use crate::mir::interpret::{AllocRange, GlobalAlloc, Pointer, Provenance, Scalar}; use crate::ty::{ self, ConstInt, DefIdTree, ParamConst, ScalarInt, Term, TermKind, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, TypeSuperVisitable, TypeVisitable, }; use crate::ty::{GenericArg, GenericArgKind}; use rustc_apfloat::ieee::{Double, Single}; use rustc_data_structures::fx::{FxHashMap, FxIndexMap}; use rustc_data_structures::sso::SsoHashSet; use rustc_hir as hir; use rustc_hir::def::{self, CtorKind, DefKind, Namespace}; use rustc_hir::def_id::{DefId, DefIdSet, CRATE_DEF_ID, LOCAL_CRATE}; use rustc_hir::definitions::{DefPathData, DefPathDataName, DisambiguatedDefPathData}; use rustc_hir::LangItem; use rustc_session::config::TrimmedDefPaths; use rustc_session::cstore::{ExternCrate, ExternCrateSource}; use rustc_session::Limit; use rustc_span::symbol::{kw, Ident, Symbol}; use rustc_target::abi::Size; use rustc_target::spec::abi::Abi; use smallvec::SmallVec; use std::cell::Cell; use std::char; use std::collections::BTreeMap; use std::convert::TryFrom; use std::fmt::{self, Write as _}; use std::iter; use std::ops::{ControlFlow, Deref, DerefMut}; // `pretty` is a separate module only for organization. use super::*; macro_rules! p { (@$lit:literal) => { write!(scoped_cx!(), $lit)? }; (@write($($data:expr),+)) => { write!(scoped_cx!(), $($data),+)? }; (@print($x:expr)) => { scoped_cx!() = $x.print(scoped_cx!())? }; (@$method:ident($($arg:expr),*)) => { scoped_cx!() = scoped_cx!().$method($($arg),*)? }; ($($elem:tt $(($($args:tt)*))?),+) => {{ $(p!(@ $elem $(($($args)*))?);)+ }}; } macro_rules! define_scoped_cx { ($cx:ident) => { #[allow(unused_macros)] macro_rules! scoped_cx { () => { $cx }; } }; } thread_local! { static FORCE_IMPL_FILENAME_LINE: Cell = const { Cell::new(false) }; static SHOULD_PREFIX_WITH_CRATE: Cell = const { Cell::new(false) }; static NO_TRIMMED_PATH: Cell = const { Cell::new(false) }; static NO_QUERIES: Cell = const { Cell::new(false) }; static NO_VISIBLE_PATH: Cell = const { Cell::new(false) }; } macro_rules! define_helper { ($($(#[$a:meta])* fn $name:ident($helper:ident, $tl:ident);)+) => { $( #[must_use] pub struct $helper(bool); impl $helper { pub fn new() -> $helper { $helper($tl.with(|c| c.replace(true))) } } $(#[$a])* pub macro $name($e:expr) { { let _guard = $helper::new(); $e } } impl Drop for $helper { fn drop(&mut self) { $tl.with(|c| c.set(self.0)) } } )+ } } define_helper!( /// Avoids running any queries during any prints that occur /// during the closure. This may alter the appearance of some /// types (e.g. forcing verbose printing for opaque types). /// This method is used during some queries (e.g. `explicit_item_bounds` /// for opaque types), to ensure that any debug printing that /// occurs during the query computation does not end up recursively /// calling the same query. fn with_no_queries(NoQueriesGuard, NO_QUERIES); /// Force us to name impls with just the filename/line number. We /// normally try to use types. But at some points, notably while printing /// cycle errors, this can result in extra or suboptimal error output, /// so this variable disables that check. fn with_forced_impl_filename_line(ForcedImplGuard, FORCE_IMPL_FILENAME_LINE); /// Adds the `crate::` prefix to paths where appropriate. fn with_crate_prefix(CratePrefixGuard, SHOULD_PREFIX_WITH_CRATE); /// Prevent path trimming if it is turned on. Path trimming affects `Display` impl /// of various rustc types, for example `std::vec::Vec` would be trimmed to `Vec`, /// if no other `Vec` is found. fn with_no_trimmed_paths(NoTrimmedGuard, NO_TRIMMED_PATH); /// Prevent selection of visible paths. `Display` impl of DefId will prefer /// visible (public) reexports of types as paths. fn with_no_visible_paths(NoVisibleGuard, NO_VISIBLE_PATH); ); /// The "region highlights" are used to control region printing during /// specific error messages. When a "region highlight" is enabled, it /// gives an alternate way to print specific regions. For now, we /// always print those regions using a number, so something like "`'0`". /// /// Regions not selected by the region highlight mode are presently /// unaffected. #[derive(Copy, Clone)] pub struct RegionHighlightMode<'tcx> { tcx: TyCtxt<'tcx>, /// If enabled, when we see the selected region, use "`'N`" /// instead of the ordinary behavior. highlight_regions: [Option<(ty::Region<'tcx>, usize)>; 3], /// If enabled, when printing a "free region" that originated from /// the given `ty::BoundRegionKind`, print it as "`'1`". Free regions that would ordinarily /// have names print as normal. /// /// This is used when you have a signature like `fn foo(x: &u32, /// y: &'a u32)` and we want to give a name to the region of the /// reference `x`. highlight_bound_region: Option<(ty::BoundRegionKind, usize)>, } impl<'tcx> RegionHighlightMode<'tcx> { pub fn new(tcx: TyCtxt<'tcx>) -> Self { Self { tcx, highlight_regions: Default::default(), highlight_bound_region: Default::default(), } } /// If `region` and `number` are both `Some`, invokes /// `highlighting_region`. pub fn maybe_highlighting_region( &mut self, region: Option>, number: Option, ) { if let Some(k) = region { if let Some(n) = number { self.highlighting_region(k, n); } } } /// Highlights the region inference variable `vid` as `'N`. pub fn highlighting_region(&mut self, region: ty::Region<'tcx>, number: usize) { let num_slots = self.highlight_regions.len(); let first_avail_slot = self.highlight_regions.iter_mut().find(|s| s.is_none()).unwrap_or_else(|| { bug!("can only highlight {} placeholders at a time", num_slots,) }); *first_avail_slot = Some((region, number)); } /// Convenience wrapper for `highlighting_region`. pub fn highlighting_region_vid(&mut self, vid: ty::RegionVid, number: usize) { self.highlighting_region(self.tcx.mk_region(ty::ReVar(vid)), number) } /// Returns `Some(n)` with the number to use for the given region, if any. fn region_highlighted(&self, region: ty::Region<'tcx>) -> Option { self.highlight_regions.iter().find_map(|h| match h { Some((r, n)) if *r == region => Some(*n), _ => None, }) } /// Highlight the given bound region. /// We can only highlight one bound region at a time. See /// the field `highlight_bound_region` for more detailed notes. pub fn highlighting_bound_region(&mut self, br: ty::BoundRegionKind, number: usize) { assert!(self.highlight_bound_region.is_none()); self.highlight_bound_region = Some((br, number)); } } /// Trait for printers that pretty-print using `fmt::Write` to the printer. pub trait PrettyPrinter<'tcx>: Printer< 'tcx, Error = fmt::Error, Path = Self, Region = Self, Type = Self, DynExistential = Self, Const = Self, > + fmt::Write { /// Like `print_def_path` but for value paths. fn print_value_path( self, def_id: DefId, substs: &'tcx [GenericArg<'tcx>], ) -> Result { self.print_def_path(def_id, substs) } fn in_binder(self, value: &ty::Binder<'tcx, T>) -> Result where T: Print<'tcx, Self, Output = Self, Error = Self::Error> + TypeFoldable<'tcx>, { value.as_ref().skip_binder().print(self) } fn wrap_binder Result>( self, value: &ty::Binder<'tcx, T>, f: F, ) -> Result where T: Print<'tcx, Self, Output = Self, Error = Self::Error> + TypeFoldable<'tcx>, { f(value.as_ref().skip_binder(), self) } /// Prints comma-separated elements. fn comma_sep(mut self, mut elems: impl Iterator) -> Result where T: Print<'tcx, Self, Output = Self, Error = Self::Error>, { if let Some(first) = elems.next() { self = first.print(self)?; for elem in elems { self.write_str(", ")?; self = elem.print(self)?; } } Ok(self) } /// Prints `{f: t}` or `{f as t}` depending on the `cast` argument fn typed_value( mut self, f: impl FnOnce(Self) -> Result, t: impl FnOnce(Self) -> Result, conversion: &str, ) -> Result { self.write_str("{")?; self = f(self)?; self.write_str(conversion)?; self = t(self)?; self.write_str("}")?; Ok(self) } /// Prints `<...>` around what `f` prints. fn generic_delimiters( self, f: impl FnOnce(Self) -> Result, ) -> Result; /// Returns `true` if the region should be printed in /// optional positions, e.g., `&'a T` or `dyn Tr + 'b`. /// This is typically the case for all non-`'_` regions. fn should_print_region(&self, region: ty::Region<'tcx>) -> bool; // Defaults (should not be overridden): /// If possible, this returns a global path resolving to `def_id` that is visible /// from at least one local module, and returns `true`. If the crate defining `def_id` is /// declared with an `extern crate`, the path is guaranteed to use the `extern crate`. fn try_print_visible_def_path(self, def_id: DefId) -> Result<(Self, bool), Self::Error> { if NO_VISIBLE_PATH.with(|flag| flag.get()) { return Ok((self, false)); } let mut callers = Vec::new(); self.try_print_visible_def_path_recur(def_id, &mut callers) } /// Try to see if this path can be trimmed to a unique symbol name. fn try_print_trimmed_def_path( mut self, def_id: DefId, ) -> Result<(Self::Path, bool), Self::Error> { if !self.tcx().sess.opts.unstable_opts.trim_diagnostic_paths || matches!