1 //! FIXME: write short doc here
5 use chalk_ir::Mutability;
9 generics::TypeParamProvenance,
11 path::{GenericArg, Path, PathKind},
12 type_ref::{TypeBound, TypeRef},
13 visibility::Visibility,
14 AssocContainerId, Lookup, ModuleId, TraitId,
16 use hir_expand::name::Name;
19 db::HirDatabase, from_assoc_type_id, from_foreign_def_id, from_placeholder_idx, primitive,
20 to_assoc_type_id, traits::chalk::from_chalk, utils::generics, AdtId, AliasEq, AliasTy,
21 CallableDefId, CallableSig, DomainGoal, ImplTraitId, Interner, Lifetime, OpaqueTy,
22 ProjectionTy, QuantifiedWhereClause, Scalar, Substitution, TraitRef, Ty, TyKind, WhereClause,
25 pub struct HirFormatter<'a> {
26 pub db: &'a dyn HirDatabase,
27 fmt: &'a mut dyn fmt::Write,
30 pub(crate) max_size: Option<usize>,
31 omit_verbose_types: bool,
32 display_target: DisplayTarget,
35 pub trait HirDisplay {
36 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError>;
38 /// Returns a `Display`able type that is human-readable.
39 fn into_displayable<'a>(
41 db: &'a dyn HirDatabase,
42 max_size: Option<usize>,
43 omit_verbose_types: bool,
44 display_target: DisplayTarget,
45 ) -> HirDisplayWrapper<'a, Self>
49 HirDisplayWrapper { db, t: self, max_size, omit_verbose_types, display_target }
52 /// Returns a `Display`able type that is human-readable.
53 /// Use this for showing types to the user (e.g. diagnostics)
54 fn display<'a>(&'a self, db: &'a dyn HirDatabase) -> HirDisplayWrapper<'a, Self>
62 omit_verbose_types: false,
63 display_target: DisplayTarget::Diagnostics,
67 /// Returns a `Display`able type that is human-readable and tries to be succinct.
68 /// Use this for showing types to the user where space is constrained (e.g. doc popups)
69 fn display_truncated<'a>(
71 db: &'a dyn HirDatabase,
72 max_size: Option<usize>,
73 ) -> HirDisplayWrapper<'a, Self>
81 omit_verbose_types: true,
82 display_target: DisplayTarget::Diagnostics,
86 /// Returns a String representation of `self` that can be inserted into the given module.
87 /// Use this when generating code (e.g. assists)
88 fn display_source_code<'a>(
90 db: &'a dyn HirDatabase,
92 ) -> Result<String, DisplaySourceCodeError> {
93 let mut result = String::new();
94 match self.hir_fmt(&mut HirFormatter {
97 buf: String::with_capacity(20),
100 omit_verbose_types: false,
101 display_target: DisplayTarget::SourceCode { module_id },
104 Err(HirDisplayError::FmtError) => panic!("Writing to String can't fail!"),
105 Err(HirDisplayError::DisplaySourceCodeError(e)) => return Err(e),
110 /// Returns a String representation of `self` for test purposes
111 fn display_test<'a>(&'a self, db: &'a dyn HirDatabase) -> HirDisplayWrapper<'a, Self>
119 omit_verbose_types: false,
120 display_target: DisplayTarget::Test,
125 impl<'a> HirFormatter<'a> {
126 pub fn write_joined<T: HirDisplay>(
128 iter: impl IntoIterator<Item = T>,
130 ) -> Result<(), HirDisplayError> {
131 let mut first = true;
134 write!(self, "{}", sep)?;
142 /// This allows using the `write!` macro directly with a `HirFormatter`.
