Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1362 insertions, 0 deletions

diff --git a/third_party/rust/syn/src/generics.rs b/third_party/rust/syn/src/generics.rs
new file mode 100644
index 0000000000..6d4fe847ed
--- /dev/null
+++ b/third_party/rust/syn/src/generics.rs
@@ -0,0 +1,1362 @@
+use super::*;
+use crate::punctuated::{Iter, IterMut, Punctuated};
+#[cfg(all(feature = "printing", feature = "extra-traits"))]
+use std::fmt::{self, Debug};
+#[cfg(all(feature = "printing", feature = "extra-traits"))]
+use std::hash::{Hash, Hasher};
+
+ast_struct! {
+    /// Lifetimes and type parameters attached to a declaration of a function,
+    /// enum, trait, etc.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub struct Generics {
+        pub lt_token: Option<Token![<]>,
+        pub params: Punctuated<GenericParam, Token![,]>,
+        pub gt_token: Option<Token![>]>,
+        pub where_clause: Option<WhereClause>,
+    }
+}
+
+ast_enum_of_structs! {
+    /// A generic type parameter, lifetime, or const generic: `T: Into<String>`,
+    /// `'a: 'b`, `const LEN: usize`.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    ///
+    /// # Syntax tree enum
+    ///
+    /// This type is a [syntax tree enum].
+    ///
+    /// [syntax tree enum]: Expr#syntax-tree-enums
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub enum GenericParam {
+        /// A generic type parameter: `T: Into<String>`.
+        Type(TypeParam),
+
+        /// A lifetime definition: `'a: 'b + 'c + 'd`.
+        Lifetime(LifetimeDef),
+
+        /// A const generic parameter: `const LENGTH: usize`.
+        Const(ConstParam),
+    }
+}
+
+ast_struct! {
+    /// A generic type parameter: `T: Into<String>`.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or
+    /// `"full"` feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub struct TypeParam {
+        pub attrs: Vec<Attribute>,
+        pub ident: Ident,
+        pub colon_token: Option<Token![:]>,
+        pub bounds: Punctuated<TypeParamBound, Token![+]>,
+        pub eq_token: Option<Token![=]>,
+        pub default: Option<Type>,
+    }
+}
+
+ast_struct! {
+    /// A lifetime definition: `'a: 'b + 'c + 'd`.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or
+    /// `"full"` feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub struct LifetimeDef {
+        pub attrs: Vec<Attribute>,
+        pub lifetime: Lifetime,
+        pub colon_token: Option<Token![:]>,
+        pub bounds: Punctuated<Lifetime, Token![+]>,
+    }
+}
+
+ast_struct! {
+    /// A const generic parameter: `const LENGTH: usize`.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or
+    /// `"full"` feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub struct ConstParam {
+        pub attrs: Vec<Attribute>,
+        pub const_token: Token![const],
+        pub ident: Ident,
+        pub colon_token: Token![:],
+        pub ty: Type,
+        pub eq_token: Option<Token![=]>,
+        pub default: Option<Expr>,
+    }
+}
+
+impl Default for Generics {
+    fn default() -> Self {
+        Generics {
+            lt_token: None,
+            params: Punctuated::new(),
+            gt_token: None,
+            where_clause: None,
+        }
+    }
+}
+
+impl Generics {
+    /// Returns an
+    /// <code
+    ///   style="padding-right:0;">Iterator&lt;Item = &amp;</code><a
+    ///   href="struct.TypeParam.html"><code
+    ///   style="padding-left:0;padding-right:0;">TypeParam</code></a><code
+    ///   style="padding-left:0;">&gt;</code>
+    /// over the type parameters in `self.params`.
+    pub fn type_params(&self) -> TypeParams {
+        TypeParams(self.params.iter())
+    }
+
+    /// Returns an
+    /// <code
+    ///   style="padding-right:0;">Iterator&lt;Item = &amp;mut </code><a
+    ///   href="struct.TypeParam.html"><code
+    ///   style="padding-left:0;padding-right:0;">TypeParam</code></a><code
+    ///   style="padding-left:0;">&gt;</code>
+    /// over the type parameters in `self.params`.
+    pub fn type_params_mut(&mut self) -> TypeParamsMut {
+        TypeParamsMut(self.params.iter_mut())
+    }
+
+    /// Returns an
+    /// <code
+    ///   style="padding-right:0;">Iterator&lt;Item = &amp;</code><a
+    ///   href="struct.LifetimeDef.html"><code
+    ///   style="padding-left:0;padding-right:0;">LifetimeDef</code></a><code
+    ///   style="padding-left:0;">&gt;</code>
+    /// over the lifetime parameters in `self.params`.
+    pub fn lifetimes(&self) -> Lifetimes {
+        Lifetimes(self.params.iter())
+    }
+
+    /// Returns an
+    /// <code
+    ///   style="padding-right:0;">Iterator&lt;Item = &amp;mut </code><a
+    ///   href="struct.LifetimeDef.html"><code
+    ///   style="padding-left:0;padding-right:0;">LifetimeDef</code></a><code
+    ///   style="padding-left:0;">&gt;</code>
+    /// over the lifetime parameters in `self.params`.
