From 6a77ec7bbe6ddbf663dce9529d11d1bb56c5489a Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Thu, 13 Aug 2020 16:35:29 +0200 Subject: Rename ra_hir_ty -> hir_ty --- crates/ra_hir_ty/src/method_resolution.rs | 769 ------------------------------ 1 file changed, 769 deletions(-) delete mode 100644 crates/ra_hir_ty/src/method_resolution.rs (limited to 'crates/ra_hir_ty/src/method_resolution.rs') diff --git a/crates/ra_hir_ty/src/method_resolution.rs b/crates/ra_hir_ty/src/method_resolution.rs deleted file mode 100644 index ec59145c7..000000000 --- a/crates/ra_hir_ty/src/method_resolution.rs +++ /dev/null @@ -1,769 +0,0 @@ -//! This module is concerned with finding methods that a given type provides. -//! For details about how this works in rustc, see the method lookup page in the -//! [rustc guide](https://rust-lang.github.io/rustc-guide/method-lookup.html) -//! and the corresponding code mostly in librustc_typeck/check/method/probe.rs. -use std::{iter, sync::Arc}; - -use arrayvec::ArrayVec; -use base_db::CrateId; -use hir_def::{ - builtin_type::{IntBitness, Signedness}, - lang_item::LangItemTarget, - type_ref::Mutability, - AssocContainerId, AssocItemId, FunctionId, HasModule, ImplId, Lookup, TraitId, -}; -use hir_expand::name::Name; -use rustc_hash::{FxHashMap, FxHashSet}; - -use super::Substs; -use crate::{ - autoderef, - db::HirDatabase, - primitive::{FloatBitness, FloatTy, IntTy}, - utils::all_super_traits, - ApplicationTy, Canonical, DebruijnIndex, InEnvironment, TraitEnvironment, TraitRef, Ty, TyKind, - TypeCtor, TypeWalk, -}; - -/// This is used as a key for indexing impls. -#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)] -pub enum TyFingerprint { - Apply(TypeCtor), -} - -impl TyFingerprint { - /// Creates a TyFingerprint for looking up an impl. Only certain types can - /// have impls: if we have some `struct S`, we can have an `impl S`, but not - /// `impl &S`. Hence, this will return `None` for reference types and such. - pub(crate) fn for_impl(ty: &Ty) -> Option { - match ty { - Ty::Apply(a_ty) => Some(TyFingerprint::Apply(a_ty.ctor)), - _ => None, - } - } -} - -pub(crate) const ALL_INT_FPS: [TyFingerprint; 12] = [ - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Unsigned, - bitness: IntBitness::X8, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Unsigned, - bitness: IntBitness::X16, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Unsigned, - bitness: IntBitness::X32, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Unsigned, - bitness: IntBitness::X64, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Unsigned, - bitness: IntBitness::X128, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Unsigned, - bitness: IntBitness::Xsize, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Signed, - bitness: IntBitness::X8, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Signed, - bitness: IntBitness::X16, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Signed, - bitness: IntBitness::X32, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Signed, - bitness: IntBitness::X64, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Signed, - bitness: IntBitness::X128, - })), - TyFingerprint::Apply(TypeCtor::Int(IntTy { - signedness: Signedness::Signed, - bitness: IntBitness::Xsize, - })), -]; - -pub(crate) const ALL_FLOAT_FPS: [TyFingerprint; 2] = [ - TyFingerprint::Apply(TypeCtor::Float(FloatTy { bitness: FloatBitness::X32 })), - TyFingerprint::Apply(TypeCtor::Float(FloatTy { bitness: FloatBitness::X64 })), -]; - -/// Trait impls defined or available in some crate. -#[derive(Debug, Eq, PartialEq)] -pub struct TraitImpls { - // If the `Option` is `None`, the impl may apply to any self type. - map: FxHashMap, Vec>>, -} - -impl TraitImpls { - pub(crate) fn