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-rw-r--r--crates/ra_hir/src/ty/infer.rs1164
-rw-r--r--crates/ra_hir/src/ty/infer/coerce.rs336
-rw-r--r--crates/ra_hir/src/ty/infer/expr.rs658
-rw-r--r--crates/ra_hir/src/ty/infer/pat.rs180
-rw-r--r--crates/ra_hir/src/ty/infer/unify.rs23
-rw-r--r--crates/ra_hir/src/ty/lower.rs39
-rw-r--r--crates/ra_hir/src/ty/tests.rs22
-rw-r--r--crates/ra_hir/src/ty/traits.rs2
-rw-r--r--crates/ra_hir/src/ty/traits/chalk.rs61
9 files changed, 1287 insertions, 1198 deletions
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index ca9aefc42..ebaff998e 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -14,7 +14,6 @@
14//! the `ena` crate, which is extracted from rustc. 14//! the `ena` crate, which is extracted from rustc.
15 15
16use std::borrow::Cow; 16use std::borrow::Cow;
17use std::iter::{repeat, repeat_with};
18use std::mem; 17use std::mem;
19use std::ops::Index; 18use std::ops::Index;
20use std::sync::Arc; 19use std::sync::Arc;
@@ -27,33 +26,39 @@ use ra_prof::profile;
27use test_utils::tested_by; 26use test_utils::tested_by;
28 27
29use super::{ 28use super::{
30 autoderef, lower, method_resolution, op, primitive, 29 lower, primitive,
31 traits::{Guidance, Obligation, ProjectionPredicate, Solution}, 30 traits::{Guidance, Obligation, ProjectionPredicate, Solution},
32 ApplicationTy, CallableDef, InEnvironment, ProjectionTy, Substs, TraitEnvironment, TraitRef, 31 ApplicationTy, InEnvironment, ProjectionTy, Substs, TraitEnvironment, TraitRef, Ty, TypableDef,
33 Ty, TypableDef, TypeCtor, TypeWalk, 32 TypeCtor, TypeWalk,
34}; 33};
35use crate::{ 34use crate::{
36 adt::VariantDef, 35 adt::VariantDef,
37 code_model::TypeAlias, 36 code_model::TypeAlias,
38 db::HirDatabase, 37 db::HirDatabase,
39 diagnostics::DiagnosticSink, 38 diagnostics::DiagnosticSink,
40 expr::{ 39 expr::{BindingAnnotation, Body, ExprId, PatId},
41 self, Array, BinaryOp, BindingAnnotation, Body, Expr, ExprId, Literal, Pat, PatId,
42 RecordFieldPat, Statement, UnaryOp,
43 },
44 generics::{GenericParams, HasGenericParams},
45 lang_item::LangItemTarget,
46 name, 40 name,
47 nameres::Namespace, 41 path::known,
48 path::{known, GenericArg, GenericArgs},
49 resolve::{Resolver, TypeNs}, 42 resolve::{Resolver, TypeNs},
50 ty::infer::diagnostics::InferenceDiagnostic, 43 ty::infer::diagnostics::InferenceDiagnostic,
51 type_ref::{Mutability, TypeRef}, 44 type_ref::{Mutability, TypeRef},
52 Adt, AssocItem, ConstData, DefWithBody, FnData, Function, HasBody, Name, Path, StructField, 45 Adt, AssocItem, ConstData, DefWithBody, FnData, Function, HasBody, Path, StructField,
53}; 46};
54 47
48macro_rules! ty_app {
49 ($ctor:pat, $param:pat) => {
50 crate::ty::Ty::Apply(crate::ty::ApplicationTy { ctor: $ctor, parameters: $param })
51 };
52 ($ctor:pat) => {
53 ty_app!($ctor, _)
54 };
55}
56
55mod unify; 57mod unify;
56mod path; 58mod path;
59mod expr;
60mod pat;
61mod coerce;
57 62
58/// The entry point of type inference. 63/// The entry point of type inference.
59pub fn infer_query(db: &impl HirDatabase, def: DefWithBody) -> Arc<InferenceResult> { 64pub fn infer_query(db: &impl HirDatabase, def: DefWithBody) -> Arc<InferenceResult> {
@@ -197,15 +202,6 @@ struct InferenceContext<'a, D: HirDatabase> {
197 coerce_unsized_map: FxHashMap<(TypeCtor, TypeCtor), usize>, 202 coerce_unsized_map: FxHashMap<(TypeCtor, TypeCtor), usize>,
198} 203}
199 204
200macro_rules! ty_app {
201 ($ctor:pat, $param:pat) => {
202 Ty::Apply(ApplicationTy { ctor: $ctor, parameters: $param })
203 };
204 ($ctor:pat) => {
205 ty_app!($ctor, _)
206 };
207}
208
209impl<'a, D: HirDatabase> InferenceContext<'a, D> { 205impl<'a, D: HirDatabase> InferenceContext<'a, D> {
210 fn new(db: &'a D, body: Arc<Body>, resolver: Resolver) -> Self { 206 fn new(db: &'a D, body: Arc<Body>, resolver: Resolver) -> Self {
211 InferenceContext { 207 InferenceContext {
@@ -221,45 +217,6 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
221 } 217 }
222 } 218 }
223 219
224 fn init_coerce_unsized_map(
225 db: &'a D,
226 resolver: &Resolver,
227 ) -> FxHashMap<(TypeCtor, TypeCtor), usize> {
228 let krate = resolver.krate().unwrap();
229 let impls = match db.lang_item(krate, "coerce_unsized".into()) {
230 Some(LangItemTarget::Trait(trait_)) => db.impls_for_trait(krate, trait_),
231 _ => return FxHashMap::default(),
232 };
233
234 impls
235 .iter()
236 .filter_map(|impl_block| {
237 // `CoerseUnsized` has one generic parameter for the target type.
238 let trait_ref = impl_block.target_trait_ref(db)?;
239 let cur_from_ty = trait_ref.substs.0.get(0)?;
240 let cur_to_ty = trait_ref.substs.0.get(1)?;
241
242 match (&cur_from_ty, cur_to_ty) {
243 (ty_app!(ctor1, st1), ty_app!(ctor2, st2)) => {
244 // FIXME: We return the first non-equal bound as the type parameter to coerce to unsized type.
245 // This works for smart-pointer-like coercion, which covers all impls from std.
246 st1.iter().zip(st2.iter()).enumerate().find_map(|(i, (ty1, ty2))| {
247 match (ty1, ty2) {
248 (Ty::Param { idx: p1, .. }, Ty::Param { idx: p2, .. })
249 if p1 != p2 =>
250 {
251 Some(((*ctor1, *ctor2), i))
252 }
253 _ => None,
254 }
255 })
256 }
257 _ => None,
258 }
259 })
260 .collect()
261 }
262
263 fn resolve_all(mut self) -> InferenceResult { 220 fn resolve_all(mut self) -> InferenceResult {
264 // FIXME resolve obligations as well (use Guidance if necessary) 221 // FIXME resolve obligations as well (use Guidance if necessary)
265 let mut result = mem::replace(&mut self.result, InferenceResult::default()); 222 let mut result = mem::replace(&mut self.result, InferenceResult::default());
@@ -457,7 +414,9 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
457 // recursive type 414 // recursive type
458 return tv.fallback_value(); 415 return tv.fallback_value();
459 } 416 }
460 if let Some(known_ty) = self.var_unification_table.probe_value(inner).known() { 417 if let Some(known_ty) =
418 self.var_unification_table.inlined_probe_value(inner).known()
419 {
461 // known_ty may contain other variables that are known by now 420 // known_ty may contain other variables that are known by now
462 tv_stack.push(inner); 421 tv_stack.push(inner);
463 let result = self.resolve_ty_as_possible(tv_stack, known_ty.clone()); 422 let result = self.resolve_ty_as_possible(tv_stack, known_ty.clone());
@@ -485,7 +444,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
485 match &*ty { 444 match &*ty {
486 Ty::Infer(tv) => { 445 Ty::Infer(tv) => {
487 let inner = tv.to_inner(); 446 let inner = tv.to_inner();
488 match self.var_unification_table.probe_value(inner).known() { 447 match self.var_unification_table.inlined_probe_value(inner).known() {
489 Some(known_ty) => { 448 Some(known_ty) => {
490 // The known_ty can't be a type var itself 449 // The known_ty can't be a type var itself
491 ty = Cow::Owned(known_ty.clone()); 450 ty = Cow::Owned(known_ty.clone());
@@ -533,7 +492,9 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
533 // recursive type 492 // recursive type
534 return tv.fallback_value(); 493 return tv.fallback_value();
535 } 494 }
536 if let Some(known_ty) = self.var_unification_table.probe_value(inner).known() { 495 if let Some(known_ty) =
496 self.var_unification_table.inlined_probe_value(inner).known()
497 {
537 // known_ty may contain other variables that are known by now 498 // known_ty may contain other variables that are known by now
538 tv_stack.push(inner); 499 tv_stack.push(inner);
539 let result = self.resolve_ty_completely(tv_stack, known_ty.clone()); 500 let result = self.resolve_ty_completely(tv_stack, known_ty.clone());
@@ -559,6 +520,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
559 match resolver.resolve_path_in_type_ns_fully(self.db, &path) { 520 match resolver.resolve_path_in_type_ns_fully(self.db, &path) {
560 Some(TypeNs::Adt(Adt::Struct(it))) => it.into(), 521 Some(TypeNs::Adt(Adt::Struct(it))) => it.into(),
561 Some(TypeNs::Adt(Adt::Union(it))) => it.into(), 522 Some(TypeNs::Adt(Adt::Union(it))) => it.into(),
523 Some(TypeNs::AdtSelfType(adt)) => adt.into(),
562 Some(TypeNs::EnumVariant(it)) => it.into(), 524 Some(TypeNs::EnumVariant(it)) => it.into(),
563 Some(TypeNs::TypeAlias(it)) => it.into(), 525 Some(TypeNs::TypeAlias(it)) => it.into(),
564 526
@@ -594,1080 +556,6 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
594 } 556 }
595 } 557 }
596 558
597 fn infer_tuple_struct_pat(
598 &mut self,
599 path: Option<&Path>,
600 subpats: &[PatId],
601 expected: &Ty,
602 default_bm: BindingMode,
603 ) -> Ty {
604 let (ty, def) = self.resolve_variant(path);
605
606 self.unify(&ty, expected);
607
608 let substs = ty.substs().unwrap_or_else(Substs::empty);
609
610 for (i, &subpat) in subpats.iter().enumerate() {
611 let expected_ty = def
612 .and_then(|d| d.field(self.db, &Name::new_tuple_field(i)))
613 .map_or(Ty::Unknown, |field| field.ty(self.db))
614 .subst(&substs);
615 let expected_ty = self.normalize_associated_types_in(expected_ty);
616 self.infer_pat(subpat, &expected_ty, default_bm);
617 }
618
619 ty
620 }
621
622 fn infer_record_pat(
623 &mut self,
624 path: Option<&Path>,
625 subpats: &[RecordFieldPat],
626 expected: &Ty,
627 default_bm: BindingMode,
628 id: PatId,
629 ) -> Ty {
630 let (ty, def) = self.resolve_variant(path);
631 if let Some(variant) = def {
632 self.write_variant_resolution(id.into(), variant);
633 }
634
635 self.unify(&ty, expected);
636
637 let substs = ty.substs().unwrap_or_else(Substs::empty);
638
639 for subpat in subpats {
640 let matching_field = def.and_then(|it| it.field(self.db, &subpat.name));
641 let expected_ty =
642 matching_field.map_or(Ty::Unknown, |field| field.ty(self.db)).subst(&substs);
643 let expected_ty = self.normalize_associated_types_in(expected_ty);
644 self.infer_pat(subpat.pat, &expected_ty, default_bm);
645 }
646
647 ty
648 }
649
650 fn infer_pat(&mut self, pat: PatId, mut expected: &Ty, mut default_bm: BindingMode) -> Ty {
651 let body = Arc::clone(&self.body); // avoid borrow checker problem
652
653 let is_non_ref_pat = match &body[pat] {
654 Pat::Tuple(..)
655 | Pat::TupleStruct { .. }
656 | Pat::Record { .. }
657 | Pat::Range { .. }
658 | Pat::Slice { .. } => true,
659 // FIXME: Path/Lit might actually evaluate to ref, but inference is unimplemented.
660 Pat::Path(..) | Pat::Lit(..) => true,
661 Pat::Wild | Pat::Bind { .. } | Pat::Ref { .. } | Pat::Missing => false,
662 };
663 if is_non_ref_pat {
664 while let Some((inner, mutability)) = expected.as_reference() {
665 expected = inner;
666 default_bm = match default_bm {
667 BindingMode::Move => BindingMode::Ref(mutability),
668 BindingMode::Ref(Mutability::Shared) => BindingMode::Ref(Mutability::Shared),
669 BindingMode::Ref(Mutability::Mut) => BindingMode::Ref(mutability),
670 }
671 }
672 } else if let Pat::Ref { .. } = &body[pat] {
673 tested_by!(match_ergonomics_ref);
674 // When you encounter a `&pat` pattern, reset to Move.
675 // This is so that `w` is by value: `let (_, &w) = &(1, &2);`
676 default_bm = BindingMode::Move;
677 }
678
679 // Lose mutability.
680 let default_bm = default_bm;
681 let expected = expected;
682
683 let ty = match &body[pat] {
684 Pat::Tuple(ref args) => {
685 let expectations = match expected.as_tuple() {
686 Some(parameters) => &*parameters.0,
687 _ => &[],
688 };
689 let expectations_iter = expectations.iter().chain(repeat(&Ty::Unknown));
690
691 let inner_tys = args
692 .iter()
693 .zip(expectations_iter)
694 .map(|(&pat, ty)| self.infer_pat(pat, ty, default_bm))
695 .collect();
696
697 Ty::apply(TypeCtor::Tuple { cardinality: args.len() as u16 }, Substs(inner_tys))
698 }
699 Pat::Ref { pat, mutability } => {
700 let expectation = match expected.as_reference() {
701 Some((inner_ty, exp_mut)) => {
702 if *mutability != exp_mut {
703 // FIXME: emit type error?
