1 //! FIXME: write short doc here
3 use std::{borrow::Cow, fmt};
5 use arrayvec::ArrayVec;
6 use chalk_ir::Mutability;
10 generics::TypeParamProvenance,
12 path::{GenericArg, Path, PathKind},
13 type_ref::{TypeBound, TypeRef},
14 visibility::Visibility,
15 AssocContainerId, Lookup, ModuleId, TraitId,
17 use hir_expand::name::Name;
20 db::HirDatabase, from_assoc_type_id, from_foreign_def_id, from_placeholder_idx, primitive,
21 to_assoc_type_id, traits::chalk::from_chalk, utils::generics, AdtId, AliasEq, AliasTy,
22 CallableDefId, CallableSig, GenericPredicate, ImplTraitId, Interner, Lifetime, Obligation,
23 OpaqueTy, ProjectionTy, Scalar, Substitution, TraitRef, Ty, TyKind,
26 pub struct HirFormatter<'a> {
27 pub db: &'a dyn HirDatabase,
28 fmt: &'a mut dyn fmt::Write,
31 pub(crate) max_size: Option<usize>,
32 omit_verbose_types: bool,
33 display_target: DisplayTarget,
36 pub trait HirDisplay {
37 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError>;
39 /// Returns a `Display`able type that is human-readable.
40 fn into_displayable<'a>(
42 db: &'a dyn HirDatabase,
43 max_size: Option<usize>,
44 omit_verbose_types: bool,
45 display_target: DisplayTarget,
46 ) -> HirDisplayWrapper<'a, Self>
50 HirDisplayWrapper { db, t: self, max_size, omit_verbose_types, display_target }
53 /// Returns a `Display`able type that is human-readable.
54 /// Use this for showing types to the user (e.g. diagnostics)
55 fn display<'a>(&'a self, db: &'a dyn HirDatabase) -> HirDisplayWrapper<'a, Self>
63 omit_verbose_types: false,
64 display_target: DisplayTarget::Diagnostics,
68 /// Returns a `Display`able type that is human-readable and tries to be succinct.
69 /// Use this for showing types to the user where space is constrained (e.g. doc popups)
70 fn display_truncated<'a>(
72 db: &'a dyn HirDatabase,
73 max_size: Option<usize>,
74 ) -> HirDisplayWrapper<'a, Self>
82 omit_verbose_types: true,
83 display_target: DisplayTarget::Diagnostics,
87 /// Returns a String representation of `self` that can be inserted into the given module.
88 /// Use this when generating code (e.g. assists)
89 fn display_source_code<'a>(
91 db: &'a dyn HirDatabase,
93 ) -> Result<String, DisplaySourceCodeError> {
94 let mut result = String::new();
95 match self.hir_fmt(&mut HirFormatter {
98 buf: String::with_capacity(20),
101 omit_verbose_types: false,
102 display_target: DisplayTarget::SourceCode { module_id },
105 Err(HirDisplayError::FmtError) => panic!("Writing to String can't fail!"),
106 Err(HirDisplayError::DisplaySourceCodeError(e)) => return Err(e),
111 /// Returns a String representation of `self` for test purposes
112 fn display_test<'a>(&'a self, db: &'a dyn HirDatabase) -> HirDisplayWrapper<'a, Self>
120 omit_verbose_types: false,
121 display_target: DisplayTarget::Test,
126 impl<'a> HirFormatter<'a> {
127 pub fn write_joined<T: HirDisplay>(
129 iter: impl IntoIterator<Item = T>,
131 ) -> Result<(), HirDisplayError> {
132 let mut first = true;
135 write!(self, "{}", sep)?;
143 /// This allows using the `write!` macro directly with a `HirFormatter`.
