From a87579500a2c35597071efd0ad6983927f0c1815 Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Wed, 27 Nov 2019 17:46:02 +0300 Subject: Move Ty --- crates/ra_hir_ty/src/infer/coerce.rs | 354 ++++++++++++++++++ crates/ra_hir_ty/src/infer/expr.rs | 686 +++++++++++++++++++++++++++++++++++ crates/ra_hir_ty/src/infer/pat.rs | 186 ++++++++++ crates/ra_hir_ty/src/infer/path.rs | 270 ++++++++++++++ crates/ra_hir_ty/src/infer/unify.rs | 162 +++++++++ 5 files changed, 1658 insertions(+) create mode 100644 crates/ra_hir_ty/src/infer/coerce.rs create mode 100644 crates/ra_hir_ty/src/infer/expr.rs create mode 100644 crates/ra_hir_ty/src/infer/pat.rs create mode 100644 crates/ra_hir_ty/src/infer/path.rs create mode 100644 crates/ra_hir_ty/src/infer/unify.rs (limited to 'crates/ra_hir_ty/src/infer') diff --git a/crates/ra_hir_ty/src/infer/coerce.rs b/crates/ra_hir_ty/src/infer/coerce.rs new file mode 100644 index 000000000..d66a21932 --- /dev/null +++ b/crates/ra_hir_ty/src/infer/coerce.rs @@ -0,0 +1,354 @@ +//! Coercion logic. Coercions are certain type conversions that can implicitly +//! happen in certain places, e.g. weakening `&mut` to `&` or deref coercions +//! like going from `&Vec` to `&[T]`. +//! +//! See: https://doc.rust-lang.org/nomicon/coercions.html + +use hir_def::{ + lang_item::LangItemTarget, + resolver::{HasResolver, Resolver}, + type_ref::Mutability, + AdtId, +}; +use rustc_hash::FxHashMap; +use test_utils::tested_by; + +use crate::{autoderef, db::HirDatabase, Substs, TraitRef, Ty, TypeCtor, TypeWalk}; + +use super::{InEnvironment, InferTy, InferenceContext, TypeVarValue}; + +impl<'a, D: HirDatabase> InferenceContext<'a, D> { + /// Unify two types, but may coerce the first one to the second one + /// using "implicit coercion rules" if needed. + pub(super) fn coerce(&mut self, from_ty: &Ty, to_ty: &Ty) -> bool { + let from_ty = self.resolve_ty_shallow(from_ty).into_owned(); + let to_ty = self.resolve_ty_shallow(to_ty); + self.coerce_inner(from_ty, &to_ty) + } + + /// Merge two types from different branches, with possible implicit coerce. + /// + /// Note that it is only possible that one type are coerced to another. + /// Coercing both types to another least upper bound type is not possible in rustc, + /// which will simply result in "incompatible types" error. + pub(super) fn coerce_merge_branch<'t>(&mut self, ty1: &Ty, ty2: &Ty) -> Ty { + if self.coerce(ty1, ty2) { + ty2.clone() + } else if self.coerce(ty2, ty1) { + ty1.clone() + } else { + tested_by!(coerce_merge_fail_fallback); + // For incompatible types, we use the latter one as result + // to be better recovery for `if` without `else`. + ty2.clone() + } + } + + pub(super) fn init_coerce_unsized_map( + db: &'a D, + resolver: &Resolver, + ) -> FxHashMap<(TypeCtor, TypeCtor), usize> { + let krate = resolver.krate().unwrap(); + let impls = match db.lang_item(krate.into(), "coerce_unsized".into()) { + Some(LangItemTarget::TraitId(trait_)) => { + db.impls_for_trait(krate.into(), trait_.into()) + } + _ => return FxHashMap::default(), + }; + + impls + .iter() + .filter_map(|&impl_id| { + let impl_data = db.impl_data(impl_id); + let resolver = impl_id.resolver(db); + let target_ty = Ty::from_hir(db, &resolver, &impl_data.target_type); + + // `CoerseUnsized` has one generic parameter for the target type. + let trait_ref = TraitRef::from_hir( + db, + &resolver, + impl_data.target_trait.as_ref()?, + Some(target_ty), + )?; + let cur_from_ty = trait_ref.substs.0.get(0)?; + let cur_to_ty = trait_ref.substs.0.get(1)?; + + match (&cur_from_ty, cur_to_ty) { + (ty_app!(ctor1, st1), ty_app!(ctor2, st2)) => { + // FIXME: We return the first non-equal bound as the type parameter to coerce to unsized type. + // This works for smart-pointer-like coercion, which covers all impls from std. + st1.iter().zip(st2.iter()).enumerate().find_map(|(i, (ty1, ty2))| { + match (ty1, ty2) { + (Ty::Param { idx: p1, .. }, Ty::Param { idx: p2, .. }) + if p1 != p2 => + { + Some(((*ctor1, *ctor2), i)) + } + _ => None, + } + }) + } + _ => None, + } + }) + .collect() + } + + fn coerce_inner(&mut self, mut from_ty: Ty, to_ty: &Ty) -> bool { + match (&from_ty, to_ty) { + // Never type will make type variable to fallback to Never Type instead of Unknown. + (ty_app!(TypeCtor::Never), Ty::Infer(InferTy::TypeVar(tv))) => { + let var = self.new_maybe_never_type_var(); + self.var_unification_table.union_value(*tv, TypeVarValue::Known(var)); + return true; + } + (ty_app!(TypeCtor::Never), _) => return true, + + // Trivial cases, this should go after `never` check to + // avoid infer result type to be never + _ => { + if self.unify_inner_trivial(&from_ty, &to_ty) { + return true; + } + } + } + + // Pointer weakening and function to pointer + match (&mut from_ty, to_ty) { + // `*mut T`, `&mut T, `&T`` -> `*const T` + // `&mut T` -> `&T` + // `&mut T` -> `*mut T` + (ty_app!(c1@TypeCtor::RawPtr(_)), ty_app!(c2@TypeCtor::RawPtr(Mutability::Shared))) + | (ty_app!(c1@TypeCtor::Ref(_)), ty_app!(c2@TypeCtor::RawPtr(Mutability::Shared))) + | (ty_app!(c1@TypeCtor::Ref(_)), ty_app!(c2@TypeCtor::Ref(Mutability::Shared))) + | (ty_app!(c1@TypeCtor::Ref(Mutability::Mut)), ty_app!(c2@TypeCtor::RawPtr(_))) => { + *c1 = *c2; + } + + // Illegal mutablity conversion + ( + ty_app!(TypeCtor::RawPtr(Mutability::Shared)), + ty_app!(TypeCtor::RawPtr(Mutability::Mut)), + ) + | ( + ty_app!(TypeCtor::Ref(Mutability::Shared)), + ty_app!(TypeCtor::Ref(Mutability::Mut)), + ) => return false, + + // `{function_type}` -> `fn()` + (ty_app!(TypeCtor::FnDef(_)), ty_app!(TypeCtor::FnPtr { .. })) => { + match from_ty.callable_sig(self.db) { + None => return false, + Some(sig) => { + let num_args = sig.params_and_return.len() as u16 - 1; + from_ty = + Ty::apply(TypeCtor::FnPtr { num_args }, Substs(sig.params_and_return)); + } + } + } + + _ => {} + } + + if let Some(ret) = self.try_coerce_unsized(&from_ty, &to_ty) { + return ret; + } + + // Auto Deref if cannot coerce + match (&from_ty, to_ty) { + // FIXME: DerefMut + (ty_app!(TypeCtor::Ref(_), st1), ty_app!(TypeCtor::Ref(_), st2)) => { + self.unify_autoderef_behind_ref(&st1[0], &st2[0]) + } + + // Otherwise, normal unify + _ => self.unify(&from_ty, to_ty), + } + } + + /// Coerce a type using `from_ty: CoerceUnsized` + /// + /// See: https://doc.rust-lang.org/nightly/std/marker/trait.CoerceUnsized.html + fn try_coerce_unsized(&mut self, from_ty: &Ty, to_ty: &Ty) -> Option { + let (ctor1, st1, ctor2, st2) = match (from_ty, to_ty) { + (ty_app!