+    pub fn lifetimes_mut(&mut self) -> LifetimesMut {
+        LifetimesMut(self.params.iter_mut())
+    }
+
+    /// Returns an
+    /// <code
+    ///   style="padding-right:0;">Iterator&lt;Item = &amp;</code><a
+    ///   href="struct.ConstParam.html"><code
+    ///   style="padding-left:0;padding-right:0;">ConstParam</code></a><code
+    ///   style="padding-left:0;">&gt;</code>
+    /// over the constant parameters in `self.params`.
+    pub fn const_params(&self) -> ConstParams {
+        ConstParams(self.params.iter())
+    }
+
+    /// Returns an
+    /// <code
+    ///   style="padding-right:0;">Iterator&lt;Item = &amp;mut </code><a
+    ///   href="struct.ConstParam.html"><code
+    ///   style="padding-left:0;padding-right:0;">ConstParam</code></a><code
+    ///   style="padding-left:0;">&gt;</code>
+    /// over the constant parameters in `self.params`.
+    pub fn const_params_mut(&mut self) -> ConstParamsMut {
+        ConstParamsMut(self.params.iter_mut())
+    }
+
+    /// Initializes an empty `where`-clause if there is not one present already.
+    pub fn make_where_clause(&mut self) -> &mut WhereClause {
+        self.where_clause.get_or_insert_with(|| WhereClause {
+            where_token: <Token![where]>::default(),
+            predicates: Punctuated::new(),
+        })
+    }
+}
+
+pub struct TypeParams<'a>(Iter<'a, GenericParam>);
+
+impl<'a> Iterator for TypeParams<'a> {
+    type Item = &'a TypeParam;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let next = match self.0.next() {
+            Some(item) => item,
+            None => return None,
+        };
+        if let GenericParam::Type(type_param) = next {
+            Some(type_param)
+        } else {
+            self.next()
+        }
+    }
+}
+
+pub struct TypeParamsMut<'a>(IterMut<'a, GenericParam>);
+
+impl<'a> Iterator for TypeParamsMut<'a> {
+    type Item = &'a mut TypeParam;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let next = match self.0.next() {
+            Some(item) => item,
+            None => return None,
+        };
+        if let GenericParam::Type(type_param) = next {
+            Some(type_param)
+        } else {
+            self.next()
+        }
+    }
+}
+
+pub struct Lifetimes<'a>(Iter<'a, GenericParam>);
+
+impl<'a> Iterator for Lifetimes<'a> {
+    type Item = &'a LifetimeDef;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let next = match self.0.next() {
+            Some(item) => item,
+            None => return None,
+        };
+        if let GenericParam::Lifetime(lifetime) = next {
+            Some(lifetime)
+        } else {
+            self.next()
+        }
+    }
+}
+
+pub struct LifetimesMut<'a>(IterMut<'a, GenericParam>);
+
+impl<'a> Iterator for LifetimesMut<'a> {
+    type Item = &'a mut LifetimeDef;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let next = match self.0.next() {
+            Some(item) => item,
+            None => return None,
+        };
+        if let GenericParam::Lifetime(lifetime) = next {
+            Some(lifetime)
+        } else {
+            self.next()
+        }
+    }
+}
+
+pub struct ConstParams<'a>(Iter<'a, GenericParam>);
+
+impl<'a> Iterator for ConstParams<'a> {
+    type Item = &'a ConstParam;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let next = match self.0.next() {
+            Some(item) => item,
+            None => return None,
+        };
+        if let GenericParam::Const(const_param) = next {
+            Some(const_param)
+        } else {
+            self.next()
+        }
+    }
+}
+
+pub struct ConstParamsMut<'a>(IterMut<'a, GenericParam>);
+
+impl<'a> Iterator for ConstParamsMut<'a> {
+    type Item = &'a mut ConstParam;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let next = match self.0.next() {
+            Some(item) => item,
+            None => return None,
+        };
+        if let GenericParam::Const(const_param) = next {
+            Some(const_param)
+        } else {
+            self.next()
+        }
+    }
+}
+
+/// Returned by `Generics::split_for_impl`.
+///
+/// *This type is available only if Syn is built with the `"derive"` or `"full"`
+/// feature and the `"printing"` feature.*
+#[cfg(feature = "printing")]
+#[cfg_attr(
+    doc_cfg,
+    doc(cfg(all(any(feature = "full", feature = "derive"), feature = "printing")))
+)]
+pub struct ImplGenerics<'a>(&'a Generics);
+
+/// Returned by `Generics::split_for_impl`.
+///
+/// *This type is available only if Syn is built with the `"derive"` or `"full"`
+/// feature and the `"printing"` feature.*
+#[cfg(feature = "printing")]
+#[cfg_attr(
+    doc_cfg,
+    doc(cfg(all(any(feature = "full", feature = "derive"), feature = "printing")))
+)]
+pub struct TypeGenerics<'a>(&'a Generics);
+
+/// Returned by `TypeGenerics::as_turbofish`.