143 pub fn write_fmt(&mut self, args: fmt::Arguments) -> Result<(), HirDisplayError> {
144 // We write to a buffer first to track output size
146 fmt::write(&mut self.buf, args)?;
147 self.curr_size += self.buf.len();
149 // Then we write to the internal formatter from the buffer
150 self.fmt.write_str(&self.buf).map_err(HirDisplayError::from)
153 pub fn should_truncate(&self) -> bool {
154 if let Some(max_size) = self.max_size {
155 self.curr_size >= max_size
161 pub fn omit_verbose_types(&self) -> bool {
162 self.omit_verbose_types
166 #[derive(Clone, Copy)]
167 pub enum DisplayTarget {
168 /// Display types for inlays, doc popups, autocompletion, etc...
169 /// Showing `{unknown}` or not qualifying paths is fine here.
170 /// There's no reason for this to fail.
172 /// Display types for inserting them in source files.
173 /// The generated code should compile, so paths need to be qualified.
174 SourceCode { module_id: ModuleId },
175 /// Only for test purpose to keep real types
180 fn is_source_code(&self) -> bool {
181 matches!(self, Self::SourceCode { .. })
183 fn is_test(&self) -> bool {
184 matches!(self, Self::Test)
189 pub enum DisplaySourceCodeError {
195 pub enum HirDisplayError {
196 /// Errors that can occur when generating source code
197 DisplaySourceCodeError(DisplaySourceCodeError),
198 /// `FmtError` is required to be compatible with std::fmt::Display
201 impl From<fmt::Error> for HirDisplayError {
202 fn from(_: fmt::Error) -> Self {
207 pub struct HirDisplayWrapper<'a, T> {
208 db: &'a dyn HirDatabase,
210 max_size: Option<usize>,
211 omit_verbose_types: bool,
212 display_target: DisplayTarget,
215 impl<'a, T> fmt::Display for HirDisplayWrapper<'a, T>
219 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
220 match self.t.hir_fmt(&mut HirFormatter {
223 buf: String::with_capacity(20),
225 max_size: self.max_size,
226 omit_verbose_types: self.omit_verbose_types,
227 display_target: self.display_target,
230 Err(HirDisplayError::FmtError) => Err(fmt::Error),
231 Err(HirDisplayError::DisplaySourceCodeError(_)) => {
232 // This should never happen
233 panic!("HirDisplay failed when calling Display::fmt!")
239 const TYPE_HINT_TRUNCATION: &str = "…";
241 impl<T: HirDisplay> HirDisplay for &'_ T {
242 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
243 HirDisplay::hir_fmt(*self, f)
247 impl HirDisplay for ProjectionTy {
248 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
249 if f.should_truncate() {
250 return write!(f, "{}", TYPE_HINT_TRUNCATION);
253 let trait_ = f.db.trait_data(self.trait_(f.db));
254 let first_parameter = self.substitution[0].into_displayable(
257 f.omit_verbose_types,
260 write!(f, "<{} as {}", first_parameter, trait_.name)?;
261 if self.substitution.len() > 1 {
263 f.write_joined(&self.substitution[1..], ", ")?;
266 write!(f, ">::{}", f.db.type_alias_data(from_assoc_type_id(self.associated_ty_id)).name)?;
271 impl HirDisplay for OpaqueTy {
272 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
273 if f.should_truncate() {
274 return write!(f, "{}", TYPE_HINT_TRUNCATION);
277 self.substitution[0].hir_fmt(f)
281 impl HirDisplay for Ty {
282 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
283 if f.should_truncate() {
284 return write!(f, "{}", TYPE_HINT_TRUNCATION);
287 match self.interned(&Interner) {
288 TyKind::Never => write!(f, "!")?,
289 TyKind::Str => write!(f, "str")?,
290 TyKind::Scalar(Scalar::Bool) => write!(f, "bool")?,
291 TyKind::Scalar(Scalar::Char) => write!(f, "char")?,
292 &TyKind::Scalar(Scalar::Float(t)) => write!(f, "{}", primitive::float_ty_to_string(t))?,
293 &TyKind::Scalar(Scalar::Int(t)) => write!(f, "{}", primitive::int_ty_to_string(t))?,
294 &TyKind::Scalar(Scalar::Uint(t)) => write!(f, "{}", primitive::uint_ty_to_string(t))?,
295 TyKind::Slice(t) => {
300 TyKind::Array(t) => {
305 TyKind::Raw(m, t) | TyKind::Ref(m, t) => {
307 t.into_displayable(f.db, f.max_size, f.omit_verbose_types, f.display_target);
309 if matches!(self.interned(&Interner), TyKind::Raw(..)) {
314 Mutability::Not => "const ",
315 Mutability::Mut => "mut ",
323 Mutability::Not => "",
324 Mutability::Mut => "mut ",
329 // FIXME: all this just to decide whether to use parentheses...
