From 22098763a10d9c1340827fcf6edab66f153b27f0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 13 Sep 2026 12:27:00 -0700 Subject: Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Don't destroy user event fields when removal fails User event fields are destroyed before the event is removed from visibility. But that can fail leaving the still visible event with no fields. Move the destroying of the fields to after the event is successfully removed from visibility. - Initialize function graph state is fork before calling copy_exec_state() For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state. If that allocation fails, ftrace_graph_exit_task() will free the tasks ret_stack pointer. Since that pointer is still using the parent's ret_stack, it mistakenly frees the parent's pointer too. Call ftrace_graph_init() on the task first which will NULL out the new tasks's ret_stack and if the copy fails, it will not free anything. - Remove FGRAPH_MAX_INDEX The macro FGRAPH_MAX_INDEX was added but never used. Remove it. - Save ent_size in function graph printing of nested functions The function graph tracer needs to look at the next event to see if the next event is the return of the current function entry. If it is, it prints a single line: ktime_get(); Otherwise it prints it like a nested function: tick_nohz_irq_exit() { ktime_get(); kcpustat_irq_exit(); } In order to look at the next event, it must save the current event so that it has the information to print from it. It saves the event in the iterator descriptor called "ent". What it doesn't save is the ent_size of the event which is now used to know if the function graph arguments are to be printed. The peek doesn't save the size so the size used happens to be that of the size of the last event that was seen. Save the entry event size in the iterator descriptor so that the correct size is used. - Fix several errors with freeing data in the histogram code The histogram code had a lot of leaked or or incorrect accounting when failures happen. Correct them. - Fix histogram regression of .percent and .graph modifiers Up until 6.3 histogram values could have "percent" or "graph" modifiers that changed how they were printed. But a change that added restricting histograms values from being strings, stack traces and other modifiers inadvertently prevented them from using the percent and graph modifiers, which were legal use cases for values. Put back the percent and graph modifiers. - Fix various typos in the comments - Set the trace_clock before initializing a histogram with clock argument The histogram API allows the user to specific which trace clock to use via a "clock=" string. The histogram is set up first before the clock is checked. If the passed in clock is not valid, it exits without fully fixing up the histogram leaving it on the list and a use-after-free can trigger. Update the clock argument first and if it fails then exit gracefully before the histogram trigger is placed on any lists. - Restore :mod: trailer after parsing in ftrace_set_clr_event The function ftrace_set_clr_event() modifies the parse string and needs to put it back to what was passed in. It searches for ":mod:" via a strsep() but fails to put back the first ':' in the string. Add back the ':' in the passed in string. - Take trace_array reference when opening a tracer options file The options files are dynamically created and some tracers add their own options. When a tracer adds their own list of options, the trace_array holding them has an array to hold the list of options for each tracer. This array increases in size via a krealloc(), and the new entry gets a newly allocated array to hold the options of the new tracer being added. The element in each entry of the tracer's option array holds a pointer back to the trace_array, a pointer to the tracer it is associated to, a pointer to the flags of the option. The issue is that these arrays are freed when the trace_array is freed when its instance it represents is removed from the instances directory. There's a race that an open of one of these options files can happen when the instance is being removed. Add a new helper function to be called by the open function of the options file