704 }
705 inner_ty
706 }
707 _ => &Ty::Unknown,
708 };
709 let subty = self.infer_pat(*pat, expectation, default_bm);
710 Ty::apply_one(TypeCtor::Ref(*mutability), subty)
711 }
712 Pat::TupleStruct { path: p, args: subpats } => {
713 self.infer_tuple_struct_pat(p.as_ref(), subpats, expected, default_bm)
714 }
715 Pat::Record { path: p, args: fields } => {
716 self.infer_record_pat(p.as_ref(), fields, expected, default_bm, pat)
717 }
718 Pat::Path(path) => {
719 // FIXME use correct resolver for the surrounding expression
720 let resolver = self.resolver.clone();
721 self.infer_path(&resolver, &path, pat.into()).unwrap_or(Ty::Unknown)
722 }
723 Pat::Bind { mode, name: _, subpat } => {
724 let mode = if mode == &BindingAnnotation::Unannotated {
725 default_bm
726 } else {
727 BindingMode::convert(*mode)
728 };
729 let inner_ty = if let Some(subpat) = subpat {
730 self.infer_pat(*subpat, expected, default_bm)
731 } else {
732 expected.clone()
733 };
734 let inner_ty = self.insert_type_vars_shallow(inner_ty);
735
736 let bound_ty = match mode {
737 BindingMode::Ref(mutability) => {
738 Ty::apply_one(TypeCtor::Ref(mutability), inner_ty.clone())
739 }
740 BindingMode::Move => inner_ty.clone(),
741 };
742 let bound_ty = self.resolve_ty_as_possible(&mut vec![], bound_ty);
743 self.write_pat_ty(pat, bound_ty);
744 return inner_ty;
745 }
746 _ => Ty::Unknown,
747 };
748 // use a new type variable if we got Ty::Unknown here
749 let ty = self.insert_type_vars_shallow(ty);
750 self.unify(&ty, expected);
751 let ty = self.resolve_ty_as_possible(&mut vec![], ty);
752 self.write_pat_ty(pat, ty.clone());
753 ty
754 }
755
756 fn substs_for_method_call(
757 &mut self,
758 def_generics: Option<Arc<GenericParams>>,
759 generic_args: Option<&GenericArgs>,
760 receiver_ty: &Ty,
761 ) -> Substs {
762 let (parent_param_count, param_count) =
763 def_generics.as_ref().map_or((0, 0), |g| (g.count_parent_params(), g.params.len()));
764 let mut substs = Vec::with_capacity(parent_param_count + param_count);
765 // Parent arguments are unknown, except for the receiver type
766 if let Some(parent_generics) = def_generics.and_then(|p| p.parent_params.clone()) {
767 for param in &parent_generics.params {
768 if param.name == name::SELF_TYPE {
769 substs.push(receiver_ty.clone());
770 } else {
771 substs.push(Ty::Unknown);
772 }
773 }
774 }
775 // handle provided type arguments
776 if let Some(generic_args) = generic_args {
777 // if args are provided, it should be all of them, but we can't rely on that
778 for arg in generic_args.args.iter().take(param_count) {
779 match arg {
780 GenericArg::Type(type_ref) => {
781 let ty = self.make_ty(type_ref);
782 substs.push(ty);
783 }
784 }
785 }
786 };
787 let supplied_params = substs.len();
788 for _ in supplied_params..parent_param_count + param_count {
789 substs.push(Ty::Unknown);
790 }
791 assert_eq!(substs.len(), parent_param_count + param_count);
792 Substs(substs.into())
793 }
794
795 fn register_obligations_for_call(&mut self, callable_ty: &Ty) {
796 if let Ty::Apply(a_ty) = callable_ty {
797 if let TypeCtor::FnDef(def) = a_ty.ctor {
798 let generic_predicates = self.db.generic_predicates(def.into());
799 for predicate in generic_predicates.iter() {
800 let predicate = predicate.clone().subst(&a_ty.parameters);
801 if let Some(obligation) = Obligation::from_predicate(predicate) {
802 self.obligations.push(obligation);
803 }
804 }
805 // add obligation for trait implementation, if this is a trait method
806 match def {
807 CallableDef::Function(f) => {
808 if let Some(trait_) = f.parent_trait(self.db) {
809 // construct a TraitDef
810 let substs = a_ty.parameters.prefix(
811 trait_.generic_params(self.db).count_params_including_parent(),
812 );
813 self.obligations.push(Obligation::Trait(TraitRef { trait_, substs }));
814 }
815 }
816 CallableDef::Struct(_) | CallableDef::EnumVariant(_) => {}
817 }
818 }
819 }
820 }
821
822 fn infer_method_call(
823 &mut self,
824 tgt_expr: ExprId,
825 receiver: ExprId,
826 args: &[ExprId],
827 method_name: &Name,
828 generic_args: Option<&GenericArgs>,
829 ) -> Ty {
830 let receiver_ty = self.infer_expr(receiver, &Expectation::none());
831 let canonicalized_receiver = self.canonicalizer().canonicalize_ty(receiver_ty.clone());
832 let resolved = method_resolution::lookup_method(
833 &canonicalized_receiver.value,
834 self.db,
835 method_name,
836 &self.resolver,
837 );
838 let (derefed_receiver_ty, method_ty, def_generics) = match resolved {
839 Some((ty, func)) => {
840 let ty = canonicalized_receiver.decanonicalize_ty(ty);
841 self.write_method_resolution(tgt_expr, func);
842 (
843 ty,
844 self.db.type_for_def(func.into(), Namespace::Values),
845 Some(func.generic_params(self.db)),
846 )
847 }
848 None => (receiver_ty, Ty::Unknown, None),
849 };
850 let substs = self.substs_for_method_call(def_generics, generic_args, &derefed_receiver_ty);
851 let method_ty = method_ty.apply_substs(substs);
852 let method_ty = self.insert_type_vars(method_ty);
853 self.register_obligations_for_call(&method_ty);
854 let (expected_receiver_ty, param_tys, ret_ty) = match method_ty.callable_sig(self.db) {
855 Some(sig) => {
856 if !sig.params().is_empty() {
857 (sig.params()[0].clone(), sig.params()[1..].to_vec(), sig.ret().clone())
858 } else {
859 (Ty::Unknown, Vec::new(), sig.ret().clone())
860 }
861 }
862 None => (Ty::Unknown, Vec::new(), Ty::Unknown),
863 };
864 // Apply autoref so the below unification works correctly
865 // FIXME: return correct autorefs from lookup_method
866 let actual_receiver_ty = match expected_receiver_ty.as_reference() {
867 Some((_, mutability)) => Ty::apply_one(TypeCtor::Ref(mutability), derefed_receiver_ty),
868 _ => derefed_receiver_ty,
869 };
870 self.unify(&expected_receiver_ty, &actual_receiver_ty);
871
872 self.check_call_arguments(args, &param_tys);
873 let ret_ty = self.normalize_associated_types_in(ret_ty);
874 ret_ty
875 }
876
877 /// Infer type of expression with possibly implicit coerce to the expected type.
878 /// Return the type after possible coercion.
879 fn infer_expr_coerce(&mut self, expr: ExprId, expected: &Expectation) -> Ty {
880 let ty = self.infer_expr_inner(expr, &expected);
881 let ty = if !self.coerce(&ty, &expected.ty) {
882 self.result
883 .type_mismatches
884 .insert(expr, TypeMismatch { expected: expected.ty.clone(), actual: ty.clone() });
885 // Return actual type when type mismatch.
886 // This is needed for diagnostic when return type mismatch.
887 ty
888 } else if expected.ty == Ty::Unknown {
889 ty
890 } else {
891 expected.ty.clone()
892 };
893
894 self.resolve_ty_as_possible(&mut vec![], ty)
895 }
896
897 /// Merge two types from different branches, with possible implicit coerce.
898 ///
899 /// Note that it is only possible that one type are coerced to another.
900 /// Coercing both types to another least upper bound type is not possible in rustc,
901 /// which will simply result in "incompatible types" error.
902 fn coerce_merge_branch<'t>(&mut self, ty1: &Ty, ty2: &Ty) -> Ty {
903 if self.coerce(ty1, ty2) {
904 ty2.clone()
905 } else if self.coerce(ty2, ty1) {
906 ty1.clone()
907 } else {
908 tested_by!(coerce_merge_fail_fallback);
909 // For incompatible types, we use the latter one as result
910 // to be better recovery for `if` without `else`.
911 ty2.clone()
912 }
913 }
914
915 /// Unify two types, but may coerce the first one to the second one
916 /// using "implicit coercion rules" if needed.
917 ///
918 /// See: https://doc.rust-lang.org/nomicon/coercions.html
919 fn coerce(&mut self, from_ty: &Ty, to_ty: &Ty) -> bool {
920 let from_ty = self.resolve_ty_shallow(from_ty).into_owned();
921 let to_ty = self.resolve_ty_shallow(to_ty);
922 self.coerce_inner(from_ty, &to_ty)
923 }
924
925 fn coerce_inner(&mut self, mut from_ty: Ty, to_ty: &Ty) -> bool {
926 match (&from_ty, to_ty) {
927 // Never type will make type variable to fallback to Never Type instead of Unknown.
928 (ty_app!(TypeCtor::Never), Ty::Infer(InferTy::TypeVar(tv))) => {
929 let var = self.new_maybe_never_type_var();
930 self.var_unification_table.union_value(*tv, TypeVarValue::Known(var));
931 return true;
932 }
933 (ty_app!(TypeCtor::Never), _) => return true,
934
935 // Trivial cases, this should go after `never` check to
936 // avoid infer result type to be never
937 _ => {
938 if self.unify_inner_trivial(&from_ty, &to_ty) {
939 return true;
940 }
941 }
942 }
943
944 // Pointer weakening and function to pointer
945 match (&mut from_ty, to_ty) {
946 // `*mut T`, `&mut T, `&T`` -> `*const T`
947 // `&mut T` -> `&T`
948 // `&mut T` -> `*mut T`
949 (ty_app!(c1@TypeCtor::RawPtr(_)), ty_app!(c2@TypeCtor::RawPtr(Mutability::Shared)))
950 | (ty_app!(c1@TypeCtor::Ref(_)), ty_app!(c2@TypeCtor::RawPtr(Mutability::Shared)))
951 | (ty_app!(c1@TypeCtor::Ref(_)), ty_app!(c2@TypeCtor::Ref(Mutability::Shared)))
952 | (ty_app!(c1@TypeCtor::Ref(Mutability::Mut)), ty_app!(c2@TypeCtor::RawPtr(_))) => {
953 *c1 = *c2;
954 }
955
956 // Illegal mutablity conversion
957 (
958 ty_app!(TypeCtor::RawPtr(Mutability::Shared)),
959 ty_app!(TypeCtor::RawPtr(Mutability::Mut)),
960 )
961 | (
962 ty_app!(TypeCtor::Ref(Mutability::Shared)),
963 ty_app!(TypeCtor::Ref(Mutability::Mut)),
964 ) => return false,
965
966 // `{function_type}` -> `fn()`
967 (ty_app!(TypeCtor::FnDef(_)), ty_app!(TypeCtor::FnPtr { .. })) => {
968 match from_ty.callable_sig(self.db) {
969 None => return false,
970 Some(sig) => {
971 let num_args = sig.params_and_return.len() as u16 - 1;
972 from_ty =
973 Ty::apply(TypeCtor::FnPtr { num_args }, Substs(sig.params_and_return));
974 }
975 }
976 }
977
978 _ => {}
979 }
980
981 if let Some(ret) = self.try_coerce_unsized(&from_ty, &to_ty) {
982 return ret;
983 }
984
985 // Auto Deref if cannot coerce
986 match (&from_ty, to_ty) {
987 // FIXME: DerefMut
988 (ty_app!(TypeCtor::Ref(_), st1), ty_app!(TypeCtor::Ref(_), st2)) => {
989 self.unify_autoderef_behind_ref(&st1[0], &st2[0])
990 }
991
992 // Otherwise, normal unify
993 _ => self.unify(&from_ty, to_ty),
994 }
995 }
996
997 /// Coerce a type using `from_ty: CoerceUnsized<ty_ty>`
998 ///
999 /// See: https://doc.rust-lang.org/nightly/std/marker/trait.CoerceUnsized.html
1000 fn try_coerce_unsized(&mut self, from_ty: &Ty, to_ty: &Ty) -> Option<bool> {
1001 let (ctor1, st1, ctor2, st2) = match (from_ty, to_ty) {
1002 (ty_app!(ctor1, st1), ty_app!(ctor2, st2)) => (ctor1, st1, ctor2, st2),
1003 _ => return None,
1004 };
1005
1006 let coerce_generic_index = *self.coerce_unsized_map.get(&(*ctor1, *ctor2))?;
1007
1008 // Check `Unsize` first
1009 match self.check_unsize_and_coerce(
1010 st1.0.get(coerce_generic_index)?,
1011 st2.0.get(coerce_generic_index)?,
1012 0,
1013 ) {
1014 Some(true) => {}
1015 ret => return ret,
1016 }
1017
1018 let ret = st1
1019 .iter()
1020 .zip(st2.iter())
1021 .enumerate()
1022 .filter(|&(idx, _)| idx != coerce_generic_index)
1023 .all(|(_, (ty1, ty2))| self.unify(ty1, ty2));
1024
1025 Some(ret)
1026 }
1027
1028 /// Check if `from_ty: Unsize<to_ty>`, and coerce to `to_ty` if it holds.
1029 ///
1030 /// It should not be directly called. It is only used by `try_coerce_unsized`.
1031 ///
1032 /// See: https://doc.rust-lang.org/nightly/std/marker/trait.Unsize.html
1033 fn check_unsize_and_coerce(&mut self, from_ty: &Ty, to_ty: &Ty, depth: usize) -> Option<bool> {
1034 if depth > 1000 {
1035 panic!("Infinite recursion in coercion");
1036 }
1037
1038 match (&from_ty, &to_ty) {
1039 // `[T; N]` -> `[T]`
1040 (ty_app!(TypeCtor::Array, st1), ty_app!(TypeCtor::Slice, st2)) => {
1041 Some(self.unify(&st1[0], &st2[0]))
1042 }
1043
1044 // `T` -> `dyn Trait` when `T: Trait`
1045 (_, Ty::Dyn(_)) => {
1046 // FIXME: Check predicates
1047 Some(true)
1048 }
1049
1050 // `(..., T)` -> `(..., U)` when `T: Unsize<U>`
1051 (
1052 ty_app!(TypeCtor::Tuple { cardinality: len1 }, st1),
1053 ty_app!(TypeCtor::Tuple { cardinality: len2 }, st2),
1054 ) => {
1055 if len1 != len2 || *len1 == 0 {
1056 return None;
1057 }
1058
1059 match self.check_unsize_and_coerce(
1060 st1.last().unwrap(),
1061 st2.last().unwrap(),
1062 depth + 1,
1063 ) {
1064 Some(true) => {}
1065 ret => return ret,
1066 }
1067
1068 let ret = st1[..st1.len() - 1]
1069 .iter()
1070 .zip(&st2[..st2.len() - 1])
1071 .all(|(ty1, ty2)| self.unify(ty1, ty2));
1072
1073 Some(ret)
1074 }
1075
1076 // Foo<..., T, ...> is Unsize<Foo<..., U, ...>> if:
1077 // - T: Unsize<U>
1078 // - Foo is a struct
1079 // - Only the last field of Foo has a type involving T
1080 // - T is not part of the type of any other fields
1081 // - Bar<T>: Unsize<Bar<U>>, if the last field of Foo has type Bar<T>
1082 (
1083 ty_app!(TypeCtor::Adt(Adt::Struct(struct1)), st1),
1084 ty_app!(TypeCtor::Adt(Adt::Struct(struct2)), st2),
1085 ) if struct1 == struct2 => {
1086 let fields = struct1.fields(self.db);
1087 let (last_field, prev_fields) = fields.split_last()?;
1088
1089 // Get the generic parameter involved in the last field.