144 pub fn write_fmt(&mut self, args: fmt::Arguments) -> Result<(), HirDisplayError> {
145 // We write to a buffer first to track output size
147 fmt::write(&mut self.buf, args)?;
148 self.curr_size += self.buf.len();
150 // Then we write to the internal formatter from the buffer
151 self.fmt.write_str(&self.buf).map_err(HirDisplayError::from)
154 pub fn should_truncate(&self) -> bool {
155 if let Some(max_size) = self.max_size {
156 self.curr_size >= max_size
162 pub fn omit_verbose_types(&self) -> bool {
163 self.omit_verbose_types
167 #[derive(Clone, Copy)]
168 pub enum DisplayTarget {
169 /// Display types for inlays, doc popups, autocompletion, etc...
170 /// Showing `{unknown}` or not qualifying paths is fine here.
171 /// There's no reason for this to fail.
173 /// Display types for inserting them in source files.
174 /// The generated code should compile, so paths need to be qualified.
175 SourceCode { module_id: ModuleId },
176 /// Only for test purpose to keep real types
181 fn is_source_code(&self) -> bool {
182 matches!(self, Self::SourceCode { .. })
184 fn is_test(&self) -> bool {
185 matches!(self, Self::Test)
190 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 = match t.interned(&Interner) {
332 TyKind::Dyn(predicates) if predicates.len() > 1 => {
333 Cow::Borrowed(predicates.as_ref())
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);
348 Cow::Owned(bounds.value)
350 Cow::Borrowed(&[][..])
353 _ => Cow::Borrowed(&[][..]),
356 if let [GenericPredicate::Implemented(trait_ref), _] = predicates.as_ref() {
357 let trait_ = trait_ref.hir_trait_id();
358 if fn_traits(f.db.upcast(), trait_).any(|it| it == trait_) {
359 return write!(f, "{}", ty_display);
363 if predicates.len() > 1 {
365 write!(f, "{}", ty_display)?;
368 write!(f, "{}", ty_display)?;
371 TyKind::Tuple(_, substs) => {
372 if substs.len() == 1 {
374 substs[0].hir_fmt(f)?;
378 f.write_joined(&*substs.0, ", ")?;
382 TyKind::Function(fn_ptr) => {
383 let sig = CallableSig::from_fn_ptr(fn_ptr);
386 TyKind::FnDef(def, parameters) => {
387 let def = from_chalk(f.db, *def);
388 let sig = f.db.callable_item_signature(def).subst(parameters);
390 CallableDefId::FunctionId(ff) => {
391 write!(f, "fn {}", f.db.function_data(ff).name)?
393 CallableDefId::StructId(s) => write!(f, "{}", f.db.struct_data(s).name)?,
394 CallableDefId::EnumVariantId(e) => {
395 write!(f, "{}", f.db.enum_data(e.parent).variants[e.local_id].name)?
398 if parameters.len() > 0 {
399 let generics = generics(f.db.upcast(), def.into());
400 let (parent_params, self_param, type_params, _impl_trait_params) =
401 generics.provenance_split();
402 let total_len = parent_params + self_param + type_params;
403 // We print all params except implicit impl Trait params. Still a bit weird; should we leave out parent and self?