trait_impls_in_crate_query(db: &dyn HirDatabase, krate: CrateId) -> Arc { - let _p = profile::span("trait_impls_in_crate_query"); - let mut impls = Self { map: FxHashMap::default() }; - - let crate_def_map = db.crate_def_map(krate); - for (_module_id, module_data) in crate_def_map.modules.iter() { - for impl_id in module_data.scope.impls() { - let target_trait = match db.impl_trait(impl_id) { - Some(tr) => tr.value.trait_, - None => continue, - }; - let self_ty = db.impl_self_ty(impl_id); - let self_ty_fp = TyFingerprint::for_impl(&self_ty.value); - impls - .map - .entry(target_trait) - .or_default() - .entry(self_ty_fp) - .or_default() - .push(impl_id); - } - } - - Arc::new(impls) - } - - pub(crate) fn trait_impls_in_deps_query(db: &dyn HirDatabase, krate: CrateId) -> Arc { - let _p = profile::span("trait_impls_in_deps_query"); - let crate_graph = db.crate_graph(); - let mut res = Self { map: FxHashMap::default() }; - - for krate in crate_graph.transitive_deps(krate) { - res.merge(&db.trait_impls_in_crate(krate)); - } - - Arc::new(res) - } - - fn merge(&mut self, other: &Self) { - for (trait_, other_map) in &other.map { - let map = self.map.entry(*trait_).or_default(); - for (fp, impls) in other_map { - let vec = map.entry(*fp).or_default(); - vec.extend(impls); - } - } - } - - /// Queries all impls of the given trait. - pub fn for_trait(&self, trait_: TraitId) -> impl Iterator + '_ { - self.map - .get(&trait_) - .into_iter() - .flat_map(|map| map.values().flat_map(|v| v.iter().copied())) - } - - /// Queries all impls of `trait_` that may apply to `self_ty`. - pub fn for_trait_and_self_ty( - &self, - trait_: TraitId, - self_ty: TyFingerprint, - ) -> impl Iterator + '_ { - self.map - .get(&trait_) - .into_iter() - .flat_map(move |map| map.get(&None).into_iter().chain(map.get(&Some(self_ty)))) - .flat_map(|v| v.iter().copied()) - } - - pub fn all_impls(&self) -> impl Iterator + '_ { - self.map.values().flat_map(|map| map.values().flat_map(|v| v.iter().copied())) - } -} - -/// Inherent impls defined in some crate. -/// -/// Inherent impls can only be defined in the crate that also defines the self type of the impl -/// (note that some primitives are considered to be defined by both libcore and liballoc). -/// -/// This makes inherent impl lookup easier than trait impl lookup since we only have to consider a -/// single crate. -#[derive(Debug, Eq, PartialEq)] -pub struct InherentImpls { - map: FxHashMap>, -} - -impl InherentImpls { - pub(crate) fn inherent_impls_in_crate_query(db: &dyn HirDatabase, krate: CrateId) -> Arc { - let mut map: FxHashMap<_, Vec<_>> = FxHashMap::default(); - - let crate_def_map = db.crate_def_map(krate); - for (_module_id, module_data) in crate_def_map.modules.iter() { - for impl_id in module_data.scope.impls() { - let data = db.impl_data(impl_id); - if data.target_trait.is_some() { - continue; - } - - let self_ty = db.impl_self_ty(impl_id); - if let Some(fp) = TyFingerprint::for_impl(&self_ty.value) { - map.entry(fp).or_default().push(impl_id); - } - } - } - - Arc::new(Self { map }) - } - - pub fn for_self_ty(&self, self_ty: &Ty) -> &[ImplId] { - match TyFingerprint::for_impl(self_ty) { - Some(fp) => self.map.get(&fp).map(|vec| vec.as_ref()).unwrap_or(&[]), - None => &[], - } - } - - pub fn all_impls(&self) -> impl Iterator + '_ { - self.map.values().flat_map(|v| v.iter().copied()) - } -} - -impl Ty { - pub fn def_crates( - &self, - db: &dyn HirDatabase, - cur_crate: CrateId, - ) -> Option> { - // Types like slice can have inherent impls in several crates, (core and alloc). - // The corresponding impls are marked with lang items, so we can use them to find the required crates. - macro_rules! lang_item_crate { - ($($name:expr),+ $(,)?) => {{ - let mut v = ArrayVec::<[LangItemTarget; 2]>::new(); - $( - v.extend(db.lang_item(cur_crate, $name.into())); - )+ - v - }}; - } - - let lang_item_targets = match self { - Ty::Apply(a_ty) => match a_ty.ctor { - TypeCtor::Adt(def_id) => { - return Some(std::iter::once(def_id.module(db.upcast()).krate).collect()) - } - TypeCtor::Bool => lang_item_crate!