to iterate all existing trace_arrays under a lock and find the one that has the given option element in one of it's tracer arrays. If found, then update the associated trace_array's reference counter to keep it from being freed. If not found, have the open call return -ENODEV. - Disable interrupts when acquiring the lock in rb_wake_up_waiters() The function rb_wake_up_waiters() assumes it will be called in interrupt context and does not disable irqs when taking cpu_buffer->reader_lock, which can be called in hard interrupt context. The issue is in PREEMPT_RT, this function is called in thread context leaving this lock open to a deadlock. Take the lock with interrupts disabled. - Use rcu_assign_pointer() for tmp_ops filter hash The tmp_ops used in update_ftrace_direct_mod() assigns its filter_hash field directly, but that field is annotated as __rcu and sparse complains. Assign it with rcu_assign_pointer() - Fix use-after-free in enable_trigger_private_data_free() The trace_event_call is accessed through the event_trigger_data's trace_event_file pointer to put the trace_event_call on freeing. The issue is that the trace_event_file data may have been freed already causing a use-after-free. Add a field to the event_trigger_data that points directly to the trace_event_call so that it can decrement its reference directly without needing to go through the trace_event_file. - Fix accounting of buffer data remote headers trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount the number of pages is needed for the asked for size as it doesn't take into account the meta data on each page. Add a helper function to do the calculation properly and use that in these functions. - Catch nr_page_va overflow in ring_buffer_desc sizing The number of pages per remote ring buffer is capped by ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to overflow that field would silently allocate a descriptor smaller than what was asked for. - Do not resize the subbuf order if any per_cpu buffer is disabled The mmapping of ring buffers disables resizing the subbuffers, but it is done per-cpu whereas the subbuf size change is done for all the per_cpu buffers under the buffer->mutex. It could change the size of some while the mapping is happening on others. Have the resize of the subbuf order check all the per_cpu buffers under the lock to see if any of them is disabled before starting and causing an inconsistency between buffers that are being mapped. * tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits) ring-buffer: Check resize_disabled before publishing the new subbuf order tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing tracing/remotes: Account for ring buffer page header in size calculation tracing: Don't dereference trace_event_file in deferred trigger free ftrace: Use rcu_assign_pointer() for tmp_ops filter hash ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters() tracing: Take trace_array reference when opening a tracer options file tracing: Fix ring_buffer_read_page_size() kernel-doc tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event() tracing: Fix memory corruption from a "STACKTRACE" histogram key tracing: Fix memory corruption from the histogram stacktrace modifier tracing: Undo the registration when enabling the histogram trigger fails tracing: Take the reference before publishing the named histogram trigger tracing: Set the trace clock before registering the histogram trigger tracing: Fix typo "preceeded" in comment tracing: Fix typo "availabe" in comment tracing: Let histogram values keep the percent and graph modifiers tracing: Keep the entry count when the histogram stats allocation fails tracing: Free histogram the field rejected for a bad modifier tracing: Free histogram the var ref when its initialization fails ... --- rust/syn/generics.rs | 1479 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1479 insertions(+) create mode 100644 rust/syn/generics.rs (limited to 'rust/syn/generics.rs') diff --git a/rust/syn/generics.rs b/rust/syn/generics.rs new file mode 100644 index 000000000..9f8df8a15 --- /dev/null +++ b/rust/syn/generics.rs @@ -0,0 +1,1479 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +use crate::attr::Attribute; +use