406 f.write_joined(¶meters.0[..total_len], ", ")?;
411 f.write_joined(sig.params(), ", ")?;
414 if *ret != Ty::unit() {
415 let ret_display = ret.into_displayable(
418 f.omit_verbose_types,
422 write!(f, " -> {}", ret_display)?;
425 TyKind::Adt(AdtId(def_id), parameters) => {
426 match f.display_target {
427 DisplayTarget::Diagnostics | DisplayTarget::Test => {
428 let name = match *def_id {
429 hir_def::AdtId::StructId(it) => f.db.struct_data(it).name.clone(),
430 hir_def::AdtId::UnionId(it) => f.db.union_data(it).name.clone(),
431 hir_def::AdtId::EnumId(it) => f.db.enum_data(it).name.clone(),
433 write!(f, "{}", name)?;
435 DisplayTarget::SourceCode { module_id } => {
436 if let Some(path) = find_path::find_path(
438 ItemInNs::Types((*def_id).into()),
441 write!(f, "{}", path)?;
443 return Err(HirDisplayError::DisplaySourceCodeError(
444 DisplaySourceCodeError::PathNotFound,
450 if parameters.len() > 0 {
451 let parameters_to_write = if f.display_target.is_source_code()
452 || f.omit_verbose_types()
455 .as_generic_def(f.db)
456 .map(|generic_def_id| f.db.generic_defaults(generic_def_id))
457 .filter(|defaults| !defaults.is_empty())
459 None => parameters.0.as_ref(),
460 Some(default_parameters) => {
461 let mut default_from = 0;
462 for (i, parameter) in parameters.iter().enumerate() {
463 match (parameter.interned(&Interner), default_parameters.get(i))
465 (&TyKind::Unknown, _) | (_, None) => {
466 default_from = i + 1;
468 (_, Some(default_parameter)) => {
469 let actual_default = default_parameter
471 .subst(¶meters.prefix(i));
472 if parameter != &actual_default {
473 default_from = i + 1;
478 ¶meters.0[0..default_from]
482 parameters.0.as_ref()
484 if !parameters_to_write.is_empty() {
486 f.write_joined(parameters_to_write, ", ")?;
491 TyKind::AssociatedType(assoc_type_id, parameters) => {
492 let type_alias = from_assoc_type_id(*assoc_type_id);
493 let trait_ = match type_alias.lookup(f.db.upcast()).container {
494 AssocContainerId::TraitId(it) => it,
495 _ => panic!("not an associated type"),
497 let trait_ = f.db.trait_data(trait_);
498 let type_alias_data = f.db.type_alias_data(type_alias);
500 // Use placeholder associated types when the target is test (https://rust-lang.github.io/chalk/book/clauses/type_equality.html#placeholder-associated-types)
501 if f.display_target.is_test() {
502 write!(f, "{}::{}", trait_.name, type_alias_data.name)?;
503 if parameters.len() > 0 {
505 f.write_joined(&*parameters.0, ", ")?;
509 let projection_ty = ProjectionTy {
510 associated_ty_id: to_assoc_type_id(type_alias),
511 substitution: parameters.clone(),
514 projection_ty.hir_fmt(f)?;
517 TyKind::ForeignType(type_alias) => {
518 let type_alias = f.db.type_alias_data(from_foreign_def_id(*type_alias));
519 write!(f, "{}", type_alias.name)?;
521 TyKind::OpaqueType(opaque_ty_id, parameters) => {
522 let impl_trait_id = f.db.lookup_intern_impl_trait_id((*opaque_ty_id).into());
523 match impl_trait_id {
524 ImplTraitId::ReturnTypeImplTrait(func, idx) => {
526 f.db.return_type_impl_traits(func).expect("impl trait id without data");
529 .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
530 let bounds = data.subst(¶meters);
531 write_bounds_like_dyn_trait_with_prefix("impl", &bounds.value, f)?;
532 // FIXME: it would maybe be good to distinguish this from the alias type (when debug printing), and to show the substitution
534 ImplTraitId::AsyncBlockTypeImplTrait(..) => {
535 write!(f, "impl Future<Output = ")?;
536 parameters[0].hir_fmt(f)?;
541 TyKind::Closure(.., substs) => {
542 let sig = substs[0].callable_sig(f.db);
543 if let Some(sig) = sig {
544 if sig.params().is_empty() {
546 } else if f.omit_verbose_types() {
547 write!(f, "|{}|", TYPE_HINT_TRUNCATION)?;
550 f.write_joined(sig.params(), ", ")?;
554 let ret_display = sig.ret().into_displayable(
557 f.omit_verbose_types,
560 write!(f, " -> {}", ret_display)?;
562 write!(f, "{{closure}}")?;
565 TyKind::Placeholder(idx) => {
566 let id = from_placeholder_idx(f.db, *idx);
567 let generics = generics(f.db.upcast(), id.parent);
568 let param_data = &generics.params.types[id.local_id];
569 match param_data.provenance {
570 TypeParamProvenance::TypeParamList | TypeParamProvenance::TraitSelf => {
571 write!(f, "{}", param_data.name.clone().unwrap_or_else(Name::missing))?