+///
+/// *This type is available only if Syn is built with the `"derive"` or `"full"`
+/// feature and the `"printing"` feature.*
+#[cfg(feature = "printing")]
+#[cfg_attr(
+    doc_cfg,
+    doc(cfg(all(any(feature = "full", feature = "derive"), feature = "printing")))
+)]
+pub struct Turbofish<'a>(&'a Generics);
+
+#[cfg(feature = "printing")]
+impl Generics {
+    /// Split a type's generics into the pieces required for impl'ing a trait
+    /// for that type.
+    ///
+    /// ```
+    /// # use proc_macro2::{Span, Ident};
+    /// # use quote::quote;
+    /// #
+    /// # let generics: syn::Generics = Default::default();
+    /// # let name = Ident::new("MyType", Span::call_site());
+    /// #
+    /// let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
+    /// quote! {
+    ///     impl #impl_generics MyTrait for #name #ty_generics #where_clause {
+    ///         // ...
+    ///     }
+    /// }
+    /// # ;
+    /// ```
+    ///
+    /// *This method is available only if Syn is built with the `"derive"` or
+    /// `"full"` feature and the `"printing"` feature.*
+    #[cfg_attr(
+        doc_cfg,
+        doc(cfg(all(any(feature = "full", feature = "derive"), feature = "printing")))
+    )]
+    pub fn split_for_impl(&self) -> (ImplGenerics, TypeGenerics, Option<&WhereClause>) {
+        (
+            ImplGenerics(self),
+            TypeGenerics(self),
+            self.where_clause.as_ref(),
+        )
+    }
+}
+
+#[cfg(feature = "printing")]
+macro_rules! generics_wrapper_impls {
+    ($ty:ident) => {
+        #[cfg(feature = "clone-impls")]
+        #[cfg_attr(doc_cfg, doc(cfg(feature = "clone-impls")))]
+        impl<'a> Clone for $ty<'a> {
+            fn clone(&self) -> Self {
+                $ty(self.0)
+            }
+        }
+
+        #[cfg(feature = "extra-traits")]
+        #[cfg_attr(doc_cfg, doc(cfg(feature = "extra-traits")))]
+        impl<'a> Debug for $ty<'a> {
+            fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                formatter
+                    .debug_tuple(stringify!($ty))
+                    .field(self.0)
+                    .finish()
+            }
+        }
+
+        #[cfg(feature = "extra-traits")]
+        #[cfg_attr(doc_cfg, doc(cfg(feature = "extra-traits")))]
+        impl<'a> Eq for $ty<'a> {}
+
+        #[cfg(feature = "extra-traits")]
+        #[cfg_attr(doc_cfg, doc(cfg(feature = "extra-traits")))]
+        impl<'a> PartialEq for $ty<'a> {
+            fn eq(&self, other: &Self) -> bool {
+                self.0 == other.0
+            }
+        }
+
+        #[cfg(feature = "extra-traits")]
+        #[cfg_attr(doc_cfg, doc(cfg(feature = "extra-traits")))]
+        impl<'a> Hash for $ty<'a> {
+            fn hash<H: Hasher>(&self, state: &mut H) {
+                self.0.hash(state);
+            }
+        }
+    };
+}
+
+#[cfg(feature = "printing")]
+generics_wrapper_impls!(ImplGenerics);
+#[cfg(feature = "printing")]
+generics_wrapper_impls!(TypeGenerics);
+#[cfg(feature = "printing")]
+generics_wrapper_impls!(Turbofish);
+
+#[cfg(feature = "printing")]
+impl<'a> TypeGenerics<'a> {
+    /// Turn a type's generics like `<X, Y>` into a turbofish like `::<X, Y>`.
+    ///
+    /// *This method is available only if Syn is built with the `"derive"` or
+    /// `"full"` feature and the `"printing"` feature.*
+    pub fn as_turbofish(&self) -> Turbofish {
+        Turbofish(self.0)
+    }
+}
+
+ast_struct! {
+    /// A set of bound lifetimes: `for<'a, 'b, 'c>`.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub struct BoundLifetimes {
+        pub for_token: Token![for],
+        pub lt_token: Token![<],
+        pub lifetimes: Punctuated<LifetimeDef, Token![,]>,
+        pub gt_token: Token![>],
+    }
+}
+
+impl Default for BoundLifetimes {
+    fn default() -> Self {
+        BoundLifetimes {
+            for_token: Default::default(),
+            lt_token: Default::default(),
+            lifetimes: Punctuated::new(),
+            gt_token: Default::default(),
+        }
+    }
+}
+
+impl LifetimeDef {
+    pub fn new(lifetime: Lifetime) -> Self {
+        LifetimeDef {
+            attrs: Vec::new(),
+            lifetime,
+            colon_token: None,
+            bounds: Punctuated::new(),
+        }
+    }
+}
+
+impl From<Ident> for TypeParam {
+    fn from(ident: Ident) -> Self {
+        TypeParam {
+            attrs: vec![],
+            ident,
+            colon_token: None,
+            bounds: Punctuated::new(),
+            eq_token: None,
+            default: None,
+        }
+    }
+}
+
+ast_enum_of_structs! {
+    /// A trait or lifetime used as a bound on a type parameter.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub enum TypeParamBound {
+        Trait(TraitBound),
+        Lifetime(Lifetime),
+    }
+}
+
+ast_struct! {
+    /// A trait used as a bound on a type parameter.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub struct TraitBound {
+        pub paren_token: Option<token::Paren>,
+        pub modifier: TraitBoundModifier,
+        /// The `for<'a>` in `for<'a> Foo<&'a T>`
+        pub lifetimes: Option<BoundLifetimes>,
+        /// The `Foo<&'a T>` in `for<'a> Foo<&'a T>`
+        pub path: Path,
+    }
+}
+
+ast_enum! {
+    /// A modifier on a trait bound, currently only used for the `?` in
+    /// `?Sized`.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub enum TraitBoundModifier {
+        None,
+        Maybe(Token![?]),
+    }
+}
+
+ast_struct! {
+    /// A `where` clause in a definition: `where T: Deserialize<'de>, D:
+    /// 'static`.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub struct WhereClause {
+        pub where_token: Token![where],
+        pub predicates: Punctuated<WherePredicate, Token![,]>,
+    }
+}
+
+ast_enum_of_structs! {
+    /// A single predicate in a `where` clause: `T: Deserialize<'de>`.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    ///
+    /// # Syntax tree enum
+    ///
+    /// This type is a [syntax tree enum].