331 let predicates: Vec<_> = match t.interned(&Interner) {
332 TyKind::Dyn(dyn_ty) if dyn_ty.bounds.skip_binders().interned().len() > 1 => {
333 dyn_ty.bounds.skip_binders().interned().iter().cloned().collect()
335 &TyKind::Alias(AliasTy::Opaque(OpaqueTy {
337 substitution: ref parameters,
339 let impl_trait_id = f.db.lookup_intern_impl_trait_id(opaque_ty_id.into());
340 if let ImplTraitId::ReturnTypeImplTrait(func, idx) = impl_trait_id {
342 f.db.return_type_impl_traits(func)
343 .expect("impl trait id without data");
346 .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
347 let bounds = data.subst(parameters);
356 if let Some(WhereClause::Implemented(trait_ref)) =
357 predicates.get(0).map(|b| b.skip_binders())
359 let trait_ = trait_ref.hir_trait_id();
360 if fn_traits(f.db.upcast(), trait_).any(|it| it == trait_)
361 && predicates.len() <= 2
363 return write!(f, "{}", ty_display);
367 if predicates.len() > 1 {
369 write!(f, "{}", ty_display)?;
372 write!(f, "{}", ty_display)?;
375 TyKind::Tuple(_, substs) => {
376 if substs.len() == 1 {
378 substs[0].hir_fmt(f)?;
382 f.write_joined(&*substs.0, ", ")?;
386 TyKind::Function(fn_ptr) => {
387 let sig = CallableSig::from_fn_ptr(fn_ptr);
390 TyKind::FnDef(def, parameters) => {
391 let def = from_chalk(f.db, *def);
392 let sig = f.db.callable_item_signature(def).subst(parameters);
394 CallableDefId::FunctionId(ff) => {
395 write!(f, "fn {}", f.db.function_data(ff).name)?
397 CallableDefId::StructId(s) => write!(f, "{}", f.db.struct_data(s).name)?,
398 CallableDefId::EnumVariantId(e) => {
399 write!(f, "{}", f.db.enum_data(e.parent).variants[e.local_id].name)?
402 if parameters.len() > 0 {
403 let generics = generics(f.db.upcast(), def.into());
404 let (parent_params, self_param, type_params, _impl_trait_params) =
405 generics.provenance_split();
406 let total_len = parent_params + self_param + type_params;
407 // We print all params except implicit impl Trait params. Still a bit weird; should we leave out parent and self?