(self.tcx().sess.opts.trimmed_def_paths, TrimmedDefPaths::Never) || NO_TRIMMED_PATH.with(|flag| flag.get()) || SHOULD_PREFIX_WITH_CRATE.with(|flag| flag.get()) { return Ok((self, false)); } match self.tcx().trimmed_def_paths(()).get(&def_id) { None => Ok((self, false)), Some(symbol) => { self.write_str(symbol.as_str())?; Ok((self, true)) } } } /// Does the work of `try_print_visible_def_path`, building the /// full definition path recursively before attempting to /// post-process it into the valid and visible version that /// accounts for re-exports. /// /// This method should only be called by itself or /// `try_print_visible_def_path`. /// /// `callers` is a chain of visible_parent's leading to `def_id`, /// to support cycle detection during recursion. /// /// This method returns false if we can't print the visible path, so /// `print_def_path` can fall back on the item's real definition path. fn try_print_visible_def_path_recur( mut self, def_id: DefId, callers: &mut Vec, ) -> Result<(Self, bool), Self::Error> { define_scoped_cx!(self); debug!("try_print_visible_def_path: def_id={:?}", def_id); // If `def_id` is a direct or injected extern crate, return the // path to the crate followed by the path to the item within the crate. if let Some(cnum) = def_id.as_crate_root() { if cnum == LOCAL_CRATE { return Ok((self.path_crate(cnum)?, true)); } // In local mode, when we encounter a crate other than // LOCAL_CRATE, execution proceeds in one of two ways: // // 1. For a direct dependency, where user added an // `extern crate` manually, we put the `extern // crate` as the parent. So you wind up with // something relative to the current crate. // 2. For an extern inferred from a path or an indirect crate, // where there is no explicit `extern crate`, we just prepend // the crate name. match self.tcx().extern_crate(def_id) { Some(&ExternCrate { src, dependency_of, span, .. }) => match (src, dependency_of) { (ExternCrateSource::Extern(def_id), LOCAL_CRATE) => { // NOTE(eddyb) the only reason `span` might be dummy, // that we're aware of, is that it's the `std`/`core` // `extern crate` injected by default. // FIXME(eddyb) find something better to key this on, // or avoid ending up with `ExternCrateSource::Extern`, // for the injected `std`/`core`. if span.is_dummy() { return Ok((self.path_crate(cnum)?, true)); } // Disable `try_print_trimmed_def_path` behavior within // the `print_def_path` call, to avoid infinite recursion // in cases where the `extern crate foo` has non-trivial // parents, e.g. it's nested in `impl foo::Trait for Bar` // (see also issues #55779 and #87932). self = with_no_visible_paths!(self.print_def_path(def_id, &[])?); return Ok((self, true)); } (ExternCrateSource::Path, LOCAL_CRATE) => { return Ok((self.path_crate(cnum)?, true)); } _ => {} }, None => { return Ok((self.path_crate(cnum)?, true)); } } } if def_id.is_local() { return Ok((self, false)); } let visible_parent_map = self.tcx().visible_parent_map(()); let mut cur_def_key = self.tcx().def_key(def_id); debug!("try_print_visible_def_path: cur_def_key={:?}", cur_def_key); // For a constructor, we want the name of its parent rather than . if let DefPathData::Ctor = cur_def_key.disambiguated_data.data { let parent = DefId { krate: def_id.krate, index: cur_def_key .parent .expect("`DefPathData::Ctor` / `VariantData` missing a parent"), }; cur_def_key = self.tcx().def_key(parent); } let Some(visible_parent) = visible_parent_map.get(&def_id).cloned() else { return Ok((self, false)); }; let actual_parent = self.tcx().opt_parent(def_id); debug!( "try_print_visible_def_path: visible_parent={:?} actual_parent={:?}", visible_parent, actual_parent, ); let mut data = cur_def_key.disambiguated_data.data; debug!( "try_print_visible_def_path: data={:?} visible_parent={:?} actual_parent={:?}", data, visible_parent, actual_parent, ); match data { // In order to output a path that could actually be imported (valid and visible), // we need to handle re-exports correctly. // // For example, take `std::os::unix::process::CommandExt`, this trait is actually // defined at `std::sys::unix::ext::process::CommandExt` (at time of writing). // // `std::os::unix` reexports the contents of `std::sys::unix::ext`. `std::sys` is // private so the "true" path to `CommandExt` isn't accessible. // // In this case, the `visible_parent_map` will look something like this: // // (child) -> (parent) // `std::sys::unix::ext::process::CommandExt` -> `std::sys::unix::ext::process` // `std::sys::unix::ext::process` -> `std::sys::unix::ext` // `std::sys::unix::ext` -> `std::os` // // This is correct, as the visible parent of `std::sys::unix::ext` is in fact // `std::os`. // // When printing the path to `CommandExt` and looking at the `cur_def_key` that // corresponds to `std::sys::unix::ext`, we would normally print `ext` and then go // to the parent - resulting in a mangled path like // `std::os::ext::process::CommandExt`. // // Instead, we must detect that there was a re-export and instead print `unix` // (which is the name `std::sys::unix::ext` was re-exported as in `std::os`). To // do this, we compare the parent of `std::sys::unix::ext` (`std::sys::unix`) with // the visible parent (`std::os`). If these do not match, then we iterate over // the children of the visible parent (as was done when computing // `visible_parent_map`), looking for the specific child we currently have and then // have access to the re-exported name. DefPathData::TypeNs(ref mut name) if Some(visible_parent) != actual_parent => { // Item might be re-exported several times, but filter for the one // that's public and whose identifier isn't `_`. let reexport = self .tcx() .module_children(visible_parent) .iter() .filter(|child| child.res.opt_def_id() == Some(def_id)) .find(|child| child.vis.is_public() && child.ident.name != kw::Underscore) .map(|child| child.ident.name); if let Some(new_name) = reexport { *name = new_name; } else { // There is no name that is public and isn't `_`, so bail. return Ok((self, false)); } } // Re-exported `extern crate` (#43189). DefPathData::CrateRoot => { data = DefPathData::TypeNs(self.tcx().crate_name(def_id.krate)); } _ => {} } debug!("try_print_visible_def_path: data={:?}", data); if callers.contains(&visible_parent) { return Ok((self, false)); } callers.push(visible_parent); // HACK(eddyb) this bypasses `path_append`'s prefix printing to avoid // knowing ahead of time whether the entire path will succeed or not. // To support printers that do not implement `PrettyPrinter`, a `Vec` or // linked list on the stack would need to be built, before any printing. match self.try_print_visible_def_path_recur(visible_parent, callers)? { (cx, false) => return Ok((cx, false)), (cx, true) => self = cx, } callers.pop(); Ok((self.path_append(Ok, &DisambiguatedDefPathData { data, disambiguator: 0 })?, true)) } fn pretty_path_qualified( self, self_ty: Ty<'tcx>, trait_ref: Option>, ) -> Result { if trait_ref.is_none() { // Inherent impls. Try to print `Foo::bar` for an inherent // impl on `Foo`, but fallback to `::bar` if self-type is // anything other than a simple path. match self_ty.kind() { ty::Adt(..) | ty::Foreign(_) | ty::Bool | ty::Char | ty::Str | ty::Int(_) | ty::Uint(_) | ty::Float(_) => { return self_ty.print(self); } _ => {} } } self.generic_delimiters(|mut cx| { define_scoped_cx!(cx); p!(print(self_ty)); if let Some(trait_ref) = trait_ref { p!(" as ", print(trait_ref.print_only_trait_path())); } Ok(cx) }) } fn pretty_path_append_impl( mut self, print_prefix: impl FnOnce(Self) -> Result, self_ty: Ty<'tcx>, trait_ref: Option>, ) -> Result { self = print_prefix(self)?; self.generic_delimiters(|mut cx| { define_scoped_cx!(cx); p!("impl "); if let Some(trait_ref) = trait_ref { p!(print(trait_ref.print_only_trait_path()), " for "); } p!(print(self_ty)); Ok(cx) }) } fn pretty_print_type(mut self, ty: Ty<'tcx>) -> Result { define_scoped_cx!(self); match *ty.kind() { ty::Bool => p!("bool"), ty::Char => p!("char"), ty::Int(t) => p!(write("{}", t.name_str())), ty::Uint(t) => p!(write("{}", t.name_str())), ty::Float(t) => p!(write("{}", t.name_str())), ty::RawPtr(ref tm) => { p!(write( "*{} ", match tm.mutbl { hir::Mutability::Mut => "mut", hir::Mutability::Not => "const", } )); p!(print(tm.ty)) } ty::Ref(r, ty, mutbl) => { p!("&"); if self.should_print_region(r) { p!(print(r), " "); } p!(print(ty::TypeAndMut { ty, mutbl })) } ty::Never => p!("!"), ty::Tuple(ref tys) => { p!("(", comma_sep(tys.iter())); if tys.len() == 1 { p!(","); } p!(")") } ty::FnDef(def_id, substs) => { let sig = self.tcx().bound_fn_sig(def_id).subst(self.tcx(), substs); p!(print(sig), " {{", print_value_path(def_id, substs), "}}"); } ty::FnPtr(ref bare_fn) => p!(print(bare_fn)), ty::Infer(infer_ty) => { let verbose = self.should_print_verbose(); if let ty::TyVar(ty_vid) = infer_ty { if let Some(name) = self.ty_infer_name(ty_vid) { p!(write("{}", name)) } else { if verbose { p!(write("{:?}", infer_ty)) } else { p!(write("{}", infer_ty)) } } } else { if verbose { p!(write("{:?}", infer_ty)) } else { p!(write("{}", infer_ty)) } } } ty::Error(_) => p!("[type error]"), ty::Param(ref param_ty) => p!(print(param_ty)), ty::Bound(debruijn, bound_ty) => match bound_ty.kind { ty::BoundTyKind::Anon => self.pretty_print_bound_var(debruijn, bound_ty.var)?, ty::BoundTyKind::Param(p) => p!(write("{}", p)), }, ty::Adt(def, substs) => { p!(print_def_path(def.did(), substs)); } ty::Dynamic(data, r, repr) => { let print_r = self.should_print_region(r); if print_r { p!