+    ///
+    /// [syntax tree enum]: Expr#syntax-tree-enums
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub enum WherePredicate {
+        /// A type predicate in a `where` clause: `for<'c> Foo<'c>: Trait<'c>`.
+        Type(PredicateType),
+
+        /// A lifetime predicate in a `where` clause: `'a: 'b + 'c`.
+        Lifetime(PredicateLifetime),
+
+        /// An equality predicate in a `where` clause (unsupported).
+        Eq(PredicateEq),
+    }
+}
+
+ast_struct! {
+    /// A type predicate in a `where` clause: `for<'c> Foo<'c>: Trait<'c>`.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or
+    /// `"full"` feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub struct PredicateType {
+        /// Any lifetimes from a `for` binding
+        pub lifetimes: Option<BoundLifetimes>,
+        /// The type being bounded
+        pub bounded_ty: Type,
+        pub colon_token: Token![:],
+        /// Trait and lifetime bounds (`Clone+Send+'static`)
+        pub bounds: Punctuated<TypeParamBound, Token![+]>,
+    }
+}
+
+ast_struct! {
+    /// A lifetime predicate in a `where` clause: `'a: 'b + 'c`.
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or
+    /// `"full"` feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub struct PredicateLifetime {
+        pub lifetime: Lifetime,
+        pub colon_token: Token![:],
+        pub bounds: Punctuated<Lifetime, Token![+]>,
+    }
+}
+
+ast_struct! {
+    /// An equality predicate in a `where` clause (unsupported).
+    ///
+    /// *This type is available only if Syn is built with the `"derive"` or
+    /// `"full"` feature.*
+    #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+    pub struct PredicateEq {
+        pub lhs_ty: Type,
+        pub eq_token: Token![=],
+        pub rhs_ty: Type,
+    }
+}
+
+#[cfg(feature = "parsing")]
+pub mod parsing {
+    use super::*;
+    use crate::ext::IdentExt;
+    use crate::parse::{Parse, ParseStream, Result};
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for Generics {
+        fn parse(input: ParseStream) -> Result<Self> {
+            if !input.peek(Token![<]) {
+                return Ok(Generics::default());
+            }
+
+            let lt_token: Token![<] = input.parse()?;
+
+            let mut params = Punctuated::new();
+            loop {
+                if input.peek(Token![>]) {
+                    break;
+                }
+
+                let attrs = input.call(Attribute::parse_outer)?;
+                let lookahead = input.lookahead1();
+                if lookahead.peek(Lifetime) {
+                    params.push_value(GenericParam::Lifetime(LifetimeDef {
+                        attrs,
+                        ..input.parse()?
+                    }));
+                } else if lookahead.peek(Ident) {
+                    params.push_value(GenericParam::Type(TypeParam {
+                        attrs,
+                        ..input.parse()?
+                    }));
+                } else if lookahead.peek(Token![const]) {
+                    params.push_value(GenericParam::Const(ConstParam {
+                        attrs,
+                        ..input.parse()?
+                    }));
+                } else if input.peek(Token![_]) {
+                    params.push_value(GenericParam::Type(TypeParam {
+                        attrs,
+                        ident: input.call(Ident::parse_any)?,
+                        colon_token: None,
+                        bounds: Punctuated::new(),
+                        eq_token: None,
+                        default: None,
+                    }));
+                } else {
+                    return Err(lookahead.error());
+                }
+
+                if input.peek(Token![>]) {
+                    break;
+                }
+                let punct = input.parse()?;
+                params.push_punct(punct);
+            }
+
+            let gt_token: Token![>] = input.parse()?;
+
+            Ok(Generics {
+                lt_token: Some(lt_token),
+                params,
+                gt_token: Some(gt_token),
+                where_clause: None,
+            })
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for GenericParam {
+        fn parse(input: ParseStream) -> Result<Self> {
+            let attrs = input.call(Attribute::parse_outer)?;
+
+            let lookahead = input.lookahead1();
+            if lookahead.peek(Ident) {
+                Ok(GenericParam::Type(TypeParam {
+                    attrs,
+                    ..input.parse()?