crate::expr::Expr; +use crate::ident::Ident; +use crate::lifetime::Lifetime; +use crate::path::Path; +use crate::punctuated::{Iter, IterMut, Punctuated}; +use crate::token; +use crate::ty::Type; +use proc_macro2::TokenStream; +#[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 struct represents two distinct optional syntactic elements, + /// [generic parameters] and [where clause]. In some locations of the + /// grammar, there may be other tokens in between these two things. + /// + /// [generic parameters]: https://doc.rust-lang.org/stable/reference/items/generics.html#generic-parameters + /// [where clause]: https://doc.rust-lang.org/stable/reference/items/generics.html#where-clauses + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct Generics { + pub lt_token: Option, + pub params: Punctuated, + pub gt_token: Option]>, + pub where_clause: Option, + } +} + +ast_enum_of_structs! { + /// A generic type parameter, lifetime, or const generic: `T: Into`, + /// `'a: 'b`, `const LEN: usize`. + /// + /// # Syntax tree enum + /// + /// This type is a [syntax tree enum]. + /// + /// [syntax tree enum]: crate::expr::Expr#syntax-tree-enums + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub enum GenericParam { + /// A lifetime parameter: `'a: 'b + 'c + 'd`. + Lifetime(LifetimeParam), + + /// A generic type parameter: `T: Into`. + Type(TypeParam), + + /// A const generic parameter: `const LENGTH: usize`. + Const(ConstParam), + } +} + +ast_struct! { + /// A lifetime definition: `'a: 'b + 'c + 'd`. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct LifetimeParam { + pub attrs: Vec, + pub lifetime: Lifetime, + pub colon_token: Option, + pub bounds: Punctuated, + } +} + +ast_struct! { + /// A generic type parameter: `T: Into`. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct TypeParam { + pub attrs: Vec, + pub ident: Ident, + pub colon_token: Option, + pub bounds: Punctuated, + pub eq_token: Option, + pub default: Option, + } +} + +ast_struct! { + /// A const generic parameter: `const LENGTH: usize`. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ConstParam { + pub attrs: Vec, + pub const_token: Token![const], + pub ident: Ident, + pub colon_token: Token![:], + pub ty: Type, + pub eq_token: Option, + pub default: Option, + } +} + +impl Default for Generics { + fn default() -> Self { + Generics { + lt_token: None, + params: Punctuated::new(), + gt_token: None, + where_clause: None, + } + } +} + +impl Generics { + return_impl_trait! { + /// Iterator over the lifetime parameters in `self.params`. + pub fn lifetimes(&self) -> impl Iterator [Lifetimes] { + Lifetimes(self.params.iter()) + } + } + + return_impl_trait! { + /// Iterator over the lifetime parameters in `self.params`. + pub fn lifetimes_mut(&mut self) -> impl Iterator [LifetimesMut] { + LifetimesMut(self.params.iter_mut()) + } + } + + return_impl_trait! { + /// Iterator over the type parameters in `self.params`. + pub fn type_params(&self) -> impl Iterator [TypeParams] { + TypeParams(self.params.iter()) + } + } + + return_impl_trait! { + /// Iterator over the type parameters in `self.params`. + pub fn type_params_mut(&mut self) -> impl Iterator [TypeParamsMut] { + TypeParamsMut(self.params.iter_mut()) + } + } + + return_impl_trait! { + /// Iterator over the constant parameters in `self.params`. + pub fn const_params(&self) -> impl Iterator [ConstParams] { + ConstParams(self.params.iter()) + } + } + + return_impl_trait! { + /// Iterator over the constant parameters in `self.params`. + pub fn const_params_mut(&mut self) -> impl Iterator [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: ::default(), + predicates: Punctuated::new(), + }) + } + + /// 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 { + /// // ... + /// } + /// } + /// # ; + /// ``` + #[cfg(feature = "printing")] + #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] + pub fn split_for_impl(&self) -> (ImplGenerics, TypeGenerics, Option<&WhereClause>) { + ( + ImplGenerics(self), + TypeGenerics(self), + self.where_clause.as_ref(), + ) + } +} + +pub struct Lifetimes<'a>(Iter<'a, GenericParam>); + +impl<'a> Iterator for Lifetimes<'a> { + type Item = &'a LifetimeParam; + + fn next(&mut self) -> Option { + if let GenericParam::Lifetime(lifetime) = self.0.next()? { + Some(lifetime) + } else { + self.next() + } + } +} + +pub struct LifetimesMut<'a>(IterMut<'a, GenericParam>); + +impl<'a> Iterator for LifetimesMut<'a> { + type Item = &'a mut LifetimeParam; + + fn next(&mut self) -> Option { + if let GenericParam::Lifetime(lifetime) = self.0.next()? { + Some(lifetime) + } else { + self.next() + } + } +} + +pub struct TypeParams<'a>(Iter<'a, GenericParam>); + +impl<'a> Iterator for TypeParams<'a> { + type Item = &'a TypeParam; + + fn next(&mut self) -> Option { + if let GenericParam::Type(type_param) = self.0.