("("); } match repr { ty::Dyn => p!("dyn "), ty::DynStar => p!("dyn* "), } p!(print(data)); if print_r { p!(" + ", print(r), ")"); } } ty::Foreign(def_id) => { p!(print_def_path(def_id, &[])); } ty::Projection(ref data) => { if !(self.should_print_verbose() || NO_QUERIES.with(|q| q.get())) && self.tcx().def_kind(data.item_def_id) == DefKind::ImplTraitPlaceholder { return self.pretty_print_opaque_impl_type(data.item_def_id, data.substs); } else { p!(print(data)) } } ty::Placeholder(placeholder) => p!(write("Placeholder({:?})", placeholder)), ty::Opaque(def_id, substs) => { // FIXME(eddyb) print this with `print_def_path`. // We use verbose printing in 'NO_QUERIES' mode, to // avoid needing to call `predicates_of`. This should // only affect certain debug messages (e.g. messages printed // from `rustc_middle::ty` during the computation of `tcx.predicates_of`), // and should have no effect on any compiler output. if self.should_print_verbose() || NO_QUERIES.with(|q| q.get()) { p!(write("Opaque({:?}, {:?})", def_id, substs)); return Ok(self); } let parent = self.tcx().parent(def_id); match self.tcx().def_kind(parent) { DefKind::TyAlias | DefKind::AssocTy => { if let ty::Opaque(d, _) = *self.tcx().type_of(parent).kind() { if d == def_id { // If the type alias directly starts with the `impl` of the // opaque type we're printing, then skip the `::{opaque#1}`. p!(print_def_path(parent, substs)); return Ok(self); } } // Complex opaque type, e.g. `type Foo = (i32, impl Debug);` p!(print_def_path(def_id, substs)); return Ok(self); } _ => return self.pretty_print_opaque_impl_type(def_id, substs), } } ty::Str => p!("str"), ty::Generator(did, substs, movability) => { p!(write("[")); let generator_kind = self.tcx().generator_kind(did).unwrap(); let should_print_movability = self.should_print_verbose() || generator_kind == hir::GeneratorKind::Gen; if should_print_movability { match movability { hir::Movability::Movable => {} hir::Movability::Static => p!("static "), } } if !self.should_print_verbose() { p!(write("{}", generator_kind)); // FIXME(eddyb) should use `def_span`. if let Some(did) = did.as_local() { let span = self.tcx().def_span(did); p!(write( "@{}", // This may end up in stderr diagnostics but it may also be emitted // into MIR. Hence we use the remapped path if available self.tcx().sess.source_map().span_to_embeddable_string(span) )); } else { p!(write("@"), print_def_path(did, substs)); } } else { p!(print_def_path(did, substs)); p!(" upvar_tys=("); if !substs.as_generator().is_valid() { p!("unavailable"); } else { self = self.comma_sep(substs.as_generator().upvar_tys())?; } p!(")"); if substs.as_generator().is_valid() { p!(" ", print(substs.as_generator().witness())); } } p!("]") } ty::GeneratorWitness(types) => { p!(in_binder(&types)); } ty::Closure(did, substs) => { p!(write("[")); if !self.should_print_verbose() { p!(write("closure")); // FIXME(eddyb) should use `def_span`. if let Some(did) = did.as_local() { if self.tcx().sess.opts.unstable_opts.span_free_formats { p!("@", print_def_path(did.to_def_id(), substs)); } else { let span = self.tcx().def_span(did); p!(write( "@{}", // This may end up in stderr diagnostics but it may also be emitted // into MIR. Hence we use the remapped path if available self.tcx().sess.source_map().span_to_embeddable_string(span) )); } } else { p!(write("@"), print_def_path(did, substs)); } } else { p!(print_def_path(did, substs)); if !substs.as_closure().is_valid() { p!(" closure_substs=(unavailable)"); p!(write(" substs={:?}", substs)); } else { p!(" closure_kind_ty=", print(substs.as_closure().kind_ty())); p!( " closure_sig_as_fn_ptr_ty=", print(substs.as_closure().sig_as_fn_ptr_ty()) ); p!(" upvar_tys=("); self = self.comma_sep(substs.as_closure().upvar_tys())?; p!(")"); } } p!("]"); } ty::Array(ty, sz) => { p!("[", print(ty), "; "); if self.should_print_verbose() { p!(write("{:?}", sz)); } else if let ty::ConstKind::Unevaluated(..) = sz.kind() { // Do not try to evaluate unevaluated constants. If we are const evaluating an // array length anon const, rustc will (with debug assertions) print the // constant's path. Which will end up here again. p!("_"); } else if let Some(n) = sz.kind().try_to_bits(self.tcx().data_layout.pointer_size) { p!(write("{}", n)); } else if let ty::ConstKind::Param(param) = sz.kind() { p!(print(param)); } else { p!("_"); } p!("]") } ty::Slice(ty) => p!("[", print(ty), "]"), } Ok(self) } fn pretty_print_opaque_impl_type( mut self, def_id: DefId, substs: &'tcx ty::List>, ) -> Result { let tcx = self.tcx(); // Grab the "TraitA + TraitB" from `impl TraitA + TraitB`, // by looking up the projections associated with the def_id. let bounds = tcx.bound_explicit_item_bounds(def_id); let mut traits = FxIndexMap::default(); let mut fn_traits = FxIndexMap::default(); let mut is_sized = false; let mut lifetimes = SmallVec::<[ty::Region<'tcx>; 1]>::new(); for (predicate, _) in bounds.subst_iter_copied(tcx, substs) { let bound_predicate = predicate.kind(); match bound_predicate.skip_binder() { ty::PredicateKind::Clause(ty::Clause::Trait(pred)) => { let trait_ref = bound_predicate.rebind(pred.trait_ref); // Don't print + Sized, but rather + ?Sized if absent. if Some(trait_ref.def_id()) == tcx.lang_items().sized_trait() { is_sized = true; continue; } self.insert_trait_and_projection(trait_ref, None, &mut traits, &mut fn_traits); } ty::PredicateKind::Clause(ty::Clause::Projection(pred)) => { let proj_ref = bound_predicate.rebind(pred); let trait_ref = proj_ref.required_poly_trait_ref(tcx); // Projection type entry -- the def-id for naming, and the ty. let proj_ty = (proj_ref.projection_def_id(), proj_ref.term()); self.insert_trait_and_projection( trait_ref, Some(proj_ty), &mut traits, &mut fn_traits, ); } ty::PredicateKind::Clause(ty::Clause::TypeOutlives(outlives)) => { lifetimes.push(outlives.1); } _ => {} } } write!(self, "impl ")?; let mut first = true; // Insert parenthesis around (Fn(A, B) -> C) if the opaque ty has more than one other trait let paren_needed = fn_traits.len() > 1 || traits.len() > 0 || !is_sized; for (fn_once_trait_ref, entry) in fn_traits { write!(self, "{}", if first { "" } else { " + " })?; write!(self, "{}", if paren_needed { "(" } else { "" })?; self = self.wrap_binder(&fn_once_trait_ref, |trait_ref, mut cx| { define_scoped_cx!(cx); // Get the (single) generic ty (the args) of this FnOnce trait ref. let generics = tcx.generics_of(trait_ref.def_id); let args = generics.own_substs_no_defaults(tcx, trait_ref.substs); match (entry.return_ty, args[0].expect_ty()) { // We can only print `impl Fn() -> ()` if we have a tuple of args and we recorded // a return type. (Some(return_ty), arg_tys) if matches!(arg_tys.kind(), ty::Tuple(_)) => { let name = if entry.fn_trait_ref.is_some() { "Fn" } else if entry.fn_mut_trait_ref.is_some() { "FnMut" } else { "FnOnce" }; p!(write("{}(", name)); for (idx, ty) in arg_tys.tuple_fields().iter().enumerate() { if idx > 0 { p!(", "); } p!(print(ty)); } p!(")"); if let Some(ty) = return_ty.skip_binder().ty() { if !ty.is_unit() { p!(" -> ", print(return_ty)); } } p!(write("{}", if paren_needed { ")" } else { "" })); first = false; } // If we got here, we can't print as a `impl Fn(A, B) -> C`. Just record the // trait_refs we collected in the OpaqueFnEntry as normal trait refs. _ => { if entry.has_fn_once { traits.entry(fn_once_trait_ref).or_default().extend( // Group the return ty with its def id, if we had one. entry .return_ty .map(|ty| (tcx.require_lang_item(LangItem::FnOnce, None), ty)), ); } if let Some(trait_ref) = entry.fn_mut_trait_ref { traits.entry(trait_ref).or_default(); } if let Some(trait_ref) = entry.fn_trait_ref { traits.entry(trait_ref).or_default(); } } } Ok(cx) })?; } // Print the rest of the trait types (that aren't Fn* family of traits) for (trait_ref, assoc_items) in traits { write!(self, "{}", if first { "" } else { " + " })?; self = self.wrap_binder(&trait_ref, |trait_ref, mut cx| { define_scoped_cx!(cx); p!(print(trait_ref.print_only_trait_name())); let generics = tcx.generics_of(trait_ref.def_id); let args = generics.own_substs_no_defaults(tcx, trait_ref.substs); if !args.is_empty() || !assoc_items.is_empty() { let mut first = true; for ty in args { if first { p!("<"); first = false; } else { p!(", "); } p!(print(ty)); } for (assoc_item_def_id, term) in assoc_items { // Skip printing `<[generator@] as Generator<_>>::Return` from async blocks, // unless we can find out what generator return type it comes from. let term = if let Some(ty) = term.skip_binder().ty() && let ty::Projection(proj) = ty.kind() && let Some(assoc) = tcx.opt_associated_item(proj.item_def_id) && assoc.trait_container(tcx) == tcx.lang_items().gen_trait() && assoc.name == rustc_span::sym::Return { if let ty::Generator(_, substs, _) = substs.type_at(0).kind() { let return_ty = substs.as_generator().return_ty(); if !return_ty.is_ty_var() { return_ty.into() } else { continue; } } else { continue; } } else { term.skip_binder() }; if first { p!("<"); first = false; } else { p!(", "); } p!(write("{} = ", tcx.associated_item(assoc_item_def_id).name)); match term.unpack() { TermKind::Ty(ty) => p!(print(ty)), TermKind::Const(c) => p!