573 TypeParamProvenance::ArgumentImplTrait => {
574 let bounds = f.db.generic_predicates_for_param(id);
575 let substs = Substitution::type_params_for_generics(f.db, &generics);
576 write_bounds_like_dyn_trait_with_prefix(
578 &bounds.iter().map(|b| b.clone().subst(&substs)).collect::<Vec<_>>(),
584 TyKind::BoundVar(idx) => write!(f, "?{}.{}", idx.debruijn.depth(), idx.index)?,
585 TyKind::Dyn(predicates) => {
586 write_bounds_like_dyn_trait_with_prefix("dyn", predicates, f)?;
588 TyKind::Alias(AliasTy::Projection(p_ty)) => p_ty.hir_fmt(f)?,
589 TyKind::Alias(AliasTy::Opaque(opaque_ty)) => {
590 let impl_trait_id = f.db.lookup_intern_impl_trait_id(opaque_ty.opaque_ty_id.into());
591 match impl_trait_id {
592 ImplTraitId::ReturnTypeImplTrait(func, idx) => {
594 f.db.return_type_impl_traits(func).expect("impl trait id without data");
597 .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
598 let bounds = data.subst(&opaque_ty.substitution);
599 write_bounds_like_dyn_trait_with_prefix("impl", &bounds.value, f)?;
601 ImplTraitId::AsyncBlockTypeImplTrait(..) => {
602 write!(f, "{{async block}}")?;
607 if f.display_target.is_source_code() {
608 return Err(HirDisplayError::DisplaySourceCodeError(
609 DisplaySourceCodeError::UnknownType,
612 write!(f, "{{unknown}}")?;
614 TyKind::InferenceVar(..) => write!(f, "_")?,
620 impl HirDisplay for CallableSig {
621 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
623 f.write_joined(self.params(), ", ")?;
625 if self.params().is_empty() {
632 let ret = self.ret();
633 if *ret != Ty::unit() {
635 ret.into_displayable(f.db, f.max_size, f.omit_verbose_types, f.display_target);
636 write!(f, " -> {}", ret_display)?;
642 fn fn_traits(db: &dyn DefDatabase, trait_: TraitId) -> impl Iterator<Item = TraitId> {
643 let krate = trait_.lookup(db).container.krate();
645 db.lang_item(krate, "fn".into()),
646 db.lang_item(krate, "fn_mut".into()),
647 db.lang_item(krate, "fn_once".into()),
649 // FIXME: Replace ArrayVec when into_iter is a thing on arrays
650 ArrayVec::from(fn_traits).into_iter().flatten().flat_map(|it| it.as_trait())
653 pub fn write_bounds_like_dyn_trait_with_prefix(
655 predicates: &[GenericPredicate],
656 f: &mut HirFormatter,
657 ) -> Result<(), HirDisplayError> {
658 write!(f, "{}", prefix)?;
659 if !predicates.is_empty() {
661 write_bounds_like_dyn_trait(predicates, f)
667 fn write_bounds_like_dyn_trait(
668 predicates: &[GenericPredicate],
669 f: &mut HirFormatter,
670 ) -> Result<(), HirDisplayError> {
671 // Note: This code is written to produce nice results (i.e.
672 // corresponding to surface Rust) for types that can occur in
673 // actual Rust. It will have weird results if the predicates
674 // aren't as expected (i.e. self types = $0, projection
675 // predicates for a certain trait come after the Implemented
676 // predicate for that trait).
