self));
+ }
+}
+
+impl ToTokens for f64 {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::f64_suffixed(*self));
+ }
+}
+
+impl ToTokens for char {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::character(*self));
+ }
+}
+
+impl ToTokens for bool {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ let word = if *self { "true" } else { "false" };
+ tokens.append(Ident::new(word, Span::call_site()));
+ }
+}
+
+impl ToTokens for CStr {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::c_string(self));
+ }
+}
+
+impl ToTokens for CString {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::c_string(self));
+ }
+}
+
+impl ToTokens for Group {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(self.clone());
+ }
+}
+
+impl ToTokens for Ident {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(self.clone());
+ }
+}
+
+impl ToTokens for Punct {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(self.clone());
+ }
+}
+
+impl ToTokens for Literal {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(self.clone());
+ }
+}
+
+impl ToTokens for TokenTree {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(self.clone());
+ }
+}
+
+impl ToTokens for TokenStream {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.extend(iter::once(self.clone()));
+ }
+
+ fn into_token_stream(self) -> TokenStream {
+ self
+ }
+}
--
2.52.0