410 f.write_joined(¶meters.0[..total_len], ", ")?;
415 f.write_joined(sig.params(), ", ")?;
418 if *ret != Ty::unit() {
419 let ret_display = ret.into_displayable(
422 f.omit_verbose_types,
426 write!(f, " -> {}", ret_display)?;
429 TyKind::Adt(AdtId(def_id), parameters) => {
430 match f.display_target {
431 DisplayTarget::Diagnostics | DisplayTarget::Test => {
432 let name = match *def_id {
433 hir_def::AdtId::StructId(it) => f.db.struct_data(it).name.clone(),
434 hir_def::AdtId::UnionId(it) => f.db.union_data(it).name.clone(),
435 hir_def::AdtId::EnumId(it) => f.db.enum_data(it).name.clone(),
437 write!(f, "{}", name)?;
439 DisplayTarget::SourceCode { module_id } => {
440 if let Some(path) = find_path::find_path(
442 ItemInNs::Types((*def_id).into()),
445 write!(f, "{}", path)?;
447 return Err(HirDisplayError::DisplaySourceCodeError(
448 DisplaySourceCodeError::PathNotFound,
454 if parameters.len() > 0 {
455 let parameters_to_write = if f.display_target.is_source_code()
456 || f.omit_verbose_types()
459 .as_generic_def(f.db)
460 .map(|generic_def_id| f.db.generic_defaults(generic_def_id))
461 .filter(|defaults| !defaults.is_empty())
463 None => parameters.0.as_ref(),
464 Some(default_parameters) => {
465 let mut default_from = 0;
466 for (i, parameter) in parameters.iter().enumerate() {
467 match (parameter.interned(&Interner), default_parameters.get(i))
469 (&TyKind::Unknown, _) | (_, None) => {
470 default_from = i + 1;
472 (_, Some(default_parameter)) => {
473 let actual_default = default_parameter
475 .subst(¶meters.prefix(i));
476 if parameter != &actual_default {
477 default_from = i + 1;
482 ¶meters.0[0..default_from]
486 parameters.0.as_ref()
488 if !parameters_to_write.is_empty() {
490 f.write_joined(parameters_to_write, ", ")?;
495 TyKind::AssociatedType(assoc_type_id, parameters) => {
496 let type_alias = from_assoc_type_id(*assoc_type_id);
497 let trait_ = match type_alias.lookup(f.db.upcast()).container {
498 AssocContainerId::TraitId(it) => it,
499 _ => panic!("not an associated type"),
501 let trait_ = f.db.trait_data(trait_);
502 let type_alias_data = f.db.type_alias_data(type_alias);
504 // Use placeholder associated types when the target is test (https://rust-lang.github.io/chalk/book/clauses/type_equality.html#placeholder-associated-types)
505 if f.display_target.is_test() {
506 write!(f, "{}::{}", trait_.name, type_alias_data.name)?;
507 if parameters.len() > 0 {
509 f.write_joined(&*parameters.0, ", ")?;
513 let projection_ty = ProjectionTy {
514 associated_ty_id: to_assoc_type_id(type_alias),
515 substitution: parameters.clone(),
518 projection_ty.hir_fmt(f)?;
521 TyKind::ForeignType(type_alias) => {
522 let type_alias = f.db.type_alias_data(from_foreign_def_id(*type_alias));
523 write!(f, "{}", type_alias.name)?;
525 TyKind::OpaqueType(opaque_ty_id, parameters) => {
526 let impl_trait_id = f.db.lookup_intern_impl_trait_id((*opaque_ty_id).into());
527 match impl_trait_id {
528 ImplTraitId::ReturnTypeImplTrait(func, idx) => {
530 f.db.return_type_impl_traits(func).expect("impl trait id without data");
533 .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
534 let bounds = data.subst(¶meters);
535 write_bounds_like_dyn_trait_with_prefix("impl", &bounds.value, f)?;
536 // FIXME: it would maybe be good to distinguish this from the alias type (when debug printing), and to show the substitution
538 ImplTraitId::AsyncBlockTypeImplTrait(..) => {
539 write!(f, "impl Future<Output = ")?;
540 parameters[0].hir_fmt(f)?;
545 TyKind::Closure(.., substs) => {
546 if f.display_target.is_source_code() {
547 return Err(HirDisplayError::DisplaySourceCodeError(
548 DisplaySourceCodeError::Closure,
551 let sig = substs[0].callable_sig(f.db);
552 if let Some(sig) = sig {
553 if sig.params().is_empty() {
555 } else if f.omit_verbose_types() {
556 write!(f, "|{}|", TYPE_HINT_TRUNCATION)?;
559 f.write_joined(sig.params(), ", ")?;
563 let ret_display = sig.ret().into_displayable(
566 f.omit_verbose_types,
569 write!(f, " -> {}", ret_display)?;
571 write!(f, "{{closure}}")?;
574 TyKind::Placeholder(idx) => {
575 let id = from_placeholder_idx(f.db, *idx);
576 let generics = generics(f.db.upcast(), id.parent);
577 let param_data = &generics.params.types[id.local_id];
578 match param_data.provenance {
579 TypeParamProvenance::TypeParamList | TypeParamProvenance::TraitSelf => {
580 write!(f, "{}", param_data.name.clone().unwrap_or_else(Name::missing))?
