vendor/syn-2.0.74/src/error.rs - toolchain/rustc - Git at Google

 #[cfg(feature = "parsing")]
 use crate::buffer::Cursor;
 use crate::thread::ThreadBound;
 use proc_macro2::{
     Delimiter, Group, Ident, LexError, Literal, Punct, Spacing, Span, TokenStream, TokenTree,
 };
 #[cfg(feature = "printing")]
 use quote::ToTokens;
 use std::fmt::{self, Debug, Display};
 use std::slice;
 use std::vec;

 /// The result of a Syn parser.
 pub type Result<T> = std::result::Result<T, Error>;

 /// Error returned when a Syn parser cannot parse the input tokens.
 ///
 /// # Error reporting in proc macros
 ///
 /// The correct way to report errors back to the compiler from a procedural
 /// macro is by emitting an appropriately spanned invocation of
 /// [`compile_error!`] in the generated code. This produces a better diagnostic
 /// message than simply panicking the macro.
 ///
 /// [`compile_error!`]: std::compile_error!
 ///
 /// When parsing macro input, the [`parse_macro_input!`] macro handles the
 /// conversion to `compile_error!` automatically.
 ///
 /// [`parse_macro_input!`]: crate::parse_macro_input!
 ///
 /// ```
 /// # extern crate proc_macro;
 /// #
 /// use proc_macro::TokenStream;
 /// use syn::parse::{Parse, ParseStream, Result};
 /// use syn::{parse_macro_input, ItemFn};
 ///
 /// # const IGNORE: &str = stringify! {
 /// #[proc_macro_attribute]
 /// # };
 /// pub fn my_attr(args: TokenStream, input: TokenStream) -> TokenStream {
 ///     let args = parse_macro_input!(args as MyAttrArgs);
 ///     let input = parse_macro_input!(input as ItemFn);
 ///
 ///     /* ... */
 ///     # TokenStream::new()
 /// }
 ///
 /// struct MyAttrArgs {
 ///     # _k: [(); { stringify! {
 ///     ...
 ///     # }; 0 }]
 /// }
 ///
 /// impl Parse for MyAttrArgs {
 ///     fn parse(input: ParseStream) -> Result<Self> {
 ///         # stringify! {
 ///         ...
 ///         # };
 ///         # unimplemented!()
 ///     }
 /// }
 /// ```
 ///
 /// For errors that arise later than the initial parsing stage, the
 /// [`.to_compile_error()`] or [`.into_compile_error()`] methods can be used to
 /// perform an explicit conversion to `compile_error!`.
 ///
 /// [`.to_compile_error()`]: Error::to_compile_error
 /// [`.into_compile_error()`]: Error::into_compile_error
 ///
 /// ```
 /// # extern crate proc_macro;
 /// #
 /// # use proc_macro::TokenStream;
 /// # use syn::{parse_macro_input, DeriveInput};
 /// #
 /// # const IGNORE: &str = stringify! {
 /// #[proc_macro_derive(MyDerive)]
 /// # };
 /// pub fn my_derive(input: TokenStream) -> TokenStream {
 ///     let input = parse_macro_input!(input as DeriveInput);
 ///
 ///     // fn(DeriveInput) -> syn::Result<proc_macro2::TokenStream>
 ///     expand::my_derive(input)
 ///         .unwrap_or_else(syn::Error::into_compile_error)
 ///         .into()
 /// }
 /// #
 /// # mod expand {
 /// #     use proc_macro2::TokenStream;
 /// #     use syn::{DeriveInput, Result};
 /// #
 /// #     pub fn my_derive(input: DeriveInput) -> Result<TokenStream> {
 /// #         unimplemented!()
 /// #     }
 /// # }
 /// ```
 pub struct Error {
     messages: Vec<ErrorMessage>,
 }

 struct ErrorMessage {
     // Span is implemented as an index into a thread-local interner to keep the
     // size small. It is not safe to access from a different thread. We want
     // errors to be Send and Sync to play nicely with ecosystem crates for error
     // handling, so pin the span we're given to its original thread and assume
     // it is Span::call_site if accessed from any other thread.
     span: ThreadBound<SpanRange>,
     message: String,
 }