(ctor1, st1), ty_app!(ctor2, st2)) => (ctor1, st1, ctor2, st2), + _ => return None, + }; + + let coerce_generic_index = *self.coerce_unsized_map.get(&(*ctor1, *ctor2))?; + + // Check `Unsize` first + match self.check_unsize_and_coerce( + st1.0.get(coerce_generic_index)?, + st2.0.get(coerce_generic_index)?, + 0, + ) { + Some(true) => {} + ret => return ret, + } + + let ret = st1 + .iter() + .zip(st2.iter()) + .enumerate() + .filter(|&(idx, _)| idx != coerce_generic_index) + .all(|(_, (ty1, ty2))| self.unify(ty1, ty2)); + + Some(ret) + } + + /// Check if `from_ty: Unsize`, and coerce to `to_ty` if it holds. + /// + /// It should not be directly called. It is only used by `try_coerce_unsized`. + /// + /// See: https://doc.rust-lang.org/nightly/std/marker/trait.Unsize.html + fn check_unsize_and_coerce(&mut self, from_ty: &Ty, to_ty: &Ty, depth: usize) -> Option { + if depth > 1000 { + panic!("Infinite recursion in coercion"); + } + + match (&from_ty, &to_ty) { + // `[T; N]` -> `[T]` + (ty_app!(TypeCtor::Array, st1), ty_app!(TypeCtor::Slice, st2)) => { + Some(self.unify(&st1[0], &st2[0])) + } + + // `T` -> `dyn Trait` when `T: Trait` + (_, Ty::Dyn(_)) => { + // FIXME: Check predicates + Some(true) + } + + // `(..., T)` -> `(..., U)` when `T: Unsize` + ( + ty_app!(TypeCtor::Tuple { cardinality: len1 }, st1), + ty_app!(TypeCtor::Tuple { cardinality: len2 }, st2), + ) => { + if len1 != len2 || *len1 == 0 { + return None; + } + + match self.check_unsize_and_coerce( + st1.last().unwrap(), + st2.last().unwrap(), + depth + 1, + ) { + Some(true) => {} + ret => return ret, + } + + let ret = st1[..st1.len() - 1] + .iter() + .zip(&st2[..st2.len() - 1]) + .all(|(ty1, ty2)| self.unify(ty1, ty2)); + + Some(ret) + } + + // Foo<..., T, ...> is Unsize> if: + // - T: Unsize + // - Foo is a struct + // - Only the last field of Foo has a type involving T + // - T is not part of the type of any other fields + // - Bar: Unsize>, if the last field of Foo has type Bar + ( + ty_app!(TypeCtor::Adt(AdtId::StructId(struct1)), st1), + ty_app!(TypeCtor::Adt(AdtId::StructId(struct2)), st2), + ) if struct1 == struct2 => { + let field_tys = self.db.field_types((*struct1).into()); + let struct_data = self.db.struct_data(*struct1); + + let mut fields = struct_data.variant_data.fields().iter(); + let (last_field_id, _data) = fields.next_back()?; + + // Get the generic parameter involved in the last field. + let unsize_generic_index = { + let mut index = None; + let mut multiple_param = false; + field_tys[last_field_id].walk(&mut |ty| match ty { + &Ty::Param { idx, .. } => { + if index.is_none() { + index = Some(idx); + } else if Some(idx) != index { + multiple_param = true; + } + } + _ => {} + }); + + if multiple_param { + return None; + } + index? + }; + + // Check other fields do not involve it. + let mut multiple_used = false; + fields.for_each(|(field_id, _data)| { + field_tys[field_id].walk(&mut |ty| match ty { + &Ty::Param { idx, .. } if idx == unsize_generic_index => { + multiple_used = true + } + _ => {} + }) + }); + if multiple_used { + return None; + } + + let unsize_generic_index = unsize_generic_index as usize; + + // Check `Unsize` first + match self.check_unsize_and_coerce( + st1.get(unsize_generic_index)?, + st2.get(unsize_generic_index)?, + depth + 1, + ) { + Some(true) => {} + ret => return ret, + } + + // Then unify other parameters + let ret = st1 + .iter() + .zip(st2.iter()) + .enumerate() + .filter(|&(idx, _)| idx != unsize_generic_index) + .all(|(_, (ty1, ty2))| self.unify(ty1, ty2)); + + Some(ret) + } + + _ => None, + } + } + + /// Unify `from_ty` to `to_ty` with optional auto Deref + /// + /// Note that the parameters are already stripped the outer reference. + fn unify_autoderef_behind_ref(&mut self, from_ty: &Ty, to_ty: &Ty) -> bool { + let canonicalized = self.canonicalizer().canonicalize_ty(from_ty.clone()); + let to_ty = self.resolve_ty_shallow(&to_ty); + // FIXME: Auto DerefMut + for derefed_ty in autoderef::autoderef( + self.db, + self.resolver.krate(), + InEnvironment { + value: canonicalized.value.clone(), + environment: self.trait_env.clone(), + }, + ) { + let derefed_ty = canonicalized.decanonicalize_ty(derefed_ty.value); + match (&*self.resolve_ty_shallow(&derefed_ty), &*to_ty) { + // Stop when constructor matches. + (ty_app!(from_ctor, st1), ty_app!(to_ctor, st2)) if from_ctor == to_ctor => { + // It will not recurse to `coerce`. + return self.unify_substs(st1, st2, 0); + } + _ => {} + } + } + + false + } +} diff --git a/crates/ra_hir_ty/src/infer/expr.rs b/crates/ra_hir_ty/src/infer/expr.rs new file mode 100644 index 000000000..2f9ca4bbb --- /dev/null +++ b/crates/ra_hir_ty/src/infer/expr.rs @@ -0,0 +1,686 @@ +//! Type inference for expressions. + +use std::iter::{repeat, repeat_with}; +use std::sync::Arc; + +use hir_def::{ + builtin_type::Signedness, + expr::{Array, BinaryOp, Expr, ExprId, Literal, Statement, UnaryOp}, + generics::GenericParams, + path::{GenericArg, GenericArgs}, + resolver::resolver_for_expr, + AdtId, ContainerId, Lookup, StructFieldId, +}; +use hir_expand::name::{self, Name}; + +use crate::{ + autoderef, db::HirDatabase, method_resolution, op, traits::InEnvironment, utils::variant_data, + CallableDef, InferTy, IntTy, Mutability, Obligation, ProjectionPredicate, ProjectionTy, Substs, + TraitRef, Ty, TypeCtor, TypeWalk, Uncertain, +}; + +use super::{BindingMode, Expectation, InferenceContext, InferenceDiagnostic, TypeMismatch}; + +impl<'a, D: HirDatabase> InferenceContext<'a, D> { + pub(super) fn infer_expr(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty { + let ty = self.infer_expr_inner(tgt_expr, expected); + let could_unify = self.unify(&ty, &expected.ty); + if !could_unify { + self.result.type_mismatches.insert( + tgt_expr, + TypeMismatch { expected: expected.ty.clone(), actual: ty.clone() }, + ); + } + let ty = self.resolve_ty_as_possible(&mut vec![], ty); + ty + } + + /// Infer type of expression with possibly implicit coerce to the expected type. + /// Return the type after possible coercion. + fn infer_expr_coerce(&mut self, expr: ExprId, expected: &Expectation) -> Ty { + let ty = self.infer_expr_inner(expr, &expected); + let ty = if !self.coerce(&ty, &expected.ty) { + self.result + .type_mismatches + .insert(expr, TypeMismatch { expected: expected.ty.clone(), actual: ty.clone() }); + // Return actual type when type mismatch. + // This is needed for diagnostic when return type mismatch. + ty + } else if expected.ty == Ty::Unknown { + ty + } else { + expected.ty.clone() + }; + + self.resolve_ty_as_possible(&mut vec![], ty) + } + + fn infer_expr_inner(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty { + let body = Arc::clone(&self.body); // avoid borrow checker problem + let ty = match &body[tgt_expr] { + Expr::Missing => Ty::Unknown, + Expr::If { condition, then_branch, else_branch } => { + // if let is desugared to match, so this is always simple if + self.infer_expr(*condition, &Expectation::has_type(Ty::simple(TypeCtor::Bool))); + + let then_ty = self.infer_expr_inner(*then_branch, &expected); + let else_ty = match else_branch { + Some(else_branch) => self.infer_expr_inner(*else_branch, &expected), + None => Ty::unit(), + }; + + self.coerce_merge_branch(&then_ty, &else_ty) + } + Expr::Block { statements, tail } => self.infer_block(statements, *tail, expected), + Expr::TryBlock { body } => { + let _inner = self.infer_expr(*body, expected); + // FIXME should be std::result::Result<{inner}, _> + Ty::Unknown + } + Expr::Loop { body } => { + self.infer_expr(*body, &Expectation::has_type(Ty::unit())); + // FIXME handle break with value + Ty::simple(TypeCtor::Never) + } + Expr::While { condition, body } => { + // while let is desugared to a match loop, so this is always simple while + self.infer_expr(*condition, &Expectation::has_type(Ty::simple(TypeCtor::Bool))); + self.infer_expr(*body, &Expectation::has_type(Ty::unit())); + Ty::unit() + } + Expr::For { iterable, body, pat } => { + let iterable_ty = self.infer_expr(*iterable, &Expectation::none()); + + let pat_ty = match self.resolve_into_iter_item() { + Some(into_iter_item_alias) => { + let pat_ty = self.new_type_var(); + let projection = ProjectionPredicate { + ty: pat_ty.clone(), + projection_ty: ProjectionTy { + associated_ty: into_iter_item_alias, + parameters: Substs::single(iterable_ty), + }, + }; + self.obligations.push(Obligation::Projection(projection)); + self.resolve_ty_as_possible(&mut vec![], pat_ty) + } + None => Ty::Unknown, + }; + + self.infer_pat(*pat, &pat_ty, BindingMode::default()); + self.infer_expr(*body, &Expectation::has_type(Ty::unit())); + Ty::unit() + } + Expr::Lambda { body, args, arg_types } => { + assert_eq!(args.len(), arg_types.len()); + + let mut sig_tys = Vec::new(); + + for (arg_pat, arg_type) in args.iter().zip(arg_types.iter()) { + let expected = if let Some(type_ref) = arg_type { + self.make_ty(type_ref) + } else { + Ty::Unknown + }; + let arg_ty = self.infer_pat(*arg_pat, &expected, BindingMode::default()); + sig_tys.push(arg_ty); + } + + // add return type + let ret_ty = self.new_type_var(); + sig_tys.push(ret_ty.clone()); + let sig_ty = Ty::apply( + TypeCtor::FnPtr { num_args: sig_tys.len() as u16 - 1 }, + Substs(sig_tys.into()), + ); + let closure_ty = Ty::apply_one( + TypeCtor::Closure { def: self.owner.into(), expr: tgt_expr }, + sig_ty, + ); + + // Eagerly try to relate the closure type with the expected + // type, otherwise we often won't have enough information to + // infer the body. + self.coerce(&closure_ty, &expected.ty); + + self.infer_expr(*body, &Expectation::has_type(ret_ty)); + closure_ty + } + Expr::Call { callee, args } => { + let callee_ty = self.infer_expr(*callee, &Expectation::none()); + let (param_tys, ret_ty) = match callee_ty.callable_sig(self.db) { + Some(sig) => (sig.params().to_vec(), sig.ret().clone()), + None => { + // Not callable + // FIXME: report an error + (Vec::new(), Ty::Unknown) + } + }; + self.register_obligations_for_call(&callee_ty); + self.check_call_arguments(args, ¶m_tys); + let ret_ty = self.normalize_associated_types_in(ret_ty); + ret_ty + } + Expr::MethodCall { receiver, args, method_name, generic_args } => self + .infer_method_call(tgt_expr, *receiver, &args, &method_name, generic_args.as_ref()), + Expr::Match { expr, arms } => { + let input_ty = self.infer_expr(*expr, &Expectation::none()); + + let mut result_ty = self.new_maybe_never_type_var(); + + for arm in arms { + for &pat in &arm.pats { + let _pat_ty = self.infer_pat(pat, &input_ty, BindingMode::default()); + } + if let Some(guard_expr) = arm.guard { + self.infer_expr( + guard_expr, + &Expectation::has_type(Ty::simple(TypeCtor::Bool)), + ); + } + + let arm_ty = self.infer_expr_inner(arm.expr, &expected); + result_ty = self.coerce_merge_branch(&result_ty, &arm_ty); + } + + result_ty + } + Expr::Path(p) => { + // FIXME this could be more efficient... + let resolver = resolver_for_expr(self.db, self.owner.into(), tgt_expr); + self.infer_path(&resolver, p, tgt_expr.into()).unwrap_or(Ty::Unknown) + } + Expr::Continue => Ty::simple(TypeCtor::Never), + Expr::Break { expr } => { + if let Some(expr) = expr { + // FIXME handle break with value + self.infer_expr(*expr, &Expectation::none()); + } + Ty::simple(TypeCtor::Never) + } + Expr::Return { expr } => { + if let Some(expr) = expr { + self.infer_expr(*expr, &Expectation::has_type(self.return_ty.clone())); + } + Ty::simple(TypeCtor::Never) + } + Expr::RecordLit { path, fields, spread } => { + let (ty, def_id) = self.resolve_variant(path.as_ref()); + if let Some(variant) = def_id { + self.write_variant_resolution(tgt_expr.into(), variant); + } + + self.unify(&ty, &expected.ty); + + let substs = ty.substs().unwrap_or_else(Substs::empty); + let field_types = + def_id.map(|it| self.db.field_types(it.into())).unwrap_or_default(); + let variant_data = def_id.map(|it| variant_data(self.db, it)); + for (field_idx, field) in fields.iter().enumerate() { + let field_def = + variant_data.as_ref().and_then(|it| match it.field(&field.name) { + Some(local_id) => { + Some(StructFieldId { parent: def_id.unwrap(), local_id }) + } + None => { + self.push_diagnostic(InferenceDiagnostic::NoSuchField { + expr: tgt_expr, + field: field_idx, + }); + None + } + }); + if let Some(field_def) = field_def { + self.result.record_field_resolutions.insert(field.expr, field_def); + } + let field_ty = field_def + .map_or(Ty::Unknown, |it| field_types[it.local_id].clone()) + .subst(&substs); + self.infer_expr_coerce(field.expr, &Expectation::has_type(field_ty)); + } + if