582 TypeParamProvenance::ArgumentImplTrait => {
583 let substs = Substitution::type_params_for_generics(f.db, &generics);
586 .generic_predicates(id.parent)
588 .map(|pred| pred.clone().subst(&substs))
589 .filter(|wc| match &wc.skip_binders() {
590 WhereClause::Implemented(tr) => tr.self_type_parameter() == self,
591 WhereClause::AliasEq(AliasEq {
592 alias: AliasTy::Projection(proj),
594 }) => proj.self_type_parameter() == self,
597 .collect::<Vec<_>>();
598 write_bounds_like_dyn_trait_with_prefix("impl", &bounds, f)?;
602 TyKind::BoundVar(idx) => write!(f, "?{}.{}", idx.debruijn.depth(), idx.index)?,
603 TyKind::Dyn(dyn_ty) => {
604 write_bounds_like_dyn_trait_with_prefix(
606 dyn_ty.bounds.skip_binders().interned(),
610 TyKind::Alias(AliasTy::Projection(p_ty)) => p_ty.hir_fmt(f)?,
611 TyKind::Alias(AliasTy::Opaque(opaque_ty)) => {
612 let impl_trait_id = f.db.lookup_intern_impl_trait_id(opaque_ty.opaque_ty_id.into());
613 match impl_trait_id {
614 ImplTraitId::ReturnTypeImplTrait(func, idx) => {
616 f.db.return_type_impl_traits(func).expect("impl trait id without data");
619 .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
620 let bounds = data.subst(&opaque_ty.substitution);
621 write_bounds_like_dyn_trait_with_prefix("impl", &bounds.value, f)?;
623 ImplTraitId::AsyncBlockTypeImplTrait(..) => {
624 write!(f, "{{async block}}")?;
629 if f.display_target.is_source_code() {
630 return Err(HirDisplayError::DisplaySourceCodeError(
631 DisplaySourceCodeError::UnknownType,
634 write!(f, "{{unknown}}")?;
636 TyKind::InferenceVar(..) => write!(f, "_")?,
642 impl HirDisplay for CallableSig {
643 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
645 f.write_joined(self.params(), ", ")?;
647 if self.params().is_empty() {
654 let ret = self.ret();
655 if *ret != Ty::unit() {
657 ret.into_displayable(f.db, f.max_size, f.omit_verbose_types, f.display_target);
658 write!(f, " -> {}", ret_display)?;
664 fn fn_traits(db: &dyn DefDatabase, trait_: TraitId) -> impl Iterator<Item = TraitId> {
665 let krate = trait_.lookup(db).container.krate();
667 db.lang_item(krate, "fn".into()),
668 db.lang_item(krate, "fn_mut".into()),
669 db.lang_item(krate, "fn_once".into()),
671 array::IntoIter::new(fn_traits).into_iter().flatten().flat_map(|it| it.as_trait())
674 pub fn write_bounds_like_dyn_trait_with_prefix(
676 predicates: &[QuantifiedWhereClause],
677 f: &mut HirFormatter,
678 ) -> Result<(), HirDisplayError> {
679 write!(f, "{}", prefix)?;
680 if !predicates.is_empty() {
682 write_bounds_like_dyn_trait(predicates, f)
688 fn write_bounds_like_dyn_trait(
689 predicates: &[QuantifiedWhereClause],
690 f: &mut HirFormatter,
691 ) -> Result<(), HirDisplayError> {
692 // Note: This code is written to produce nice results (i.e.