1090 let unsize_generic_index = {
1091 let mut index = None;
1092 let mut multiple_param = false;
1093 last_field.ty(self.db).walk(&mut |ty| match ty {
1094 &Ty::Param { idx, .. } => {
1095 if index.is_none() {
1096 index = Some(idx);
1097 } else if Some(idx) != index {
1098 multiple_param = true;
1099 }
1100 }
1101 _ => {}
1102 });
1103
1104 if multiple_param {
1105 return None;
1106 }
1107 index?
1108 };
1109
1110 // Check other fields do not involve it.
1111 let mut multiple_used = false;
1112 prev_fields.iter().for_each(|field| {
1113 field.ty(self.db).walk(&mut |ty| match ty {
1114 &Ty::Param { idx, .. } if idx == unsize_generic_index => {
1115 multiple_used = true
1116 }
1117 _ => {}
1118 })
1119 });
1120 if multiple_used {
1121 return None;
1122 }
1123
1124 let unsize_generic_index = unsize_generic_index as usize;
1125
1126 // Check `Unsize` first
1127 match self.check_unsize_and_coerce(
1128 st1.get(unsize_generic_index)?,
1129 st2.get(unsize_generic_index)?,
1130 depth + 1,
1131 ) {
1132 Some(true) => {}
1133 ret => return ret,
1134 }
1135
1136 // Then unify other parameters
1137 let ret = st1
1138 .iter()
1139 .zip(st2.iter())
1140 .enumerate()
1141 .filter(|&(idx, _)| idx != unsize_generic_index)
1142 .all(|(_, (ty1, ty2))| self.unify(ty1, ty2));
1143
1144 Some(ret)
1145 }
1146
1147 _ => None,
1148 }
1149 }
1150
1151 /// Unify `from_ty` to `to_ty` with optional auto Deref
1152 ///
1153 /// Note that the parameters are already stripped the outer reference.
1154 fn unify_autoderef_behind_ref(&mut self, from_ty: &Ty, to_ty: &Ty) -> bool {
1155 let canonicalized = self.canonicalizer().canonicalize_ty(from_ty.clone());
1156 let to_ty = self.resolve_ty_shallow(&to_ty);
1157 // FIXME: Auto DerefMut
1158 for derefed_ty in
1159 autoderef::autoderef(self.db, &self.resolver.clone(), canonicalized.value.clone())
1160 {
1161 let derefed_ty = canonicalized.decanonicalize_ty(derefed_ty.value);
1162 match (&*self.resolve_ty_shallow(&derefed_ty), &*to_ty) {
1163 // Stop when constructor matches.
1164 (ty_app!(from_ctor, st1), ty_app!(to_ctor, st2)) if from_ctor == to_ctor => {
1165 // It will not recurse to `coerce`.
1166 return self.unify_substs(st1, st2, 0);
1167 }
1168 _ => {}
1169 }
1170 }
1171
1172 false
1173 }
1174
1175 fn infer_expr(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
1176 let ty = self.infer_expr_inner(tgt_expr, expected);
1177 let could_unify = self.unify(&ty, &expected.ty);
1178 if !could_unify {
1179 self.result.type_mismatches.insert(
1180 tgt_expr,
1181 TypeMismatch { expected: expected.ty.clone(), actual: ty.clone() },
1182 );
1183 }
1184 let ty = self.resolve_ty_as_possible(&mut vec![], ty);
1185 ty
1186 }
1187
1188 fn infer_expr_inner(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
1189 let body = Arc::clone(&self.body); // avoid borrow checker problem
1190 let ty = match &body[tgt_expr] {
1191 Expr::Missing => Ty::Unknown,
1192 Expr::If { condition, then_branch, else_branch } => {
1193 // if let is desugared to match, so this is always simple if
1194 self.infer_expr(*condition, &Expectation::has_type(Ty::simple(TypeCtor::Bool)));
1195
1196 let then_ty = self.infer_expr_inner(*then_branch, &expected);
1197 let else_ty = match else_branch {
1198 Some(else_branch) => self.infer_expr_inner(*else_branch, &expected),
1199 None => Ty::unit(),
1200 };
1201
1202 self.coerce_merge_branch(&then_ty, &else_ty)
1203 }
1204 Expr::Block { statements, tail } => self.infer_block(statements, *tail, expected),
1205 Expr::TryBlock { body } => {
1206 let _inner = self.infer_expr(*body, expected);
1207 // FIXME should be std::result::Result<{inner}, _>
1208 Ty::Unknown
1209 }
1210 Expr::Loop { body } => {
1211 self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
1212 // FIXME handle break with value
1213 Ty::simple(TypeCtor::Never)
1214 }
1215 Expr::While { condition, body } => {
1216 // while let is desugared to a match loop, so this is always simple while
1217 self.infer_expr(*condition, &Expectation::has_type(Ty::simple(TypeCtor::Bool)));
1218 self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
1219 Ty::unit()
1220 }
1221 Expr::For { iterable, body, pat } => {
1222 let iterable_ty = self.infer_expr(*iterable, &Expectation::none());
1223
1224 let pat_ty = match self.resolve_into_iter_item() {
1225 Some(into_iter_item_alias) => {
1226 let pat_ty = self.new_type_var();
1227 let projection = ProjectionPredicate {
1228 ty: pat_ty.clone(),
1229 projection_ty: ProjectionTy {
1230 associated_ty: into_iter_item_alias,
1231 parameters: Substs::single(iterable_ty),
1232 },
1233 };
1234 self.obligations.push(Obligation::Projection(projection));
1235 self.resolve_ty_as_possible(&mut vec![], pat_ty)
1236 }
1237 None => Ty::Unknown,
1238 };
1239
1240 self.infer_pat(*pat, &pat_ty, BindingMode::default());
1241 self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
1242 Ty::unit()
1243 }
1244 Expr::Lambda { body, args, arg_types } => {
1245 assert_eq!(args.len(), arg_types.len());
1246
1247 let mut sig_tys = Vec::new();
1248
1249 for (arg_pat, arg_type) in args.iter().zip(arg_types.iter()) {
1250 let expected = if let Some(type_ref) = arg_type {
1251 self.make_ty(type_ref)
1252 } else {
1253 Ty::Unknown
1254 };
1255 let arg_ty = self.infer_pat(*arg_pat, &expected, BindingMode::default());
1256 sig_tys.push(arg_ty);
1257 }
1258
1259 // add return type
1260 let ret_ty = self.new_type_var();
1261 sig_tys.push(ret_ty.clone());
1262 let sig_ty = Ty::apply(
1263 TypeCtor::FnPtr { num_args: sig_tys.len() as u16 - 1 },
1264 Substs(sig_tys.into()),
1265 );
1266 let closure_ty = Ty::apply_one(
1267 TypeCtor::Closure { def: self.body.owner(), expr: tgt_expr },
1268 sig_ty,
1269 );
1270
1271 // Eagerly try to relate the closure type with the expected
1272 // type, otherwise we often won't have enough information to
1273 // infer the body.
1274 self.coerce(&closure_ty, &expected.ty);
1275
1276 self.infer_expr(*body, &Expectation::has_type(ret_ty));
1277 closure_ty
1278 }
1279 Expr::Call { callee, args } => {
1280 let callee_ty = self.infer_expr(*callee, &Expectation::none());
1281 let (param_tys, ret_ty) = match callee_ty.callable_sig(self.db) {
1282 Some(sig) => (sig.params().to_vec(), sig.ret().clone()),
1283 None => {
1284 // Not callable
1285 // FIXME: report an error
1286 (Vec::new(), Ty::Unknown)
1287 }
1288 };
1289 self.register_obligations_for_call(&callee_ty);
1290 self.check_call_arguments(args, &param_tys);
1291 let ret_ty = self.normalize_associated_types_in(ret_ty);
1292 ret_ty
1293 }
1294 Expr::MethodCall { receiver, args, method_name, generic_args } => self
1295 .infer_method_call(tgt_expr, *receiver, &args, &method_name, generic_args.as_ref()),
1296 Expr::Match { expr, arms } => {
1297 let input_ty = self.infer_expr(*expr, &Expectation::none());
1298
1299 let mut result_ty = self.new_maybe_never_type_var();
1300
1301 for arm in arms {
1302 for &pat in &arm.pats {
1303 let _pat_ty = self.infer_pat(pat, &input_ty, BindingMode::default());
1304 }
1305 if let Some(guard_expr) = arm.guard {
1306 self.infer_expr(
1307 guard_expr,
1308 &Expectation::has_type(Ty::simple(TypeCtor::Bool)),
1309 );
1310 }
1311
1312 let arm_ty = self.infer_expr_inner(arm.expr, &expected);
1313 result_ty = self.coerce_merge_branch(&result_ty, &arm_ty);
1314 }
1315
1316 result_ty
1317 }
1318 Expr::Path(p) => {
1319 // FIXME this could be more efficient...
1320 let resolver = expr::resolver_for_expr(self.body.clone(), self.db, tgt_expr);
1321 self.infer_path(&resolver, p, tgt_expr.into()).unwrap_or(Ty::Unknown)
1322 }
1323 Expr::Continue => Ty::simple(TypeCtor::Never),
1324 Expr::Break { expr } => {
1325 if let Some(expr) = expr {
1326 // FIXME handle break with value
1327 self.infer_expr(*expr, &Expectation::none());
1328 }
1329 Ty::simple(TypeCtor::Never)
1330 }
1331 Expr::Return { expr } => {
1332 if let Some(expr) = expr {
1333 self.infer_expr(*expr, &Expectation::has_type(self.return_ty.clone()));
1334 }
1335 Ty::simple(TypeCtor::Never)
1336 }
1337 Expr::RecordLit { path, fields, spread } => {
1338 let (ty, def_id) = self.resolve_variant(path.as_ref());
1339 if let Some(variant) = def_id {
1340 self.write_variant_resolution(tgt_expr.into(), variant);
1341 }
1342
1343 self.unify(&ty, &expected.ty);
1344
1345 let substs = ty.substs().unwrap_or_else(Substs::empty);
1346 for (field_idx, field) in fields.iter().enumerate() {
1347 let field_ty = def_id
1348 .and_then(|it| match it.field(self.db, &field.name) {
1349 Some(field) => Some(field),
1350 None => {
1351 self.push_diagnostic(InferenceDiagnostic::NoSuchField {
1352 expr: tgt_expr,
1353 field: field_idx,
1354 });
1355 None
1356 }
1357 })
1358 .map_or(Ty::Unknown, |field| field.ty(self.db))
1359 .subst(&substs);
1360 self.infer_expr_coerce(field.expr, &Expectation::has_type(field_ty));
1361 }
1362 if let Some(expr) = spread {
1363 self.infer_expr(*expr, &Expectation::has_type(ty.clone()));
1364 }
1365 ty
1366 }
1367 Expr::Field { expr, name } => {
1368 let receiver_ty = self.infer_expr(*expr, &Expectation::none());
1369 let canonicalized = self.canonicalizer().canonicalize_ty(receiver_ty);
1370 let ty = autoderef::autoderef(
1371 self.db,
1372 &self.resolver.clone(),
1373 canonicalized.value.clone(),
1374 )
1375 .find_map(|derefed_ty| match canonicalized.decanonicalize_ty(derefed_ty.value) {
1376 Ty::Apply(a_ty) => match a_ty.ctor {
1377 TypeCtor::Tuple { .. } => name
1378 .as_tuple_index()
1379 .and_then(|idx| a_ty.parameters.0.get(idx).cloned()),
1380 TypeCtor::Adt(Adt::Struct(s)) => s.field(self.db, name).map(|field| {
1381 self.write_field_resolution(tgt_expr, field);
1382 field.ty(self.db).subst(&a_ty.parameters)
1383 }),
1384 _ => None,
1385 },
1386 _ => None,
1387 })
1388 .unwrap_or(Ty::Unknown);
1389 let ty = self.insert_type_vars(ty);
1390 self.normalize_associated_types_in(ty)
1391 }
1392 Expr::Await { expr } => {
1393 let inner_ty = self.infer_expr(*expr, &Expectation::none());
1394 let ty = match self.resolve_future_future_output() {
1395 Some(future_future_output_alias) => {
1396 let ty = self.new_type_var();
1397 let projection = ProjectionPredicate {
1398 ty: ty.clone(),
1399 projection_ty: ProjectionTy {
1400 associated_ty: future_future_output_alias,
1401 parameters: Substs::single(inner_ty),
1402 },
1403 };
1404 self.obligations.push(Obligation::Projection(projection));
1405 self.resolve_ty_as_possible(&mut vec![], ty)
1406 }
1407 None => Ty::Unknown,
1408 };
1409 ty
1410 }
1411 Expr::Try { expr } => {
1412 let inner_ty = self.infer_expr(*expr, &Expectation::none());
1413 let ty = match self.resolve_ops_try_ok() {
1414 Some(ops_try_ok_alias) => {
1415 let ty = self.new_type_var();
1416 let projection = ProjectionPredicate {
1417 ty: ty.clone(),
1418 projection_ty: ProjectionTy {
1419 associated_ty: ops_try_ok_alias,
1420 parameters: Substs::single(inner_ty),
1421 },
1422 };
1423 self.obligations.push(Obligation::Projection(projection));
1424 self.resolve_ty_as_possible(&mut vec![], ty)
1425 }
1426 None => Ty::Unknown,
1427 };
1428 ty
1429 }
1430 Expr::Cast { expr, type_ref } => {
1431 let _inner_ty = self.infer_expr(*expr, &Expectation::none());
1432 let cast_ty = self.make_ty(type_ref);
1433 // FIXME check the cast...
1434 cast_ty
1435 }
1436 Expr::Ref { expr, mutability } => {
1437 let expectation =
1438 if let Some((exp_inner, exp_mutability)) = &expected.ty.as_reference() {
1439 if *exp_mutability == Mutability::Mut && *mutability == Mutability::Shared {
1440 // FIXME: throw type error - expected mut reference but found shared ref,
1441 // which cannot be coerced
1442 }
1443 Expectation::has_type(Ty::clone(exp_inner))
1444 } else {
1445 Expectation::none()
1446 };
1447 // FIXME reference coercions etc.
1448 let inner_ty = self.infer_expr(*expr, &expectation);
1449 Ty::apply_one(TypeCtor::Ref(*mutability), inner_ty)
1450 }
1451 Expr::Box { expr } => {
1452 let inner_ty = self.infer_expr(*expr, &Expectation::none());
1453 if let Some(box_) = self.resolve_boxed_box() {
1454 Ty::apply_one(TypeCtor::Adt(box_), inner_ty)
1455 } else {
1456 Ty::Unknown
1457 }
1458 }
1459 Expr::UnaryOp { expr, op } => {
1460 let inner_ty = self.infer_expr(*expr, &Expectation::none());
1461 match op {
1462 UnaryOp::Deref => {
1463 let canonicalized = self.canonicalizer().canonicalize_ty(inner_ty);
1464 if let Some(derefed_ty) =
1465 autoderef::deref(self.db, &self.resolver, &canonicalized.value)
1466 {
1467 canonicalized.decanonicalize_ty(derefed_ty.value)
1468 } else {
1469 Ty::Unknown
1470 }
1471 }
1472 UnaryOp::Neg => {
1473 match &inner_ty {
1474 Ty::Apply(a_ty) => match a_ty.ctor {
1475 TypeCtor::Int(primitive::UncertainIntTy::Unknown)
1476 | TypeCtor::Int(primitive::UncertainIntTy::Known(
1477 primitive::IntTy {
1478 signedness: primitive::Signedness::Signed,
1479 ..