(print(c)), }; } if !first { p!(">"); } } first = false; Ok(cx) })?; } if !is_sized { write!(self, "{}?Sized", if first { "" } else { " + " })?; } else if first { write!(self, "Sized")?; } for re in lifetimes { write!(self, " + ")?; self = self.print_region(re)?; } Ok(self) } /// Insert the trait ref and optionally a projection type associated with it into either the /// traits map or fn_traits map, depending on if the trait is in the Fn* family of traits. fn insert_trait_and_projection( &mut self, trait_ref: ty::PolyTraitRef<'tcx>, proj_ty: Option<(DefId, ty::Binder<'tcx, Term<'tcx>>)>, traits: &mut FxIndexMap< ty::PolyTraitRef<'tcx>, FxIndexMap>>, >, fn_traits: &mut FxIndexMap, OpaqueFnEntry<'tcx>>, ) { let trait_def_id = trait_ref.def_id(); // If our trait_ref is FnOnce or any of its children, project it onto the parent FnOnce // super-trait ref and record it there. if let Some(fn_once_trait) = self.tcx().lang_items().fn_once_trait() { // If we have a FnOnce, then insert it into if trait_def_id == fn_once_trait { let entry = fn_traits.entry(trait_ref).or_default(); // Optionally insert the return_ty as well. if let Some((_, ty)) = proj_ty { entry.return_ty = Some(ty); } entry.has_fn_once = true; return; } else if Some(trait_def_id) == self.tcx().lang_items().fn_mut_trait() { let super_trait_ref = crate::traits::util::supertraits(self.tcx(), trait_ref) .find(|super_trait_ref| super_trait_ref.def_id() == fn_once_trait) .unwrap(); fn_traits.entry(super_trait_ref).or_default().fn_mut_trait_ref = Some(trait_ref); return; } else if Some(trait_def_id) == self.tcx().lang_items().fn_trait() { let super_trait_ref = crate::traits::util::supertraits(self.tcx(), trait_ref) .find(|super_trait_ref| super_trait_ref.def_id() == fn_once_trait) .unwrap(); fn_traits.entry(super_trait_ref).or_default().fn_trait_ref = Some(trait_ref); return; } } // Otherwise, just group our traits and projection types. traits.entry(trait_ref).or_default().extend(proj_ty); } fn pretty_print_bound_var( &mut self, debruijn: ty::DebruijnIndex, var: ty::BoundVar, ) -> Result<(), Self::Error> { if debruijn == ty::INNERMOST { write!(self, "^{}", var.index()) } else { write!(self, "^{}_{}", debruijn.index(), var.index()) } } fn ty_infer_name(&self, _: ty::TyVid) -> Option { None } fn const_infer_name(&self, _: ty::ConstVid<'tcx>) -> Option { None } fn pretty_print_dyn_existential( mut self, predicates: &'tcx ty::List>, ) -> Result { // Generate the main trait ref, including associated types. let mut first = true; if let Some(principal) = predicates.principal() { self = self.wrap_binder(&principal, |principal, mut cx| { define_scoped_cx!(cx); p!(print_def_path(principal.def_id, &[])); let mut resugared = false; // Special-case `Fn(...) -> ...` and re-sugar it. let fn_trait_kind = cx.tcx().fn_trait_kind_from_def_id(principal.def_id); if !cx.should_print_verbose() && fn_trait_kind.is_some() { if let ty::Tuple(tys) = principal.substs.type_at(0).kind() { let mut projections = predicates.projection_bounds(); if let (Some(proj), None) = (projections.next(), projections.next()) { p!(pretty_fn_sig( tys, false, proj.skip_binder().term.ty().expect("Return type was a const") )); resugared = true; } } } // HACK(eddyb) this duplicates `FmtPrinter`'s `path_generic_args`, // in order to place the projections inside the `<...>`. if !resugared { // Use a type that can't appear in defaults of type parameters. let dummy_cx = cx.tcx().mk_ty_infer(ty::FreshTy(0)); let principal = principal.with_self_ty(cx.tcx(), dummy_cx); let args = cx .tcx() .generics_of(principal.def_id) .own_substs_no_defaults(cx.tcx(), principal.substs); let mut projections = predicates.projection_bounds(); let mut args = args.iter().cloned(); let arg0 = args.next(); let projection0 = projections.next(); if arg0.is_some() || projection0.is_some() { let args = arg0.into_iter().chain(args); let projections = projection0.into_iter().chain(projections); p!(generic_delimiters(|mut cx| { cx = cx.comma_sep(args)?; if arg0.is_some() && projection0.is_some() { write!(cx, ", ")?; } cx.comma_sep(projections) })); } } Ok(cx) })?; first = false; } define_scoped_cx!(self); // Builtin bounds. // FIXME(eddyb) avoid printing twice (needed to ensure // that the auto traits are sorted *and* printed via cx). let mut auto_traits: Vec<_> = predicates.auto_traits().collect(); // The auto traits come ordered by `DefPathHash`. While // `DefPathHash` is *stable* in the sense that it depends on // neither the host nor the phase of the moon, it depends // "pseudorandomly" on the compiler version and the target. // // To avoid causing instabilities in compiletest // output, sort the auto-traits alphabetically. auto_traits.sort_by_cached_key(|did| with_no_trimmed_paths!(self.tcx().def_path_str(*did))); for def_id in auto_traits { if !first { p!(" + "); } first = false; p!(print_def_path(def_id, &[])); } Ok(self) } fn pretty_fn_sig( mut self, inputs: &[Ty<'tcx>], c_variadic: bool, output: Ty<'tcx>, ) -> Result { define_scoped_cx!(self); p!("(", comma_sep(inputs.iter().copied())); if c_variadic { if !inputs.is_empty() { p!(", "); } p!("..."); } p!(")"); if !output.is_unit() { p!(" -> ", print(output)); } Ok(self) } fn pretty_print_const( mut self, ct: ty::Const<'tcx>, print_ty: bool, ) -> Result { define_scoped_cx!(self); if self.should_print_verbose() { p!(write("Const({:?}: {:?})", ct.kind(), ct.ty())); return Ok(self); } macro_rules! print_underscore { () => {{ if print_ty { self = self.typed_value( |mut this| { write!(this, "_")?; Ok(this) }, |this| this.print_type(ct.ty()), ": ", )?; } else { write!(self, "_")?; } }}; } match ct.kind() { ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }) => { match self.tcx().def_kind(def.did) { DefKind::Static(..) | DefKind::Const | DefKind::AssocConst => { p!(print_value_path(def.did, substs)) } _ => { if def.is_local() { let span = self.tcx().def_span(def.did); if let Ok(snip) = self.tcx().sess.source_map().span_to_snippet(span) { p!(write("{}", snip)) } else { print_underscore!() } } else { print_underscore!() } } } } ty::ConstKind::Infer(infer_ct) => { match infer_ct { ty::InferConst::Var(ct_vid) if let Some(name) = self.const_infer_name(ct_vid) => p!(write("{}", name)), _ => print_underscore!(), } } ty::ConstKind::Param(ParamConst { name, .. }) => p!(write("{}", name)), ty::ConstKind::Value(value) => { return self.pretty_print_const_valtree(value, ct.ty(), print_ty); } ty::ConstKind::Bound(debruijn, bound_var) => { self.pretty_print_bound_var(debruijn, bound_var)? } ty::ConstKind::Placeholder(placeholder) => p!(write("Placeholder({:?})", placeholder)), // FIXME(generic_const_exprs): // write out some legible representation of an abstract const? ty::ConstKind::Expr(_) => p!("[Const Expr]"), ty::ConstKind::Error(_) => p!("[const error]"), }; Ok(self) } fn pretty_print_const_scalar( self, scalar: Scalar, ty: Ty<'tcx>, print_ty: bool, ) -> Result { match scalar { Scalar::Ptr(ptr, _size) => self.pretty_print_const_scalar_ptr(ptr, ty, print_ty), Scalar::Int(int) => self.pretty_print_const_scalar_int(int, ty, print_ty), } } fn pretty_print_const_scalar_ptr( mut self, ptr: Pointer, ty: Ty<'tcx>, print_ty: bool, ) -> Result { define_scoped_cx!(self); let (alloc_id, offset) = ptr.into_parts(); match ty.kind() { // Byte strings (&[u8; N]) ty::Ref(_, inner, _) => { if let ty::Array(elem, len) = inner.kind() { if let ty::Uint(ty::UintTy::U8) = elem.kind() { if let ty::ConstKind::Value(ty::ValTree::Leaf(int)) = len.kind() { match self.tcx().try_get_global_alloc(alloc_id) { Some(GlobalAlloc::Memory(alloc)) => { let len = int.assert_bits(self.tcx().data_layout.pointer_size); let range = AllocRange { start: offset, size: Size::from_bytes(len) }; if let Ok(byte_str) = alloc.inner().get_bytes_strip_provenance(&self.tcx(), range) { p!(pretty_print_byte_str(byte_str)) } else { p!("") } } // FIXME: for statics, vtables, and functions, we could in principle print more detail. Some(GlobalAlloc::Static(def_id)) => { p!(write("", def_id)) } Some(GlobalAlloc::Function(_)) => p!(""), Some(GlobalAlloc::VTable(..)) => p!(""), None => p!(""), } return Ok(self); } } } } ty::FnPtr(_) => { // FIXME: We should probably have a helper method to share code with the "Byte strings" // printing above (which also has to handle pointers to all sorts of things). if let Some(GlobalAlloc::Function(instance)) = self.tcx().try_get_global_alloc(alloc_id) { self = self.typed_value( |this| this.print_value_path(instance.def_id(), instance.substs), |this| this.print_type(ty), " as ", )?; return Ok(self); } } _ => {} } // Any pointer values not covered by a branch above self = self.pretty_print_const_pointer(ptr, ty, print_ty)?; Ok(self) } fn pretty_print_const_scalar_int( mut self, int: ScalarInt, ty: Ty<'tcx>, print_ty: bool, ) -> Result { define_scoped_cx!(self); match ty.kind() { // Bool ty::Bool if int == ScalarInt::FALSE => p!("false"), ty::Bool if int == ScalarInt::TRUE => p!("true"), // Float ty::Float(ty::FloatTy::F32) => { p!(write("{}f32", Single::try_from(int).unwrap())) } ty::Float(ty::FloatTy::F64) => { p!(write("{}f64", Double::try_from(int).unwrap())) } // Int ty::Uint(_) | ty::Int(_) => { let int = ConstInt::new(int, matches!(ty.kind(), ty::Int(_)), ty.is_ptr_sized_integral()); if print_ty { p!