+                }))
+            } else if lookahead.peek(Lifetime) {
+                Ok(GenericParam::Lifetime(LifetimeDef {
+                    attrs,
+                    ..input.parse()?
+                }))
+            } else if lookahead.peek(Token![const]) {
+                Ok(GenericParam::Const(ConstParam {
+                    attrs,
+                    ..input.parse()?
+                }))
+            } else {
+                Err(lookahead.error())
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for LifetimeDef {
+        fn parse(input: ParseStream) -> Result<Self> {
+            let has_colon;
+            Ok(LifetimeDef {
+                attrs: input.call(Attribute::parse_outer)?,
+                lifetime: input.parse()?,
+                colon_token: {
+                    if input.peek(Token![:]) {
+                        has_colon = true;
+                        Some(input.parse()?)
+                    } else {
+                        has_colon = false;
+                        None
+                    }
+                },
+                bounds: {
+                    let mut bounds = Punctuated::new();
+                    if has_colon {
+                        loop {
+                            if input.peek(Token![,]) || input.peek(Token![>]) {
+                                break;
+                            }
+                            let value = input.parse()?;
+                            bounds.push_value(value);
+                            if !input.peek(Token![+]) {
+                                break;
+                            }
+                            let punct = input.parse()?;
+                            bounds.push_punct(punct);
+                        }
+                    }
+                    bounds
+                },
+            })
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for BoundLifetimes {
+        fn parse(input: ParseStream) -> Result<Self> {
+            Ok(BoundLifetimes {
+                for_token: input.parse()?,
+                lt_token: input.parse()?,
+                lifetimes: {
+                    let mut lifetimes = Punctuated::new();
+                    while !input.peek(Token![>]) {
+                        lifetimes.push_value(input.parse()?);
+                        if input.peek(Token![>]) {
+                            break;
+                        }
+                        lifetimes.push_punct(input.parse()?);
+                    }
+                    lifetimes
+                },
+                gt_token: input.parse()?,
+            })
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for Option<BoundLifetimes> {
+        fn parse(input: ParseStream) -> Result<Self> {
+            if input.peek(Token![for]) {
+                input.parse().map(Some)
+            } else {
+                Ok(None)
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for TypeParam {
+        fn parse(input: ParseStream) -> Result<Self> {
+            let attrs = input.call(Attribute::parse_outer)?;
+            let ident: Ident = input.parse()?;
+            let colon_token: Option<Token![:]> = input.parse()?;
+
+            let begin_bound = input.fork();
+            let mut is_maybe_const = false;
+            let mut bounds = Punctuated::new();
+            if colon_token.is_some() {
+                loop {
+                    if input.peek(Token![,]) || input.peek(Token![>]) || input.peek(Token![=]) {
+                        break;
+                    }
+                    if input.peek(Token![~]) && input.peek2(Token![const]) {
+                        input.parse::<Token![~]>()?;
+                        input.parse::<Token![const]>()?;
+                        is_maybe_const = true;
+                    }
+                    let value: TypeParamBound = input.parse()?;
+                    bounds.push_value(value);
+                    if !input.peek(Token![+]) {
+                        break;
+                    }
+                    let punct: Token![+] = input.parse()?;
+                    bounds.push_punct(punct);
+                }
+            }
+
+            let mut eq_token: Option<Token![=]> = input.parse()?;
+            let mut default = if eq_token.is_some() {
+                Some(input.parse::<Type>()?)
+            } else {
+                None
+            };
+
+            if is_maybe_const {
+                bounds.clear();
+                eq_token = None;
+                default = Some(Type::Verbatim(verbatim::between(begin_bound, input)));
+            }
+
+            Ok(TypeParam {
+                attrs,
+                ident,
+                colon_token,
+                bounds,
+                eq_token,
+                default,
+            })
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for TypeParamBound {
+        fn parse(input: ParseStream) -> Result<Self> {
+            if input.peek(Lifetime) {
+                return input.parse().map(TypeParamBound::Lifetime);
+            }
+
+            if input.peek(token::Paren) {
+                let content;
+                let paren_token = parenthesized!(content in input);
+                let mut bound: TraitBound = content.parse()?;
+                bound.paren_token = Some(paren_token);
+                return Ok(TypeParamBound::Trait(bound));
+            }
+
+            input.parse().map(TypeParamBound::Trait)
+        }
+    }
+
+    impl TypeParamBound {
+        pub(crate) fn parse_multiple(
+            input: ParseStream,
+            allow_plus: bool,
+        ) -> Result<Punctuated<Self, Token![+]>> {
+            let mut bounds = Punctuated::new();
+            loop {
+                bounds.push_value(input.parse()?);
+                if !(allow_plus && input.peek(Token![+])) {
+                    break;
+                }
+                bounds.push_punct(input.parse()?);
+                if !(input.peek(Ident::peek_any)
+                    || input.peek(Token![::])
+                    || input.peek(Token![?])