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 { + if let GenericParam::Type(type_param) = self.0.next()? { + Some(type_param) + } 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 { + if let GenericParam::Const(const_param) = self.0.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 { + if let GenericParam::Const(const_param) = self.0.next()? { + Some(const_param) + } else { + self.next() + } + } +} + +/// Returned by `Generics::split_for_impl`. +#[cfg(feature = "printing")] +#[cfg_attr( + docsrs, + doc(cfg(all(any(feature = "full", feature = "derive"), feature = "printing"))) +)] +pub struct ImplGenerics<'a>(&'a Generics); + +/// Returned by `Generics::split_for_impl`. +#[cfg(feature = "printing")] +#[cfg_attr( + docsrs, + doc(cfg(all(any(feature = "full", feature = "derive"), feature = "printing"))) +)] +pub struct TypeGenerics<'a>(&'a Generics); + +/// Returned by `TypeGenerics::as_turbofish`. +#[cfg(feature = "printing")] +#[cfg_attr( + docsrs, + doc(cfg(all(any(feature = "full", feature = "derive"), feature = "printing"))) +)] +pub struct Turbofish<'a>(&'a Generics); + +#[cfg(feature = "printing")] +macro_rules! generics_wrapper_impls { + ($ty:ident) => { + #[cfg(feature = "clone-impls")] + #[cfg_attr(docsrs, doc(cfg(feature = "clone-impls")))] + impl<'a> Clone for $ty<'a> { + fn clone(&self) -> Self { + $ty(self.0) + } + } + + #[cfg(feature = "extra-traits")] + #[cfg_attr(docsrs, 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(docsrs, doc(cfg(feature = "extra-traits")))] + impl<'a> Eq for $ty<'a> {} + + #[cfg(feature = "extra-traits")] + #[cfg_attr(docsrs, 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(docsrs, doc(cfg(feature = "extra-traits")))] + impl<'a> Hash for $ty<'a> { + fn hash(&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 `` into a turbofish like `::`. + pub fn as_turbofish(&self) -> Turbofish<'a> { + Turbofish(self.0) + } +} + +ast_struct! { + /// A set of bound lifetimes: `for<'a, 'b, 'c>`. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct BoundLifetimes { + pub for_token: Token![for], + pub lt_token: Token![<], + pub lifetimes: Punctuated, + 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 LifetimeParam { + pub fn new(lifetime: Lifetime) -> Self { + LifetimeParam { + attrs: Vec::new(), + lifetime, + colon_token: None, + bounds: Punctuated::new(), + } + } +} + +impl From 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. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + #[non_exhaustive] + pub enum TypeParamBound { + Trait(TraitBound), + Lifetime(Lifetime), + PreciseCapture(PreciseCapture), + Verbatim(TokenStream), + } +} + +ast_struct! { + /// A trait used as a bound on a type parameter. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct TraitBound { + pub paren_token: Option, + pub modifier: TraitBoundModifier, + /// The `for<'a>` in `for<'a> Foo<&'a T>` + pub lifetimes: Option, + /// 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`. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub enum TraitBoundModifier { + None, + Maybe(Token![?]), + } +} + +ast_struct! { + /// Precise capturing bound: the 'use<…>' in `impl Trait + + /// use<'a, T>`. + #[cfg_attr(docsrs, doc(cfg(feature = "full")))] + pub struct PreciseCapture #full { + pub use_token: Token![use], + pub lt_token: Token![<], + pub params: Punctuated, + pub gt_token: Token![>], + } +} + +#[cfg(feature = "full")] +ast_enum! { + /// Single parameter in a precise capturing bound. + #[cfg_attr(docsrs, doc(cfg(feature = "full")))] + #[non_exhaustive] + pub enum CapturedParam { + /// A lifetime parameter in precise capturing bound: `fn f<'a>() -> impl + /// Trait + use<'a>`. + Lifetime(Lifetime), + /// A type parameter or const generic parameter in precise capturing + /// bound: `fn f() -> impl Trait + use` or `fn f() -> + /// impl Trait + use`. + Ident(Ident), + } +} + +ast_struct! { + /// A `where` clause in a definition: `where T: Deserialize<'de>, D: + /// 'static`. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct WhereClause { + pub where_token: Token![where], + pub predicates: Punctuated, + } +} + +ast_enum_of_structs! { + /// A single predicate in a `where` clause: `T: Deserialize<'de>`. + /// + /// # Syntax tree enum + /// + /// This type is a [syntax tree enum]. + /// + /// [syntax tree enum]: crate::expr::Expr#syntax-tree-enums + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + #[non_exhaustive] + pub enum WherePredicate { + /// A lifetime predicate in a `where` clause: `'a: 'b + 'c`. + Lifetime(PredicateLifetime), + + /// A type predicate in a `where` clause: `for<'c> Foo<'c>: Trait<'c>`. + Type(PredicateType), + } +} + +ast_struct! { + /// A lifetime predicate in a `where` clause: `'a: 'b + 'c`. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct PredicateLifetime { + pub lifetime: Lifetime, + pub colon_token: Token![:], + pub bounds: Punctuated, + } +} + +ast_struct! { + /// A type predicate in a `where` clause: `for<'c> Foo<'c>: Trait<'c>`. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct PredicateType { + /// Any lifetimes from a `for` binding + pub lifetimes: Option, + /// The type being bounded + pub bounded_ty: Type, + pub colon_token: Token![:], + /// Trait and lifetime bounds (`Clone+Send+'static`) + pub bounds: Punctuated, + } +} + +#[cfg(feature = "parsing")] +pub(crate) mod parsing { + use crate::attr::Attribute; + #[cfg(feature = "full")] + use crate::error; + use crate::error::{Error, Result}; + use crate::ext::IdentExt as _; + use crate::generics::{ + BoundLifetimes, ConstParam, GenericParam, Generics, LifetimeParam, PredicateLifetime, + PredicateType, TraitBound, TraitBoundModifier, TypeParam, TypeParamBound, WhereClause, + WherePredicate, + }; + #[cfg(feature = "full")] + use crate::generics::{CapturedParam, PreciseCapture}; + use crate::ident::Ident; + use crate::lifetime::Lifetime; + use crate::parse::{Parse, ParseStream}; + use crate::path::{self, ParenthesizedGenericArguments, Path, PathArguments}; + use crate::punctuated::Punctuated; + use crate::token; + use crate::ty::Type; + use crate::verbatim; + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for Generics { + fn parse(input: ParseStream) -> Result { + 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(LifetimeParam { + 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(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for GenericParam { + fn parse(input: ParseStream) -> Result { + 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(LifetimeParam { + attrs, + ..input.parse()? + })) + } else if lookahead.peek(Token![const]) { + Ok(GenericParam::Const(ConstParam { + attrs, + ..input.parse()? + })) + } else { + Err(lookahead.error()) + } + } + } + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for LifetimeParam { + fn parse(input: ParseStream) -> Result { + let has_colon; + Ok(LifetimeParam { + 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(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for BoundLifetimes { + fn parse(input: ParseStream) -> Result { + 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(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for Option { + fn parse(input: ParseStream) -> Result { + if input.peek(Token![for]) { + input.parse().map(Some) + } else { + Ok(None) + } + } + } + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for TypeParam { + fn parse(input: ParseStream) -> Result { + let attrs = input.call(Attribute::parse_outer)?; + let ident: Ident = input.parse()?; + let colon_token: Option = input.parse()?; + + let mut bounds = Punctuated::new(); + if colon_token.is_some() { + loop { + if input.peek(Token![,]) || input.peek(Token![>]) || input.peek(Token![=]) { + break; + } + bounds.push_value({ + let allow_precise_capture = false; + let allow_const = true; + TypeParamBound::parse_single(input, allow_precise_capture, allow_const)? + }); + if !input.peek(Token![+]) { + break; + } + let punct: Token![+] = input.parse()?; + bounds.push_punct(punct); + } + } + + let eq_token: Option = input.parse()?; + let default = if eq_token.is_some() { + Some(input.parse::()?) + } else { + None + }; + + Ok(TypeParam { + attrs, + ident, + colon_token, + bounds, + eq_token, + default, + }) + } + } + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for TypeParamBound { + fn parse(input: ParseStream) -> Result { + let allow_precise_capture = true; + let allow_const = true; + Self::parse_single(input, allow_precise_capture, allow_const) + } + } + + impl TypeParamBound { + pub(crate) fn parse_single( + input: ParseStream, + #[cfg_attr(not(feature = "full"), allow(unused_variables))] allow_precise_capture: bool, + allow_const: bool, + ) -> Result { + if input.peek(Lifetime) { + return input.parse().map(TypeParamBound::Lifetime); + } + + #[cfg(feature = "full")] + { + if input.peek(Token![use]) { + let precise_capture: PreciseCapture = input.parse()?; + return if allow_precise_capture { + Ok(TypeParamBound::PreciseCapture(precise_capture)) + } else { + let msg = "`use<...>` precise capturing syntax is not allowed here"; + Err(error::new2( + precise_capture.use_token.span, + precise_capture.gt_token.span, + msg, + )) + }; + } + } + + let begin = input.fork(); + + let content; + let (paren_token, content) = if input.peek(token::Paren) { + (Some(parenthesized!(content in input)), &content) + } else { + (None, input) + }; + + if let Some(mut bound) = TraitBound::do_parse(content, allow_const)? { + bound.paren_token = paren_token; + Ok(TypeParamBound::Trait(bound)) + } else { + Ok(TypeParamBound::Verbatim(verbatim::between(&begin, input))) + } + } + + pub(crate) fn parse_multiple( + input: ParseStream, + allow_plus: bool, + allow_precise_capture: bool, + allow_const: bool, + ) -> Result> { + let mut bounds = Punctuated::new(); + loop { + let bound = Self::parse_single(input, allow_precise_capture, allow_const)?; + bounds.push_value(bound); + 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) + || (allow_const && (input.peek(token::Bracket) || input.peek(Token![const])))) + { + break; + } + } + Ok(bounds) + } + } + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for TraitBound { + fn parse(input: ParseStream) -> Result { + let allow_const = false; + Self::do_parse(input, allow_const).map(Option::unwrap) + } + } + + impl TraitBound { + fn do_parse(input: ParseStream, allow_const: bool) -> Result> { + let mut lifetimes: Option = input.parse()?; + + let is_conditionally_const = cfg!(feature = "full") && input.peek(token::Bracket); + let is_unconditionally_const = cfg!(feature = "full") && input.peek(Token![const]); + if is_conditionally_const { + let conditionally_const; + let bracket_token = bracketed!(conditionally_const in input); + conditionally_const.parse::()?; + if !allow_const { + let msg = "`[const]` is not allowed here"; + return Err(Error::new(bracket_token.span.join(), msg)); + } + } else if is_unconditionally_const { + let const_token: Token![const] = input.parse()?; + if !allow_const { + let msg = "`const` is not allowed here"; + return Err(Error::new(const_token.span, msg)); + } + } + + let modifier: TraitBoundModifier = input.parse()?; + if lifetimes.is_none() && matches!(modifier, TraitBoundModifier::Maybe(_)) { + lifetimes = 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::>()?; + let args: ParenthesizedGenericArguments = input.parse()?; + let parenthesized = PathArguments::Parenthesized(args); + path.segments.last_mut().unwrap().arguments = parenthesized; + } + + if lifetimes.is_some() { + match modifier { + TraitBoundModifier::None => {} + TraitBoundModifier::Maybe(maybe) => { + let msg = "`for<...>` binder not allowed with `?