1480 },
1481 ))
1482 | TypeCtor::Float(..) => inner_ty,
1483 _ => Ty::Unknown,
1484 },
1485 Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => {
1486 inner_ty
1487 }
1488 // FIXME: resolve ops::Neg trait
1489 _ => Ty::Unknown,
1490 }
1491 }
1492 UnaryOp::Not => {
1493 match &inner_ty {
1494 Ty::Apply(a_ty) => match a_ty.ctor {
1495 TypeCtor::Bool | TypeCtor::Int(_) => inner_ty,
1496 _ => Ty::Unknown,
1497 },
1498 Ty::Infer(InferTy::IntVar(..)) => inner_ty,
1499 // FIXME: resolve ops::Not trait for inner_ty
1500 _ => Ty::Unknown,
1501 }
1502 }
1503 }
1504 }
1505 Expr::BinaryOp { lhs, rhs, op } => match op {
1506 Some(op) => {
1507 let lhs_expectation = match op {
1508 BinaryOp::LogicOp(..) => Expectation::has_type(Ty::simple(TypeCtor::Bool)),
1509 _ => Expectation::none(),
1510 };
1511 let lhs_ty = self.infer_expr(*lhs, &lhs_expectation);
1512 // FIXME: find implementation of trait corresponding to operation
1513 // symbol and resolve associated `Output` type
1514 let rhs_expectation = op::binary_op_rhs_expectation(*op, lhs_ty);
1515 let rhs_ty = self.infer_expr(*rhs, &Expectation::has_type(rhs_expectation));
1516
1517 // FIXME: similar as above, return ty is often associated trait type
1518 op::binary_op_return_ty(*op, rhs_ty)
1519 }
1520 _ => Ty::Unknown,
1521 },
1522 Expr::Index { base, index } => {
1523 let _base_ty = self.infer_expr(*base, &Expectation::none());
1524 let _index_ty = self.infer_expr(*index, &Expectation::none());
1525 // FIXME: use `std::ops::Index::Output` to figure out the real return type
1526 Ty::Unknown
1527 }
1528 Expr::Tuple { exprs } => {
1529 let mut tys = match &expected.ty {
1530 ty_app!(TypeCtor::Tuple { .. }, st) => st
1531 .iter()
1532 .cloned()
1533 .chain(repeat_with(|| self.new_type_var()))
1534 .take(exprs.len())
1535 .collect::<Vec<_>>(),
1536 _ => (0..exprs.len()).map(|_| self.new_type_var()).collect(),
1537 };
1538
1539 for (expr, ty) in exprs.iter().zip(tys.iter_mut()) {
1540 self.infer_expr_coerce(*expr, &Expectation::has_type(ty.clone()));
1541 }
1542
1543 Ty::apply(TypeCtor::Tuple { cardinality: tys.len() as u16 }, Substs(tys.into()))
1544 }
1545 Expr::Array(array) => {
1546 let elem_ty = match &expected.ty {
1547 ty_app!(TypeCtor::Array, st) | ty_app!(TypeCtor::Slice, st) => {
1548 st.as_single().clone()
1549 }
1550 _ => self.new_type_var(),
1551 };
1552
1553 match array {
1554 Array::ElementList(items) => {
1555 for expr in items.iter() {
1556 self.infer_expr_coerce(*expr, &Expectation::has_type(elem_ty.clone()));
1557 }
1558 }
1559 Array::Repeat { initializer, repeat } => {
1560 self.infer_expr_coerce(
1561 *initializer,
1562 &Expectation::has_type(elem_ty.clone()),
1563 );
1564 self.infer_expr(
1565 *repeat,
1566 &Expectation::has_type(Ty::simple(TypeCtor::Int(
1567 primitive::UncertainIntTy::Known(primitive::IntTy::usize()),
1568 ))),
1569 );
1570 }
1571 }
1572
1573 Ty::apply_one(TypeCtor::Array, elem_ty)
1574 }
1575 Expr::Literal(lit) => match lit {
1576 Literal::Bool(..) => Ty::simple(TypeCtor::Bool),
1577 Literal::String(..) => {
1578 Ty::apply_one(TypeCtor::Ref(Mutability::Shared), Ty::simple(TypeCtor::Str))
1579 }
1580 Literal::ByteString(..) => {
1581 let byte_type = Ty::simple(TypeCtor::Int(primitive::UncertainIntTy::Known(
1582 primitive::IntTy::u8(),
1583 )));
1584 let slice_type = Ty::apply_one(TypeCtor::Slice, byte_type);
1585 Ty::apply_one(TypeCtor::Ref(Mutability::Shared), slice_type)
1586 }
1587 Literal::Char(..) => Ty::simple(TypeCtor::Char),
1588 Literal::Int(_v, ty) => Ty::simple(TypeCtor::Int(*ty)),
1589 Literal::Float(_v, ty) => Ty::simple(TypeCtor::Float(*ty)),
1590 },
1591 };
1592 // use a new type variable if we got Ty::Unknown here
1593 let ty = self.insert_type_vars_shallow(ty);
1594 let ty = self.resolve_ty_as_possible(&mut vec![], ty);
1595 self.write_expr_ty(tgt_expr, ty.clone());
1596 ty
1597 }
1598
1599 fn infer_block(
1600 &mut self,
1601 statements: &[Statement],
1602 tail: Option<ExprId>,
1603 expected: &Expectation,
1604 ) -> Ty {
1605 let mut diverges = false;
1606 for stmt in statements {
1607 match stmt {
1608 Statement::Let { pat, type_ref, initializer } => {
1609 let decl_ty =
1610 type_ref.as_ref().map(|tr| self.make_ty(tr)).unwrap_or(Ty::Unknown);
1611
1612 // Always use the declared type when specified
1613 let mut ty = decl_ty.clone();
1614
1615 if let Some(expr) = initializer {
1616 let actual_ty =
1617 self.infer_expr_coerce(*expr, &Expectation::has_type(decl_ty.clone()));
1618 if decl_ty == Ty::Unknown {
1619 ty = actual_ty;
1620 }
1621 }
1622
1623 let ty = self.resolve_ty_as_possible(&mut vec![], ty);
1624 self.infer_pat(*pat, &ty, BindingMode::default());
1625 }
1626 Statement::Expr(expr) => {
1627 if let ty_app!(TypeCtor::Never) = self.infer_expr(*expr, &Expectation::none()) {
1628 diverges = true;
1629 }
1630 }
1631 }
1632 }
1633
1634 let ty = if let Some(expr) = tail {
1635 self.infer_expr_coerce(expr, expected)
1636 } else {
1637 self.coerce(&Ty::unit(), &expected.ty);
1638 Ty::unit()
1639 };
1640 if diverges {
1641 Ty::simple(TypeCtor::Never)
1642 } else {
1643 ty
1644 }
1645 }
1646
1647 fn check_call_arguments(&mut self, args: &[ExprId], param_tys: &[Ty]) {
1648 // Quoting https://github.com/rust-lang/rust/blob/6ef275e6c3cb1384ec78128eceeb4963ff788dca/src/librustc_typeck/check/mod.rs#L3325 --
1649 // We do this in a pretty awful way: first we type-check any arguments
1650 // that are not closures, then we type-check the closures. This is so
1651 // that we have more information about the types of arguments when we
1652 // type-check the functions. This isn't really the right way to do this.
1653 for &check_closures in &[false, true] {
1654 let param_iter = param_tys.iter().cloned().chain(repeat(Ty::Unknown));
1655 for (&arg, param_ty) in args.iter().zip(param_iter) {
1656 let is_closure = match &self.body[arg] {
1657 Expr::Lambda { .. } => true,
1658 _ => false,
1659 };
1660
1661 if is_closure != check_closures {
1662 continue;
1663 }
1664
1665 let param_ty = self.normalize_associated_types_in(param_ty);
1666 self.infer_expr_coerce(arg, &Expectation::has_type(param_ty.clone()));
1667 }
1668 }
1669 }
1670
1671 fn collect_const(&mut self, data: &ConstData) { 559 fn collect_const(&mut self, data: &ConstData) {
1672 self.return_ty = self.make_ty(data.type_ref()); 560 self.return_ty = self.make_ty(data.type_ref());
1673 } 561 }
diff --git a/crates/ra_hir/src/ty/infer/coerce.rs b/crates/ra_hir/src/ty/infer/coerce.rs
new file mode 100644
index 000000000..0429a9866
--- /dev/null
+++ b/crates/ra_hir/src/ty/infer/coerce.rs
@@ -0,0 +1,336 @@
1//! Coercion logic. Coercions are certain type conversions that can implicitly
2//! happen in certain places, e.g. weakening `&mut` to `&` or deref coercions
3//! like going from `&Vec<T>` to `&[T]`.
4//!
5//! See: https://doc.rust-lang.org/nomicon/coercions.html
6
7use rustc_hash::FxHashMap;
8
9use test_utils::tested_by;
10
11use super::{InferTy, InferenceContext, TypeVarValue};
12use crate::{
13 db::HirDatabase,
14 lang_item::LangItemTarget,
15 resolve::Resolver,
16 ty::{autoderef, Substs, Ty, TypeCtor, TypeWalk},
17 type_ref::Mutability,
18 Adt,
19};
20
21impl<'a, D: HirDatabase> InferenceContext<'a, D> {
22 /// Unify two types, but may coerce the first one to the second one
23 /// using "implicit coercion rules" if needed.
24 pub(super) fn coerce(&mut self, from_ty: &Ty, to_ty: &Ty) -> bool {
25 let from_ty = self.resolve_ty_shallow(from_ty).into_owned();
26 let to_ty = self.resolve_ty_shallow(to_ty);
27 self.coerce_inner(from_ty, &to_ty)
28 }
29
30 /// Merge two types from different branches, with possible implicit coerce.
31 ///
32 /// Note that it is only possible that one type are coerced to another.
33 /// Coercing both types to another least upper bound type is not possible in rustc,
34 /// which will simply result in "incompatible types" error.
35 pub(super) fn coerce_merge_branch<'t>(&mut self, ty1: &Ty, ty2: &Ty) -> Ty {
36 if self.coerce(ty1, ty2) {
37 ty2.clone()
38 } else if self.coerce(ty2, ty1) {
39 ty1.clone()
40 } else {
41 tested_by!(coerce_merge_fail_fallback);
42 // For incompatible types, we use the latter one as result
43 // to be better recovery for `if` without `else`.
44 ty2.clone()
45 }
46 }
47
48 pub(super) fn init_coerce_unsized_map(
49 db: &'a D,
50 resolver: &Resolver,
51 ) -> FxHashMap<(TypeCtor, TypeCtor), usize> {
52 let krate = resolver.krate().unwrap();
53 let impls = match db.lang_item(krate, "coerce_unsized".into()) {
54 Some(LangItemTarget::Trait(trait_)) => db.impls_for_trait(krate, trait_),
55 _ => return FxHashMap::default(),
56 };
57
58 impls
59 .iter()
60 .filter_map(|impl_block| {
61 // `CoerseUnsized` has one generic parameter for the target type.
62 let trait_ref = impl_block.target_trait_ref(db)?;
63 let cur_from_ty = trait_ref.substs.0.get(0)?;
64 let cur_to_ty = trait_ref.substs.0.get(1)?;
65
66 match (&cur_from_ty, cur_to_ty) {
67 (ty_app!(ctor1, st1), ty_app!(ctor2, st2)) => {
68 // FIXME: We return the first non-equal bound as the type parameter to coerce to unsized type.
69 // This works for smart-pointer-like coercion, which covers all impls from std.
70 st1.iter().zip(st2.iter()).enumerate().find_map(|(i, (ty1, ty2))| {
71 match (ty1, ty2) {
72 (Ty::Param { idx: p1, .. }, Ty::Param { idx: p2, .. })
73 if p1 != p2 =>
74 {
75 Some(((*ctor1, *ctor2), i))
76 }
77 _ => None,
78 }
79 })
80 }
81 _ => None,
82 }
83 })
84 .collect()
85 }
86
87 fn coerce_inner(&mut self, mut from_ty: Ty, to_ty: &Ty) -> bool {
88 match (&from_ty, to_ty) {
89 // Never type will make type variable to fallback to Never Type instead of Unknown.
90 (ty_app!(TypeCtor::Never), Ty::Infer(InferTy::TypeVar(tv))) => {
91 let var = self.new_maybe_never_type_var();
92 self.var_unification_table.union_value(*tv, TypeVarValue::Known(var));
93 return true;
94 }
95 (ty_app!(TypeCtor::Never), _) => return true,
96
97 // Trivial cases, this should go after `never` check to
98 // avoid infer result type to be never
99 _ => {
100 if self.unify_inner_trivial(&from_ty, &to_ty) {
101 return true;
102 }
103 }
104 }
105
106 // Pointer weakening and function to pointer
107 match (&mut from_ty, to_ty) {
108 // `*mut T`, `&mut T, `&T`` -> `*const T`
109 // `&mut T` -> `&T`
110 // `&mut T` -> `*mut T`
111 (ty_app!(c1@TypeCtor::RawPtr(_)), ty_app!(c2@TypeCtor::RawPtr(Mutability::Shared)))
112 | (ty_app!(c1@TypeCtor::Ref(_)), ty_app!(c2@TypeCtor::RawPtr(Mutability::Shared)))
113 | (ty_app!(c1@TypeCtor::Ref(_)), ty_app!(c2@TypeCtor::Ref(Mutability::Shared)))
114 | (ty_app!(c1@TypeCtor::Ref(Mutability::Mut)), ty_app!(c2@TypeCtor::RawPtr(_))) => {
115 *c1 = *c2;
116 }
117
118 // Illegal mutablity conversion
119 (
120 ty_app!(TypeCtor::RawPtr(Mutability::Shared)),
121 ty_app!(TypeCtor::RawPtr(Mutability::Mut)),
122 )
123 | (
124 ty_app!(TypeCtor::Ref(Mutability::Shared)),
125 ty_app!(TypeCtor::Ref(Mutability::Mut)),
126 ) => return false,
127
128 // `{function_type}` -> `fn()`
129 (ty_app!(TypeCtor::FnDef(_)), ty_app!(TypeCtor::FnPtr { .. })) => {
130 match from_ty.callable_sig(self.db) {
131 None => return false,
132 Some(sig) => {
133 let num_args = sig.params_and_return.len() as u16 - 1;
134 from_ty =
135 Ty::apply(TypeCtor::FnPtr { num_args }, Substs(sig.params_and_return));
136 }
137 }
138 }
139
140 _ => {}
141 }
142
143 if let Some(ret) = self.try_coerce_unsized(&from_ty, &to_ty) {
144 return ret;
145 }
146
147 // Auto Deref if cannot coerce
148 match (&from_ty, to_ty) {
149 // FIXME: DerefMut
150 (ty_app!(TypeCtor::Ref(_), st1), ty_app!(TypeCtor::Ref(_), st2)) => {
151 self.unify_autoderef_behind_ref(&st1[0], &st2[0])
152 }
153
154 // Otherwise, normal unify
155 _ => self.unify(&from_ty, to_ty),
156 }
157 }
158
159 /// Coerce a type using `from_ty: CoerceUnsized<ty_ty>`
160 ///
161 /// See: https://doc.rust-lang.org/nightly/std/marker/trait.CoerceUnsized.html
162 fn try_coerce_unsized(&mut self, from_ty: &Ty, to_ty: &Ty) -> Option<bool> {
163 let (ctor1, st1, ctor2, st2) = match (from_ty, to_ty) {
164 (ty_app!(ctor1, st1), ty_app!(ctor2, st2)) => (ctor1, st1, ctor2, st2),
165 _ => return None,
166 };
167
168 let coerce_generic_index = *self.coerce_unsized_map.get(&(*ctor1, *ctor2))?;
169
170 // Check `Unsize` first
171 match self.check_unsize_and_coerce(
172 st1.0.get(coerce_generic_index)?,
173 st2.0.get(coerce_generic_index)?,
174 0,
175 ) {
176 Some(true) => {}
177 ret => return ret,
178 }
179
180 let ret = st1
181 .iter()
182 .zip(st2.iter())
183 .enumerate()
184 .filter(|&(idx, _)| idx != coerce_generic_index)
185 .all(|(_, (ty1, ty2))| self.unify(ty1, ty2));
186
187 Some(ret)
188 }
189
190 /// Check if `from_ty: Unsize<to_ty>`, and coerce to `to_ty` if it holds.