 // Cannot use std::ops::Range<Span> because that does not implement Copy,
 // whereas ThreadBound<T> requires a Copy impl as a way to ensure no Drop impls
 // are involved.
 struct SpanRange {
     start: Span,
     end: Span,
 }

 #[cfg(test)]
 struct _Test
 where
     Error: Send + Sync;

 impl Error {
     /// Usually the [`ParseStream::error`] method will be used instead, which
     /// automatically uses the correct span from the current position of the
     /// parse stream.
     ///
     /// Use `Error::new` when the error needs to be triggered on some span other
     /// than where the parse stream is currently positioned.
     ///
     /// [`ParseStream::error`]: crate::parse::ParseBuffer::error
     ///
     /// # Example
     ///
     /// ```
     /// use syn::{Error, Ident, LitStr, Result, Token};
     /// use syn::parse::ParseStream;
     ///
     /// // Parses input that looks like `name = "string"` where the key must be
     /// // the identifier `name` and the value may be any string literal.
     /// // Returns the string literal.
     /// fn parse_name(input: ParseStream) -> Result<LitStr> {
     ///     let name_token: Ident = input.parse()?;
     ///     if name_token != "name" {
     ///         // Trigger an error not on the current position of the stream,
     ///         // but on the position of the unexpected identifier.
     ///         return Err(Error::new(name_token.span(), "expected `name`"));
     ///     }
     ///     input.parse::<Token![=]>()?;
     ///     let s: LitStr = input.parse()?;
     ///     Ok(s)
     /// }
     /// ```
     pub fn new<T: Display>(span: Span, message: T) -> Self {
         return new(span, message.to_string());

         fn new(span: Span, message: String) -> Error {
             Error {
                 messages: vec![ErrorMessage {
                     span: ThreadBound::new(SpanRange {
                         start: span,
                         end: span,
                     }),
                     message,
                 }],
             }
         }
     }

     /// Creates an error with the specified message spanning the given syntax
     /// tree node.
     ///
     /// Unlike the `Error::new` constructor, this constructor takes an argument
     /// `tokens` which is a syntax tree node. This allows the resulting `Error`
     /// to attempt to span all tokens inside of `tokens`. While you would
     /// typically be able to use the `Spanned` trait with the above `Error::new`
     /// constructor, implementation limitations today mean that
     /// `Error::new_spanned` may provide a higher-quality error message on
     /// stable Rust.
     ///
     /// When in doubt it's recommended to stick to `Error::new` (or
     /// `ParseStream::error`)!
     #[cfg(feature = "printing")]
     #[cfg_attr(docsrs, doc(cfg(feature = "printing")))]
     pub fn new_spanned<T: ToTokens, U: Display>(tokens: T, message: U) -> Self {
         return new_spanned(tokens.into_token_stream(), message.to_string());

         fn new_spanned(tokens: TokenStream, message: String) -> Error {
             let mut iter = tokens.into_iter();
             let start = iter.next().map_or_else(Span::call_site, |t| t.span());
             let end = iter.last().map_or(start, |t| t.span());
             Error {
                 messages: vec![ErrorMessage {
                     span: ThreadBound::new(SpanRange { start, end }),
                     message,
                 }],
             }
         }
     }

     /// The source location of the error.
     ///
     /// Spans are not thread-safe so this function returns `Span::call_site()`
     /// if called from a different thread than the one on which the `Error` was
     /// originally created.
     pub fn span(&self) -> Span {
         let SpanRange { start, end } = match self.messages[0].span.get() {
             Some(span) => *span,
             None => return Span::call_site(),
         };
         start.join(end).unwrap_or(start)
     }

     /// Render the error as an invocation of [`compile_error!`].
     ///
     /// The [`parse_macro_input!`] macro provides a convenient way to invoke
     /// this method correctly in a procedural macro.
     ///
     /// [`compile_error!`]: std::compile_error!
     /// [`parse_macro_input!`]: crate::parse_macro_input!
     pub fn to_compile_error(&self) -> TokenStream {
         self.messages
             .iter()
             .map(ErrorMessage::to_compile_error)
             .collect()
     }