let Some(expr) = spread { + self.infer_expr(*expr, &Expectation::has_type(ty.clone())); + } + ty + } + Expr::Field { expr, name } => { + let receiver_ty = self.infer_expr(*expr, &Expectation::none()); + let canonicalized = self.canonicalizer().canonicalize_ty(receiver_ty); + let ty = autoderef::autoderef( + self.db, + self.resolver.krate(), + InEnvironment { + value: canonicalized.value.clone(), + environment: self.trait_env.clone(), + }, + ) + .find_map(|derefed_ty| match canonicalized.decanonicalize_ty(derefed_ty.value) { + Ty::Apply(a_ty) => match a_ty.ctor { + TypeCtor::Tuple { .. } => name + .as_tuple_index() + .and_then(|idx| a_ty.parameters.0.get(idx).cloned()), + TypeCtor::Adt(AdtId::StructId(s)) => { + self.db.struct_data(s).variant_data.field(name).map(|local_id| { + let field = StructFieldId { parent: s.into(), local_id }.into(); + self.write_field_resolution(tgt_expr, field); + self.db.field_types(s.into())[field.local_id] + .clone() + .subst(&a_ty.parameters) + }) + } + // FIXME: + TypeCtor::Adt(AdtId::UnionId(_)) => None, + _ => None, + }, + _ => None, + }) + .unwrap_or(Ty::Unknown); + let ty = self.insert_type_vars(ty); + self.normalize_associated_types_in(ty) + } + Expr::Await { expr } => { + let inner_ty = self.infer_expr(*expr, &Expectation::none()); + let ty = match self.resolve_future_future_output() { + Some(future_future_output_alias) => { + let ty = self.new_type_var(); + let projection = ProjectionPredicate { + ty: ty.clone(), + projection_ty: ProjectionTy { + associated_ty: future_future_output_alias, + parameters: Substs::single(inner_ty), + }, + }; + self.obligations.push(Obligation::Projection(projection)); + self.resolve_ty_as_possible(&mut vec![], ty) + } + None => Ty::Unknown, + }; + ty + } + Expr::Try { expr } => { + let inner_ty = self.infer_expr(*expr, &Expectation::none()); + let ty = match self.resolve_ops_try_ok() { + Some(ops_try_ok_alias) => { + let ty = self.new_type_var(); + let projection = ProjectionPredicate { + ty: ty.clone(), + projection_ty: ProjectionTy { + associated_ty: ops_try_ok_alias, + parameters: Substs::single(inner_ty), + }, + }; + self.obligations.push(Obligation::Projection(projection)); + self.resolve_ty_as_possible(&mut vec![], ty) + } + None => Ty::Unknown, + }; + ty + } + Expr::Cast { expr, type_ref } => { + let _inner_ty = self.infer_expr(*expr, &Expectation::none()); + let cast_ty = self.make_ty(type_ref); + // FIXME check the cast... + cast_ty + } + Expr::Ref { expr, mutability } => { + let expectation = + if let Some((exp_inner, exp_mutability)) = &expected.ty.as_reference() { + if *exp_mutability == Mutability::Mut && *mutability == Mutability::Shared { + // FIXME: throw type error - expected mut reference but found shared ref, + // which cannot be coerced + } + Expectation::has_type(Ty::clone(exp_inner)) + } else { + Expectation::none() + }; + // FIXME reference coercions etc. + let inner_ty = self.infer_expr(*expr, &expectation); + Ty::apply_one(TypeCtor::Ref(*mutability), inner_ty) + } + Expr::Box { expr } => { + let inner_ty = self.infer_expr(*expr, &Expectation::none()); + if let Some(box_) = self.resolve_boxed_box() { + Ty::apply_one(TypeCtor::Adt(box_), inner_ty) + } else { + Ty::Unknown + } + } + Expr::UnaryOp { expr, op } => { + let inner_ty = self.infer_expr(*expr, &Expectation::none()); + match op { + UnaryOp::Deref => match self.resolver.krate() { + Some(krate) => { + let canonicalized = self.canonicalizer().canonicalize_ty(inner_ty); + match autoderef::deref( + self.db, + krate, + InEnvironment { + value: &canonicalized.value, + environment: self.trait_env.clone(), + }, + ) { + Some(derefed_ty) => { + canonicalized.decanonicalize_ty(derefed_ty.value) + } + None => Ty::Unknown, + } + } + None => Ty::Unknown, + }, + UnaryOp::Neg => { + match &inner_ty { + Ty::Apply(a_ty) => match a_ty.ctor { + TypeCtor::Int(Uncertain::Unknown) + | TypeCtor::Int(Uncertain::Known(IntTy { + signedness: Signedness::Signed, + .. + })) + | TypeCtor::Float(..) => inner_ty, + _ => Ty::Unknown, + }, + Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => { + inner_ty + } + // FIXME: resolve ops::Neg trait + _ => Ty::Unknown, + } + } + UnaryOp::Not => { + match &inner_ty { + Ty::Apply(a_ty) => match a_ty.ctor { + TypeCtor::Bool | TypeCtor::Int(_) => inner_ty, + _ => Ty::Unknown, + }, + Ty::Infer(InferTy::IntVar(..)) => inner_ty, + // FIXME: resolve ops::Not trait for inner_ty + _ => Ty::Unknown, + } + } + } + } + Expr::BinaryOp { lhs, rhs, op } => match op { + Some(op) => { + let lhs_expectation = match op { + BinaryOp::LogicOp(..) => Expectation::has_type(Ty::simple(TypeCtor::Bool)), + _ => Expectation::none(), + }; + let lhs_ty = self.infer_expr(*lhs, &lhs_expectation); + // FIXME: find implementation of trait corresponding to operation + // symbol and resolve associated `Output` type + let rhs_expectation = op::binary_op_rhs_expectation(*op, lhs_ty); + let rhs_ty = self.infer_expr(*rhs, &Expectation::has_type(rhs_expectation)); + + // FIXME: similar as above, return ty is often associated trait type + op::binary_op_return_ty(*op, rhs_ty) + } + _ => Ty::Unknown, + }, + Expr::Index { base, index } => { + let _base_ty = self.infer_expr(*base, &Expectation::none()); + let _index_ty = self.infer_expr(*index, &Expectation::none()); + // FIXME: use `std::ops::Index::Output` to figure out the real return type + Ty::Unknown + } + Expr::Tuple { exprs } => { + let mut tys = match &expected.ty { + ty_app!(TypeCtor::Tuple { .. }, st) => st + .iter() + .cloned() + .chain(repeat_with(|| self.new_type_var())) + .take(exprs.len()) + .collect::>(), + _ => (0..exprs.len()).map(|_| self.new_type_var()).collect(), + }; + + for (expr, ty) in exprs.iter().zip(tys.iter_mut()) { + self.infer_expr_coerce(*expr, &Expectation::has_type(ty.clone())); + } + + Ty::apply(TypeCtor::Tuple { cardinality: tys.len() as u16 }, Substs(tys.into())) + } + Expr::Array(array) => { + let elem_ty = match &expected.ty { + ty_app!(TypeCtor::Array, st) | ty_app!