693 // corresponding to surface Rust) for types that can occur in
694 // actual Rust. It will have weird results if the predicates
695 // aren't as expected (i.e. self types = $0, projection
696 // predicates for a certain trait come after the Implemented
697 // predicate for that trait).
698 let mut first = true;
699 let mut angle_open = false;
700 let mut is_fn_trait = false;
701 for p in predicates.iter() {
702 match p.skip_binders() {
703 WhereClause::Implemented(trait_ref) => {
704 let trait_ = trait_ref.hir_trait_id();
706 is_fn_trait = fn_traits(f.db.upcast(), trait_).any(|it| it == trait_);
708 if !is_fn_trait && angle_open {
715 // We assume that the self type is $0 (i.e. the
716 // existential) here, which is the only thing that's
717 // possible in actual Rust, and hence don't print it
718 write!(f, "{}", f.db.trait_data(trait_).name)?;
719 if let [_, params @ ..] = &*trait_ref.substitution.0 {
721 if let Some(args) = params.first().and_then(|it| it.as_tuple()) {
723 f.write_joined(&*args.0, ", ")?;
726 } else if !params.is_empty() {
728 f.write_joined(params, ", ")?;
729 // there might be assoc type bindings, so we leave the angle brackets open
734 WhereClause::AliasEq(alias_eq) if is_fn_trait => {
737 alias_eq.ty.hir_fmt(f)?;
739 WhereClause::AliasEq(AliasEq { ty, alias }) => {
740 // in types in actual Rust, these will always come
741 // after the corresponding Implemented predicate
748 if let AliasTy::Projection(proj) = alias {
750 f.db.type_alias_data(from_assoc_type_id(proj.associated_ty_id));
751 write!(f, "{} = ", type_alias.name)?;
765 fn hir_fmt_ext(&self, f: &mut HirFormatter, use_as: bool) -> Result<(), HirDisplayError> {
766 if f.should_truncate() {
767 return write!(f, "{}", TYPE_HINT_TRUNCATION);
770 self.substitution[0].hir_fmt(f)?;
776 write!(f, "{}", f.db.trait_data(self.hir_trait_id()).name)?;
777 if self.substitution.len() > 1 {
779 f.write_joined(&self.substitution[1..], ", ")?;
786 impl HirDisplay for TraitRef {
787 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
788 self.hir_fmt_ext(f, false)
792 impl HirDisplay for WhereClause {
793 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
794 if f.should_truncate() {
795 return write!(f, "{}", TYPE_HINT_TRUNCATION);
799 WhereClause::Implemented(trait_ref) => trait_ref.hir_fmt(f)?,
800 WhereClause::AliasEq(AliasEq { alias: AliasTy::Projection(projection_ty), ty }) => {
802 projection_ty.trait_ref(f.db).hir_fmt_ext(f, true)?;
806 f.db.type_alias_data(from_assoc_type_id(projection_ty.associated_ty_id)).name,
810 WhereClause::AliasEq(_) => write!(f, "{{error}}")?,
816 impl HirDisplay for Lifetime {
817 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
819 Lifetime::Parameter(id) => {
820 let generics = generics(f.db.upcast(), id.parent);
821 let param_data = &generics.params.lifetimes[id.local_id];
822 write!(f, "{}", ¶m_data.name)
824 Lifetime::Static => write!(f, "'static"),
829 impl HirDisplay for DomainGoal {
830 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
832 DomainGoal::Holds(wc) => {
833 write!(f, "Holds(")?;
841 pub fn write_visibility(
844 f: &mut HirFormatter,
845 ) -> Result<(), HirDisplayError> {
847 Visibility::Public => write!(f, "pub "),
848 Visibility::Module(vis_id) => {
849 let def_map = module_id.def_map(f.db.upcast());