     /// Render the error as an invocation of [`compile_error!`].
     ///
     /// [`compile_error!`]: std::compile_error!
     ///
     /// # Example
     ///
     /// ```
     /// # extern crate proc_macro;
     /// #
     /// use proc_macro::TokenStream;
     /// use syn::{parse_macro_input, DeriveInput, Error};
     ///
     /// # const _: &str = stringify! {
     /// #[proc_macro_derive(MyTrait)]
     /// # };
     /// pub fn derive_my_trait(input: TokenStream) -> TokenStream {
     ///     let input = parse_macro_input!(input as DeriveInput);
     ///     my_trait::expand(input)
     ///         .unwrap_or_else(Error::into_compile_error)
     ///         .into()
     /// }
     ///
     /// mod my_trait {
     ///     use proc_macro2::TokenStream;
     ///     use syn::{DeriveInput, Result};
     ///
     ///     pub(crate) fn expand(input: DeriveInput) -> Result<TokenStream> {
     ///         /* ... */
     ///         # unimplemented!()
     ///     }
     /// }
     /// ```
     pub fn into_compile_error(self) -> TokenStream {
         self.to_compile_error()
     }

     /// Add another error message to self such that when `to_compile_error()` is
     /// called, both errors will be emitted together.
     pub fn combine(&mut self, another: Error) {
         self.messages.extend(another.messages);
     }
 }

 impl ErrorMessage {
     fn to_compile_error(&self) -> TokenStream {
         let (start, end) = match self.span.get() {
             Some(range) => (range.start, range.end),
             None => (Span::call_site(), Span::call_site()),
         };

         // ::core::compile_error!($message)
         TokenStream::from_iter([
             TokenTree::Punct({
                 let mut punct = Punct::new(':', Spacing::Joint);
                 punct.set_span(start);
                 punct
             }),
             TokenTree::Punct({
                 let mut punct = Punct::new(':', Spacing::Alone);
                 punct.set_span(start);
                 punct
             }),
             TokenTree::Ident(Ident::new("core", start)),
             TokenTree::Punct({
                 let mut punct = Punct::new(':', Spacing::Joint);
                 punct.set_span(start);
                 punct
             }),
             TokenTree::Punct({
                 let mut punct = Punct::new(':', Spacing::Alone);
                 punct.set_span(start);
                 punct
             }),
             TokenTree::Ident(Ident::new("compile_error", start)),
             TokenTree::Punct({
                 let mut punct = Punct::new('!', Spacing::Alone);
                 punct.set_span(start);
                 punct
             }),
             TokenTree::Group({
                 let mut group = Group::new(Delimiter::Brace, {
                     TokenStream::from_iter([TokenTree::Literal({
                         let mut string = Literal::string(&self.message);
                         string.set_span(end);
                         string
                     })])
                 });
                 group.set_span(end);
                 group
             }),
         ])
     }
 }

 #[cfg(feature = "parsing")]
 pub(crate) fn new_at<T: Display>(scope: Span, cursor: Cursor, message: T) -> Error {
     if cursor.eof() {
         Error::new(scope, format!("unexpected end of input, {}", message))
     } else {
         let span = crate::buffer::open_span_of_group(cursor);
         Error::new(span, message)
     }
 }

 #[cfg(all(feature = "parsing", any(feature = "full", feature = "derive")))]
 pub(crate) fn new2<T: Display>(start: Span, end: Span, message: T) -> Error {
     return new2(start, end, message.to_string());

     fn new2(start: Span, end: Span, message: String) -> Error {
         Error {
             messages: vec![ErrorMessage {
                 span: ThreadBound::new(SpanRange { start, end }),
                 message,
             }],
         }
     }
 }

 impl Debug for Error {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         if self.messages.len() == 1 {
             formatter
                 .debug_tuple("Error")
                 .field(&self.messages[0])
                 .finish()
         } else {
             formatter
                 .debug_tuple("Error")
                 .field(&self.messages)
                 .finish()
         }
     }
 }