191 ///
192 /// It should not be directly called. It is only used by `try_coerce_unsized`.
193 ///
194 /// See: https://doc.rust-lang.org/nightly/std/marker/trait.Unsize.html
195 fn check_unsize_and_coerce(&mut self, from_ty: &Ty, to_ty: &Ty, depth: usize) -> Option<bool> {
196 if depth > 1000 {
197 panic!("Infinite recursion in coercion");
198 }
199
200 match (&from_ty, &to_ty) {
201 // `[T; N]` -> `[T]`
202 (ty_app!(TypeCtor::Array, st1), ty_app!(TypeCtor::Slice, st2)) => {
203 Some(self.unify(&st1[0], &st2[0]))
204 }
205
206 // `T` -> `dyn Trait` when `T: Trait`
207 (_, Ty::Dyn(_)) => {
208 // FIXME: Check predicates
209 Some(true)
210 }
211
212 // `(..., T)` -> `(..., U)` when `T: Unsize<U>`
213 (
214 ty_app!(TypeCtor::Tuple { cardinality: len1 }, st1),
215 ty_app!(TypeCtor::Tuple { cardinality: len2 }, st2),
216 ) => {
217 if len1 != len2 || *len1 == 0 {
218 return None;
219 }
220
221 match self.check_unsize_and_coerce(
222 st1.last().unwrap(),
223 st2.last().unwrap(),
224 depth + 1,
225 ) {
226 Some(true) => {}
227 ret => return ret,
228 }
229
230 let ret = st1[..st1.len() - 1]
231 .iter()
232 .zip(&st2[..st2.len() - 1])
233 .all(|(ty1, ty2)| self.unify(ty1, ty2));
234
235 Some(ret)
236 }
237
238 // Foo<..., T, ...> is Unsize<Foo<..., U, ...>> if:
239 // - T: Unsize<U>
240 // - Foo is a struct
241 // - Only the last field of Foo has a type involving T
242 // - T is not part of the type of any other fields
243 // - Bar<T>: Unsize<Bar<U>>, if the last field of Foo has type Bar<T>
244 (
245 ty_app!(TypeCtor::Adt(Adt::Struct(struct1)), st1),
246 ty_app!(TypeCtor::Adt(Adt::Struct(struct2)), st2),
247 ) if struct1 == struct2 => {
248 let fields = struct1.fields(self.db);
249 let (last_field, prev_fields) = fields.split_last()?;
250
251 // Get the generic parameter involved in the last field.
252 let unsize_generic_index = {
253 let mut index = None;
254 let mut multiple_param = false;
255 last_field.ty(self.db).walk(&mut |ty| match ty {
256 &Ty::Param { idx, .. } => {
257 if index.is_none() {
258 index = Some(idx);
259 } else if Some(idx) != index {
260 multiple_param = true;
261 }
262 }
263 _ => {}
264 });
265
266 if multiple_param {
267 return None;
268 }
269 index?
270 };
271
272 // Check other fields do not involve it.
273 let mut multiple_used = false;
274 prev_fields.iter().for_each(|field| {
275 field.ty(self.db).walk(&mut |ty| match ty {
276 &Ty::Param { idx, .. } if idx == unsize_generic_index => {
277 multiple_used = true
278 }
279 _ => {}
280 })
281 });
282 if multiple_used {
283 return None;
284 }
285
286 let unsize_generic_index = unsize_generic_index as usize;
287
288 // Check `Unsize` first
289 match self.check_unsize_and_coerce(
290 st1.get(unsize_generic_index)?,
291 st2.get(unsize_generic_index)?,
292 depth + 1,
293 ) {
294 Some(true) => {}
295 ret => return ret,
296 }
297
298 // Then unify other parameters
299 let ret = st1
300 .iter()
301 .zip(st2.iter())
302 .enumerate()
303 .filter(|&(idx, _)| idx != unsize_generic_index)
304 .all(|(_, (ty1, ty2))| self.unify(ty1, ty2));
305
306 Some(ret)
307 }
308
309 _ => None,
310 }
311 }
312
313 /// Unify `from_ty` to `to_ty` with optional auto Deref
314 ///
315 /// Note that the parameters are already stripped the outer reference.
316 fn unify_autoderef_behind_ref(&mut self, from_ty: &Ty, to_ty: &Ty) -> bool {
317 let canonicalized = self.canonicalizer().canonicalize_ty(from_ty.clone());
318 let to_ty = self.resolve_ty_shallow(&to_ty);
319 // FIXME: Auto DerefMut
320 for derefed_ty in
321 autoderef::autoderef(self.db, &self.resolver.clone(), canonicalized.value.clone())
322 {
323 let derefed_ty = canonicalized.decanonicalize_ty(derefed_ty.value);
324 match (&*self.resolve_ty_shallow(&derefed_ty), &*to_ty) {
325 // Stop when constructor matches.
326 (ty_app!(from_ctor, st1), ty_app!(to_ctor, st2)) if from_ctor == to_ctor => {
327 // It will not recurse to `coerce`.
328 return self.unify_substs(st1, st2, 0);
329 }
330 _ => {}
331 }
332 }
333
334 false
335 }
336}
diff --git a/crates/ra_hir/src/ty/infer/expr.rs b/crates/ra_hir/src/ty/infer/expr.rs
new file mode 100644
index 000000000..f8807c742
--- /dev/null
+++ b/crates/ra_hir/src/ty/infer/expr.rs
@@ -0,0 +1,658 @@
1//! Type inference for expressions.
2
3use std::iter::{repeat, repeat_with};
4use std::sync::Arc;
5
6use super::{BindingMode, Expectation, InferenceContext, InferenceDiagnostic, TypeMismatch};
7use crate::{
8 db::HirDatabase,
9 expr::{self, Array, BinaryOp, Expr, ExprId, Literal, Statement, UnaryOp},
10 generics::{GenericParams, HasGenericParams},
11 name,
12 nameres::Namespace,
13 path::{GenericArg, GenericArgs},
14 ty::{
15 autoderef, method_resolution, op, primitive, CallableDef, InferTy, Mutability, Obligation,
16 ProjectionPredicate, ProjectionTy, Substs, TraitRef, Ty, TypeCtor, TypeWalk,
17 },
18 Adt, Name,
19};
20
21impl<'a, D: HirDatabase> InferenceContext<'a, D> {
22 pub(super) fn infer_expr(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
23 let ty = self.infer_expr_inner(tgt_expr, expected);
24 let could_unify = self.unify(&ty, &expected.ty);
25 if !could_unify {
26 self.result.type_mismatches.insert(
27 tgt_expr,
28 TypeMismatch { expected: expected.ty.clone(), actual: ty.clone() },
29 );
30 }
31 let ty = self.resolve_ty_as_possible(&mut vec![], ty);
32 ty
33 }
34
35 /// Infer type of expression with possibly implicit coerce to the expected type.
36 /// Return the type after possible coercion.
37 fn infer_expr_coerce(&mut self, expr: ExprId, expected: &Expectation) -> Ty {
38 let ty = self.infer_expr_inner(expr, &expected);
39 let ty = if !self.coerce(&ty, &expected.ty) {
40 self.result
41 .type_mismatches
42 .insert(expr, TypeMismatch { expected: expected.ty.clone(), actual: ty.clone() });
43 // Return actual type when type mismatch.
44 // This is needed for diagnostic when return type mismatch.
45 ty
46 } else if expected.ty == Ty::Unknown {
47 ty
48 } else {
49 expected.ty.clone()
50 };
51
52 self.resolve_ty_as_possible(&mut vec![], ty)
53 }
54
55 fn infer_expr_inner(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
56 let body = Arc::clone(&self.body); // avoid borrow checker problem
57 let ty = match &body[tgt_expr] {
58 Expr::Missing => Ty::Unknown,
59 Expr::If { condition, then_branch, else_branch } => {
60 // if let is desugared to match, so this is always simple if
61 self.infer_expr(*condition, &Expectation::has_type(Ty::simple(TypeCtor::Bool)));
62
63 let then_ty = self.infer_expr_inner(*then_branch, &expected);
64 let else_ty = match else_branch {
65 Some(else_branch) => self.infer_expr_inner(*else_branch, &expected),
66 None => Ty::unit(),
67 };
68
69 self.coerce_merge_branch(&then_ty, &else_ty)
70 }
71 Expr::Block { statements, tail } => self.infer_block(statements, *tail, expected),
72 Expr::TryBlock { body } => {
73 let _inner = self.infer_expr(*body, expected);
74 // FIXME should be std::result::Result<{inner}, _>
75 Ty::Unknown
76 }
77 Expr::Loop { body } => {
78 self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
79 // FIXME handle break with value
80 Ty::simple(TypeCtor::Never)
81 }
82 Expr::While { condition, body } => {
83 // while let is desugared to a match loop, so this is always simple while
84 self.infer_expr(*condition, &Expectation::has_type(Ty::simple(TypeCtor::Bool)));
85 self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
86 Ty::unit()
87 }
88 Expr::For { iterable, body, pat } => {
89 let iterable_ty = self.infer_expr(*iterable, &Expectation::none());
90
91 let pat_ty = match self.resolve_into_iter_item() {
92 Some(into_iter_item_alias) => {
93 let pat_ty = self.new_type_var();
94 let projection = ProjectionPredicate {
95 ty: pat_ty.clone(),
96 projection_ty: ProjectionTy {
97 associated_ty: into_iter_item_alias,
98 parameters: Substs::single(iterable_ty),
99 },
100 };
101 self.obligations.push(Obligation::Projection(projection));
102 self.resolve_ty_as_possible(&mut vec![], pat_ty)
103 }
104 None => Ty::Unknown,
105 };
106
107 self.infer_pat(*pat, &pat_ty, BindingMode::default());
108 self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
109 Ty::unit()
110 }
111 Expr::Lambda { body, args, arg_types } => {
112 assert_eq!(args.len(), arg_types.len());
113
114 let mut sig_tys = Vec::new();
115
116 for (arg_pat, arg_type) in args.iter().zip(arg_types.iter()) {
117 let expected = if let Some(type_ref) = arg_type {
118 self.make_ty(type_ref)
119 } else {
120 Ty::Unknown
121 };
122 let arg_ty = self.infer_pat(*arg_pat, &expected, BindingMode::default());
123 sig_tys.push(arg_ty);
124 }
125
126 // add return type
127 let ret_ty = self.new_type_var();
128 sig_tys.push(ret_ty.clone());
129 let sig_ty = Ty::apply(
130 TypeCtor::FnPtr { num_args: sig_tys.len() as u16 - 1 },
131 Substs(sig_tys.into()),
132 );
133 let closure_ty = Ty::apply_one(
134 TypeCtor::Closure { def: self.body.owner(), expr: tgt_expr },
135 sig_ty,
136 );
137
138 // Eagerly try to relate the closure type with the expected
139 // type, otherwise we often won't have enough information to
140 // infer the body.
141 self.coerce(&closure_ty, &expected.ty);
142
143 self.infer_expr(*body, &Expectation::has_type(ret_ty));
144 closure_ty
145 }
146 Expr::Call { callee, args } => {
147 let callee_ty = self.infer_expr(*callee, &Expectation::none());
148 let (param_tys, ret_ty) = match callee_ty.callable_sig(self.db) {
149 Some(sig) => (sig.params().to_vec(), sig.ret().clone()),
150 None => {
151 // Not callable
152 // FIXME: report an error
153 (Vec::new(), Ty::Unknown)
154 }
155 };
156 self.register_obligations_for_call(&callee_ty);
157 self.check_call_arguments(args, &param_tys);
158 let ret_ty = self.normalize_associated_types_in(ret_ty);
159 ret_ty
160 }
161 Expr::MethodCall { receiver, args, method_name, generic_args } => self
162 .infer_method_call(tgt_expr, *receiver, &args, &method_name, generic_args.as_ref()),
163 Expr::Match { expr, arms } => {
164 let input_ty = self.infer_expr(*expr, &Expectation::none());
165
166 let mut result_ty = self.new_maybe_never_type_var();
167
168 for arm in arms {
169 for &pat in &arm.pats {
170 let _pat_ty = self.infer_pat(pat, &input_ty, BindingMode::default());
171 }
172 if let Some(guard_expr) = arm.guard {
173 self.infer_expr(
174 guard_expr,
175 &Expectation::has_type(Ty::simple(TypeCtor::Bool)),
176 );
177 }
178
179 let arm_ty = self.infer_expr_inner(arm.expr, &expected);
180 result_ty = self.coerce_merge_branch(&result_ty, &arm_ty);
181 }
182
183 result_ty
184 }
185 Expr::Path(p) => {
186 // FIXME this could be more efficient...