("bool"), - TypeCtor::Char => lang_item_crate!("char"), - TypeCtor::Float(f) => match f.bitness { - // There are two lang items: one in libcore (fXX) and one in libstd (fXX_runtime) - FloatBitness::X32 => lang_item_crate!("f32", "f32_runtime"), - FloatBitness::X64 => lang_item_crate!("f64", "f64_runtime"), - }, - TypeCtor::Int(i) => lang_item_crate!(i.ty_to_string()), - TypeCtor::Str => lang_item_crate!("str_alloc", "str"), - TypeCtor::Slice => lang_item_crate!("slice_alloc", "slice"), - TypeCtor::RawPtr(Mutability::Shared) => lang_item_crate!("const_ptr"), - TypeCtor::RawPtr(Mutability::Mut) => lang_item_crate!("mut_ptr"), - _ => return None, - }, - _ => return None, - }; - let res = lang_item_targets - .into_iter() - .filter_map(|it| match it { - LangItemTarget::ImplDefId(it) => Some(it), - _ => None, - }) - .map(|it| it.lookup(db.upcast()).container.module(db.upcast()).krate) - .collect(); - Some(res) - } -} -/// Look up the method with the given name, returning the actual autoderefed -/// receiver type (but without autoref applied yet). -pub(crate) fn lookup_method( - ty: &Canonical, - db: &dyn HirDatabase, - env: Arc, - krate: CrateId, - traits_in_scope: &FxHashSet, - name: &Name, -) -> Option<(Ty, FunctionId)> { - iterate_method_candidates( - ty, - db, - env, - krate, - &traits_in_scope, - Some(name), - LookupMode::MethodCall, - |ty, f| match f { - AssocItemId::FunctionId(f) => Some((ty.clone(), f)), - _ => None, - }, - ) -} - -/// Whether we're looking up a dotted method call (like `v.len()`) or a path -/// (like `Vec::new`). -#[derive(Copy, Clone, Debug, PartialEq, Eq)] -pub enum LookupMode { - /// Looking up a method call like `v.len()`: We only consider candidates - /// that have a `self` parameter, and do autoderef. - MethodCall, - /// Looking up a path like `Vec::new` or `Vec::default`: We consider all - /// candidates including associated constants, but don't do autoderef. - Path, -} - -// This would be nicer if it just returned an iterator, but that runs into -// lifetime problems, because we need to borrow temp `CrateImplDefs`. -// FIXME add a context type here? -pub fn iterate_method_candidates( - ty: &Canonical, - db: &dyn HirDatabase, - env: Arc, - krate: CrateId, - traits_in_scope: &FxHashSet, - name: Option<&Name>, - mode: LookupMode, - mut callback: impl FnMut(&Ty, AssocItemId) -> Option, -) -> Option { - let mut slot = None; - iterate_method_candidates_impl( - ty, - db, - env, - krate, - traits_in_scope, - name, - mode, - &mut |ty, item| { - assert!(slot.is_none()); - slot = callback(ty, item); - slot.is_some() - }, - ); - slot -} - -fn iterate_method_candidates_impl( - ty: &Canonical, - db: &dyn HirDatabase, - env: Arc, - krate: CrateId, - traits_in_scope: &FxHashSet, - name: Option<&Name>, - mode: LookupMode, - callback: &mut dyn FnMut(&Ty, AssocItemId) -> bool, -) -> bool { - match mode { - LookupMode::MethodCall => { - // For method calls, rust first does any number of autoderef, and then one - // autoref (i.e. when the method takes &self or &mut self). We just ignore - // the autoref currently -- when we find a method matching the given name, - // we assume it fits. - - // Also note that when we've got a receiver like &S, even if the method we - // find in the end takes &self, we still do the autoderef step (just as - // rustc does an autoderef and then autoref again). - let ty = InEnvironment { value: ty.clone(), environment: env.clone() }; - - // We have to be careful about the order we're looking at candidates - // in here. Consider the case where we're resolving `x.clone()` - // where `x: &Vec<_>`. This resolves to the clone method with self - // type `Vec<_>`, *not* `&_`. I.e. we need to consider methods where - // the receiver type exactly matches before cases where we have to - // do autoref. But in the autoderef steps, the `&_` self type comes - // up *before* the `Vec<_>` self type. - // - // On the other hand, we don't want to just pick any by-value method - // before any by-autoref method; it's just that we need to consider - // the methods by autoderef order of *receiver types*, not *self - // types*. - - let deref_chain = autoderef_method_receiver(db, krate, ty); - for i in 0..deref_chain.len() { - if iterate_method_candidates_with_autoref( - &deref_chain[i..], - db, - env.clone(), - krate, - traits_in_scope, - name, - callback, - ) { - return true; - } - } - false - } - LookupMode::Path => { - // No autoderef for path lookups - iterate_method_candidates_for_self_ty( - &ty, - db, - env, - krate, - traits_in_scope, - name, - callback, - ) - } - } -} - -fn iterate_method_candidates_with_autoref( - deref_chain: &[Canonical], - db: &dyn HirDatabase, - env: Arc, - krate: CrateId, - traits_in_scope: &FxHashSet, - name: Option<&Name>, - mut callback: &mut dyn FnMut(&Ty, AssocItemId) -> bool, -) -> bool { - if iterate_method_candidates_by_receiver( - &deref_chain[0], - &deref_chain[1..], - db, - env.clone(), - krate, - &traits_in_scope, - name, - &mut callback, - ) { - return true; - } - let refed = Canonical { - kinds: deref_chain[0].kinds.clone(), - value: Ty::apply_one(TypeCtor::Ref(Mutability::Shared), deref_chain[0].value.clone()), - }; - if iterate_method_candidates_by_receiver( - &refed, - deref_chain, - db, - env.clone(), - krate, - &traits_in_scope, - name, - &mut callback, - ) { - return true; - } - let ref_muted = Canonical { - kinds: deref_chain[0].kinds.clone(), - value: Ty::apply_one(TypeCtor::Ref(Mutability::Mut), deref_chain[0].value.clone()), - }; - if iterate_method_candidates_by_receiver( - &ref_muted, - deref_chain, - db, - env, - krate, - &traits_in_scope, - name, - &mut callback, - ) { - return true; - } - false -} - -fn iterate_method_candidates_by_receiver( - receiver_ty: &Canonical, - rest_of_deref_chain: &[Canonical], - db: &dyn HirDatabase, - env: Arc, - krate: CrateId, - traits_in_scope: &FxHashSet, - name: Option<&Name>, - mut callback: &mut dyn FnMut(&Ty, AssocItemId) -> bool, -) -> bool { - // We're looking for methods with *receiver* type receiver_ty. These could - // be found in any of the derefs of receiver_ty, so we have to go through - // that. - for self_ty in std::iter::once(receiver_ty).chain(rest_of_deref_chain) { - if iterate_inherent_methods(self_ty, db, name, Some(receiver_ty), krate, &mut callback) { - return true; - } - } - for self_ty in std::iter::once(receiver_ty).chain(rest_of_deref_chain) { - if iterate_trait_method_candidates( - self_ty, - db, - env.clone(), - krate, - &traits_in_scope, - name, - Some(receiver_ty), - &mut callback, - ) { - return true; - } - } - false -} - -fn iterate_method_candidates_for_self_ty( - self_ty: &Canonical, - db: &dyn HirDatabase, - env: Arc, - krate: CrateId, - traits_in_scope: &FxHashSet, - name: Option<&Name>, - mut callback: &mut dyn FnMut(&Ty, AssocItemId) -> bool, -) -> bool { - if iterate_inherent_methods(self_ty, db, name, None, krate, &mut callback) { - return true; - } - iterate_trait_method_candidates(self_ty, db, env, krate, traits_in_scope, name, None, callback) -} - -fn iterate_trait_method_candidates( - self_ty: &Canonical, - db: &dyn HirDatabase, - env: Arc, - krate: CrateId, - traits_in_scope: &FxHashSet, - name: Option<&Name>, - receiver_ty: Option<&Canonical>, - callback: &mut dyn FnMut(&Ty, AssocItemId) -> bool, -) -> bool { - // if ty is `dyn Trait`, the trait doesn't need to be in scope - let inherent_trait = - self_ty.value.dyn_trait().into_iter().flat_map(|t| all_super_traits(db.upcast(), t)); - let env_traits = if let Ty::Placeholder(_) = self_ty.value { - // if we have `T: Trait` in the param env, the trait doesn't need to be in scope - env.trait_predicates_for_self_ty(&self_ty.value) - .map(|tr| tr.trait_) - .flat_map(|t| all_super_traits(db.upcast(), t)) - .collect() - } else { - Vec::new() - }; - let traits = - inherent_trait.chain(env_traits.into_iter()).chain(traits_in_scope.iter().copied()); - 'traits: for t in traits { - let data = db.trait_data(t); - - // we'll be lazy about checking whether the type implements the - // trait, but if we find out it doesn't, we'll skip the rest of the - // iteration - let mut known_implemented = false; - for (_name, item) in data.items.iter() { - if !is_valid_candidate(db, name, receiver_ty, *item, self_ty) { - continue; - } - if !known_implemented { - let goal = generic_implements_goal(db, env.clone(), t, self_ty.clone()); - if db.trait_solve(krate, goal).is_none() { - continue 'traits; - } - } - known_implemented = true; - if callback(&self_ty.value, *item) { - return true; - } - } - } - false -} - -fn iterate_inherent_methods( - self_ty: &Canonical, - db: &dyn HirDatabase, - name: Option<&Name>, - receiver_ty: Option<&Canonical>, - krate: CrateId, - callback: &mut dyn FnMut(&Ty, AssocItemId) -> bool, -) -> bool { - let def_crates = match self_ty.value.def_crates(db, krate) { - Some(k) => k, - None => return false, - }; - for krate in def_crates { - let impls = db.inherent_impls_in_crate(krate); - - for &impl_def in impls.for_self_ty(&self_ty.value) { - for &item in db.impl_data(impl_def).items.iter() { - if !is_valid_candidate(db, name, receiver_ty, item, self_ty) { - continue; - } - // we have to check whether the self type unifies with the type - // that the impl is for. If we have a receiver type, this - // already happens in `is_valid_candidate` above; if not, we - // check it here - if receiver_ty.is_none() && inherent_impl_substs(db, impl_def, self_ty).is_none() { - test_utils::mark::hit!(impl_self_type_match_without_receiver); - continue; - } - if callback(&self_ty.value, item) { - return true; - } - } - } - } - false -} - -/// Returns the self type for the index trait call. -pub fn resolve_indexing_op( - db: &dyn HirDatabase, - ty: &Canonical, - env: Arc, - krate: CrateId, - index_trait: TraitId, -) -> Option> { - let ty = InEnvironment { value: ty.clone(), environment: env.clone() }; - let deref_chain = autoderef_method_receiver(db, krate, ty); - for ty in deref_chain { - let goal = generic_implements_goal(db, env.clone(), index_trait, ty.clone()); - if db.trait_solve(krate, goal).is_some() { - return Some(ty); - } - } - None -} - -fn is_valid_candidate( - db: &dyn HirDatabase, - name: Option<&Name>, - receiver_ty: Option<&Canonical>, - item: AssocItemId, - self_ty: &Canonical, -) -> bool { - match item { - AssocItemId::FunctionId(m) => { - let data = db.function_data(m); - if let Some(name) = name { - if &data.name != name { - return false; - } - } - if let Some(receiver_ty) = receiver_ty { - if !data.has_self_param { - return false; - } - let transformed_receiver_ty = match transform_receiver_ty(db, m, self_ty) { - Some(ty) => ty, - None => return false, - }; - if transformed_receiver_ty != receiver_ty.value { - return false; - } - } - true - } - AssocItemId::ConstId(c) => { - let data = db.const_data(c); - name.map_or(true, |name| data.name.as_ref() == Some(name)) && receiver_ty.is_none() - } - _ => false, - } -} - -pub(crate) fn