` trait polarity modifier"; + return Err(Error::new(maybe.span, msg)); + } + } + } + + if is_conditionally_const || is_unconditionally_const { + Ok(None) + } else { + Ok(Some(TraitBound { + paren_token: None, + modifier, + lifetimes, + path, + })) + } + } + } + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for TraitBoundModifier { + fn parse(input: ParseStream) -> Result { + if input.peek(Token![?]) { + input.parse().map(TraitBoundModifier::Maybe) + } else { + Ok(TraitBoundModifier::None) + } + } + } + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for ConstParam { + fn parse(input: ParseStream) -> Result { + 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(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for WhereClause { + fn parse(input: ParseStream) -> Result { + let where_token: Token![where] = input.parse()?; + + if choose_generics_over_qpath(input) { + return Err(input + .error("generic parameters on `where` clauses are reserved for future use")); + } + + Ok(WhereClause { + where_token, + 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(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for Option { + fn parse(input: ParseStream) -> Result { + if input.peek(Token![where]) { + input.parse().map(Some) + } else { + Ok(None) + } + } + } + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for WherePredicate { + fn parse(input: ParseStream) -> Result { + 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; + } + bounds.push_value({ + let allow_precise_capture = false; + let allow_const = true; + TypeParamBound::parse_single( + input, + allow_precise_capture, + allow_const, + )? + }); + if !input.peek(Token![+]) { + break; + } + let punct = input.parse()?; + bounds.push_punct(punct); + } + bounds + }, + })) + } + } + } + + #[cfg(feature = "full")] + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for PreciseCapture { + fn parse(input: ParseStream) -> Result { + let use_token: Token![use] = input.parse()?; + let lt_token: Token![<] = input.parse()?; + let mut params = Punctuated::new(); + loop { + let lookahead = input.lookahead1(); + params.push_value( + if lookahead.peek(Lifetime) || lookahead.peek(Ident) || input.peek(Token![Self]) + { + input.parse::()? + } else if lookahead.peek(Token![>]) { + break; + } else { + return Err(lookahead.error()); + }, + ); + let lookahead = input.lookahead1(); + params.push_punct(if lookahead.peek(Token![,]) { + input.parse::()? + } else if lookahead.peek(Token![>]) { + break; + } else { + return Err(lookahead.error()); + }); + } + let gt_token: Token![>] = input.parse()?; + Ok(PreciseCapture { + use_token, + lt_token, + params, + gt_token, + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for CapturedParam { + fn parse(input: ParseStream) -> Result { + let lookahead = input.lookahead1(); + if lookahead.peek(Lifetime) { + input.parse().map(CapturedParam::Lifetime) + } else if lookahead.peek(Ident) || input.peek(Token![Self]) { + input.call(Ident::parse_any).map(CapturedParam::Ident) + } else { + Err(lookahead.error()) + } + } + } + + pub(crate) fn choose_generics_over_qpath(input: ParseStream) -> bool { + // Rust syntax has an ambiguity between generic parameters and qualified + // paths. In `impl :: Thing {}` this may either be a generic + // inherent impl `impl ::Thing` or a non-generic inherent impl + // for an associated type `impl ::Thing`. + // + // After `<` the following continuations can only begin generics, not a + // qualified path: + // + // `<` `>` - empty generic parameters + // `<` `#` - generic parameters with attribute + // `<` LIFETIME `>` - single lifetime parameter + // `<` (LIFETIME|IDENT) `,` - first generic parameter in a list + // `<` (LIFETIME|IDENT) `:` - generic parameter with bounds + // `<` (LIFETIME|IDENT) `=` - generic parameter with a default + // `<` const - generic const parameter + // + // The only truly ambiguous case is: + // + // `<` IDENT `>` `::` IDENT ... + // + // which we disambiguate in favor of generics because this is almost + // always the expected one in the context of real-world code. + input.peek(Token![<]) + && (input.peek2(Token![>]) + || input.peek2(Token![#]) + || (input.peek2(Lifetime) || input.peek2(Ident)) + && (input.peek3(Token![>]) + || input.peek3(Token![,]) + || input.peek3(Token![:]) && !input.peek3(Token![::]) + || input.peek3(Token![=])) + || input.peek2(Token![const])) + } + + #[cfg(feature = "full")] + pub(crate) fn choose_generics_over_qpath_after_keyword(input: ParseStream) -> bool { + let input = input.fork(); + input.call(Ident::parse_any).unwrap(); // `impl` or `for` or `where` + choose_generics_over_qpath(&input) + } +} + +#[cfg(feature = "printing")] +pub(crate) mod