187 let resolver = expr::resolver_for_expr(self.body.clone(), self.db, tgt_expr);
188 self.infer_path(&resolver, p, tgt_expr.into()).unwrap_or(Ty::Unknown)
189 }
190 Expr::Continue => Ty::simple(TypeCtor::Never),
191 Expr::Break { expr } => {
192 if let Some(expr) = expr {
193 // FIXME handle break with value
194 self.infer_expr(*expr, &Expectation::none());
195 }
196 Ty::simple(TypeCtor::Never)
197 }
198 Expr::Return { expr } => {
199 if let Some(expr) = expr {
200 self.infer_expr(*expr, &Expectation::has_type(self.return_ty.clone()));
201 }
202 Ty::simple(TypeCtor::Never)
203 }
204 Expr::RecordLit { path, fields, spread } => {
205 let (ty, def_id) = self.resolve_variant(path.as_ref());
206 if let Some(variant) = def_id {
207 self.write_variant_resolution(tgt_expr.into(), variant);
208 }
209
210 self.unify(&ty, &expected.ty);
211
212 let substs = ty.substs().unwrap_or_else(Substs::empty);
213 for (field_idx, field) in fields.iter().enumerate() {
214 let field_ty = def_id
215 .and_then(|it| match it.field(self.db, &field.name) {
216 Some(field) => Some(field),
217 None => {
218 self.push_diagnostic(InferenceDiagnostic::NoSuchField {
219 expr: tgt_expr,
220 field: field_idx,
221 });
222 None
223 }
224 })
225 .map_or(Ty::Unknown, |field| field.ty(self.db))
226 .subst(&substs);
227 self.infer_expr_coerce(field.expr, &Expectation::has_type(field_ty));
228 }
229 if let Some(expr) = spread {
230 self.infer_expr(*expr, &Expectation::has_type(ty.clone()));
231 }
232 ty
233 }
234 Expr::Field { expr, name } => {
235 let receiver_ty = self.infer_expr(*expr, &Expectation::none());
236 let canonicalized = self.canonicalizer().canonicalize_ty(receiver_ty);
237 let ty = autoderef::autoderef(
238 self.db,
239 &self.resolver.clone(),
240 canonicalized.value.clone(),
241 )
242 .find_map(|derefed_ty| match canonicalized.decanonicalize_ty(derefed_ty.value) {
243 Ty::Apply(a_ty) => match a_ty.ctor {
244 TypeCtor::Tuple { .. } => name
245 .as_tuple_index()
246 .and_then(|idx| a_ty.parameters.0.get(idx).cloned()),
247 TypeCtor::Adt(Adt::Struct(s)) => s.field(self.db, name).map(|field| {
248 self.write_field_resolution(tgt_expr, field);
249 field.ty(self.db).subst(&a_ty.parameters)
250 }),
251 _ => None,
252 },
253 _ => None,
254 })
255 .unwrap_or(Ty::Unknown);
256 let ty = self.insert_type_vars(ty);
257 self.normalize_associated_types_in(ty)
258 }
259 Expr::Await { expr } => {
260 let inner_ty = self.infer_expr(*expr, &Expectation::none());
261 let ty = match self.resolve_future_future_output() {
262 Some(future_future_output_alias) => {
263 let ty = self.new_type_var();
264 let projection = ProjectionPredicate {
265 ty: ty.clone(),
266 projection_ty: ProjectionTy {
267 associated_ty: future_future_output_alias,
268 parameters: Substs::single(inner_ty),
269 },
270 };
271 self.obligations.push(Obligation::Projection(projection));
272 self.resolve_ty_as_possible(&mut vec![], ty)
273 }
274 None => Ty::Unknown,
275 };
276 ty
277 }
278 Expr::Try { expr } => {
279 let inner_ty = self.infer_expr(*expr, &Expectation::none());
280 let ty = match self.resolve_ops_try_ok() {
281 Some(ops_try_ok_alias) => {
282 let ty = self.new_type_var();
283 let projection = ProjectionPredicate {
284 ty: ty.clone(),
285 projection_ty: ProjectionTy {
286 associated_ty: ops_try_ok_alias,
287 parameters: Substs::single(inner_ty),
288 },
289 };
290 self.obligations.push(Obligation::Projection(projection));
291 self.resolve_ty_as_possible(&mut vec![], ty)
292 }
293 None => Ty::Unknown,
294 };
295 ty
296 }
297 Expr::Cast { expr, type_ref } => {
298 let _inner_ty = self.infer_expr(*expr, &Expectation::none());
299 let cast_ty = self.make_ty(type_ref);
300 // FIXME check the cast...
301 cast_ty
302 }
303 Expr::Ref { expr, mutability } => {
304 let expectation =
305 if let Some((exp_inner, exp_mutability)) = &expected.ty.as_reference() {
306 if *exp_mutability == Mutability::Mut && *mutability == Mutability::Shared {
307 // FIXME: throw type error - expected mut reference but found shared ref,
308 // which cannot be coerced
309 }
310 Expectation::has_type(Ty::clone(exp_inner))
311 } else {
312 Expectation::none()
313 };
314 // FIXME reference coercions etc.
315 let inner_ty = self.infer_expr(*expr, &expectation);
316 Ty::apply_one(TypeCtor::Ref(*mutability), inner_ty)
317 }
318 Expr::Box { expr } => {
319 let inner_ty = self.infer_expr(*expr, &Expectation::none());
320 if let Some(box_) = self.resolve_boxed_box() {
321 Ty::apply_one(TypeCtor::Adt(box_), inner_ty)
322 } else {
323 Ty::Unknown
324 }
325 }
326 Expr::UnaryOp { expr, op } => {
327 let inner_ty = self.infer_expr(*expr, &Expectation::none());
328 match op {
329 UnaryOp::Deref => {
330 let canonicalized = self.canonicalizer().canonicalize_ty(inner_ty);
331 if let Some(derefed_ty) =
332 autoderef::deref(self.db, &self.resolver, &canonicalized.value)
333 {
334 canonicalized.decanonicalize_ty(derefed_ty.value)
335 } else {
336 Ty::Unknown
337 }
338 }
339 UnaryOp::Neg => {
340 match &inner_ty {
341 Ty::Apply(a_ty) => match a_ty.ctor {
342 TypeCtor::Int(primitive::UncertainIntTy::Unknown)
343 | TypeCtor::Int(primitive::UncertainIntTy::Known(
344 primitive::IntTy {
345 signedness: primitive::Signedness::Signed,
346 ..
347 },
348 ))
349 | TypeCtor::Float(..) => inner_ty,
350 _ => Ty::Unknown,
351 },
352 Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => {
353 inner_ty
354 }
355 // FIXME: resolve ops::Neg trait
356 _ => Ty::Unknown,
357 }
358 }
359 UnaryOp::Not => {
360 match &inner_ty {
361 Ty::Apply(a_ty) => match a_ty.ctor {
362 TypeCtor::Bool | TypeCtor::Int(_) => inner_ty,
363 _ => Ty::Unknown,
364 },
365 Ty::Infer(InferTy::IntVar(..)) => inner_ty,
366 // FIXME: resolve ops::Not trait for inner_ty
367 _ => Ty::Unknown,
368 }
369 }
370 }
371 }
372 Expr::BinaryOp { lhs, rhs, op } => match op {
373 Some(op) => {
374 let lhs_expectation = match op {
375 BinaryOp::LogicOp(..) => Expectation::has_type(Ty::simple(TypeCtor::Bool)),
376 _ => Expectation::none(),
377 };
378 let lhs_ty = self.infer_expr(*lhs, &lhs_expectation);
379 // FIXME: find implementation of trait corresponding to operation
380 // symbol and resolve associated `Output` type
381 let rhs_expectation = op::binary_op_rhs_expectation(*op, lhs_ty);
382 let rhs_ty = self.infer_expr(*rhs, &Expectation::has_type(rhs_expectation));
383
384 // FIXME: similar as above, return ty is often associated trait type
385 op::binary_op_return_ty(*op, rhs_ty)
386 }
387 _ => Ty::Unknown,
388 },
389 Expr::Index { base, index } => {
390 let _base_ty = self.infer_expr(*base, &Expectation::none());
391 let _index_ty = self.infer_expr(*index, &Expectation::none());
392 // FIXME: use `std::ops::Index::Output` to figure out the real return type
393 Ty::Unknown
394 }
395 Expr::Tuple { exprs } => {
396 let mut tys = match &expected.ty {
397 ty_app!(TypeCtor::Tuple { .. }, st) => st
398 .iter()
399 .cloned()
400 .chain(repeat_with(|| self.new_type_var()))
401 .take(exprs.len())
402 .collect::<Vec<_>>(),
403 _ => (0..exprs.len()).map(|_| self.new_type_var()).collect(),
404 };
405
406 for (expr, ty) in exprs.iter().zip(tys.iter_mut()) {
407 self.infer_expr_coerce(*expr, &Expectation::has_type(ty.clone()));
408 }
409
410 Ty::apply(TypeCtor::Tuple { cardinality: tys.len() as u16 }, Substs(tys.into()))
411 }
412 Expr::Array(array) => {
413 let elem_ty = match &expected.ty {
414 ty_app!(TypeCtor::Array, st) | ty_app!(TypeCtor::Slice, st) => {
415 st.as_single().clone()
416 }
417 _ => self.new_type_var(),
418 };
419
420 match array {
421 Array::ElementList(items) => {
422 for expr in items.iter() {
423 self.infer_expr_coerce(*expr, &Expectation::has_type(elem_ty.clone()));
424 }
425 }
426 Array::Repeat { initializer, repeat } => {
427 self.infer_expr_coerce(
428 *initializer,
429 &Expectation::has_type(elem_ty.clone()),
430 );
431 self.infer_expr(
432 *repeat,
433 &Expectation::has_type(Ty::simple(TypeCtor::Int(
434 primitive::UncertainIntTy::Known(primitive::IntTy::usize()),
435 ))),
436 );
437 }
438 }
439
440 Ty::apply_one(TypeCtor::Array, elem_ty)
441 }
442 Expr::Literal(lit) => match lit {
443 Literal::Bool(..) => Ty::simple(TypeCtor::Bool),
444 Literal::String(..) => {
445 Ty::apply_one(TypeCtor::Ref(Mutability::Shared), Ty::simple(TypeCtor::Str))
446 }
447 Literal::ByteString(..) => {
448 let byte_type = Ty::simple(TypeCtor::Int(primitive::UncertainIntTy::Known(
449 primitive::IntTy::u8(),
450 )));
451 let slice_type = Ty::apply_one(TypeCtor::Slice, byte_type);
452 Ty::apply_one(TypeCtor::Ref(Mutability::Shared), slice_type)
453 }
454 Literal::Char(..) => Ty::simple(TypeCtor::Char),
455 Literal::Int(_v, ty) => Ty::simple(TypeCtor::Int(*ty)),
456 Literal::Float(_v, ty) => Ty::simple(TypeCtor::Float(*ty)),
457 },
458 };
459 // use a new type variable if we got Ty::Unknown here
460 let ty = self.insert_type_vars_shallow(ty);
461 let ty = self.resolve_ty_as_possible(&mut vec![], ty);
462 self.write_expr_ty(tgt_expr, ty.clone());
463 ty
464 }
465
466 fn infer_block(
467 &mut self,
468 statements: &[Statement],
469 tail: Option<ExprId>,
470 expected: &Expectation,
471 ) -> Ty {
472 let mut diverges = false;
473 for stmt in statements {
474 match stmt {
475 Statement::Let { pat, type_ref, initializer } => {
476 let decl_ty =
477 type_ref.as_ref().map(|tr| self.make_ty(tr)).unwrap_or(Ty::Unknown);
478
479 // Always use the declared type when specified
480 let mut ty = decl_ty.clone();
481
482 if let Some(expr) = initializer {
483 let actual_ty =
484 self.infer_expr_coerce(*expr, &Expectation::has_type(decl_ty.clone()));
485 if decl_ty == Ty::Unknown {
486 ty = actual_ty;
487 }
488 }
489
490 let ty = self.resolve_ty_as_possible(&mut vec![], ty);
491 self.infer_pat(*pat, &ty, BindingMode::default());
492 }
493 Statement::Expr(expr) => {
494 if let ty_app!(TypeCtor::Never) = self.infer_expr(*expr, &Expectation::none()) {
495 diverges = true;
496 }
497 }
498 }
499 }
500
501 let ty = if let Some(expr) = tail {
502 self.infer_expr_coerce(expr, expected)
503 } else {
504 self.coerce(&Ty::unit(), &expected.ty);
505 Ty::unit()
506 };
507 if diverges {
508 Ty::simple(TypeCtor::Never)
509 } else {
510 ty
511 }
512 }
513
514 fn infer_method_call(
515 &mut self,
516 tgt_expr: ExprId,
517 receiver: ExprId,
518 args: &[ExprId],
519 method_name: &Name,
520 generic_args: Option<&GenericArgs>,
521 ) -> Ty {
522 let receiver_ty = self.infer_expr(receiver, &Expectation::none());
523 let canonicalized_receiver = self.canonicalizer().canonicalize_ty(receiver_ty.clone());
524 let resolved = method_resolution::lookup_method(
525 &canonicalized_receiver.value,
526 self.db,
527 method_name,
528 &self.resolver,
529 );
530 let (derefed_receiver_ty, method_ty, def_generics) = match resolved {
531 Some((ty, func)) => {
532 let ty = canonicalized_receiver.decanonicalize_ty(ty);
533 self.write_method_resolution(tgt_expr, func);
534 (
535 ty,
536 self.db.type_for_def(func.into(), Namespace::Values),
537 Some(func.generic_params(self.db)),
538 )
539 }
540 None => (receiver_ty, Ty::Unknown, None),
541 };
542 let substs = self.substs_for_method_call(def_generics, generic_args, &derefed_receiver_ty);
543 let method_ty = method_ty.apply_substs(substs);
544 let method_ty = self.insert_type_vars(method_ty);
545 self.register_obligations_for_call(&method_ty);
546 let (expected_receiver_ty, param_tys, ret_ty) = match method_ty.callable_sig(self.db) {
547 Some(sig) => {
548 if !sig.params().is_empty() {
549 (sig.params()[0].clone(), sig.params()[1..].to_vec(), sig.ret().clone())
550 } else {
551 (Ty::Unknown, Vec::new(), sig.ret().clone())
552 }
553 }
554 None => (Ty::Unknown, Vec::new(), Ty::Unknown),
555 };
556 // Apply autoref so the below unification works correctly
557 // FIXME: return correct autorefs from lookup_method
558 let actual_receiver_ty = match expected_receiver_ty.as_reference() {
559 Some((_, mutability)) => Ty::apply_one(TypeCtor::Ref(mutability), derefed_receiver_ty),
560 _ => derefed_receiver_ty,
561 };
562 self.unify(&expected_receiver_ty, &actual_receiver_ty);
563
564 self.check_call_arguments(args, &param_tys);
565 let ret_ty = self.normalize_associated_types_in(ret_ty);
566 ret_ty
567 }
568
569 fn check_call_arguments(&mut self, args: &[ExprId], param_tys: &[Ty]) {
570 // Quoting https://github.com/rust-lang/rust/blob/6ef275e6c3cb1384ec78128eceeb4963ff788dca/src/librustc_typeck/check/mod.rs#L3325 --
571 // We do this in a pretty awful way: first we type-check any arguments
572 // that are not closures, then we type-check the closures. This is so
573 // that we have more information about the types of arguments when we
574 // type-check the functions. This isn't really the right way to do this.