(TypeCtor::Slice, st) => { + st.as_single().clone() + } + _ => self.new_type_var(), + }; + + match array { + Array::ElementList(items) => { + for expr in items.iter() { + self.infer_expr_coerce(*expr, &Expectation::has_type(elem_ty.clone())); + } + } + Array::Repeat { initializer, repeat } => { + self.infer_expr_coerce( + *initializer, + &Expectation::has_type(elem_ty.clone()), + ); + self.infer_expr( + *repeat, + &Expectation::has_type(Ty::simple(TypeCtor::Int(Uncertain::Known( + IntTy::usize(), + )))), + ); + } + } + + Ty::apply_one(TypeCtor::Array, elem_ty) + } + Expr::Literal(lit) => match lit { + Literal::Bool(..) => Ty::simple(TypeCtor::Bool), + Literal::String(..) => { + Ty::apply_one(TypeCtor::Ref(Mutability::Shared), Ty::simple(TypeCtor::Str)) + } + Literal::ByteString(..) => { + let byte_type = Ty::simple(TypeCtor::Int(Uncertain::Known(IntTy::u8()))); + let slice_type = Ty::apply_one(TypeCtor::Slice, byte_type); + Ty::apply_one(TypeCtor::Ref(Mutability::Shared), slice_type) + } + Literal::Char(..) => Ty::simple(TypeCtor::Char), + Literal::Int(_v, ty) => Ty::simple(TypeCtor::Int((*ty).into())), + Literal::Float(_v, ty) => Ty::simple(TypeCtor::Float((*ty).into())), + }, + }; + // use a new type variable if we got Ty::Unknown here + let ty = self.insert_type_vars_shallow(ty); + let ty = self.resolve_ty_as_possible(&mut vec![], ty); + self.write_expr_ty(tgt_expr, ty.clone()); + ty + } + + fn infer_block( + &mut self, + statements: &[Statement], + tail: Option, + expected: &Expectation, + ) -> Ty { + let mut diverges = false; + for stmt in statements { + match stmt { + Statement::Let { pat, type_ref, initializer } => { + let decl_ty = + type_ref.as_ref().map(|tr| self.make_ty(tr)).unwrap_or(Ty::Unknown); + + // Always use the declared type when specified + let mut ty = decl_ty.clone(); + + if let Some(expr) = initializer { + let actual_ty = + self.infer_expr_coerce(*expr, &Expectation::has_type(decl_ty.clone())); + if decl_ty == Ty::Unknown { + ty = actual_ty; + } + } + + let ty = self.resolve_ty_as_possible(&mut vec![], ty); + self.infer_pat(*pat, &ty, BindingMode::default()); + } + Statement::Expr(expr) => { + if let ty_app!(TypeCtor::Never) = self.infer_expr(*expr, &Expectation::none()) { + diverges = true; + } + } + } + } + + let ty = if let Some(expr) = tail { + self.infer_expr_coerce(expr, expected) + } else { + self.coerce(&Ty::unit(), &expected.ty); + Ty::unit() + }; + if diverges { + Ty::simple(TypeCtor::Never) + } else { + ty + } + } + + fn infer_method_call( + &mut self, + tgt_expr: ExprId, + receiver: ExprId, + args: &[ExprId], + method_name: &Name, + generic_args: Option<&GenericArgs>, + ) -> Ty { + let receiver_ty = self.infer_expr(receiver, &Expectation::none()); + let canonicalized_receiver = self.canonicalizer().canonicalize_ty(receiver_ty.clone()); + let resolved = method_resolution::lookup_method( + &canonicalized_receiver.value, + self.db, + method_name, + &self.resolver, + ); + let (derefed_receiver_ty, method_ty, def_generics) = match resolved { + Some((ty, func)) => { + let ty = canonicalized_receiver.decanonicalize_ty(ty); + self.write_method_resolution(tgt_expr, func); + (ty, self.db.value_ty(func.into()), Some(self.db.generic_params(func.into()))) + } + None => (receiver_ty, Ty::Unknown, None), + }; + let substs = self.substs_for_method_call(def_generics, generic_args, &derefed_receiver_ty); + let method_ty = method_ty.apply_substs(substs); + let method_ty = self.insert_type_vars(method_ty); + self.register_obligations_for_call(&method_ty); + let (expected_receiver_ty, param_tys, ret_ty) = match method_ty.callable_sig(self.db) { + Some(sig) => { + if !sig.params().is_empty() { + (sig.params()[0].clone(), sig.params()[1..].to_vec(), sig.ret().clone()) + } else { + (Ty::Unknown, Vec::new(), sig.ret().clone()) + } + } + None => (Ty::Unknown, Vec::new(), Ty::Unknown), + }; + // Apply autoref so the below unification works correctly + // FIXME: return correct autorefs from lookup_method + let actual_receiver_ty = match expected_receiver_ty.as_reference() { + Some((_, mutability)) => Ty::apply_one(TypeCtor::Ref(mutability), derefed_receiver_ty), + _ => derefed_receiver_ty, + }; + self.unify(&expected_receiver_ty, &actual_receiver_ty); + + self.check_call_arguments(args, ¶m_tys); + let ret_ty = self.normalize_associated_types_in(ret_ty); + ret_ty + } + + fn check_call_arguments(&mut self, args: &[ExprId], param_tys: &[Ty]) { + // Quoting https://github.com/rust-lang/rust/blob/6ef275e6c3cb1384ec78128eceeb4963ff788dca/src/librustc_typeck/check/mod.rs#L3325 -- + // We do this in a pretty awful way: first we type-check any arguments + // that are not closures, then we type-check the closures. This is so + // that we have more information about the types of arguments when we + // type-check the functions. This isn't really the right way to do this. + for &check_closures in &[false, true] { + let param_iter = param_tys.iter().cloned().chain(repeat(Ty::Unknown)); + for (&arg, param_ty) in args.iter().zip(param_iter) { + let is_closure = match &self.body[arg] { + Expr::Lambda { .. } => true, + _ => false, + }; + + if is_closure != check_closures { + continue; + } + + let param_ty = self.normalize_associated_types_in(param_ty); + self.infer_expr_coerce(arg, &Expectation::has_type(param_ty.clone())); + } + } + } + + fn substs_for_method_call( + &mut self, + def_generics: Option>, + generic_args: Option<&GenericArgs>, + receiver_ty: &Ty, + ) -> Substs { + let (parent_param_count, param_count) = + def_generics.as_ref().map_or((0, 0), |g| (g.count_parent_params(), g.params.len())); + let mut substs = Vec::with_capacity(parent_param_count + param_count); + // Parent arguments are unknown, except for the receiver type + if let Some(parent_generics) = def_generics.and_then(|p| p.parent_params.clone()) { + for param in &parent_generics.params { + if param.name == name::SELF_TYPE { + substs.push(receiver_ty.clone()); + } else { + substs.push(Ty::Unknown); + } + } + } + // handle provided type arguments + if let Some(generic_args) = generic_args { + // if args are provided, it should be all of them, but we can't rely on that + for arg in generic_args.args.iter().take(param_count) { + match arg { + GenericArg::Type(type_ref) => { + let ty = self.make_ty(type_ref); + substs.push(ty); + } + } + } + }; + let supplied_params = substs.len(); + for _ in supplied_params..parent_param_count + param_count { + substs.push(Ty::Unknown); + } + assert_eq!