 impl Debug for ErrorMessage {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         Debug::fmt(&self.message, formatter)
     }
 }

 impl Display for Error {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         formatter.write_str(&self.messages[0].message)
     }
 }

 impl Clone for Error {
     fn clone(&self) -> Self {
         Error {
             messages: self.messages.clone(),
         }
     }
 }

 impl Clone for ErrorMessage {
     fn clone(&self) -> Self {
         ErrorMessage {
             span: self.span,
             message: self.message.clone(),
         }
     }
 }

 impl Clone for SpanRange {
     fn clone(&self) -> Self {
         *self
     }
 }

 impl Copy for SpanRange {}

 impl std::error::Error for Error {}

 impl From<LexError> for Error {
     fn from(err: LexError) -> Self {
         Error::new(err.span(), err)
     }
 }

 impl IntoIterator for Error {
     type Item = Error;
     type IntoIter = IntoIter;

     fn into_iter(self) -> Self::IntoIter {
         IntoIter {
             messages: self.messages.into_iter(),
         }
     }
 }

 pub struct IntoIter {
     messages: vec::IntoIter<ErrorMessage>,
 }

 impl Iterator for IntoIter {
     type Item = Error;

     fn next(&mut self) -> Option<Self::Item> {
         Some(Error {
             messages: vec![self.messages.next()?],
         })
     }
 }

 impl<'a> IntoIterator for &'a Error {
     type Item = Error;
     type IntoIter = Iter<'a>;

     fn into_iter(self) -> Self::IntoIter {
         Iter {
             messages: self.messages.iter(),
         }
     }
 }

 pub struct Iter<'a> {
     messages: slice::Iter<'a, ErrorMessage>,
 }

 impl<'a> Iterator for Iter<'a> {
     type Item = Error;

     fn next(&mut self) -> Option<Self::Item> {
         Some(Error {
             messages: vec![self.messages.next()?.clone()],
         })
     }
 }

 impl Extend<Error> for Error {
     fn extend<T: IntoIterator<Item = Error>>(&mut self, iter: T) {
         for err in iter {
             self.combine(err);
         }
     }
 }
	#[cfg(feature = "parsing")]
	use crate::buffer::Cursor;
	use crate::thread::ThreadBound;
	use proc_macro2::{
	Delimiter, Group, Ident, LexError, Literal, Punct, Spacing, Span, TokenStream, TokenTree,
	};
	#[cfg(feature = "printing")]
	use quote::ToTokens;
	use std::fmt::{self, Debug, Display};
	use std::slice;
	use std::vec;

	/// The result of a Syn parser.
	pub type Result<T> = std::result::Result<T, Error>;