677 let mut first = true;
678 let mut angle_open = false;
679 let mut is_fn_trait = false;
680 for p in predicates.iter() {
682 GenericPredicate::Implemented(trait_ref) => {
683 let trait_ = trait_ref.hir_trait_id();
685 is_fn_trait = fn_traits(f.db.upcast(), trait_).any(|it| it == trait_);
687 if !is_fn_trait && angle_open {
694 // We assume that the self type is $0 (i.e. the
695 // existential) here, which is the only thing that's
696 // possible in actual Rust, and hence don't print it
697 write!(f, "{}", f.db.trait_data(trait_).name)?;
698 if let [_, params @ ..] = &*trait_ref.substitution.0 {
700 if let Some(args) = params.first().and_then(|it| it.as_tuple()) {
702 f.write_joined(&*args.0, ", ")?;
705 } else if !params.is_empty() {
707 f.write_joined(params, ", ")?;
708 // there might be assoc type bindings, so we leave the angle brackets open
713 GenericPredicate::AliasEq(alias_eq) if is_fn_trait => {
716 alias_eq.ty.hir_fmt(f)?;
718 GenericPredicate::AliasEq(AliasEq { ty, alias }) => {
719 // in types in actual Rust, these will always come
720 // after the corresponding Implemented predicate
727 if let AliasTy::Projection(proj) = alias {
729 f.db.type_alias_data(from_assoc_type_id(proj.associated_ty_id));
730 write!(f, "{} = ", type_alias.name)?;
734 GenericPredicate::Error => {
736 // impl Trait<X, {error}>
739 // impl Trait + {error}
754 fn hir_fmt_ext(&self, f: &mut HirFormatter, use_as: bool) -> Result<(), HirDisplayError> {
755 if f.should_truncate() {
756 return write!(f, "{}", TYPE_HINT_TRUNCATION);
759 self.substitution[0].hir_fmt(f)?;
765 write!(f, "{}", f.db.trait_data(self.hir_trait_id()).name)?;
766 if self.substitution.len() > 1 {
768 f.write_joined(&self.substitution[1..], ", ")?;
775 impl HirDisplay for TraitRef {
776 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
777 self.hir_fmt_ext(f, false)
781 impl HirDisplay for GenericPredicate {
782 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
783 if f.should_truncate() {
784 return write!(f, "{}", TYPE_HINT_TRUNCATION);
788 GenericPredicate::Implemented(trait_ref) => trait_ref.hir_fmt(f)?,
789 GenericPredicate::AliasEq(AliasEq {
790 alias: AliasTy::Projection(projection_ty),
794 projection_ty.trait_ref(f.db).hir_fmt_ext(f, true)?;
798 f.db.type_alias_data(from_assoc_type_id(projection_ty.associated_ty_id)).name,
802 GenericPredicate::AliasEq(_) | GenericPredicate::Error => write!(f, "{{error}}")?,
808 impl HirDisplay for Lifetime {
809 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
811 Lifetime::Parameter(id) => {
812 let generics = generics(f.db.upcast(), id.parent);
813 let param_data = &generics.params.lifetimes[id.local_id];
814 write!(f, "{}", ¶m_data.name)
816 Lifetime::Static => write!(f, "'static"),
821 impl HirDisplay for Obligation {
822 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
824 Obligation::Trait(tr) => {
825 write!(f, "Implements(")?;
829 Obligation::AliasEq(AliasEq { alias, ty }) => {
830 write!(f, "Normalize(")?;
832 AliasTy::Projection(projection_ty) => projection_ty.hir_fmt(f)?,
833 AliasTy::Opaque(opaque) => opaque.hir_fmt(f)?,
843 pub fn write_visibility(
846 f: &mut HirFormatter,
847 ) -> Result<(), HirDisplayError> {
849 Visibility::Public => write!(f, "pub "),
850 Visibility::Module(vis_id) => {
851 let def_map = module_id.def_map(f.db.upcast());