(substs.len(), parent_param_count + param_count); + Substs(substs.into()) + } + + fn register_obligations_for_call(&mut self, callable_ty: &Ty) { + if let Ty::Apply(a_ty) = callable_ty { + if let TypeCtor::FnDef(def) = a_ty.ctor { + let generic_predicates = self.db.generic_predicates(def.into()); + for predicate in generic_predicates.iter() { + let predicate = predicate.clone().subst(&a_ty.parameters); + if let Some(obligation) = Obligation::from_predicate(predicate) { + self.obligations.push(obligation); + } + } + // add obligation for trait implementation, if this is a trait method + match def { + CallableDef::FunctionId(f) => { + if let ContainerId::TraitId(trait_) = f.lookup(self.db).container { + // construct a TraitDef + let substs = a_ty.parameters.prefix( + self.db + .generic_params(trait_.into()) + .count_params_including_parent(), + ); + self.obligations.push(Obligation::Trait(TraitRef { + trait_: trait_.into(), + substs, + })); + } + } + CallableDef::StructId(_) | CallableDef::EnumVariantId(_) => {} + } + } + } + } +} diff --git a/crates/ra_hir_ty/src/infer/pat.rs b/crates/ra_hir_ty/src/infer/pat.rs new file mode 100644 index 000000000..1ebb36239 --- /dev/null +++ b/crates/ra_hir_ty/src/infer/pat.rs @@ -0,0 +1,186 @@ +//! Type inference for patterns. + +use std::iter::repeat; +use std::sync::Arc; + +use hir_def::{ + expr::{BindingAnnotation, Pat, PatId, RecordFieldPat}, + path::Path, + type_ref::Mutability, +}; +use hir_expand::name::Name; +use test_utils::tested_by; + +use super::{BindingMode, InferenceContext}; +use crate::{db::HirDatabase, utils::variant_data, Substs, Ty, TypeCtor, TypeWalk}; + +impl<'a, D: HirDatabase> InferenceContext<'a, D> { + fn infer_tuple_struct_pat( + &mut self, + path: Option<&Path>, + subpats: &[PatId], + expected: &Ty, + default_bm: BindingMode, + ) -> Ty { + let (ty, def) = self.resolve_variant(path); + let var_data = def.map(|it| variant_data(self.db, it)); + self.unify(&ty, expected); + + let substs = ty.substs().unwrap_or_else(Substs::empty); + + let field_tys = def.map(|it| self.db.field_types(it.into())).unwrap_or_default(); + + for (i, &subpat) in subpats.iter().enumerate() { + let expected_ty = var_data + .as_ref() + .and_then(|d| d.field(&Name::new_tuple_field(i))) + .map_or(Ty::Unknown, |field| field_tys[field].clone()) + .subst(&substs); + let expected_ty = self.normalize_associated_types_in(expected_ty); + self.infer_pat(subpat, &expected_ty, default_bm); + } + + ty + } + + fn infer_record_pat( + &mut self, + path: Option<&Path>, + subpats: &[RecordFieldPat], + expected: &Ty, + default_bm: BindingMode, + id: PatId, + ) -> Ty { + let (ty, def) = self.resolve_variant(path); + let var_data = def.map(|it| variant_data(self.db, it)); + if let Some(variant) = def { + self.write_variant_resolution(id.into(), variant); + } + + self.unify(&ty, expected); + + let substs = ty.substs().unwrap_or_else(Substs::empty); + + let field_tys = def.map(|it| self.db.field_types(it.into())).unwrap_or_default(); + for subpat in subpats { + let matching_field = var_data.as_ref().and_then(|it| it.field(&subpat.name)); + let expected_ty = + matching_field.map_or(Ty::Unknown, |field| field_tys[field].clone()).subst(&substs); + let expected_ty = self.normalize_associated_types_in(expected_ty); + self.infer_pat(subpat.pat, &expected_ty, default_bm); + } + + ty + } + + pub(super) fn infer_pat( + &mut self, + pat: PatId, + mut expected: &Ty, + mut default_bm: BindingMode, + ) -> Ty { + let body = Arc::clone(&self.body); // avoid borrow checker problem + + let is_non_ref_pat = match &body[pat] { + Pat::Tuple(..) + | Pat::TupleStruct { .. } + | Pat::Record { .. } + | Pat::Range { .. } + | Pat::Slice { .. } => true, + // FIXME: Path/Lit might actually evaluate to ref, but inference is unimplemented. + Pat::Path(..) | Pat::Lit(..) => true, + Pat::Wild | Pat::Bind { .. } | Pat::Ref { .. } | Pat::Missing => false, + }; + if is_non_ref_pat { + while let Some((inner, mutability)) = expected.as_reference() { + expected = inner; + default_bm = match default_bm { + BindingMode::Move => BindingMode::Ref(mutability), + BindingMode::Ref(Mutability::Shared) => BindingMode::Ref(Mutability::Shared), + BindingMode::Ref(Mutability::Mut) => BindingMode::Ref(mutability), + } + } + } else if let Pat::Ref { .. } = &body[pat] { + tested_by!(match_ergonomics_ref); + // When you encounter a `&pat` pattern, reset to Move. + // This is so that `w` is by value: `let (_, &w) = &(1, &2);` + default_bm = BindingMode::Move; + } + + // Lose mutability. + let default_bm = default_bm; + let expected = expected; + + let ty = match &body[pat] { + Pat::Tuple(ref args) => { + let expectations = match expected.as_tuple() { + Some(parameters) => &*parameters.0, + _ => &[], + }; + let expectations_iter = expectations.iter().chain(repeat(&Ty::Unknown)); + + let inner_tys = args + .iter() + .zip(expectations_iter) + .map(|(&pat, ty)| self.infer_pat(pat, ty, default_bm)) + .collect(); + + Ty::apply(TypeCtor::Tuple { cardinality: args.len() as u16 }, Substs(inner_tys)) + } + Pat::Ref { pat, mutability } => { + let expectation = match expected.as_reference() { + Some((inner_ty, exp_mut)) => { + if *mutability != exp_mut { + // FIXME: emit type error? + } + inner_ty + } + _ => &Ty::Unknown, + }; + let subty = self.infer_pat(*pat, expectation, default_bm); + Ty::apply_one(TypeCtor::Ref(*mutability), subty) + } + Pat::TupleStruct { path: p, args: subpats } => { + self.infer_tuple_struct_pat(p.as_ref(), subpats, expected, default_bm) + } + Pat::Record { path: p, args: fields } => { + self.infer_record_pat(p.as_ref(), fields, expected, default_bm, pat) + } + Pat::Path(path) => { + // FIXME use correct resolver for the surrounding expression + let resolver = self.resolver.clone(); + self.infer_path(&resolver, &path, pat.into()).unwrap_or(Ty::Unknown) + } + Pat::Bind { mode, name: _, subpat } => { + let mode = if mode == &BindingAnnotation::Unannotated { + default_bm + } else { + BindingMode::convert(*mode) + }; + let inner_ty = if let Some(subpat) = subpat { + self.infer_pat(*subpat, expected, default_bm) + } else { + expected.clone() + }; + let inner_ty = self.insert_type_vars_shallow(inner_ty); + + let bound_ty = match mode { + BindingMode::Ref(mutability) => { + Ty::apply_one(TypeCtor::Ref(mutability), inner_ty.clone()) + } + BindingMode::Move => inner_ty.clone(), + }; + let bound_ty = self.resolve_ty_as_possible(&mut vec![], bound_ty); + self.write_pat_ty(pat, bound_ty); + return inner_ty; + } + _ => Ty::Unknown, + }; + // use a new type variable if we got Ty::Unknown here + let ty = self.insert_type_vars_shallow(ty); + self.unify(&ty, expected); + let ty = self.resolve_ty_as_possible(&mut vec![], ty); + self.write_pat_ty(pat, ty.clone()); + ty + } +} diff --git a/crates/ra_hir_ty/src/infer/path.rs b/crates/ra_hir_ty/src/infer/path.rs new file mode 100644 index 000000000..e6676e1aa --- /dev/null +++ b/crates/ra_hir_ty/src/infer/path.rs @@ -0,0 +1,270 @@ +//! Path expression resolution. + +use hir_def::{ + path::{Path, PathKind, PathSegment}, + resolver::{HasResolver, ResolveValueResult, Resolver, TypeNs, ValueNs}, + AssocItemId, ContainerId, Lookup, +}; +use hir_expand::name::Name; + +use crate::{db::HirDatabase, method_resolution, Substs, Ty, TypeWalk, ValueTyDefId}; + +use super::{ExprOrPatId, InferenceContext, TraitRef}; + +impl<'a, D: HirDatabase> InferenceContext<'a, D> { + pub(super) fn infer_path( + &mut self, + resolver: &Resolver, + path: &Path, + id: ExprOrPatId, + ) -> Option { + let ty = self.resolve_value_path(resolver, path, id)?; + let ty = self.insert_type_vars(ty); + let ty = self.normalize_associated_types_in(ty); + Some(ty) + } + + fn resolve_value_path( + &mut self, + resolver: &Resolver, + path: &Path, + id: ExprOrPatId, + ) -> Option { + let (value, self_subst) = if let PathKind::Type(type_ref) = &path.kind { + if path.segments.is_empty() { + // This can't actually happen syntax-wise + return None; + } + let ty = self.make_ty(type_ref); + let remaining_segments_for_ty = &path.segments[..path.segments.len() - 1]; + let ty = Ty::from_type_relative_path(self.db, resolver, ty, remaining_segments_for_ty); + self.resolve_ty_assoc_item( + ty, + &path.segments.last().expect("path had at least one segment").name, + id, + )? + } else { + let value_or_partial = resolver.resolve_path_in_value_ns(self.db, &path)?; + + match value_or_partial { + ResolveValueResult::ValueNs(it) => (it, None), + ResolveValueResult::Partial(def, remaining_index) => { + self.resolve_assoc_item(def, path, remaining_index, id)? + } + } + }; + + let typable: ValueTyDefId = match value { + ValueNs::LocalBinding(pat) => { + let ty = self.result.type_of_pat.get(pat)?.clone(); + let ty = self.resolve_ty_as_possible(&mut vec![], ty); + return Some(ty); + } + ValueNs::FunctionId(it) => it.into(), + ValueNs::ConstId(it) => it.into(), + ValueNs::StaticId(it) => it.into(), + ValueNs::StructId(it) => it.into(), + ValueNs::EnumVariantId(it) => it.into(), + }; + + let mut ty = self.db.value_ty(typable); + if let Some(self_subst) = self_subst { + ty = ty.subst(&self_subst); + } + let substs = Ty::substs_from_path(self.db, &self.resolver, path, typable); + let ty = ty.subst(&substs); + Some(ty) + } + + fn resolve_assoc_item( + &mut self, + def: TypeNs, + path: &Path, + remaining_index: usize, + id: ExprOrPatId, + ) -> Option<(ValueNs, Option)> { + assert!(remaining_index < path.segments.len()); + // there may be more intermediate segments between the resolved one and + // the end. Only the last segment needs to be resolved to a value; from + // the segments before that, we need to get either a type or a trait ref. + + let resolved_segment = &path.segments[remaining_index - 1]; + let remaining_segments = &path.segments[remaining_index..]; + let is_before_last = remaining_segments.len() == 1; + + match (def, is_before_last) { + (TypeNs::TraitId(trait_), true) => { + let segment = + remaining_segments.last().expect("there should be at least one segment here"); + let trait_ref = TraitRef::from_resolved_path( + self.db, + &self.resolver, + trait_.into(), + resolved_segment, + None, + ); + self.resolve_trait_assoc_item(trait_ref, segment, id) + } + (def, _) => { + // Either we already have a type (e.g. `Vec::new`), or we have a + // trait but it's not the last segment, so the next segment + // should resolve to an associated type of that trait (e.g. `::Item::default`) + let remaining_segments_for_ty = &remaining_segments[..remaining_segments.len() - 1]; + let ty = Ty::from_partly_resolved_hir_path( + self.db, + &self.resolver, + def, + resolved_segment, + remaining_segments_for_ty, + ); + if let Ty::Unknown = ty { + return None; + } + + let ty = self.insert_type_vars(ty); + let ty = self.normalize_associated_types_in(ty); + + let segment = + remaining_segments.last().expect("there should be at least one segment here"); + + self.resolve_ty_assoc_item(ty, &segment.name, id) + } + } + } + + fn resolve_trait_assoc_item( + &mut self, + trait_ref: TraitRef, + segment: &PathSegment, + id: ExprOrPatId, + ) -> Option<(ValueNs, Option)> { + let trait_ = trait_ref.trait_; + let item = self + .db + .trait_data(trait_) + .items + .iter() + .map(|(_name, id)| (*id).into()) + .find_map(|item| match item { + AssocItemId::FunctionId(func) => { + if segment.name == self.db.function_data(func).name { + Some(AssocItemId::FunctionId(func)) + } else { + None + } + } + + AssocItemId::ConstId(konst) => { + if self.db.const_data(konst).name.as_ref().map_or(false, |n| n == &segment.name) + { + Some(AssocItemId::ConstId(konst)) + } else { + None + } + } + AssocItemId::TypeAliasId(_) => None, + })?; + let def = match item { + AssocItemId::FunctionId(f) => ValueNs::FunctionId(f), + AssocItemId::ConstId(c) => ValueNs::ConstId(c), + AssocItemId::TypeAliasId(_) => unreachable!(), + }; + let substs = Substs::build_for_def(self.db, item) + .use_parent_substs(&trait_ref.substs) + .fill_with_params() + .build(); + + self.write_assoc_resolution(id, item); + Some((def, Some(substs))) + } + + fn resolve_ty_assoc_item( + &mut self, + ty: Ty, + name: &Name, + id: ExprOrPatId, + ) -> Option<(ValueNs, Option)> { + if let Ty::Unknown = ty { + return None; + } + + let canonical_ty = self.canonicalizer().canonicalize_ty(ty.clone()); + + method_resolution::iterate_method_candidates( + &canonical_ty.value, + self.db, + &self.resolver.clone(), + Some(name), + method_resolution::LookupMode::Path, + move |_ty, item| { + let (def, container) = match item { + AssocItemId::FunctionId(f) => { + (ValueNs::FunctionId(f), f.lookup(self.db).container) + } + AssocItemId::ConstId(c) => (ValueNs::ConstId(c), c.lookup(self.db).container), + AssocItemId::TypeAliasId(_) => unreachable!