(write("{:#?}", int)) } else { p!(write("{:?}", int)) } } // Char ty::Char if char::try_from(int).is_ok() => { p!(write("{:?}", char::try_from(int).unwrap())) } // Pointer types ty::Ref(..) | ty::RawPtr(_) | ty::FnPtr(_) => { let data = int.assert_bits(self.tcx().data_layout.pointer_size); self = self.typed_value( |mut this| { write!(this, "0x{:x}", data)?; Ok(this) }, |this| this.print_type(ty), " as ", )?; } // Nontrivial types with scalar bit representation _ => { let print = |mut this: Self| { if int.size() == Size::ZERO { write!(this, "transmute(())")?; } else { write!(this, "transmute(0x{:x})", int)?; } Ok(this) }; self = if print_ty { self.typed_value(print, |this| this.print_type(ty), ": ")? } else { print(self)? }; } } Ok(self) } /// This is overridden for MIR printing because we only want to hide alloc ids from users, not /// from MIR where it is actually useful. fn pretty_print_const_pointer( mut self, _: Pointer, ty: Ty<'tcx>, print_ty: bool, ) -> Result { if print_ty { self.typed_value( |mut this| { this.write_str("&_")?; Ok(this) }, |this| this.print_type(ty), ": ", ) } else { self.write_str("&_")?; Ok(self) } } fn pretty_print_byte_str(mut self, byte_str: &'tcx [u8]) -> Result { write!(self, "b\"{}\"", byte_str.escape_ascii())?; Ok(self) } fn pretty_print_const_valtree( mut self, valtree: ty::ValTree<'tcx>, ty: Ty<'tcx>, print_ty: bool, ) -> Result { define_scoped_cx!(self); if self.should_print_verbose() { p!(write("ValTree({:?}: ", valtree), print(ty), ")"); return Ok(self); } let u8_type = self.tcx().types.u8; match (valtree, ty.kind()) { (ty::ValTree::Branch(_), ty::Ref(_, inner_ty, _)) => match inner_ty.kind() { ty::Slice(t) if *t == u8_type => { let bytes = valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| { bug!( "expected to convert valtree {:?} to raw bytes for type {:?}", valtree, t ) }); return self.pretty_print_byte_str(bytes); } ty::Str => { let bytes = valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| { bug!("expected to convert valtree to raw bytes for type {:?}", ty) }); p!(write("{:?}", String::from_utf8_lossy(bytes))); return Ok(self); } _ => { p!("&"); p!(pretty_print_const_valtree(valtree, *inner_ty, print_ty)); return Ok(self); } }, (ty::ValTree::Branch(_), ty::Array(t, _)) if *t == u8_type => { let bytes = valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| { bug!("expected to convert valtree to raw bytes for type {:?}", t) }); p!("*"); p!(pretty_print_byte_str(bytes)); return Ok(self); } // Aggregates, printed as array/tuple/struct/variant construction syntax. (ty::ValTree::Branch(_), ty::Array(..) | ty::Tuple(..) | ty::Adt(..)) => { let contents = self.tcx().destructure_const(self.tcx().mk_const(valtree, ty)); let fields = contents.fields.iter().copied(); match *ty.kind() { ty::Array(..) => { p!("[", comma_sep(fields), "]"); } ty::Tuple(..) => { p!("(", comma_sep(fields)); if contents.fields.len() == 1 { p!(","); } p!(")"); } ty::Adt(def, _) if def.variants().is_empty() => { self = self.typed_value( |mut this| { write!(this, "unreachable()")?; Ok(this) }, |this| this.print_type(ty), ": ", )?; } ty::Adt(def, substs) => { let variant_idx = contents.variant.expect("destructed const of adt without variant idx"); let variant_def = &def.variant(variant_idx); p!(print_value_path(variant_def.def_id, substs)); match variant_def.ctor_kind() { Some(CtorKind::Const) => {} Some(CtorKind::Fn) => { p!("(", comma_sep(fields), ")"); } None => { p!(" {{ "); let mut first = true; for (field_def, field) in iter::zip(&variant_def.fields, fields) { if !first { p!(", "); } p!(write("{}: ", field_def.name), print(field)); first = false; } p!(" }}"); } } } _ => unreachable!(), } return Ok(self); } (ty::ValTree::Leaf(leaf), ty::Ref(_, inner_ty, _)) => { p!(write("&")); return self.pretty_print_const_scalar_int(leaf, *inner_ty, print_ty); } (ty::ValTree::Leaf(leaf), _) => { return self.pretty_print_const_scalar_int(leaf, ty, print_ty); } // FIXME(oli-obk): also pretty print arrays and other aggregate constants by reading // their fields instead of just dumping the memory. _ => {} } // fallback if valtree == ty::ValTree::zst() { p!(write("")); } else { p!(write("{:?}", valtree)); } if print_ty { p!(": ", print(ty)); } Ok(self) } fn pretty_closure_as_impl( mut self, closure: ty::ClosureSubsts<'tcx>, ) -> Result { let sig = closure.sig(); let kind = closure.kind_ty().to_opt_closure_kind().unwrap_or(ty::ClosureKind::Fn); write!(self, "impl ")?; self.wrap_binder(&sig, |sig, mut cx| { define_scoped_cx!(cx); p!(print(kind), "("); for (i, arg) in sig.inputs()[0].tuple_fields().iter().enumerate() { if i > 0 { p!(", "); } p!(print(arg)); } p!(")"); if !sig.output().is_unit() { p!(" -> ", print(sig.output())); } Ok(cx) }) } fn should_print_verbose(&self) -> bool { self.tcx().sess.verbose() } } // HACK(eddyb) boxed to avoid moving around a large struct by-value. pub struct FmtPrinter<'a, 'tcx>(Box>); pub struct FmtPrinterData<'a, 'tcx> { tcx: TyCtxt<'tcx>, fmt: String, empty_path: bool, in_value: bool, pub print_alloc_ids: bool, // set of all named (non-anonymous) region names used_region_names: FxHashSet, region_index: usize, binder_depth: usize, printed_type_count: usize, type_length_limit: Limit, truncated: bool, pub region_highlight_mode: RegionHighlightMode<'tcx>, pub ty_infer_name_resolver: Option Option + 'a>>, pub const_infer_name_resolver: Option) -> Option + 'a>>, } impl<'a, 'tcx> Deref for FmtPrinter<'a, 'tcx> { type Target = FmtPrinterData<'a, 'tcx>; fn deref(&self) -> &Self::Target { &self.0 } } impl DerefMut for FmtPrinter<'_, '_> { fn deref_mut(&mut self) -> &mut Self::Target { &mut self.0 } } impl<'a, 'tcx> FmtPrinter<'a, 'tcx> { pub fn new(tcx: TyCtxt<'tcx>, ns: Namespace) -> Self { Self::new_with_limit(tcx, ns, tcx.type_length_limit()) } pub fn new_with_limit(tcx: TyCtxt<'tcx>, ns: Namespace, type_length_limit: Limit) -> Self { FmtPrinter(Box::new(FmtPrinterData { tcx, // Estimated reasonable capacity to allocate upfront based on a few // benchmarks. fmt: String::with_capacity(64), empty_path: false, in_value: ns == Namespace::ValueNS, print_alloc_ids: false, used_region_names: Default::default(), region_index: 0, binder_depth: 0, printed_type_count: 0, type_length_limit, truncated: false, region_highlight_mode: RegionHighlightMode::new(tcx), ty_infer_name_resolver: None, const_infer_name_resolver: None, })) } pub fn into_buffer(self) -> String { self.0.fmt } } // HACK(eddyb) get rid of `def_path_str` and/or pass `Namespace` explicitly always // (but also some things just print a `DefId` generally so maybe we need this?) fn guess_def_namespace(tcx: TyCtxt<'_>, def_id: DefId) -> Namespace { match tcx.def_key(def_id).disambiguated_data.data { DefPathData::TypeNs(..) | DefPathData::CrateRoot | DefPathData::ImplTrait => { Namespace::TypeNS } DefPathData::ValueNs(..) | DefPathData::AnonConst | DefPathData::ClosureExpr | DefPathData::Ctor => Namespace::ValueNS, DefPathData::MacroNs(..) => Namespace::MacroNS, _ => Namespace::TypeNS, } } impl<'t> TyCtxt<'t> { /// Returns a string identifying this `DefId`. This string is /// suitable for user output. pub fn def_path_str(self, def_id: DefId) -> String { self.def_path_str_with_substs(def_id, &[]) } pub fn def_path_str_with_substs(self, def_id: DefId, substs: &'t [GenericArg<'t>]) -> String { let ns = guess_def_namespace(self, def_id); debug!("def_path_str: def_id={:?}, ns={:?}", def_id, ns); FmtPrinter::new(self, ns).print_def_path(def_id, substs).unwrap().into_buffer() } pub fn value_path_str_with_substs(self, def_id: DefId, substs: &'t [GenericArg<'t>]) -> String { let ns = guess_def_namespace(self, def_id); debug!("value_path_str: def_id={:?}, ns={:?}", def_id, ns); FmtPrinter::new(self, ns).print_value_path(def_id, substs).unwrap().into_buffer() } } impl fmt::Write for FmtPrinter<'_, '_> { fn write_str(&mut self, s: &str) -> fmt::Result { self.fmt.push_str(s); Ok(()) } } impl<'tcx> Printer<'tcx> for FmtPrinter<'_, 'tcx> { type Error = fmt::Error; type Path = Self; type Region = Self; type Type = Self; type DynExistential = Self; type Const = Self; fn tcx<'a>(&'a self) -> TyCtxt<'tcx> { self.tcx } fn print_def_path( mut self, def_id: DefId, substs: &'tcx [GenericArg<'tcx>], ) -> Result { define_scoped_cx!(self); if substs.is_empty() { match self.try_print_trimmed_def_path(def_id)? { (cx, true) => return Ok(cx), (cx, false) => self = cx, } match self.try_print_visible_def_path(def_id)? { (cx, true) => return Ok(cx), (cx, false) => self = cx, } } let key = self.tcx.def_key(def_id); if let DefPathData::Impl = key.disambiguated_data.data { // Always use types for non-local impls, where types are always // available, and filename/line-number is mostly uninteresting. let use_types = !def_id.is_local() || { // Otherwise, use filename/line-number if forced. let force_no_types = FORCE_IMPL_FILENAME_LINE.with(|f| f.get()); !force_no_types }; if !use_types { // If no type info is available, fall back to // pretty printing some span information. This should // only occur very early in the compiler pipeline. let parent_def_id = DefId { index: key.parent.unwrap(), ..def_id }; let span = self.tcx.def_span(def_id); self = self.print_def_path(parent_def_id, &[])?; // HACK(eddyb) copy of `path_append` to avoid // constructing a `DisambiguatedDefPathData`. if !self.empty_path { write!