	/// Error returned when a Syn parser cannot parse the input tokens.
	///
	/// # Error reporting in proc macros
	///
	/// The correct way to report errors back to the compiler from a procedural
	/// macro is by emitting an appropriately spanned invocation of
	/// [`compile_error!`] in the generated code. This produces a better diagnostic
	/// message than simply panicking the macro.
	///
	/// [`compile_error!`]: std::compile_error!
	///
	/// When parsing macro input, the [`parse_macro_input!`] macro handles the
	/// conversion to `compile_error!` automatically.
	///
	/// [`parse_macro_input!`]: crate::parse_macro_input!
	///
	/// ```
	/// # extern crate proc_macro;
	/// #
	/// use proc_macro::TokenStream;
	/// use syn::parse::{Parse, ParseStream, Result};
	/// use syn::{parse_macro_input, ItemFn};
	///
	/// # const IGNORE: &str = stringify! {
	/// #[proc_macro_attribute]
	/// # };
	/// pub fn my_attr(args: TokenStream, input: TokenStream) -> TokenStream {
	/// let args = parse_macro_input!(args as MyAttrArgs);
	/// let input = parse_macro_input!(input as ItemFn);
	///
	/// /* ... */
	/// # TokenStream::new()
	/// }
	///
	/// struct MyAttrArgs {
	/// # _k: [(); { stringify! {
	/// ...
	/// # }; 0 }]
	/// }
	///
	/// impl Parse for MyAttrArgs {
	/// fn parse(input: ParseStream) -> Result<Self> {
	/// # stringify! {
	/// ...
	/// # };
	/// # unimplemented!()
	/// }
	/// }
	/// ```
	///
	/// For errors that arise later than the initial parsing stage, the
	/// [`.to_compile_error()`] or [`.into_compile_error()`] methods can be used to
	/// perform an explicit conversion to `compile_error!`.
	///
	/// [`.to_compile_error()`]: Error::to_compile_error
	/// [`.into_compile_error()`]: Error::into_compile_error
	///
	/// ```
	/// # extern crate proc_macro;
	/// #
	/// # use proc_macro::TokenStream;
	/// # use syn::{parse_macro_input, DeriveInput};
	/// #
	/// # const IGNORE: &str = stringify! {
	/// #[proc_macro_derive(MyDerive)]
	/// # };
	/// pub fn my_derive(input: TokenStream) -> TokenStream {
	/// let input = parse_macro_input!(input as DeriveInput);
	///
	/// // fn(DeriveInput) -> syn::Result<proc_macro2::TokenStream>
	/// expand::my_derive(input)
	/// .unwrap_or_else(syn::Error::into_compile_error)
	/// .into()
	/// }
	/// #
	/// # mod expand {
	/// # use proc_macro2::TokenStream;
	/// # use syn::{DeriveInput, Result};
	/// #
	/// # pub fn my_derive(input: DeriveInput) -> Result<TokenStream> {
	/// # unimplemented!()
	/// # }
	/// # }
	/// ```
	pub struct Error {
	messages: Vec<ErrorMessage>,
	}

	struct ErrorMessage {
	// Span is implemented as an index into a thread-local interner to keep the
	// size small. It is not safe to access from a different thread. We want
	// errors to be Send and Sync to play nicely with ecosystem crates for error
	// handling, so pin the span we're given to its original thread and assume
	// it is Span::call_site if accessed from any other thread.
	span: ThreadBound<SpanRange>,
	message: String,
	}

	// Cannot use std::ops::Range<Span> because that does not implement Copy,
	// whereas ThreadBound<T> requires a Copy impl as a way to ensure no Drop impls
	// are involved.
	struct SpanRange {
	start: Span,
	end: Span,
	}

	#[cfg(test)]
	struct _Test
	where
	Error: Send + Sync;

	impl Error {
	/// Usually the [`ParseStream::error`] method will be used instead, which
	/// automatically uses the correct span from the current position of the
	/// parse stream.
	///
	/// Use `Error::new` when the error needs to be triggered on some span other
	/// than where the parse stream is currently positioned.
	///
	/// [`ParseStream::error`]: crate::parse::ParseBuffer::error
	///
	/// # Example
	///
	/// ```
	/// use syn::{Error, Ident, LitStr, Result, Token};
	/// use syn::parse::ParseStream;
	///
	/// // Parses input that looks like `name = "string"` where the key must be
	/// // the identifier `name` and the value may be any string literal.
	/// // Returns the string literal.
	/// fn parse_name(input: ParseStream) -> Result<LitStr> {
	/// let name_token: Ident = input.parse()?;
	/// if name_token != "name" {
	/// // Trigger an error not on the current position of the stream,
	/// // but on the position of the unexpected identifier.
	/// return Err(Error::new(name_token.span(), "expected `name`"));
	/// }
	/// input.parse::<Token![=]>()?;
	/// let s: LitStr = input.parse()?;
	/// Ok(s)
	/// }
	/// ```
	pub fn new<T: Display>(span: Span, message: T) -> Self {
	return new(span, message.to_string());

	fn new(span: Span, message: String) -> Error {
	Error {
	messages: vec![ErrorMessage {
	span: ThreadBound::new(SpanRange {
	start: span,
	end: span,
	}),
	message,
	}],
	}
	}
	}