(), + }; + let substs = match container { + ContainerId::ImplId(_) => self.find_self_types(&def, ty.clone()), + ContainerId::TraitId(trait_) => { + // we're picking this method + let trait_substs = Substs::build_for_def(self.db, trait_) + .push(ty.clone()) + .fill(std::iter::repeat_with(|| self.new_type_var())) + .build(); + let substs = Substs::build_for_def(self.db, item) + .use_parent_substs(&trait_substs) + .fill_with_params() + .build(); + self.obligations.push(super::Obligation::Trait(TraitRef { + trait_, + substs: trait_substs, + })); + Some(substs) + } + ContainerId::ModuleId(_) => None, + }; + + self.write_assoc_resolution(id, item.into()); + Some((def, substs)) + }, + ) + } + + fn find_self_types(&self, def: &ValueNs, actual_def_ty: Ty) -> Option { + if let ValueNs::FunctionId(func) = *def { + // We only do the infer if parent has generic params + let gen = self.db.generic_params(func.into()); + if gen.count_parent_params() == 0 { + return None; + } + + let impl_id = match func.lookup(self.db).container { + ContainerId::ImplId(it) => it, + _ => return None, + }; + let resolver = impl_id.resolver(self.db); + let impl_data = self.db.impl_data(impl_id); + let impl_block = Ty::from_hir(self.db, &resolver, &impl_data.target_type); + let impl_block_substs = impl_block.substs()?; + let actual_substs = actual_def_ty.substs()?; + + let mut new_substs = vec![Ty::Unknown; gen.count_parent_params()]; + + // The following code *link up* the function actual parma type + // and impl_block type param index + impl_block_substs.iter().zip(actual_substs.iter()).for_each(|(param, pty)| { + if let Ty::Param { idx, .. } = param { + if let Some(s) = new_substs.get_mut(*idx as usize) { + *s = pty.clone(); + } + } + }); + + Some(Substs(new_substs.into())) + } else { + None + } + } +} diff --git a/crates/ra_hir_ty/src/infer/unify.rs b/crates/ra_hir_ty/src/infer/unify.rs new file mode 100644 index 000000000..f3a875678 --- /dev/null +++ b/crates/ra_hir_ty/src/infer/unify.rs @@ -0,0 +1,162 @@ +//! Unification and canonicalization logic. + +use super::{InferenceContext, Obligation}; +use crate::{ + db::HirDatabase, utils::make_mut_slice, Canonical, InEnvironment, InferTy, ProjectionPredicate, + ProjectionTy, Substs, TraitRef, Ty, TypeWalk, +}; + +impl<'a, D: HirDatabase> InferenceContext<'a, D> { + pub(super) fn canonicalizer<'b>(&'b mut self) -> Canonicalizer<'a, 'b, D> + where + 'a: 'b, + { + Canonicalizer { ctx: self, free_vars: Vec::new(), var_stack: Vec::new() } + } +} + +pub(super) struct Canonicalizer<'a, 'b, D: HirDatabase> +where + 'a: 'b, +{ + ctx: &'b mut InferenceContext<'a, D>, + free_vars: Vec, + /// A stack of type variables that is used to detect recursive types (which + /// are an error, but we need to protect against them to avoid stack + /// overflows). + var_stack: Vec, +} + +pub(super) struct Canonicalized { + pub value: Canonical, + free_vars: Vec, +} + +impl<'a, 'b, D: HirDatabase> Canonicalizer<'a, 'b, D> +where + 'a: 'b, +{ + fn add(&mut self, free_var: InferTy) -> usize { + self.free_vars.iter().position(|&v| v == free_var).unwrap_or_else(|| { + let next_index = self.free_vars.len(); + self.free_vars.push(free_var); + next_index + }) + } + + fn do_canonicalize_ty(&mut self, ty: Ty) -> Ty { + ty.fold(&mut |ty| match ty { + Ty::Infer(tv) => { + let inner = tv.to_inner(); + if self.var_stack.contains(&inner) { + // recursive type + return tv.fallback_value(); + } + if let Some(known_ty) = + self.ctx.var_unification_table.inlined_probe_value(inner).known() + { + self.var_stack.push(inner); + let result = self.do_canonicalize_ty(known_ty.clone()); + self.var_stack.pop(); + result + } else { + let root = self.ctx.var_unification_table.find(inner); + let free_var = match tv { + InferTy::TypeVar(_) => InferTy::TypeVar(root), + InferTy::IntVar(_) => InferTy::IntVar(root), + InferTy::FloatVar(_) => InferTy::FloatVar(root), + InferTy::MaybeNeverTypeVar(_) => InferTy::MaybeNeverTypeVar(root), + }; + let position = self.add(free_var); + Ty::Bound(position as u32) + } + } + _ => ty, + }) + } + + fn do_canonicalize_trait_ref(&mut self, mut trait_ref: TraitRef) -> TraitRef { + for ty in make_mut_slice(&mut trait_ref.substs.0) { + *ty = self.do_canonicalize_ty(ty.clone()); + } + trait_ref + } + + fn into_canonicalized(self, result: T) -> Canonicalized { + Canonicalized { + value: Canonical { value: result, num_vars: self.free_vars.len() }, + free_vars: self.free_vars, + } + } + + fn do_canonicalize_projection_ty(&mut self, mut projection_ty: ProjectionTy) -> ProjectionTy { + for ty in make_mut_slice(&mut projection_ty.parameters.0) { + *ty = self.do_canonicalize_ty(ty.clone()); + } + projection_ty + } + + fn do_canonicalize_projection_predicate( + &mut self, + projection: ProjectionPredicate, + ) -> ProjectionPredicate { + let ty = self.do_canonicalize_ty(projection.ty); + let projection_ty = self.do_canonicalize_projection_ty(projection.projection_ty); + + ProjectionPredicate { ty, projection_ty } + } + + // FIXME: add some point, we need to introduce a `Fold` trait that abstracts + // over all the things that can be canonicalized (like Chalk and rustc have) + + pub(crate) fn canonicalize_ty(mut self, ty: Ty) -> Canonicalized { + let result = self.do_canonicalize_ty(ty); + self.into_canonicalized(result) + } + + pub(crate) fn canonicalize_obligation( + mut self, + obligation: InEnvironment, + ) -> Canonicalized> { + let result = match obligation.value { + Obligation::Trait(tr) => Obligation::Trait(self.do_canonicalize_trait_ref(tr)), + Obligation::Projection(pr) => { + Obligation::Projection(self.do_canonicalize_projection_predicate(pr)) + } + }; + self.into_canonicalized(InEnvironment { + value: result, + environment: obligation.environment, + }) + } +} + +impl Canonicalized { + pub fn decanonicalize_ty(&self, mut ty: Ty) -> Ty { + ty.walk_mut_binders( + &mut |ty, binders| match ty { + &mut Ty::Bound(idx) => { + if idx as usize >= binders && (idx as usize - binders) < self.free_vars.len() { + *ty = Ty::Infer(self.free_vars[idx as usize - binders]); + } + } + _ => {} + }, + 0, + ); + ty + } + + pub fn apply_solution( + &self, + ctx: &mut InferenceContext<'_, impl HirDatabase>, + solution: Canonical>, + ) { + // the solution may contain new variables, which we need to convert to new inference vars + let new_vars = Substs((0..solution.num_vars).map(|_| ctx.new_type_var()).collect()); + for (i, ty) in solution.value.into_iter().enumerate() { + let var = self.free_vars[i]; + ctx.unify(&Ty::Infer(var), &ty.subst_bound_vars(&new_vars)); + } + } +} -- cgit v1.2.3