852 let root_module_id = def_map.module_id(def_map.root());
853 if vis_id == module_id {
854 // pub(self) or omitted
856 } else if root_module_id == vis_id {
857 write!(f, "pub(crate) ")
858 } else if module_id.containing_module(f.db.upcast()) == Some(vis_id) {
859 write!(f, "pub(super) ")
861 write!(f, "pub(in ...) ")
867 impl HirDisplay for TypeRef {
868 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
870 TypeRef::Never => write!(f, "!")?,
871 TypeRef::Placeholder => write!(f, "_")?,
872 TypeRef::Tuple(elems) => {
874 f.write_joined(elems, ", ")?;
875 if elems.len() == 1 {
880 TypeRef::Path(path) => path.hir_fmt(f)?,
881 TypeRef::RawPtr(inner, mutability) => {
882 let mutability = match mutability {
883 hir_def::type_ref::Mutability::Shared => "*const ",
884 hir_def::type_ref::Mutability::Mut => "*mut ",
886 write!(f, "{}", mutability)?;
889 TypeRef::Reference(inner, lifetime, mutability) => {
890 let mutability = match mutability {
891 hir_def::type_ref::Mutability::Shared => "",
892 hir_def::type_ref::Mutability::Mut => "mut ",
895 if let Some(lifetime) = lifetime {
896 write!(f, "{} ", lifetime.name)?;
898 write!(f, "{}", mutability)?;
901 TypeRef::Array(inner) => {
904 // FIXME: Array length?
907 TypeRef::Slice(inner) => {
912 TypeRef::Fn(tys, is_varargs) => {
913 // FIXME: Function pointer qualifiers.
915 f.write_joined(&tys[..tys.len() - 1], ", ")?;
917 write!(f, "{}...", if tys.len() == 1 { "" } else { ", " })?;
920 let ret_ty = tys.last().unwrap();
922 TypeRef::Tuple(tup) if tup.is_empty() => {}
929 TypeRef::ImplTrait(bounds) => {
931 f.write_joined(bounds, " + ")?;
933 TypeRef::DynTrait(bounds) => {
935 f.write_joined(bounds, " + ")?;
937 TypeRef::Error => write!(f, "{{error}}")?,
943 impl HirDisplay for TypeBound {
944 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
946 TypeBound::Path(path) => path.hir_fmt(f),
947 TypeBound::Lifetime(lifetime) => write!(f, "{}", lifetime.name),
948 TypeBound::Error => write!(f, "{{error}}"),
953 impl HirDisplay for Path {
954 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
955 match (self.type_anchor(), self.kind()) {
956 (Some(anchor), _) => {
961 (_, PathKind::Plain) => {}
962 (_, PathKind::Abs) => write!(f, "::")?,
963 (_, PathKind::Crate) => write!(f, "crate")?,
964 (_, PathKind::Super(0)) => write!(f, "self")?,
965 (_, PathKind::Super(n)) => {
968 write!(f, "::super")?;
971 (_, PathKind::DollarCrate(_)) => write!(f, "{{extern_crate}}")?,
974 for (seg_idx, segment) in self.segments().iter().enumerate() {
978 write!(f, "{}", segment.name)?;
979 if let Some(generic_args) = segment.args_and_bindings {
980 // We should be in type context, so format as `Foo<Bar>` instead of `Foo::<Bar>`.
981 // Do we actually format expressions?
983 let mut first = true;
984 for arg in &generic_args.args {
987 if generic_args.has_self_type {
988 // FIXME: Convert to `<Ty as Trait>` form.
989 write!(f, "Self = ")?;
996 for binding in &generic_args.bindings {
1002 write!(f, "{}", binding.name)?;
1003 match &binding.type_ref {
1010 f.write_joined(&binding.bounds, " + ")?;
1021 impl HirDisplay for GenericArg {
1022 fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
1024 GenericArg::Type(ty) => ty.hir_fmt(f),
1025 GenericArg::Lifetime(lifetime) => write!(f, "{}", lifetime.name),