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Diffstat (limited to 'vendor/syn/src/error.rs')
| -rw-r--r-- | vendor/syn/src/error.rs | 467 |
1 files changed, 0 insertions, 467 deletions
diff --git a/vendor/syn/src/error.rs b/vendor/syn/src/error.rs deleted file mode 100644 index 71247cd..0000000 --- a/vendor/syn/src/error.rs +++ /dev/null @@ -1,467 +0,0 @@ -#[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(doc_cfg, 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(vec![ - 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(vec![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); - } - } -} |