+                    || input.peek(Lifetime)
+                    || input.peek(token::Paren))
+                {
+                    break;
+                }
+            }
+            Ok(bounds)
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for TraitBound {
+        fn parse(input: ParseStream) -> Result<Self> {
+            #[cfg(feature = "full")]
+            let tilde_const = if input.peek(Token![~]) && input.peek2(Token![const]) {
+                let tilde_token = input.parse::<Token![~]>()?;
+                let const_token = input.parse::<Token![const]>()?;
+                Some((tilde_token, const_token))
+            } else {
+                None
+            };
+
+            let modifier: TraitBoundModifier = input.parse()?;
+            let lifetimes: Option<BoundLifetimes> = input.parse()?;
+
+            let mut path: Path = input.parse()?;
+            if path.segments.last().unwrap().arguments.is_empty()
+                && (input.peek(token::Paren) || input.peek(Token![::]) && input.peek3(token::Paren))
+            {
+                input.parse::<Option<Token![::]>>()?;
+                let args: ParenthesizedGenericArguments = input.parse()?;
+                let parenthesized = PathArguments::Parenthesized(args);
+                path.segments.last_mut().unwrap().arguments = parenthesized;
+            }
+
+            #[cfg(feature = "full")]
+            {
+                if let Some((tilde_token, const_token)) = tilde_const {
+                    path.segments.insert(
+                        0,
+                        PathSegment {
+                            ident: Ident::new("const", const_token.span),
+                            arguments: PathArguments::None,
+                        },
+                    );
+                    let (_const, punct) = path.segments.pairs_mut().next().unwrap().into_tuple();
+                    *punct.unwrap() = Token![::](tilde_token.span);
+                }
+            }
+
+            Ok(TraitBound {
+                paren_token: None,
+                modifier,
+                lifetimes,
+                path,
+            })
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for TraitBoundModifier {
+        fn parse(input: ParseStream) -> Result<Self> {
+            if input.peek(Token![?]) {
+                input.parse().map(TraitBoundModifier::Maybe)
+            } else {
+                Ok(TraitBoundModifier::None)
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for ConstParam {
+        fn parse(input: ParseStream) -> Result<Self> {
+            let mut default = None;
+            Ok(ConstParam {
+                attrs: input.call(Attribute::parse_outer)?,
+                const_token: input.parse()?,
+                ident: input.parse()?,
+                colon_token: input.parse()?,
+                ty: input.parse()?,
+                eq_token: {
+                    if input.peek(Token![=]) {
+                        let eq_token = input.parse()?;
+                        default = Some(path::parsing::const_argument(input)?);
+                        Some(eq_token)
+                    } else {
+                        None
+                    }
+                },
+                default,
+            })
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for WhereClause {
+        fn parse(input: ParseStream) -> Result<Self> {
+            Ok(WhereClause {
+                where_token: input.parse()?,
+                predicates: {
+                    let mut predicates = Punctuated::new();
+                    loop {
+                        if input.is_empty()
+                            || input.peek(token::Brace)
+                            || input.peek(Token![,])
+                            || input.peek(Token![;])
+                            || input.peek(Token![:]) && !input.peek(Token![::])
+                            || input.peek(Token![=])
+                        {
+                            break;
+                        }
+                        let value = input.parse()?;
+                        predicates.push_value(value);
+                        if !input.peek(Token![,]) {
+                            break;
+                        }
+                        let punct = input.parse()?;
+                        predicates.push_punct(punct);
+                    }
+                    predicates
+                },
+            })
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for Option<WhereClause> {
+        fn parse(input: ParseStream) -> Result<Self> {
+            if input.peek(Token![where]) {
+                input.parse().map(Some)
+            } else {
+                Ok(None)
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+    impl Parse for WherePredicate {
+        fn parse(input: ParseStream) -> Result<Self> {
+            if input.peek(Lifetime) && input.peek2(Token![:]) {
+                Ok(WherePredicate::Lifetime(PredicateLifetime {
+                    lifetime: input.parse()?,
+                    colon_token: input.parse()?,
+                    bounds: {
+                        let mut bounds = Punctuated::new();
+                        loop {
+                            if input.is_empty()
+                                || input.peek(token::Brace)
+                                || input.peek(Token![,])
+                                || input.peek(Token![;])
+                                || input.peek(Token![:])
+                                || input.peek(Token![=])
+                            {
+                                break;
+                            }
+                            let value = input.parse()?;
+                            bounds.push_value(value);
+                            if !input.peek(Token![+]) {
+                                break;
+                            }
+                            let punct = input.parse()?;
+                            bounds.push_punct(punct);
+                        }
+                        bounds
+                    },
+                }))
+            } else {
+                Ok(WherePredicate::Type(PredicateType {
+                    lifetimes: input.parse()?,
+                    bounded_ty: input.parse()?,
+                    colon_token: input.parse()?,
+                    bounds: {
+                        let mut bounds = Punctuated::new();
+                        loop {
+                            if input.is_empty()
+                                || input.peek(token::Brace)
+                                || input.peek(Token![,])
+                                || input.peek(Token![;])
+                                || input.peek(Token![:]) && !input.peek(Token![::])
+                                || input.peek(Token![=])
+                            {
+                                break;
+                            }
+                            let value = input.parse()?;
+                            bounds.push_value(value);
+                            if !input.peek(Token![+]) {
+                                break;
+                            }
+                            let punct = input.parse()?;
+                            bounds.push_punct(punct);
+                        }
+                        bounds
+                    },
+                }))
+            }
+        }
+    }
+}
+
+#[cfg(feature = "printing")]
+mod printing {
+    use super::*;
+    use crate::attr::FilterAttrs;
+    use crate::print::TokensOrDefault;
+    #[cfg(feature = "full")]
+    use crate::punctuated::Pair;
+    use proc_macro2::TokenStream;
+    #[cfg(feature = "full")]
+    use proc_macro2::TokenTree;
+    use quote::{ToTokens, TokenStreamExt};
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for Generics {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            if self.params.is_empty() {
+                return;
+            }
+
+            TokensOrDefault(&self.lt_token).to_tokens(tokens);
+
+            // Print lifetimes before types and consts, regardless of their
+            // order in self.params.