	/// Creates an error with the specified message spanning the given syntax
	/// tree node.
	///
	/// Unlike the `Error::new` constructor, this constructor takes an argument
	/// `tokens` which is a syntax tree node. This allows the resulting `Error`
	/// to attempt to span all tokens inside of `tokens`. While you would
	/// typically be able to use the `Spanned` trait with the above `Error::new`
	/// constructor, implementation limitations today mean that
	/// `Error::new_spanned` may provide a higher-quality error message on
	/// stable Rust.
	///
	/// When in doubt it's recommended to stick to `Error::new` (or
	/// `ParseStream::error`)!
	#[cfg(feature = "printing")]
	#[cfg_attr(docsrs, doc(cfg(feature = "printing")))]
	pub fn new_spanned<T: ToTokens, U: Display>(tokens: T, message: U) -> Self {
	return new_spanned(tokens.into_token_stream(), message.to_string());

	fn new_spanned(tokens: TokenStream, message: String) -> Error {
	let mut iter = tokens.into_iter();
	let start = iter.next().map_or_else(Span::call_site, \|t\| t.span());
	let end = iter.last().map_or(start, \|t\| t.span());
	Error {
	messages: vec![ErrorMessage {
	span: ThreadBound::new(SpanRange { start, end }),
	message,
	}],
	}
	}
	}

	/// The source location of the error.
	///
	/// Spans are not thread-safe so this function returns `Span::call_site()`
	/// if called from a different thread than the one on which the `Error` was
	/// originally created.
	pub fn span(&self) -> Span {
	let SpanRange { start, end } = match self.messages[0].span.get() {
	Some(span) => *span,
	None => return Span::call_site(),
	};
	start.join(end).unwrap_or(start)
	}

	/// Render the error as an invocation of [`compile_error!`].
	///
	/// The [`parse_macro_input!`] macro provides a convenient way to invoke
	/// this method correctly in a procedural macro.
	///
	/// [`compile_error!`]: std::compile_error!
	/// [`parse_macro_input!`]: crate::parse_macro_input!
	pub fn to_compile_error(&self) -> TokenStream {
	self.messages
	.iter()
	.map(ErrorMessage::to_compile_error)
	.collect()
	}

	/// Render the error as an invocation of [`compile_error!`].
	///
	/// [`compile_error!`]: std::compile_error!
	///
	/// # Example
	///
	/// ```
	/// # extern crate proc_macro;
	/// #
	/// use proc_macro::TokenStream;
	/// use syn::{parse_macro_input, DeriveInput, Error};
	///
	/// # const _: &str = stringify! {
	/// #[proc_macro_derive(MyTrait)]
	/// # };
	/// pub fn derive_my_trait(input: TokenStream) -> TokenStream {
	/// let input = parse_macro_input!(input as DeriveInput);
	/// my_trait::expand(input)
	/// .unwrap_or_else(Error::into_compile_error)
	/// .into()
	/// }
	///
	/// mod my_trait {
	/// use proc_macro2::TokenStream;
	/// use syn::{DeriveInput, Result};
	///
	/// pub(crate) fn expand(input: DeriveInput) -> Result<TokenStream> {
	/// /* ... */
	/// # unimplemented!()
	/// }
	/// }
	/// ```
	pub fn into_compile_error(self) -> TokenStream {
	self.to_compile_error()
	}

	/// Add another error message to self such that when `to_compile_error()` is
	/// called, both errors will be emitted together.
	pub fn combine(&mut self, another: Error) {
	self.messages.extend(another.messages);
	}
	}

	impl ErrorMessage {
	fn to_compile_error(&self) -> TokenStream {
	let (start, end) = match self.span.get() {
	Some(range) => (range.start, range.end),
	None => (Span::call_site(), Span::call_site()),
	};