575 for &check_closures in &[false, true] {
576 let param_iter = param_tys.iter().cloned().chain(repeat(Ty::Unknown));
577 for (&arg, param_ty) in args.iter().zip(param_iter) {
578 let is_closure = match &self.body[arg] {
579 Expr::Lambda { .. } => true,
580 _ => false,
581 };
582
583 if is_closure != check_closures {
584 continue;
585 }
586
587 let param_ty = self.normalize_associated_types_in(param_ty);
588 self.infer_expr_coerce(arg, &Expectation::has_type(param_ty.clone()));
589 }
590 }
591 }
592
593 fn substs_for_method_call(
594 &mut self,
595 def_generics: Option<Arc<GenericParams>>,
596 generic_args: Option<&GenericArgs>,
597 receiver_ty: &Ty,
598 ) -> Substs {
599 let (parent_param_count, param_count) =
600 def_generics.as_ref().map_or((0, 0), |g| (g.count_parent_params(), g.params.len()));
601 let mut substs = Vec::with_capacity(parent_param_count + param_count);
602 // Parent arguments are unknown, except for the receiver type
603 if let Some(parent_generics) = def_generics.and_then(|p| p.parent_params.clone()) {
604 for param in &parent_generics.params {
605 if param.name == name::SELF_TYPE {
606 substs.push(receiver_ty.clone());
607 } else {
608 substs.push(Ty::Unknown);
609 }
610 }
611 }
612 // handle provided type arguments
613 if let Some(generic_args) = generic_args {
614 // if args are provided, it should be all of them, but we can't rely on that
615 for arg in generic_args.args.iter().take(param_count) {
616 match arg {
617 GenericArg::Type(type_ref) => {
618 let ty = self.make_ty(type_ref);
619 substs.push(ty);
620 }
621 }
622 }
623 };
624 let supplied_params = substs.len();
625 for _ in supplied_params..parent_param_count + param_count {
626 substs.push(Ty::Unknown);
627 }
628 assert_eq!(substs.len(), parent_param_count + param_count);
629 Substs(substs.into())
630 }
631
632 fn register_obligations_for_call(&mut self, callable_ty: &Ty) {
633 if let Ty::Apply(a_ty) = callable_ty {
634 if let TypeCtor::FnDef(def) = a_ty.ctor {
635 let generic_predicates = self.db.generic_predicates(def.into());
636 for predicate in generic_predicates.iter() {
637 let predicate = predicate.clone().subst(&a_ty.parameters);
638 if let Some(obligation) = Obligation::from_predicate(predicate) {
639 self.obligations.push(obligation);
640 }
641 }
642 // add obligation for trait implementation, if this is a trait method
643 match def {
644 CallableDef::Function(f) => {
645 if let Some(trait_) = f.parent_trait(self.db) {
646 // construct a TraitDef
647 let substs = a_ty.parameters.prefix(
648 trait_.generic_params(self.db).count_params_including_parent(),
649 );
650 self.obligations.push(Obligation::Trait(TraitRef { trait_, substs }));
651 }
652 }
653 CallableDef::Struct(_) | CallableDef::EnumVariant(_) => {}
654 }
655 }
656 }
657 }
658}
diff --git a/crates/ra_hir/src/ty/infer/pat.rs b/crates/ra_hir/src/ty/infer/pat.rs
new file mode 100644
index 000000000..c125ddfbc
--- /dev/null
+++ b/crates/ra_hir/src/ty/infer/pat.rs
@@ -0,0 +1,180 @@
1//! Type inference for patterns.
2
3use std::iter::repeat;
4use std::sync::Arc;
5
6use test_utils::tested_by;
7
8use super::{BindingMode, InferenceContext};
9use crate::{
10 db::HirDatabase,
11 expr::{BindingAnnotation, Pat, PatId, RecordFieldPat},
12 ty::{Mutability, Substs, Ty, TypeCtor, TypeWalk},
13 Name, Path,
14};
15
16impl<'a, D: HirDatabase> InferenceContext<'a, D> {
17 fn infer_tuple_struct_pat(
18 &mut self,
19 path: Option<&Path>,
20 subpats: &[PatId],
21 expected: &Ty,
22 default_bm: BindingMode,
23 ) -> Ty {
24 let (ty, def) = self.resolve_variant(path);
25
26 self.unify(&ty, expected);
27
28 let substs = ty.substs().unwrap_or_else(Substs::empty);
29
30 for (i, &subpat) in subpats.iter().enumerate() {
31 let expected_ty = def
32 .and_then(|d| d.field(self.db, &Name::new_tuple_field(i)))
33 .map_or(Ty::Unknown, |field| field.ty(self.db))
34 .subst(&substs);
35 let expected_ty = self.normalize_associated_types_in(expected_ty);
36 self.infer_pat(subpat, &expected_ty, default_bm);
37 }
38
39 ty
40 }
41
42 fn infer_record_pat(
43 &mut self,
44 path: Option<&Path>,
45 subpats: &[RecordFieldPat],
46 expected: &Ty,
47 default_bm: BindingMode,
48 id: PatId,
49 ) -> Ty {
50 let (ty, def) = self.resolve_variant(path);
51 if let Some(variant) = def {
52 self.write_variant_resolution(id.into(), variant);
53 }
54
55 self.unify(&ty, expected);
56
57 let substs = ty.substs().unwrap_or_else(Substs::empty);
58
59 for subpat in subpats {
60 let matching_field = def.and_then(|it| it.field(self.db, &subpat.name));
61 let expected_ty =
62 matching_field.map_or(Ty::Unknown, |field| field.ty(self.db)).subst(&substs);
63 let expected_ty = self.normalize_associated_types_in(expected_ty);
64 self.infer_pat(subpat.pat, &expected_ty, default_bm);
65 }
66
67 ty
68 }
69
70 pub(super) fn infer_pat(
71 &mut self,
72 pat: PatId,
73 mut expected: &Ty,
74 mut default_bm: BindingMode,
75 ) -> Ty {
76 let body = Arc::clone(&self.body); // avoid borrow checker problem
77
78 let is_non_ref_pat = match &body[pat] {
79 Pat::Tuple(..)
80 | Pat::TupleStruct { .. }
81 | Pat::Record { .. }
82 | Pat::Range { .. }
83 | Pat::Slice { .. } => true,
84 // FIXME: Path/Lit might actually evaluate to ref, but inference is unimplemented.
85 Pat::Path(..) | Pat::Lit(..) => true,
86 Pat::Wild | Pat::Bind { .. } | Pat::Ref { .. } | Pat::Missing => false,
87 };
88 if is_non_ref_pat {
89 while let Some((inner, mutability)) = expected.as_reference() {
90 expected = inner;
91 default_bm = match default_bm {
92 BindingMode::Move => BindingMode::Ref(mutability),
93 BindingMode::Ref(Mutability::Shared) => BindingMode::Ref(Mutability::Shared),
94 BindingMode::Ref(Mutability::Mut) => BindingMode::Ref(mutability),
95 }
96 }
97 } else if let Pat::Ref { .. } = &body[pat] {
98 tested_by!(match_ergonomics_ref);
99 // When you encounter a `&pat` pattern, reset to Move.
100 // This is so that `w` is by value: `let (_, &w) = &(1, &2);`
101 default_bm = BindingMode::Move;
102 }
103
104 // Lose mutability.
105 let default_bm = default_bm;
106 let expected = expected;
107
108 let ty = match &body[pat] {
109 Pat::Tuple(ref args) => {
110 let expectations = match expected.as_tuple() {
111 Some(parameters) => &*parameters.0,
112 _ => &[],
113 };
114 let expectations_iter = expectations.iter().chain(repeat(&Ty::Unknown));
115
116 let inner_tys = args
117 .iter()
118 .zip(expectations_iter)
119 .map(|(&pat, ty)| self.infer_pat(pat, ty, default_bm))
120 .collect();
121
122 Ty::apply(TypeCtor::Tuple { cardinality: args.len() as u16 }, Substs(inner_tys))
123 }
124 Pat::Ref { pat, mutability } => {
125 let expectation = match expected.as_reference() {
126 Some((inner_ty, exp_mut)) => {
127 if *mutability != exp_mut {
128 // FIXME: emit type error?
129 }
130 inner_ty
131 }
132 _ => &Ty::Unknown,
133 };
134 let subty = self.infer_pat(*pat, expectation, default_bm);
135 Ty::apply_one(TypeCtor::Ref(*mutability), subty)
136 }
137 Pat::TupleStruct { path: p, args: subpats } => {
138 self.infer_tuple_struct_pat(p.as_ref(), subpats, expected, default_bm)
139 }
140 Pat::Record { path: p, args: fields } => {
141 self.infer_record_pat(p.as_ref(), fields, expected, default_bm, pat)
142 }
143 Pat::Path(path) => {
144 // FIXME use correct resolver for the surrounding expression
145 let resolver = self.resolver.clone();
146 self.infer_path(&resolver, &path, pat.into()).unwrap_or(Ty::Unknown)
147 }
148 Pat::Bind { mode, name: _, subpat } => {
149 let mode = if mode == &BindingAnnotation::Unannotated {
150 default_bm
151 } else {
152 BindingMode::convert(*mode)
153 };
154 let inner_ty = if let Some(subpat) = subpat {
155 self.infer_pat(*subpat, expected, default_bm)
156 } else {
157 expected.clone()
158 };
159 let inner_ty = self.insert_type_vars_shallow(inner_ty);
160
161 let bound_ty = match mode {
162 BindingMode::Ref(mutability) => {
163 Ty::apply_one(TypeCtor::Ref(mutability), inner_ty.clone())
164 }
165 BindingMode::Move => inner_ty.clone(),
166 };
167 let bound_ty = self.resolve_ty_as_possible(&mut vec![], bound_ty);
168 self.write_pat_ty(pat, bound_ty);
169 return inner_ty;
170 }
171 _ => Ty::Unknown,
172 };
173 // use a new type variable if we got Ty::Unknown here
174 let ty = self.insert_type_vars_shallow(ty);
175 self.unify(&ty, expected);
176 let ty = self.resolve_ty_as_possible(&mut vec![], ty);
177 self.write_pat_ty(pat, ty.clone());
178 ty
179 }
180}
diff --git a/crates/ra_hir/src/ty/infer/unify.rs b/crates/ra_hir/src/ty/infer/unify.rs
index d161aa6b3..ca33cc7f8 100644
--- a/crates/ra_hir/src/ty/infer/unify.rs
+++ b/crates/ra_hir/src/ty/infer/unify.rs
@@ -6,6 +6,7 @@ use crate::ty::{
6 Canonical, InEnvironment, InferTy, ProjectionPredicate, ProjectionTy, Substs, TraitRef, Ty, 6 Canonical, InEnvironment, InferTy, ProjectionPredicate, ProjectionTy, Substs, TraitRef, Ty,
7 TypeWalk, 7 TypeWalk,
8}; 8};
9use crate::util::make_mut_slice;
9 10
10impl<'a, D: HirDatabase> InferenceContext<'a, D> { 11impl<'a, D: HirDatabase> InferenceContext<'a, D> {
11 pub(super) fn canonicalizer<'b>(&'b mut self) -> Canonicalizer<'a, 'b, D> 12 pub(super) fn canonicalizer<'b>(&'b mut self) -> Canonicalizer<'a, 'b, D>
@@ -53,7 +54,9 @@ where
53 // recursive type 54 // recursive type
54 return tv.fallback_value(); 55 return tv.fallback_value();
55 } 56 }
56 if let Some(known_ty) = self.ctx.var_unification_table.probe_value(inner).known() { 57 if let Some(known_ty) =
58 self.ctx.var_unification_table.inlined_probe_value(inner).known()
59 {
57 self.var_stack.push(inner); 60 self.var_stack.push(inner);
58 let result = self.do_canonicalize_ty(known_ty.clone()); 61 let result = self.do_canonicalize_ty(known_ty.clone());
59 self.var_stack.pop(); 62 self.var_stack.pop();
@@ -74,10 +77,11 @@ where
74 }) 77 })
75 } 78 }
76 79
77 fn do_canonicalize_trait_ref(&mut self, trait_ref: TraitRef) -> TraitRef { 80 fn do_canonicalize_trait_ref(&mut self, mut trait_ref: TraitRef) -> TraitRef {
78 let substs = 81 for ty in make_mut_slice(&mut trait_ref.substs.0) {
79 trait_ref.substs.iter().map(|ty| self.do_canonicalize_ty(ty.clone())).collect(); 82 *ty = self.do_canonicalize_ty(ty.clone());
80 TraitRef { trait_: trait_ref.trait_, substs: Substs(substs) } 83 }
84 trait_ref
81 } 85 }
82 86
83 fn into_canonicalized<T>(self, result: T) -> Canonicalized<T> { 87 fn into_canonicalized<T>(self, result: T) -> Canonicalized<T> {
@@ -87,10 +91,11 @@ where
87 } 91 }
88 } 92 }
89 93
90 fn do_canonicalize_projection_ty(&mut self, projection_ty: ProjectionTy) -> ProjectionTy { 94 fn do_canonicalize_projection_ty(&mut self, mut projection_ty: ProjectionTy) -> ProjectionTy {
91 let params = 95 for ty in make_mut_slice(&mut projection_ty.parameters.0) {
92 projection_ty.parameters.iter().map(|ty| self.do_canonicalize_ty(ty.clone())).collect(); 96 *ty = self.do_canonicalize_ty(ty.clone());
93 ProjectionTy { associated_ty: projection_ty.associated_ty, parameters: Substs(params) } 97 }
98 projection_ty
94 } 99 }
95 100
96 fn do_canonicalize_projection_predicate( 101 fn do_canonicalize_projection_predicate(
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index 4b67c82e7..366556134 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -22,6 +22,7 @@ use crate::{
22 resolve::{Resolver, TypeNs}, 22 resolve::{Resolver, TypeNs},
23 ty::Adt, 23 ty::Adt,
24 type_ref::{TypeBound, TypeRef}, 24 type_ref::{TypeBound, TypeRef},
25 util::make_mut_slice,
25 BuiltinType, Const, Enum, EnumVariant, Function, ModuleDef, Path, Static, Struct, StructField, 26 BuiltinType, Const, Enum, EnumVariant, Function, ModuleDef, Path, Static, Struct, StructField,
26 Trait, TypeAlias, Union, 27 Trait, TypeAlias, Union,
27}; 28};
@@ -31,11 +32,11 @@ impl Ty {
31 match type_ref { 32 match type_ref {
32 TypeRef::Never => Ty::simple(TypeCtor::Never), 33 TypeRef::Never => Ty::simple(TypeCtor::Never),
33 TypeRef::Tuple(inner) => { 34 TypeRef::Tuple(inner) => {
34 let inner_tys = 35 let inner_tys: Arc<[Ty]> =
35 inner.iter().map(|tr| Ty::from_hir(db, resolver, tr)).collect::<Vec<_>>(); 36 inner.iter().map(|tr| Ty::from_hir(db, resolver, tr)).collect();
36 Ty::apply( 37 Ty::apply(
37 TypeCtor::Tuple { cardinality: inner_tys.len() as u16 }, 38 TypeCtor::Tuple { cardinality: inner_tys.len() as u16 },
38 Substs(inner_tys.into()), 39 Substs(inner_tys),