(self, "::")?; } write!( self, "", // This may end up in stderr diagnostics but it may also be emitted // into MIR. Hence we use the remapped path if available self.tcx.sess.source_map().span_to_embeddable_string(span) )?; self.empty_path = false; return Ok(self); } } self.default_print_def_path(def_id, substs) } fn print_region(self, region: ty::Region<'tcx>) -> Result { self.pretty_print_region(region) } fn print_type(mut self, ty: Ty<'tcx>) -> Result { if self.type_length_limit.value_within_limit(self.printed_type_count) { self.printed_type_count += 1; self.pretty_print_type(ty) } else { self.truncated = true; write!(self, "...")?; Ok(self) } } fn print_dyn_existential( self, predicates: &'tcx ty::List>, ) -> Result { self.pretty_print_dyn_existential(predicates) } fn print_const(self, ct: ty::Const<'tcx>) -> Result { self.pretty_print_const(ct, false) } fn path_crate(mut self, cnum: CrateNum) -> Result { self.empty_path = true; if cnum == LOCAL_CRATE { if self.tcx.sess.rust_2018() { // We add the `crate::` keyword on Rust 2018, only when desired. if SHOULD_PREFIX_WITH_CRATE.with(|flag| flag.get()) { write!(self, "{}", kw::Crate)?; self.empty_path = false; } } } else { write!(self, "{}", self.tcx.crate_name(cnum))?; self.empty_path = false; } Ok(self) } fn path_qualified( mut self, self_ty: Ty<'tcx>, trait_ref: Option>, ) -> Result { self = self.pretty_path_qualified(self_ty, trait_ref)?; self.empty_path = false; Ok(self) } fn path_append_impl( mut self, print_prefix: impl FnOnce(Self) -> Result, _disambiguated_data: &DisambiguatedDefPathData, self_ty: Ty<'tcx>, trait_ref: Option>, ) -> Result { self = self.pretty_path_append_impl( |mut cx| { cx = print_prefix(cx)?; if !cx.empty_path { write!(cx, "::")?; } Ok(cx) }, self_ty, trait_ref, )?; self.empty_path = false; Ok(self) } fn path_append( mut self, print_prefix: impl FnOnce(Self) -> Result, disambiguated_data: &DisambiguatedDefPathData, ) -> Result { self = print_prefix(self)?; // Skip `::{{extern}}` blocks and `::{{constructor}}` on tuple/unit structs. if let DefPathData::ForeignMod | DefPathData::Ctor = disambiguated_data.data { return Ok(self); } let name = disambiguated_data.data.name(); if !self.empty_path { write!(self, "::")?; } if let DefPathDataName::Named(name) = name { if Ident::with_dummy_span(name).is_raw_guess() { write!(self, "r#")?; } } let verbose = self.should_print_verbose(); disambiguated_data.fmt_maybe_verbose(&mut self, verbose)?; self.empty_path = false; Ok(self) } fn path_generic_args( mut self, print_prefix: impl FnOnce(Self) -> Result, args: &[GenericArg<'tcx>], ) -> Result { self = print_prefix(self)?; if args.first().is_some() { if self.in_value { write!(self, "::")?; } self.generic_delimiters(|cx| cx.comma_sep(args.iter().cloned())) } else { Ok(self) } } } impl<'tcx> PrettyPrinter<'tcx> for FmtPrinter<'_, 'tcx> { fn ty_infer_name(&self, id: ty::TyVid) -> Option { self.0.ty_infer_name_resolver.as_ref().and_then(|func| func(id)) } fn const_infer_name(&self, id: ty::ConstVid<'tcx>) -> Option { self.0.const_infer_name_resolver.as_ref().and_then(|func| func(id)) } fn print_value_path( mut self, def_id: DefId, substs: &'tcx [GenericArg<'tcx>], ) -> Result { let was_in_value = std::mem::replace(&mut self.in_value, true); self = self.print_def_path(def_id, substs)?; self.in_value = was_in_value; Ok(self) } fn in_binder(self, value: &ty::Binder<'tcx, T>) -> Result where T: Print<'tcx, Self, Output = Self, Error = Self::Error> + TypeFoldable<'tcx>, { self.pretty_in_binder(value) } fn wrap_binder Result>( self, value: &ty::Binder<'tcx, T>, f: C, ) -> Result where T: Print<'tcx, Self, Output = Self, Error = Self::Error> + TypeFoldable<'tcx>, { self.pretty_wrap_binder(value, f) } fn typed_value( mut self, f: impl FnOnce(Self) -> Result, t: impl FnOnce(Self) -> Result, conversion: &str, ) -> Result { self.write_str("{")?; self = f(self)?; self.write_str(conversion)?; let was_in_value = std::mem::replace(&mut self.in_value, false); self = t(self)?; self.in_value = was_in_value; self.write_str("}")?; Ok(self) } fn generic_delimiters( mut self, f: impl FnOnce(Self) -> Result, ) -> Result { write!(self, "<")?; let was_in_value = std::mem::replace(&mut self.in_value, false); let mut inner = f(self)?; inner.in_value = was_in_value; write!(inner, ">")?; Ok(inner) } fn should_print_region(&self, region: ty::Region<'tcx>) -> bool { let highlight = self.region_highlight_mode; if highlight.region_highlighted(region).is_some() { return true; } if self.should_print_verbose() { return true; } let identify_regions = self.tcx.sess.opts.unstable_opts.identify_regions; match *region { ty::ReEarlyBound(ref data) => data.has_name(), ty::ReLateBound(_, ty::BoundRegion { kind: br, .. }) | ty::ReFree(ty::FreeRegion { bound_region: br, .. }) | ty::RePlaceholder(ty::Placeholder { name: br, .. }) => { if br.is_named() { return true; } if let Some((region, _)) = highlight.highlight_bound_region { if br == region { return true; } } false } ty::ReVar(_) if identify_regions => true, ty::ReVar(_) | ty::ReErased => false, ty::ReStatic => true, } } fn pretty_print_const_pointer( self, p: Pointer, ty: Ty<'tcx>, print_ty: bool, ) -> Result { let print = |mut this: Self| { define_scoped_cx!(this); if this.print_alloc_ids { p!(write("{:?}", p)); } else { p!("&_"); } Ok(this) }; if print_ty { self.typed_value(print, |this| this.print_type(ty), ": ") } else { print(self) } } } // HACK(eddyb) limited to `FmtPrinter` because of `region_highlight_mode`. impl<'tcx> FmtPrinter<'_, 'tcx> { pub fn pretty_print_region(mut self, region: ty::Region<'tcx>) -> Result { define_scoped_cx!(self); // Watch out for region highlights. let highlight = self.region_highlight_mode; if let Some(n) = highlight.region_highlighted(region) { p!(write("'{}", n)); return Ok(self); } if self.should_print_verbose() { p!(write("{:?}", region)); return Ok(self); } let identify_regions = self.tcx.sess.opts.unstable_opts.identify_regions; // These printouts are concise. They do not contain all the information // the user might want to diagnose an error, but there is basically no way // to fit that into a short string. Hence the recommendation to use // `explain_region()` or `note_and_explain_region()`. match *region { ty::ReEarlyBound(ref data) => { if data.name != kw::Empty { p!(write("{}", data.name)); return Ok(self); } } ty::ReLateBound(_, ty::BoundRegion { kind: br, .. }) | ty::ReFree(ty::FreeRegion { bound_region: br, .. }) | ty::RePlaceholder(ty::Placeholder { name: br, .. }) => { if let ty::BrNamed(_, name) = br && br.is_named() { p!(write("{}", name)); return Ok(self); } if let Some((region, counter)) = highlight.highlight_bound_region { if br == region { p!(write("'{}", counter)); return Ok(self); } } } ty::ReVar(region_vid) if identify_regions => { p!(write("{:?}", region_vid)); return Ok(self); } ty::ReVar(_) => {} ty::ReErased => {} ty::ReStatic => { p!("'static"); return Ok(self); } } p!("'_"); Ok(self) } } /// Folds through bound vars and placeholders, naming them struct RegionFolder<'a, 'tcx> { tcx: TyCtxt<'tcx>, current_index: ty::DebruijnIndex, region_map: BTreeMap>, name: &'a mut ( dyn FnMut( Option, // Debruijn index of the folded late-bound region ty::DebruijnIndex, // Index corresponding to binder level ty::BoundRegion, ) -> ty::Region<'tcx> + 'a ), } impl<'a, 'tcx> ty::TypeFolder<'tcx> for RegionFolder<'a, 'tcx> { fn tcx<'b>(&'b self) -> TyCtxt<'tcx> { self.tcx } fn fold_binder>( &mut self, t: ty::Binder<'tcx, T>, ) -> ty::Binder<'tcx, T> { self.current_index.shift_in(1); let t = t.super_fold_with(self); self.current_index.shift_out(1); t } fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> { match *t.kind() { _ if t.has_vars_bound_at_or_above(self.current_index) || t.has_placeholders() => { return t.super_fold_with(self); } _ => {} } t } fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> { let name = &mut self.name; let region = match *r { ty::ReLateBound(db, br) if db >= self.current_index => { *self.region_map.entry(br).or_insert_with(|| name(Some(db), self.current_index, br)) } ty::RePlaceholder(ty::PlaceholderRegion { name: kind, .. }) => { // If this is an anonymous placeholder, don't rename. Otherwise, in some // async fns, we get a `for<'r> Send` bound match kind { ty::BrAnon(..) | ty::BrEnv => r, _ => { // Index doesn't matter, since this is just for naming and these never get bound let br = ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind }; *self .region_map .entry(br) .or_insert_with(|| name(None, self.current_index, br)) } } } _ => return r, }; if let ty::ReLateBound(debruijn1, br) = *region { assert_eq!(debruijn1, ty::INNERMOST); self.tcx.mk_region(ty::ReLateBound(self.current_index, br)) } else { region } } } // HACK(eddyb) limited to `FmtPrinter` because of `binder_depth`, // `region_index` and `used_region_names`. impl<'tcx> FmtPrinter<'_, 'tcx> { pub fn name_all_regions( mut self, value: &ty::Binder<'tcx, T>, ) -> Result<(Self, T, BTreeMap>), fmt::Error> where T: Print<'tcx, Self, Output = Self, Error = fmt::Error> + TypeFoldable<'tcx>, { fn name_by_region_index( index: usize, available_names: &mut Vec, num_available: usize, ) -> Symbol { if let Some(name) = available_names.pop() { name } else { Symbol::intern(&format!