inherent_impl_substs( - db: &dyn HirDatabase, - impl_id: ImplId, - self_ty: &Canonical, -) -> Option { - // we create a var for each type parameter of the impl; we need to keep in - // mind here that `self_ty` might have vars of its own - let vars = Substs::build_for_def(db, impl_id) - .fill_with_bound_vars(DebruijnIndex::INNERMOST, self_ty.kinds.len()) - .build(); - let self_ty_with_vars = db.impl_self_ty(impl_id).subst(&vars); - let mut kinds = self_ty.kinds.to_vec(); - kinds.extend(iter::repeat(TyKind::General).take(vars.len())); - let tys = Canonical { kinds: kinds.into(), value: (self_ty_with_vars, self_ty.value.clone()) }; - let substs = super::infer::unify(&tys); - // We only want the substs for the vars we added, not the ones from self_ty. - // Also, if any of the vars we added are still in there, we replace them by - // Unknown. I think this can only really happen if self_ty contained - // Unknown, and in that case we want the result to contain Unknown in those - // places again. - substs.map(|s| fallback_bound_vars(s.suffix(vars.len()), self_ty.kinds.len())) -} - -/// This replaces any 'free' Bound vars in `s` (i.e. those with indices past -/// num_vars_to_keep) by `Ty::Unknown`. -fn fallback_bound_vars(s: Substs, num_vars_to_keep: usize) -> Substs { - s.fold_binders( - &mut |ty, binders| { - if let Ty::Bound(bound) = &ty { - if bound.index >= num_vars_to_keep && bound.debruijn >= binders { - Ty::Unknown - } else { - ty - } - } else { - ty - } - }, - DebruijnIndex::INNERMOST, - ) -} - -fn transform_receiver_ty( - db: &dyn HirDatabase, - function_id: FunctionId, - self_ty: &Canonical, -) -> Option { - let substs = match function_id.lookup(db.upcast()).container { - AssocContainerId::TraitId(_) => Substs::build_for_def(db, function_id) - .push(self_ty.value.clone()) - .fill_with_unknown() - .build(), - AssocContainerId::ImplId(impl_id) => inherent_impl_substs(db, impl_id, &self_ty)?, - AssocContainerId::ContainerId(_) => unreachable!(), - }; - let sig = db.callable_item_signature(function_id.into()); - Some(sig.value.params()[0].clone().subst_bound_vars(&substs)) -} - -pub fn implements_trait( - ty: &Canonical, - db: &dyn HirDatabase, - env: Arc, - krate: CrateId, - trait_: TraitId, -) -> bool { - let goal = generic_implements_goal(db, env, trait_, ty.clone()); - let solution = db.trait_solve(krate, goal); - - solution.is_some() -} - -/// This creates Substs for a trait with the given Self type and type variables -/// for all other parameters, to query Chalk with it. -fn generic_implements_goal( - db: &dyn HirDatabase, - env: Arc, - trait_: TraitId, - self_ty: Canonical, -) -> Canonical> { - let mut kinds = self_ty.kinds.to_vec(); - let substs = super::Substs::build_for_def(db, trait_) - .push(self_ty.value) - .fill_with_bound_vars(DebruijnIndex::INNERMOST, kinds.len()) - .build(); - kinds.extend(iter::repeat(TyKind::General).take(substs.len() - 1)); - let trait_ref = TraitRef { trait_, substs }; - let obligation = super::Obligation::Trait(trait_ref); - Canonical { kinds: kinds.into(), value: InEnvironment::new(env, obligation) } -} - -fn autoderef_method_receiver( - db: &dyn HirDatabase, - krate: CrateId, - ty: InEnvironment>, -) -> Vec> { - let mut deref_chain: Vec<_> = autoderef::autoderef(db, Some(krate), ty).collect(); - // As a last step, we can do array unsizing (that's the only unsizing that rustc does for method receivers!) - if let Some(Ty::Apply(ApplicationTy { ctor: TypeCtor::Array, parameters })) = - deref_chain.last().map(|ty| &ty.value) - { - let kinds = deref_chain.last().unwrap().kinds.clone(); - let unsized_ty = Ty::apply(TypeCtor::Slice, parameters.clone()); - deref_chain.push(Canonical { value: unsized_ty, kinds }) - } - deref_chain -} -- cgit v1.2.3