+            //
+            // TODO: ordering rules for const parameters vs type parameters have
+            // not been settled yet. https://github.com/rust-lang/rust/issues/44580
+            let mut trailing_or_empty = true;
+            for param in self.params.pairs() {
+                if let GenericParam::Lifetime(_) = **param.value() {
+                    param.to_tokens(tokens);
+                    trailing_or_empty = param.punct().is_some();
+                }
+            }
+            for param in self.params.pairs() {
+                match **param.value() {
+                    GenericParam::Type(_) | GenericParam::Const(_) => {
+                        if !trailing_or_empty {
+                            <Token![,]>::default().to_tokens(tokens);
+                            trailing_or_empty = true;
+                        }
+                        param.to_tokens(tokens);
+                    }
+                    GenericParam::Lifetime(_) => {}
+                }
+            }
+
+            TokensOrDefault(&self.gt_token).to_tokens(tokens);
+        }
+    }
+
+    impl<'a> ToTokens for ImplGenerics<'a> {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            if self.0.params.is_empty() {
+                return;
+            }
+
+            TokensOrDefault(&self.0.lt_token).to_tokens(tokens);
+
+            // Print lifetimes before types and consts, regardless of their
+            // order in self.params.
+            //
+            // TODO: ordering rules for const parameters vs type parameters have
+            // not been settled yet. https://github.com/rust-lang/rust/issues/44580
+            let mut trailing_or_empty = true;
+            for param in self.0.params.pairs() {
+                if let GenericParam::Lifetime(_) = **param.value() {
+                    param.to_tokens(tokens);
+                    trailing_or_empty = param.punct().is_some();
+                }
+            }
+            for param in self.0.params.pairs() {
+                if let GenericParam::Lifetime(_) = **param.value() {
+                    continue;
+                }
+                if !trailing_or_empty {
+                    <Token![,]>::default().to_tokens(tokens);
+                    trailing_or_empty = true;
+                }
+                match *param.value() {
+                    GenericParam::Lifetime(_) => unreachable!(),
+                    GenericParam::Type(param) => {
+                        // Leave off the type parameter defaults
+                        tokens.append_all(param.attrs.outer());
+                        param.ident.to_tokens(tokens);
+                        if !param.bounds.is_empty() {
+                            TokensOrDefault(&param.colon_token).to_tokens(tokens);
+                            param.bounds.to_tokens(tokens);
+                        }
+                    }
+                    GenericParam::Const(param) => {
+                        // Leave off the const parameter defaults
+                        tokens.append_all(param.attrs.outer());
+                        param.const_token.to_tokens(tokens);
+                        param.ident.to_tokens(tokens);
+                        param.colon_token.to_tokens(tokens);
+                        param.ty.to_tokens(tokens);
+                    }
+                }
+                param.punct().to_tokens(tokens);
+            }
+
+            TokensOrDefault(&self.0.gt_token).to_tokens(tokens);
+        }
+    }
+
+    impl<'a> ToTokens for TypeGenerics<'a> {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            if self.0.params.is_empty() {
+                return;
+            }
+
+            TokensOrDefault(&self.0.lt_token).to_tokens(tokens);
+
+            // Print lifetimes before types and consts, regardless of their
+            // order in self.params.