printing { + use crate::attr::FilterAttrs; + #[cfg(feature = "full")] + use crate::expr; + use crate::expr::Expr; + #[cfg(feature = "full")] + use crate::fixup::FixupContext; + use crate::generics::{ + BoundLifetimes, ConstParam, GenericParam, Generics, ImplGenerics, LifetimeParam, + PredicateLifetime, PredicateType, TraitBound, TraitBoundModifier, Turbofish, TypeGenerics, + TypeParam, WhereClause, + }; + #[cfg(feature = "full")] + use crate::generics::{CapturedParam, PreciseCapture}; + use crate::print::TokensOrDefault; + use crate::token; + use proc_macro2::TokenStream; + use quote::{ToTokens, TokenStreamExt}; + + #[cfg_attr(docsrs, 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. + 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 { + ::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. + 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 { + ::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(¶m.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. + 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 { + ::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() { + ::default().to_tokens(tokens); + TypeGenerics(self.0).to_tokens(tokens); + } + } + } + + #[cfg_attr(docsrs, 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(docsrs, doc(cfg(feature = "printing")))] + impl ToTokens for LifetimeParam { + 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(docsrs, 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 { + TokensOrDefault(&self.eq_token).to_tokens(tokens); + default.to_tokens(tokens); + } + } + } + + #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] + impl ToTokens for TraitBound { + fn to_tokens(&self, tokens: &mut TokenStream) { + let to_tokens = |tokens: &mut TokenStream| { + self.modifier.to_tokens(tokens); + self.lifetimes.to_tokens(tokens); + self.path.to_tokens(tokens); + }; + match &self.paren_token { + Some(paren) => paren.surround(tokens, to_tokens), + None => to_tokens(tokens), + } + } + } + + #[cfg_attr(docsrs, 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(docsrs, 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); + print_const_argument(default, tokens); + } + } + } + + #[cfg_attr(docsrs, 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(docsrs, 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(docsrs, 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(feature = "full")] + #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] + impl ToTokens for PreciseCapture { + fn to_tokens(&self, tokens: &mut TokenStream) { + self.use_token.to_tokens(tokens); + self.lt_token.to_tokens(tokens); + + // Print lifetimes before types and consts, regardless of their + // order in self.params. + let mut trailing_or_empty = true; + for param in self.params.pairs() { + if let CapturedParam::Lifetime(_) = **param.value() { + param.to_tokens(tokens); + trailing_or_empty = param.punct().is_some(); + } + } + for param in self.params.pairs() { + if let CapturedParam::Ident(_) = **param.value() { + if !trailing_or_empty { + ::default().to_tokens(tokens); + trailing_or_empty = true; + } + param.to_tokens(tokens); + } + } + + self.gt_token.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] + impl ToTokens for CapturedParam { + fn to_tokens(&self, tokens: &mut TokenStream) { + match self { + CapturedParam::Lifetime(lifetime) => lifetime.to_tokens(tokens), + CapturedParam::Ident(ident) => ident.to_tokens(tokens), + } + } + } + + pub(crate) fn print_const_argument(expr: &Expr, tokens: &mut TokenStream) { + match expr { + Expr::Lit(expr) => expr.to_tokens(tokens), + + Expr::Path(expr) + if expr.attrs.is_empty() + && expr.qself.is_none() + && expr.path.get_ident().is_some() => + { + expr.to_tokens(tokens); + } + + #[cfg(feature = "full")] + Expr::Block(expr) => expr.to_tokens(tokens), + + #[cfg(not(feature = "full"))] + Expr::Verbatim(expr) => expr.to_tokens(tokens), + + // ERROR CORRECTION: Add braces to make sure that the + // generated code is valid. + _ => token::Brace::default().surround(tokens, |tokens| { + #[cfg(feature = "full")] + expr::printing::print_expr(expr, tokens, FixupContext::new_stmt()); + + #[cfg(not(feature = "full"))] + expr.to_tokens(tokens); + }), + } + } +} -- cgit v1.3.1