("'z{}", index - num_available)) } } debug!("name_all_regions"); // Replace any anonymous late-bound regions with named // variants, using new unique identifiers, so that we can // clearly differentiate between named and unnamed regions in // the output. We'll probably want to tweak this over time to // decide just how much information to give. if self.binder_depth == 0 { self.prepare_region_info(value); } debug!("self.used_region_names: {:?}", &self.used_region_names); let mut empty = true; let mut start_or_continue = |cx: &mut Self, start: &str, cont: &str| { let w = if empty { empty = false; start } else { cont }; let _ = write!(cx, "{}", w); }; let do_continue = |cx: &mut Self, cont: Symbol| { let _ = write!(cx, "{}", cont); }; define_scoped_cx!(self); let possible_names = ('a'..='z').rev().map(|s| Symbol::intern(&format!("'{s}"))); let mut available_names = possible_names .filter(|name| !self.used_region_names.contains(&name)) .collect::>(); debug!(?available_names); let num_available = available_names.len(); let mut region_index = self.region_index; let mut next_name = |this: &Self| { let mut name; loop { name = name_by_region_index(region_index, &mut available_names, num_available); region_index += 1; if !this.used_region_names.contains(&name) { break; } } name }; // If we want to print verbosely, then print *all* binders, even if they // aren't named. Eventually, we might just want this as the default, but // this is not *quite* right and changes the ordering of some output // anyways. let (new_value, map) = if self.should_print_verbose() { for var in value.bound_vars().iter() { start_or_continue(&mut self, "for<", ", "); write!(self, "{:?}", var)?; } start_or_continue(&mut self, "", "> "); (value.clone().skip_binder(), BTreeMap::default()) } else { let tcx = self.tcx; // Closure used in `RegionFolder` to create names for anonymous late-bound // regions. We use two `DebruijnIndex`es (one for the currently folded // late-bound region and the other for the binder level) to determine // whether a name has already been created for the currently folded region, // see issue #102392. let mut name = |lifetime_idx: Option, binder_level_idx: ty::DebruijnIndex, br: ty::BoundRegion| { let (name, kind) = match br.kind { ty::BrAnon(..) | ty::BrEnv => { let name = next_name(&self); if let Some(lt_idx) = lifetime_idx { if lt_idx > binder_level_idx { let kind = ty::BrNamed(CRATE_DEF_ID.to_def_id(), name); return tcx.mk_region(ty::ReLateBound( ty::INNERMOST, ty::BoundRegion { var: br.var, kind }, )); } } (name, ty::BrNamed(CRATE_DEF_ID.to_def_id(), name)) } ty::BrNamed(def_id, kw::UnderscoreLifetime | kw::Empty) => { let name = next_name(&self); if let Some(lt_idx) = lifetime_idx { if lt_idx > binder_level_idx { let kind = ty::BrNamed(def_id, name); return tcx.mk_region(ty::ReLateBound( ty::INNERMOST, ty::BoundRegion { var: br.var, kind }, )); } } (name, ty::BrNamed(def_id, name)) } ty::BrNamed(_, name) => { if let Some(lt_idx) = lifetime_idx { if lt_idx > binder_level_idx { let kind = br.kind; return tcx.mk_region(ty::ReLateBound( ty::INNERMOST, ty::BoundRegion { var: br.var, kind }, )); } } (name, br.kind) } }; start_or_continue(&mut self, "for<", ", "); do_continue(&mut self, name); tcx.mk_region(ty::ReLateBound(ty::INNERMOST, ty::BoundRegion { var: br.var, kind })) }; let mut folder = RegionFolder { tcx, current_index: ty::INNERMOST, name: &mut name, region_map: BTreeMap::new(), }; let new_value = value.clone().skip_binder().fold_with(&mut folder); let region_map = folder.region_map; start_or_continue(&mut self, "", "> "); (new_value, region_map) }; self.binder_depth += 1; self.region_index = region_index; Ok((self, new_value, map)) } pub fn pretty_in_binder(self, value: &ty::Binder<'tcx, T>) -> Result where T: Print<'tcx, Self, Output = Self, Error = fmt::Error> + TypeFoldable<'tcx>, { let old_region_index = self.region_index; let (new, new_value, _) = self.name_all_regions(value)?; let mut inner = new_value.print(new)?; inner.region_index = old_region_index; inner.binder_depth -= 1; Ok(inner) } pub fn pretty_wrap_binder Result>( self, value: &ty::Binder<'tcx, T>, f: C, ) -> Result where T: Print<'tcx, Self, Output = Self, Error = fmt::Error> + TypeFoldable<'tcx>, { let old_region_index = self.region_index; let (new, new_value, _) = self.name_all_regions(value)?; let mut inner = f(&new_value, new)?; inner.region_index = old_region_index; inner.binder_depth -= 1; Ok(inner) } fn prepare_region_info(&mut self, value: &ty::Binder<'tcx, T>) where T: TypeVisitable<'tcx>, { struct RegionNameCollector<'tcx> { used_region_names: FxHashSet, type_collector: SsoHashSet>, } impl<'tcx> RegionNameCollector<'tcx> { fn new() -> Self { RegionNameCollector { used_region_names: Default::default(), type_collector: SsoHashSet::new(), } } } impl<'tcx> ty::visit::TypeVisitor<'tcx> for RegionNameCollector<'tcx> { type BreakTy = (); fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow { trace!("address: {:p}", r.0.0); // Collect all named lifetimes. These allow us to prevent duplication // of already existing lifetime names when introducing names for // anonymous late-bound regions. if let Some(name) = r.get_name() { self.used_region_names.insert(name); } r.super_visit_with(self) } // We collect types in order to prevent really large types from compiling for // a really long time. See issue #83150 for why this is necessary. fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow { let not_previously_inserted = self.type_collector.insert(ty); if not_previously_inserted { ty.super_visit_with(self) } else { ControlFlow::CONTINUE } } } let mut collector = RegionNameCollector::new(); value.visit_with(&mut collector); self.used_region_names = collector.used_region_names; self.region_index = 0; } } impl<'tcx, T, P: PrettyPrinter<'tcx>> Print<'tcx, P> for ty::Binder<'tcx, T> where T: Print<'tcx, P, Output = P, Error = P::Error> + TypeFoldable<'tcx>, { type Output = P; type Error = P::Error; fn print(&self, cx: P) -> Result { cx.in_binder(self) } } impl<'tcx, T, U, P: PrettyPrinter<'tcx>> Print<'tcx, P> for ty::OutlivesPredicate where T: Print<'tcx, P, Output = P, Error = P::Error>, U: Print<'tcx, P, Output = P, Error = P::Error>, { type Output = P; type Error = P::Error; fn print(&self, mut cx: P) -> Result { define_scoped_cx!(cx); p!(print(self.0), ": ", print(self.1)); Ok(cx) } } macro_rules! forward_display_to_print { ($($ty:ty),+) => { // Some of the $ty arguments may not actually use 'tcx $(#[allow(unused_lifetimes)] impl<'tcx> fmt::Display for $ty { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { ty::tls::with(|tcx| { let cx = tcx.lift(*self) .expect("could not lift for printing") .print(FmtPrinter::new(tcx, Namespace::TypeNS))?; f.write_str(&cx.into_buffer())?; Ok(()) }) } })+ }; } macro_rules! define_print_and_forward_display { (($self:ident, $cx:ident): $($ty:ty $print:block)+) => { $(impl<'tcx, P: PrettyPrinter<'tcx>> Print<'tcx, P> for $ty { type Output = P; type Error = fmt::Error; fn print(&$self, $cx: P) -> Result { #[allow(unused_mut)] let mut $cx = $cx; define_scoped_cx!($cx); let _: () = $print; #[allow(unreachable_code)] Ok($cx) } })+ forward_display_to_print!($($ty),+); }; } /// Wrapper type for `ty::TraitRef` which opts-in to pretty printing only /// the trait path. That is, it will print `Trait` instead of /// `>`. #[derive(Copy, Clone, TypeFoldable, TypeVisitable, Lift)] pub struct TraitRefPrintOnlyTraitPath<'tcx>(ty::TraitRef<'tcx>); impl<'tcx> fmt::Debug for TraitRefPrintOnlyTraitPath<'tcx> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Display::fmt(self, f) } } /// Wrapper type for `ty::TraitRef` which opts-in to pretty printing only /// the trait name. That is, it will print `Trait` instead of /// `>`. #[derive(Copy, Clone, TypeFoldable, TypeVisitable, Lift)] pub struct TraitRefPrintOnlyTraitName<'tcx>(ty::TraitRef<'tcx>); impl<'tcx> fmt::Debug for TraitRefPrintOnlyTraitName<'tcx> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Display::fmt(self, f) } } impl<'tcx> ty::TraitRef<'tcx> { pub fn print_only_trait_path(self) -> TraitRefPrintOnlyTraitPath<'tcx> { TraitRefPrintOnlyTraitPath(self) } pub fn print_only_trait_name(self) -> TraitRefPrintOnlyTraitName<'tcx> { TraitRefPrintOnlyTraitName(self) } } impl<'tcx> ty::Binder<'tcx, ty::TraitRef<'tcx>> { pub fn print_only_trait_path(self) -> ty::Binder<'tcx, TraitRefPrintOnlyTraitPath<'tcx>> { self.map_bound(|tr| tr.print_only_trait_path()) } } #[derive(Copy, Clone, TypeFoldable, TypeVisitable, Lift)] pub struct TraitPredPrintModifiersAndPath<'tcx>(ty::TraitPredicate<'tcx>); impl<'tcx> fmt::Debug for TraitPredPrintModifiersAndPath<'tcx> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Display::fmt(self, f) } } impl<'tcx> ty::TraitPredicate<'tcx> { pub fn print_modifiers_and_trait_path(self) -> TraitPredPrintModifiersAndPath<'tcx> { TraitPredPrintModifiersAndPath(self) } } impl<'tcx> ty::PolyTraitPredicate<'tcx> { pub fn print_modifiers_and_trait_path( self, ) -> ty::Binder<'tcx, TraitPredPrintModifiersAndPath<'tcx>> { self.map_bound(TraitPredPrintModifiersAndPath) } } #[derive(Debug, Copy, Clone, TypeFoldable, TypeVisitable, Lift)] pub struct PrintClosureAsImpl<'tcx> { pub closure: ty::ClosureSubsts<'tcx>, } forward_display_to_print! { ty::Region<'tcx>, Ty<'tcx>, &'tcx ty::List>, ty::Const<'tcx>, // HACK(eddyb) these are exhaustive instead of generic, // because `for<'tcx>` isn't possible yet. ty::PolyExistentialPredicate<'tcx>, ty::Binder<'tcx, ty::TraitRef<'tcx>>, ty::Binder<'tcx, ty::ExistentialTraitRef<'tcx>>, ty::Binder<'tcx, TraitRefPrintOnlyTraitPath<'tcx>>, ty::Binder<'tcx, TraitRefPrintOnlyTraitName<'tcx>>, ty::Binder<'tcx, ty::FnSig<'tcx>>, ty::Binder<'tcx, ty::TraitPredicate<'tcx>>, ty::Binder<'tcx, TraitPredPrintModifiersAndPath<'tcx>>, ty::Binder<'tcx, ty::SubtypePredicate<'tcx>>, ty::Binder<'tcx, ty::ProjectionPredicate<'tcx>>, ty::Binder<'tcx, ty::OutlivesPredicate, ty::Region<'tcx>>>, ty::Binder<'tcx, ty::OutlivesPredicate, ty::Region<'tcx>>>, ty::OutlivesPredicate, ty::Region<'tcx>>, ty::OutlivesPredicate, ty::Region<'tcx>> } define_print_and_forward_display! { (self, cx): &'tcx ty::List> { p!