850 let root_module_id = def_map.module_id(def_map.root());
851 if vis_id == module_id {
852 // pub(self) or omitted
854 } else if root_module_id == vis_id {
855 write!(f, "pub(crate) ")
856 } else if module_id.containing_module(f.db.upcast()) == Some(vis_id) {
857 write!(f, "pub(super) ")
859 write!(f, "pub(in ...) ")
865 impl HirDisplay for TypeRef {
866 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
868 TypeRef::Never => write!(f, "!")?,
869 TypeRef::Placeholder => write!(f, "_")?,
870 TypeRef::Tuple(elems) => {
872 f.write_joined(elems, ", ")?;
873 if elems.len() == 1 {
878 TypeRef::Path(path) => path.hir_fmt(f)?,
879 TypeRef::RawPtr(inner, mutability) => {
880 let mutability = match mutability {
881 hir_def::type_ref::Mutability::Shared => "*const ",
882 hir_def::type_ref::Mutability::Mut => "*mut ",
884 write!(f, "{}", mutability)?;
887 TypeRef::Reference(inner, lifetime, mutability) => {
888 let mutability = match mutability {
889 hir_def::type_ref::Mutability::Shared => "",
890 hir_def::type_ref::Mutability::Mut => "mut ",
893 if let Some(lifetime) = lifetime {
894 write!(f, "{} ", lifetime.name)?;
896 write!(f, "{}", mutability)?;
899 TypeRef::Array(inner) => {
902 // FIXME: Array length?
905 TypeRef::Slice(inner) => {
910 TypeRef::Fn(tys, is_varargs) => {
911 // FIXME: Function pointer qualifiers.
913 f.write_joined(&tys[..tys.len() - 1], ", ")?;
915 write!(f, "{}...", if tys.len() == 1 { "" } else { ", " })?;
918 let ret_ty = tys.last().unwrap();
920 TypeRef::Tuple(tup) if tup.is_empty() => {}
927 TypeRef::ImplTrait(bounds) => {
929 f.write_joined(bounds, " + ")?;
931 TypeRef::DynTrait(bounds) => {
933 f.write_joined(bounds, " + ")?;
935 TypeRef::Error => write!(f, "{{error}}")?,
941 impl HirDisplay for TypeBound {
942 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
944 TypeBound::Path(path) => path.hir_fmt(f),
945 TypeBound::Lifetime(lifetime) => write!(f, "{}", lifetime.name),
946 TypeBound::Error => write!(f, "{{error}}"),
951 impl HirDisplay for Path {
952 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
953 match (self.type_anchor(), self.kind()) {
954 (Some(anchor), _) => {
959 (_, PathKind::Plain) => {}
960 (_, PathKind::Abs) => write!(f, "::")?,
961 (_, PathKind::Crate) => write!(f, "crate")?,
962 (_, PathKind::Super(0)) => write!(f, "self")?,
963 (_, PathKind::Super(n)) => {
966 write!(f, "::super")?;
969 (_, PathKind::DollarCrate(_)) => write!(f, "{{extern_crate}}")?,
972 for (seg_idx, segment) in self.segments().iter().enumerate() {
976 write!(f, "{}", segment.name)?;
977 if let Some(generic_args) = segment.args_and_bindings {
978 // We should be in type context, so format as `Foo<Bar>` instead of `Foo::<Bar>`.
979 // Do we actually format expressions?
981 let mut first = true;
982 for arg in &generic_args.args {
985 if generic_args.has_self_type {
986 // FIXME: Convert to `<Ty as Trait>` form.
987 write!(f, "Self = ")?;
994 for binding in &generic_args.bindings {
1000 write!(f, "{}", binding.name)?;
1001 match &binding.type_ref {
1008 f.write_joined(&binding.bounds, " + ")?;
1019 impl HirDisplay for GenericArg {
1020 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
1022 GenericArg::Type(ty) => ty.hir_fmt(f),
1023 GenericArg::Lifetime(lifetime) => write!(f, "{}", lifetime.name),