+            //
+            // TODO: ordering rules for const parameters vs type parameters have
+            // not been settled yet. https://github.com/rust-lang/rust/issues/44580
+            let mut trailing_or_empty = true;
+            for param in self.0.params.pairs() {
+                if let GenericParam::Lifetime(def) = *param.value() {
+                    // Leave off the lifetime bounds and attributes
+                    def.lifetime.to_tokens(tokens);
+                    param.punct().to_tokens(tokens);
+                    trailing_or_empty = param.punct().is_some();
+                }
+            }
+            for param in self.0.params.pairs() {
+                if let GenericParam::Lifetime(_) = **param.value() {
+                    continue;
+                }
+                if !trailing_or_empty {
+                    <Token![,]>::default().to_tokens(tokens);
+                    trailing_or_empty = true;
+                }
+                match *param.value() {
+                    GenericParam::Lifetime(_) => unreachable!(),
+                    GenericParam::Type(param) => {
+                        // Leave off the type parameter defaults
+                        param.ident.to_tokens(tokens);
+                    }
+                    GenericParam::Const(param) => {
+                        // Leave off the const parameter defaults
+                        param.ident.to_tokens(tokens);
+                    }
+                }
+                param.punct().to_tokens(tokens);
+            }
+
+            TokensOrDefault(&self.0.gt_token).to_tokens(tokens);
+        }
+    }
+
+    impl<'a> ToTokens for Turbofish<'a> {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            if !self.0.params.is_empty() {
+                <Token![::]>::default().to_tokens(tokens);
+                TypeGenerics(self.0).to_tokens(tokens);
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for BoundLifetimes {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            self.for_token.to_tokens(tokens);
+            self.lt_token.to_tokens(tokens);
+            self.lifetimes.to_tokens(tokens);
+            self.gt_token.to_tokens(tokens);
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for LifetimeDef {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            tokens.append_all(self.attrs.outer());
+            self.lifetime.to_tokens(tokens);
+            if !self.bounds.is_empty() {
+                TokensOrDefault(&self.colon_token).to_tokens(tokens);
+                self.bounds.to_tokens(tokens);
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for TypeParam {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            tokens.append_all(self.attrs.outer());
+            self.ident.to_tokens(tokens);
+            if !self.bounds.is_empty() {
+                TokensOrDefault(&self.colon_token).to_tokens(tokens);
+                self.bounds.to_tokens(tokens);
+            }
+            if let Some(default) = &self.default {
+                #[cfg(feature = "full")]
+                {
+                    if self.eq_token.is_none() {
+                        if let Type::Verbatim(default) = default {
+                            let mut iter = default.clone().into_iter().peekable();
+                            while let Some(token) = iter.next() {
+                                if let TokenTree::Punct(q) = token {
+                                    if q.as_char() == '~' {
+                                        if let Some(TokenTree::Ident(c)) = iter.peek() {
+                                            if c == "const" {
+                                                if self.bounds.is_empty() {
+                                                    TokensOrDefault(&self.colon_token)
+                                                        .to_tokens(tokens);
+                                                }
+                                                return default.to_tokens(tokens);
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+                TokensOrDefault(&self.eq_token).to_tokens(tokens);
+                default.to_tokens(tokens);
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for TraitBound {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            let to_tokens = |tokens: &mut TokenStream| {
+                #[cfg(feature = "full")]
+                let skip = match self.path.segments.pairs().next() {
+                    Some(Pair::Punctuated(t, p)) if t.ident == "const" => {
+                        Token![~](p.spans[0]).to_tokens(tokens);
+                        t.to_tokens(tokens);
+                        1
+                    }
+                    _ => 0,
+                };
+                self.modifier.to_tokens(tokens);
+                self.lifetimes.to_tokens(tokens);
+                #[cfg(feature = "full")]
+                {
+                    self.path.leading_colon.to_tokens(tokens);
+                    tokens.append_all(self.path.segments.pairs().skip(skip));
+                }
+                #[cfg(not(feature = "full"))]
+                {
+                    self.path.to_tokens(tokens);
+                }
+            };
+            match &self.paren_token {
+                Some(paren) => paren.surround(tokens, to_tokens),
+                None => to_tokens(tokens),
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for TraitBoundModifier {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            match self {
+                TraitBoundModifier::None => {}
+                TraitBoundModifier::Maybe(t) => t.to_tokens(tokens),
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for ConstParam {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            tokens.append_all(self.attrs.outer());
+            self.const_token.to_tokens(tokens);
+            self.ident.to_tokens(tokens);
+            self.colon_token.to_tokens(tokens);
+            self.ty.to_tokens(tokens);
+            if let Some(default) = &self.default {
+                TokensOrDefault(&self.eq_token).to_tokens(tokens);
+                default.to_tokens(tokens);
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for WhereClause {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            if !self.predicates.is_empty() {
+                self.where_token.to_tokens(tokens);
+                self.predicates.to_tokens(tokens);
+            }
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for PredicateType {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            self.lifetimes.to_tokens(tokens);
+            self.bounded_ty.to_tokens(tokens);
+            self.colon_token.to_tokens(tokens);
+            self.bounds.to_tokens(tokens);
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for PredicateLifetime {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            self.lifetime.to_tokens(tokens);
+            self.colon_token.to_tokens(tokens);
+            self.bounds.to_tokens(tokens);
+        }
+    }
+
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+    impl ToTokens for PredicateEq {
+        fn to_tokens(&self, tokens: &mut TokenStream) {
+            self.lhs_ty.to_tokens(tokens);
+            self.eq_token.to_tokens(tokens);
+            self.rhs_ty.to_tokens(tokens);
+        }
+    }
+}