1 files changed, 0 insertions, 168 deletions
diff --git a/syn/src/lookahead.rs b/syn/src/lookahead.rs
deleted file mode 100644
index 6a67909..0000000
--- a/syn/src/lookahead.rs
+++ /dev/null
@@ -1,168 +0,0 @@
-use std::cell::RefCell;
-
-use proc_macro2::{Delimiter, Span};
-
-use crate::buffer::Cursor;
-use crate::error::{self, Error};
-use crate::sealed::lookahead::Sealed;
-use crate::span::IntoSpans;
-use crate::token::Token;
-
-/// Support for checking the next token in a stream to decide how to parse.
-///
-/// An important advantage over [`ParseStream::peek`] is that here we
-/// automatically construct an appropriate error message based on the token
-/// alternatives that get peeked. If you are producing your own error message,
-/// go ahead and use `ParseStream::peek` instead.
-///
-/// Use [`ParseStream::lookahead1`] to construct this object.
-///
-/// [`ParseStream::peek`]: crate::parse::ParseBuffer::peek
-/// [`ParseStream::lookahead1`]: crate::parse::ParseBuffer::lookahead1
-///
-/// # Example
-///
-/// ```
-/// use syn::{ConstParam, Ident, Lifetime, LifetimeDef, Result, Token, TypeParam};
-/// use syn::parse::{Parse, ParseStream};
-///
-/// // A generic parameter, a single one of the comma-separated elements inside
-/// // angle brackets in:
-/// //
-/// //     fn f<T: Clone, 'a, 'b: 'a, const N: usize>() { ... }
-/// //
-/// // On invalid input, lookahead gives us a reasonable error message.
-/// //
-/// //     error: expected one of: identifier, lifetime, `const`
-/// //       |
-/// //     5 |     fn f<!Sized>() {}
-/// //       |          ^
-/// enum GenericParam {
-///     Type(TypeParam),
-///     Lifetime(LifetimeDef),
-///     Const(ConstParam),
-/// }
-///
-/// impl Parse for GenericParam {
-///     fn parse(input: ParseStream) -> Result<Self> {
-///         let lookahead = input.lookahead1();
-///         if lookahead.peek(Ident) {
-///             input.parse().map(GenericParam::Type)
-///         } else if lookahead.peek(Lifetime) {
-///             input.parse().map(GenericParam::Lifetime)
-///         } else if lookahead.peek(Token![const]) {
-///             input.parse().map(GenericParam::Const)
-///         } else {
-///             Err(lookahead.error())
-///         }
-///     }
-/// }
-/// ```
-pub struct Lookahead1<'a> {
-    scope: Span,
-    cursor: Cursor<'a>,
-    comparisons: RefCell<Vec<&'static str>>,
-}
-
-pub fn new(scope: Span, cursor: Cursor) -> Lookahead1 {
-    Lookahead1 {
-        scope,
-        cursor,
-        comparisons: RefCell::new(Vec::new()),
-    }
-}
-
-fn peek_impl(
-    lookahead: &Lookahead1,
-    peek: fn(Cursor) -> bool,
-    display: fn() -> &'static str,
-) -> bool {
-    if peek(lookahead.cursor) {
-        return true;
-    }
-    lookahead.comparisons.borrow_mut().push(display());
-    false
-}
-
-impl<'a> Lookahead1<'a> {
-    /// Looks at the next token in the parse stream to determine whether it
-    /// matches the requested type of token.
-    ///
-    /// # Syntax
-    ///
-    /// Note that this method does not use turbofish syntax. Pass the peek type
-    /// inside of parentheses.
-    ///
-    /// - `input.peek(Token![struct])`
-    /// - `input.peek(Token![==])`
-    /// - `input.peek(Ident)`&emsp;*(does not accept keywords)*
-    /// - `input.peek(Ident::peek_any)`
-    /// - `input.peek(Lifetime)`
-    /// - `input.peek(token::Brace)`
-    pub fn peek<T: Peek>(&self, token: T) -> bool {
-        let _ = token;
-        peek_impl(self, T::Token::peek, T::Token::display)
-    }
-
-    /// Triggers an error at the current position of the parse stream.
-    ///
-    /// The error message will identify all of the expected token types that
-    /// have been peeked against this lookahead instance.
-    pub fn error(self) -> Error {
-        let comparisons = self.comparisons.borrow();
-        match comparisons.len() {
-            0 => {
-                if self.cursor.eof() {
-                    Error::new(self.scope, "unexpected end of input")
-                } else {
-                    Error::new(self.cursor.span(), "unexpected token")
-                }
-            }
-            1 => {
-                let message = format!("expected {}", comparisons[0]);
-                error::new_at(self.scope, self.cursor, message)
-            }
-            2 => {
-                let message = format!("expected {} or {}", comparisons[0], comparisons[1]);
-                error::new_at(self.scope, self.cursor, message)
-            }
-            _ => {
-                let join = comparisons.join(", ");
-                let message = format!("expected one of: {}", join);
-                error::new_at(self.scope, self.cursor, message)
-            }
-        }
-    }
-}
-
-/// Types that can be parsed by looking at just one token.
-///
-/// Use [`ParseStream::peek`] to peek one of these types in a parse stream
-/// without consuming it from the stream.
-///
-/// This trait is sealed and cannot be implemented for types outside of Syn.
-///
-/// [`ParseStream::peek`]: crate::parse::ParseBuffer::peek
-pub trait Peek: Sealed {
-    // Not public API.
-    #[doc(hidden)]
-    type Token: Token;
-}
-
-impl<F: Copy + FnOnce(TokenMarker) -> T, T: Token> Peek for F {
-    type Token = T;
-}
-
-pub enum TokenMarker {}
-
-impl<S> IntoSpans<S> for TokenMarker {
-    fn into_spans(self) -> S {
-        match self {}
-    }
-}
-
-pub fn is_delimiter(cursor: Cursor, delimiter: Delimiter) -> bool {
-    cursor.group(delimiter).is_some()
-}
-
-impl<F: Copy + FnOnce(TokenMarker) -> T, T: Token> Sealed for F {}