("{{", comma_sep(self.iter()), "}}") } ty::TypeAndMut<'tcx> { p!(write("{}", self.mutbl.prefix_str()), print(self.ty)) } ty::ExistentialTraitRef<'tcx> { // Use a type that can't appear in defaults of type parameters. let dummy_self = cx.tcx().mk_ty_infer(ty::FreshTy(0)); let trait_ref = self.with_self_ty(cx.tcx(), dummy_self); p!(print(trait_ref.print_only_trait_path())) } ty::ExistentialProjection<'tcx> { let name = cx.tcx().associated_item(self.item_def_id).name; p!(write("{} = ", name), print(self.term)) } ty::ExistentialPredicate<'tcx> { match *self { ty::ExistentialPredicate::Trait(x) => p!(print(x)), ty::ExistentialPredicate::Projection(x) => p!(print(x)), ty::ExistentialPredicate::AutoTrait(def_id) => { p!(print_def_path(def_id, &[])); } } } ty::FnSig<'tcx> { p!(write("{}", self.unsafety.prefix_str())); if self.abi != Abi::Rust { p!(write("extern {} ", self.abi)); } p!("fn", pretty_fn_sig(self.inputs(), self.c_variadic, self.output())); } ty::TraitRef<'tcx> { p!(write("<{} as {}>", self.self_ty(), self.print_only_trait_path())) } TraitRefPrintOnlyTraitPath<'tcx> { p!(print_def_path(self.0.def_id, self.0.substs)); } TraitRefPrintOnlyTraitName<'tcx> { p!(print_def_path(self.0.def_id, &[])); } TraitPredPrintModifiersAndPath<'tcx> { if let ty::BoundConstness::ConstIfConst = self.0.constness { p!("~const ") } if let ty::ImplPolarity::Negative = self.0.polarity { p!("!") } p!(print(self.0.trait_ref.print_only_trait_path())); } PrintClosureAsImpl<'tcx> { p!(pretty_closure_as_impl(self.closure)) } ty::ParamTy { p!(write("{}", self.name)) } ty::ParamConst { p!(write("{}", self.name)) } ty::SubtypePredicate<'tcx> { p!(print(self.a), " <: ", print(self.b)) } ty::CoercePredicate<'tcx> { p!(print(self.a), " -> ", print(self.b)) } ty::TraitPredicate<'tcx> { p!(print(self.trait_ref.self_ty()), ": "); if let ty::BoundConstness::ConstIfConst = self.constness && cx.tcx().features().const_trait_impl { p!("~const "); } p!(print(self.trait_ref.print_only_trait_path())) } ty::ProjectionPredicate<'tcx> { p!(print(self.projection_ty), " == ", print(self.term)) } ty::Term<'tcx> { match self.unpack() { ty::TermKind::Ty(ty) => p!(print(ty)), ty::TermKind::Const(c) => p!(print(c)), } } ty::ProjectionTy<'tcx> { p!(print_def_path(self.item_def_id, self.substs)); } ty::ClosureKind { match *self { ty::ClosureKind::Fn => p!("Fn"), ty::ClosureKind::FnMut => p!("FnMut"), ty::ClosureKind::FnOnce => p!("FnOnce"), } } ty::Predicate<'tcx> { let binder = self.kind(); p!(print(binder)) } ty::PredicateKind<'tcx> { match *self { ty::PredicateKind::Clause(ty::Clause::Trait(ref data)) => { p!(print(data)) } ty::PredicateKind::Subtype(predicate) => p!(print(predicate)), ty::PredicateKind::Coerce(predicate) => p!(print(predicate)), ty::PredicateKind::Clause(ty::Clause::RegionOutlives(predicate)) => p!(print(predicate)), ty::PredicateKind::Clause(ty::Clause::TypeOutlives(predicate)) => p!(print(predicate)), ty::PredicateKind::Clause(ty::Clause::Projection(predicate)) => p!(print(predicate)), ty::PredicateKind::WellFormed(arg) => p!(print(arg), " well-formed"), ty::PredicateKind::ObjectSafe(trait_def_id) => { p!("the trait `", print_def_path(trait_def_id, &[]), "` is object-safe") } ty::PredicateKind::ClosureKind(closure_def_id, _closure_substs, kind) => { p!("the closure `", print_value_path(closure_def_id, &[]), write("` implements the trait `{}`", kind)) } ty::PredicateKind::ConstEvaluatable(ct) => { p!("the constant `", print(ct), "` can be evaluated") } ty::PredicateKind::ConstEquate(c1, c2) => { p!("the constant `", print(c1), "` equals `", print(c2), "`") } ty::PredicateKind::TypeWellFormedFromEnv(ty) => { p!("the type `", print(ty), "` is found in the environment") } ty::PredicateKind::Ambiguous => p!("ambiguous"), } } GenericArg<'tcx> { match self.unpack() { GenericArgKind::Lifetime(lt) => p!(print(lt)), GenericArgKind::Type(ty) => p!(print(ty)), GenericArgKind::Const(ct) => p!(print(ct)), } } } fn for_each_def(tcx: TyCtxt<'_>, mut collect_fn: impl for<'b> FnMut(&'b Ident, Namespace, DefId)) { // Iterate all local crate items no matter where they are defined. let hir = tcx.hir(); for id in hir.items() { if matches!(tcx.def_kind(id.owner_id), DefKind::Use) { continue; } let item = hir.item(id); if item.ident.name == kw::Empty { continue; } let def_id = item.owner_id.to_def_id(); let ns = tcx.def_kind(def_id).ns().unwrap_or(Namespace::TypeNS); collect_fn(&item.ident, ns, def_id); } // Now take care of extern crate items. let queue = &mut Vec::new(); let mut seen_defs: DefIdSet = Default::default(); for &cnum in tcx.crates(()).iter() { let def_id = cnum.as_def_id(); // Ignore crates that are not direct dependencies. match tcx.extern_crate(def_id) { None => continue, Some(extern_crate) => { if !extern_crate.is_direct() { continue; } } } queue.push(def_id); } // Iterate external crate defs but be mindful about visibility while let Some(def) = queue.pop() { for child in tcx.module_children(def).iter() { if !child.vis.is_public() { continue; } match child.res { def::Res::Def(DefKind::AssocTy, _) => {} def::Res::Def(DefKind::TyAlias, _) => {} def::Res::Def(defkind, def_id) => { if let Some(ns) = defkind.ns() { collect_fn(&child.ident, ns, def_id); } if matches!(defkind, DefKind::Mod | DefKind::Enum | DefKind::Trait) && seen_defs.insert(def_id) { queue.push(def_id); } } _ => {} } } } } /// The purpose of this function is to collect public symbols names that are unique across all /// crates in the build. Later, when printing about types we can use those names instead of the /// full exported path to them. /// /// So essentially, if a symbol name can only be imported from one place for a type, and as /// long as it was not glob-imported anywhere in the current crate, we can trim its printed /// path and print only the name. /// /// This has wide implications on error messages with types, for example, shortening /// `std::vec::Vec` to just `Vec`, as long as there is no other `Vec` importable anywhere. /// /// The implementation uses similar import discovery logic to that of 'use' suggestions. fn trimmed_def_paths(tcx: TyCtxt<'_>, (): ()) -> FxHashMap { let mut map: FxHashMap = FxHashMap::default(); if let TrimmedDefPaths::GoodPath = tcx.sess.opts.trimmed_def_paths { // For good paths causing this bug, the `rustc_middle::ty::print::with_no_trimmed_paths` // wrapper can be used to suppress this query, in exchange for full paths being formatted. tcx.sess.delay_good_path_bug("trimmed_def_paths constructed"); } let unique_symbols_rev: &mut FxHashMap<(Namespace, Symbol), Option> = &mut FxHashMap::default(); for symbol_set in tcx.resolutions(()).glob_map.values() { for symbol in symbol_set { unique_symbols_rev.insert((Namespace::TypeNS, *symbol), None); unique_symbols_rev.insert((Namespace::ValueNS, *symbol), None); unique_symbols_rev.insert((Namespace::MacroNS, *symbol), None); } } for_each_def(tcx, |ident, ns, def_id| { use std::collections::hash_map::Entry::{Occupied, Vacant}; match unique_symbols_rev.entry((ns, ident.name)) { Occupied(mut v) => match v.get() { None => {} Some(existing) => { if *existing != def_id { v.insert(None); } } }, Vacant(v) => { v.insert(Some(def_id)); } } }); for ((_, symbol), opt_def_id) in unique_symbols_rev.drain() { use std::collections::hash_map::Entry::{Occupied, Vacant}; if let Some(def_id) = opt_def_id { match map.entry(def_id) { Occupied(mut v) => { // A single DefId can be known under multiple names (e.g., // with a `pub use ... as ...;`). We need to ensure that the // name placed in this map is chosen deterministically, so // if we find multiple names (`symbol`) resolving to the // same `def_id`, we prefer the lexicographically smallest // name. // // Any stable ordering would be fine here though. if *v.get() != symbol { if v.get().as_str() > symbol.as_str() { v.insert(symbol); } } } Vacant(v) => { v.insert(symbol); } } } } map } pub fn provide(providers: &mut ty::query::Providers) { *providers = ty::query::Providers { trimmed_def_paths, ..*providers }; } #[derive(Default)] pub struct OpaqueFnEntry<'tcx> { // The trait ref is already stored as a key, so just track if we have it as a real predicate has_fn_once: bool, fn_mut_trait_ref: Option>, fn_trait_ref: Option>, return_ty: Option>>, }