	// ::core::compile_error!($message)
	TokenStream::from_iter([
	TokenTree::Punct({
	let mut punct = Punct::new(':', Spacing::Joint);
	punct.set_span(start);
	punct
	}),
	TokenTree::Punct({
	let mut punct = Punct::new(':', Spacing::Alone);
	punct.set_span(start);
	punct
	}),
	TokenTree::Ident(Ident::new("core", start)),
	TokenTree::Punct({
	let mut punct = Punct::new(':', Spacing::Joint);
	punct.set_span(start);
	punct
	}),
	TokenTree::Punct({
	let mut punct = Punct::new(':', Spacing::Alone);
	punct.set_span(start);
	punct
	}),
	TokenTree::Ident(Ident::new("compile_error", start)),
	TokenTree::Punct({
	let mut punct = Punct::new('!', Spacing::Alone);
	punct.set_span(start);
	punct
	}),
	TokenTree::Group({
	let mut group = Group::new(Delimiter::Brace, {
	TokenStream::from_iter([TokenTree::Literal({
	let mut string = Literal::string(&self.message);
	string.set_span(end);
	string
	})])
	});
	group.set_span(end);
	group
	}),
	])
	}
	}

	#[cfg(feature = "parsing")]
	pub(crate) fn new_at<T: Display>(scope: Span, cursor: Cursor, message: T) -> Error {
	if cursor.eof() {
	Error::new(scope, format!("unexpected end of input, {}", message))
	} else {
	let span = crate::buffer::open_span_of_group(cursor);
	Error::new(span, message)
	}
	}

	#[cfg(all(feature = "parsing", any(feature = "full", feature = "derive")))]
	pub(crate) fn new2<T: Display>(start: Span, end: Span, message: T) -> Error {
	return new2(start, end, message.to_string());

	fn new2(start: Span, end: Span, message: String) -> Error {
	Error {
	messages: vec![ErrorMessage {
	span: ThreadBound::new(SpanRange { start, end }),
	message,
	}],
	}
	}
	}

	impl Debug for Error {
	fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
	if self.messages.len() == 1 {
	formatter
	.debug_tuple("Error")
	.field(&self.messages[0])
	.finish()
	} else {
	formatter
	.debug_tuple("Error")
	.field(&self.messages)
	.finish()
	}
	}
	}

	impl Debug for ErrorMessage {
	fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
	Debug::fmt(&self.message, formatter)
	}
	}

	impl Display for Error {
	fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
	formatter.write_str(&self.messages[0].message)
	}
	}

	impl Clone for Error {
	fn clone(&self) -> Self {
	Error {
	messages: self.messages.clone(),
	}
	}
	}

	impl Clone for ErrorMessage {
	fn clone(&self) -> Self {
	ErrorMessage {
	span: self.span,
	message: self.message.clone(),
	}
	}
	}

	impl Clone for SpanRange {
	fn clone(&self) -> Self {
	*self
	}
	}

	impl Copy for SpanRange {}

	impl std::error::Error for Error {}

	impl From<LexError> for Error {
	fn from(err: LexError) -> Self {
	Error::new(err.span(), err)
	}
	}

	impl IntoIterator for Error {
	type Item = Error;
	type IntoIter = IntoIter;

	fn into_iter(self) -> Self::IntoIter {
	IntoIter {
	messages: self.messages.into_iter(),
	}
	}
	}

	pub struct IntoIter {
	messages: vec::IntoIter<ErrorMessage>,
	}

	impl Iterator for IntoIter {
	type Item = Error;

	fn next(&mut self) -> Option<Self::Item> {
	Some(Error {
	messages: vec![self.messages.next()?],
	})
	}
	}

	impl<'a> IntoIterator for &'a Error {
	type Item = Error;
	type IntoIter = Iter<'a>;

	fn into_iter(self) -> Self::IntoIter {
	Iter {
	messages: self.messages.iter(),
	}
	}
	}

	pub struct Iter<'a> {
	messages: slice::Iter<'a, ErrorMessage>,
	}

	impl<'a> Iterator for Iter<'a> {
	type Item = Error;

	fn next(&mut self) -> Option<Self::Item> {
	Some(Error {
	messages: vec![self.messages.next()?.clone()],
	})
	}
	}

	impl Extend<Error> for Error {
	fn extend<T: IntoIterator<Item = Error>>(&mut self, iter: T) {
	for err in iter {
	self.combine(err);
	}
	}
	}