39 ) 40 )
40 } 41 }
41 TypeRef::Path(path) => Ty::from_hir_path(db, resolver, path), 42 TypeRef::Path(path) => Ty::from_hir_path(db, resolver, path),
@@ -57,9 +58,7 @@ impl Ty {
57 } 58 }
58 TypeRef::Placeholder => Ty::Unknown, 59 TypeRef::Placeholder => Ty::Unknown,
59 TypeRef::Fn(params) => { 60 TypeRef::Fn(params) => {
60 let inner_tys = 61 let sig = Substs(params.iter().map(|tr| Ty::from_hir(db, resolver, tr)).collect());
61 params.iter().map(|tr| Ty::from_hir(db, resolver, tr)).collect::<Vec<_>>();
62 let sig = Substs(inner_tys.into());
63 Ty::apply(TypeCtor::FnPtr { num_args: sig.len() as u16 - 1 }, sig) 62 Ty::apply(TypeCtor::FnPtr { num_args: sig.len() as u16 - 1 }, sig)
64 } 63 }
65 TypeRef::DynTrait(bounds) => { 64 TypeRef::DynTrait(bounds) => {
@@ -69,8 +68,8 @@ impl Ty {
69 .flat_map(|b| { 68 .flat_map(|b| {
70 GenericPredicate::from_type_bound(db, resolver, b, self_ty.clone()) 69 GenericPredicate::from_type_bound(db, resolver, b, self_ty.clone())
71 }) 70 })
72 .collect::<Vec<_>>(); 71 .collect();
73 Ty::Dyn(predicates.into()) 72 Ty::Dyn(predicates)
74 } 73 }
75 TypeRef::ImplTrait(bounds) => { 74 TypeRef::ImplTrait(bounds) => {
76 let self_ty = Ty::Bound(0); 75 let self_ty = Ty::Bound(0);
@@ -79,8 +78,8 @@ impl Ty {
79 .flat_map(|b| { 78 .flat_map(|b| {
80 GenericPredicate::from_type_bound(db, resolver, b, self_ty.clone()) 79 GenericPredicate::from_type_bound(db, resolver, b, self_ty.clone())
81 }) 80 })
82 .collect::<Vec<_>>(); 81 .collect();
83 Ty::Opaque(predicates.into()) 82 Ty::Opaque(predicates)
84 } 83 }
85 TypeRef::Error => Ty::Unknown, 84 TypeRef::Error => Ty::Unknown,
86 } 85 }
@@ -175,6 +174,7 @@ impl Ty {
175 Ty::Param { idx, name } 174 Ty::Param { idx, name }
176 } 175 }
177 TypeNs::SelfType(impl_block) => impl_block.target_ty(db), 176 TypeNs::SelfType(impl_block) => impl_block.target_ty(db),
177 TypeNs::AdtSelfType(adt) => adt.ty(db),
178 178
179 TypeNs::Adt(it) => Ty::from_hir_path_inner(db, resolver, resolved_segment, it.into()), 179 TypeNs::Adt(it) => Ty::from_hir_path_inner(db, resolver, resolved_segment, it.into()),
180 TypeNs::BuiltinType(it) => { 180 TypeNs::BuiltinType(it) => {
@@ -391,10 +391,7 @@ impl TraitRef {
391 ) -> Self { 391 ) -> Self {
392 let mut substs = TraitRef::substs_from_path(db, resolver, segment, resolved); 392 let mut substs = TraitRef::substs_from_path(db, resolver, segment, resolved);
393 if let Some(self_ty) = explicit_self_ty { 393 if let Some(self_ty) = explicit_self_ty {
394 // FIXME this could be nicer 394 make_mut_slice(&mut substs.0)[0] = self_ty;
395 let mut substs_vec = substs.0.to_vec();
396 substs_vec[0] = self_ty;
397 substs.0 = substs_vec.into();
398 } 395 }
399 TraitRef { trait_: resolved, substs } 396 TraitRef { trait_: resolved, substs }
400 } 397 }
@@ -557,13 +554,12 @@ pub(crate) fn generic_predicates_for_param_query(
557 param_idx: u32, 554 param_idx: u32,
558) -> Arc<[GenericPredicate]> { 555) -> Arc<[GenericPredicate]> {
559 let resolver = def.resolver(db); 556 let resolver = def.resolver(db);
560 let predicates = resolver 557 resolver
561 .where_predicates_in_scope() 558 .where_predicates_in_scope()
562 // we have to filter out all other predicates *first*, before attempting to lower them 559 // we have to filter out all other predicates *first*, before attempting to lower them
563 .filter(|pred| Ty::from_hir_only_param(db, &resolver, &pred.type_ref) == Some(param_idx)) 560 .filter(|pred| Ty::from_hir_only_param(db, &resolver, &pred.type_ref) == Some(param_idx))
564 .flat_map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred)) 561 .flat_map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred))
565 .collect::<Vec<_>>(); 562 .collect()
566 predicates.into()
567} 563}
568 564
569pub(crate) fn trait_env( 565pub(crate) fn trait_env(
@@ -584,11 +580,10 @@ pub(crate) fn generic_predicates_query(
584 def: GenericDef, 580 def: GenericDef,
585) -> Arc<[GenericPredicate]> { 581) -> Arc<[GenericPredicate]> {
586 let resolver = def.resolver(db); 582 let resolver = def.resolver(db);
587 let predicates = resolver 583 resolver
588 .where_predicates_in_scope() 584 .where_predicates_in_scope()
589 .flat_map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred)) 585 .flat_map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred))
590 .collect::<Vec<_>>(); 586 .collect()
591 predicates.into()
592} 587}
593 588
594/// Resolve the default type params from generics 589/// Resolve the default type params from generics
@@ -602,9 +597,9 @@ pub(crate) fn generic_defaults_query(db: &impl HirDatabase, def: GenericDef) ->
602 .map(|p| { 597 .map(|p| {
603 p.default.as_ref().map_or(Ty::Unknown, |path| Ty::from_hir_path(db, &resolver, path)) 598 p.default.as_ref().map_or(Ty::Unknown, |path| Ty::from_hir_path(db, &resolver, path))
604 }) 599 })
605 .collect::<Vec<_>>(); 600 .collect();
606 601
607 Substs(defaults.into()) 602 Substs(defaults)
608} 603}
609 604
610fn fn_sig_for_fn(db: &impl HirDatabase, def: Function) -> FnSig { 605fn fn_sig_for_fn(db: &impl HirDatabase, def: Function) -> FnSig {
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index 25dad81eb..c12326643 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -3,7 +3,6 @@ use std::sync::Arc;
3 3
4use insta::assert_snapshot; 4use insta::assert_snapshot;
5 5
6use ra_cfg::CfgOptions;
7use ra_db::{salsa::Database, FilePosition, SourceDatabase}; 6use ra_db::{salsa::Database, FilePosition, SourceDatabase};
8use ra_syntax::{ 7use ra_syntax::{
9 algo, 8 algo,
@@ -62,7 +61,7 @@ impl S {
62"#, 61"#,
63 ); 62 );
64 db.set_crate_graph_from_fixture(crate_graph! { 63 db.set_crate_graph_from_fixture(crate_graph! {
65 "main": ("/main.rs", ["foo"], CfgOptions::default().atom("test".into())), 64 "main": ("/main.rs", ["foo"], cfg = { "test" }),
66 "foo": ("/foo.rs", []), 65 "foo": ("/foo.rs", []),
67 }); 66 });
68 assert_eq!("(i32, {unknown}, i32, {unknown})", type_at_pos(&db, pos)); 67 assert_eq!("(i32, {unknown}, i32, {unknown})", type_at_pos(&db, pos));
@@ -135,6 +134,25 @@ mod boxed {
135} 134}
136 135
137#[test] 136#[test]
137fn infer_adt_self() {
138 let (db, pos) = MockDatabase::with_position(
139 r#"
140//- /main.rs
141enum Nat { Succ(Self), Demo(Nat), Zero }
142
143fn test() {
144 let foo: Nat = Nat::Zero;
145 if let Nat::Succ(x) = foo {
146 x<|>
147 }
148}
149
150"#,
151 );
152 assert_eq!("Nat", type_at_pos(&db, pos));
153}
154
155#[test]
138fn infer_try() { 156fn infer_try() {
139 let (mut db, pos) = MockDatabase::with_position( 157 let (mut db, pos) = MockDatabase::with_position(
140 r#" 158 r#"
diff --git a/crates/ra_hir/src/ty/traits.rs b/crates/ra_hir/src/ty/traits.rs
index b0f67ae50..0cb5c3798 100644
--- a/crates/ra_hir/src/ty/traits.rs
+++ b/crates/ra_hir/src/ty/traits.rs
@@ -89,7 +89,7 @@ pub(crate) fn impls_for_trait_query(
89 } 89 }
90 let crate_impl_blocks = db.impls_in_crate(krate); 90 let crate_impl_blocks = db.impls_in_crate(krate);
91 impls.extend(crate_impl_blocks.lookup_impl_blocks_for_trait(trait_)); 91 impls.extend(crate_impl_blocks.lookup_impl_blocks_for_trait(trait_));
92 impls.into_iter().collect::<Vec<_>>().into() 92 impls.into_iter().collect()
93} 93}
94 94
95/// A set of clauses that we assume to be true. E.g. if we are inside this function: 95/// A set of clauses that we assume to be true. E.g. if we are inside this function:
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index 2642a54bf..00aaf65d9 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -126,8 +126,7 @@ impl ToChalk for Substs {
126 chalk_ir::Parameter(chalk_ir::ParameterKind::Ty(ty)) => from_chalk(db, ty), 126 chalk_ir::Parameter(chalk_ir::ParameterKind::Ty(ty)) => from_chalk(db, ty),
127 chalk_ir::Parameter(chalk_ir::ParameterKind::Lifetime(_)) => unimplemented!(), 127 chalk_ir::Parameter(chalk_ir::ParameterKind::Lifetime(_)) => unimplemented!(),
128 }) 128 })
129 .collect::<Vec<_>>() 129 .collect();
130 .into();
131 Substs(tys) 130 Substs(tys)
132 } 131 }
133} 132}
@@ -491,15 +490,16 @@ pub(crate) fn trait_datum_query(
491 }, 490 },
492 associated_ty_ids: Vec::new(), 491 associated_ty_ids: Vec::new(),
493 where_clauses: Vec::new(), 492 where_clauses: Vec::new(),
494 flags: chalk_rust_ir::TraitFlags {
495 non_enumerable: true,
496 auto: false,
497 marker: false,
498 upstream: true,
499 fundamental: false,
500 },
501 }; 493 };
502 return Arc::new(TraitDatum { binders: make_binders(trait_datum_bound, 1) }); 494
495 let flags = chalk_rust_ir::TraitFlags {
496 auto: false,
497 marker: false,
498 upstream: true,
499 fundamental: false,
500 non_enumerable: true,
501 };
502 return Arc::new(TraitDatum { binders: make_binders(trait_datum_bound, 1), flags });
503 } 503 }
504 let trait_: Trait = from_chalk(db, trait_id); 504 let trait_: Trait = from_chalk(db, trait_id);
505 debug!("trait {:?} = {:?}", trait_id, trait_.name(db)); 505 debug!("trait {:?} = {:?}", trait_id, trait_.name(db));
@@ -525,8 +525,9 @@ pub(crate) fn trait_datum_query(
525 .map(|type_alias| type_alias.to_chalk(db)) 525 .map(|type_alias| type_alias.to_chalk(db))
526 .collect(); 526 .collect();
527 let trait_datum_bound = 527 let trait_datum_bound =
528 chalk_rust_ir::TraitDatumBound { trait_ref, where_clauses, flags, associated_ty_ids }; 528 chalk_rust_ir::TraitDatumBound { trait_ref, where_clauses, associated_ty_ids };
529 let trait_datum = TraitDatum { binders: make_binders(trait_datum_bound, bound_vars.len()) }; 529 let trait_datum =
530 TraitDatum { binders: make_binders(trait_datum_bound, bound_vars.len()), flags };
530 Arc::new(trait_datum) 531 Arc::new(trait_datum)
531} 532}
532 533
@@ -632,18 +633,20 @@ fn impl_block_datum(
632 }) 633 })
633 .collect(); 634 .collect();
634 635
635 let impl_datum_bound = chalk_rust_ir::ImplDatumBound { 636 let polarity = if negative {
636 trait_ref: if negative { 637 chalk_rust_ir::Polarity::Negative
637 chalk_rust_ir::PolarizedTraitRef::Negative(trait_ref) 638 } else {
638 } else { 639 chalk_rust_ir::Polarity::Positive
639 chalk_rust_ir::PolarizedTraitRef::Positive(trait_ref)
640 },
641 where_clauses,
642 associated_ty_values,
643 impl_type,
644 }; 640 };
641
642 let impl_datum_bound =
643 chalk_rust_ir::ImplDatumBound { trait_ref, where_clauses, associated_ty_values };
645 debug!("impl_datum: {:?}", impl_datum_bound); 644 debug!("impl_datum: {:?}", impl_datum_bound);
646 let impl_datum = ImplDatum { binders: make_binders(impl_datum_bound, bound_vars.len()) }; 645 let impl_datum = ImplDatum {
646 binders: make_binders(impl_datum_bound, bound_vars.len()),
647 impl_type,
648 polarity,
649 };
647 Arc::new(impl_datum) 650 Arc::new(impl_datum)
648} 651}
649 652
@@ -653,12 +656,15 @@ fn invalid_impl_datum() -> Arc<ImplDatum> {
653 parameters: vec![chalk_ir::Ty::BoundVar(0).cast()], 656 parameters: vec![chalk_ir::Ty::BoundVar(0).cast()],
654 }; 657 };
655 let impl_datum_bound = chalk_rust_ir::ImplDatumBound { 658 let impl_datum_bound = chalk_rust_ir::ImplDatumBound {
656 trait_ref: chalk_rust_ir::PolarizedTraitRef::Positive(trait_ref), 659 trait_ref,
657 where_clauses: Vec::new(), 660 where_clauses: Vec::new(),
658 associated_ty_values: Vec::new(), 661 associated_ty_values: Vec::new(),
662 };
663 let impl_datum = ImplDatum {
664 binders: make_binders(impl_datum_bound, 1),
659 impl_type: chalk_rust_ir::ImplType::External, 665 impl_type: chalk_rust_ir::ImplType::External,
666 polarity: chalk_rust_ir::Polarity::Positive,
660 }; 667 };
661 let impl_datum = ImplDatum { binders: make_binders(impl_datum_bound, 1) };
662 Arc::new(impl_datum) 668 Arc::new(impl_datum)
663} 669}
664 670
@@ -713,12 +719,15 @@ fn closure_fn_trait_impl_datum(
713 let impl_type = chalk_rust_ir::ImplType::External; 719 let impl_type = chalk_rust_ir::ImplType::External;
714 720
715 let impl_datum_bound = chalk_rust_ir::ImplDatumBound { 721 let impl_datum_bound = chalk_rust_ir::ImplDatumBound {
716 trait_ref: chalk_rust_ir::PolarizedTraitRef::Positive(trait_ref.to_chalk(db)), 722 trait_ref: trait_ref.to_chalk(db),
717 where_clauses: Vec::new(), 723 where_clauses: Vec::new(),
718 associated_ty_values: vec![output_ty_value], 724 associated_ty_values: vec![output_ty_value],
725 };
726 let impl_datum = ImplDatum {
727 binders: make_binders(impl_datum_bound, num_args as usize + 1),
719 impl_type, 728 impl_type,
729 polarity: chalk_rust_ir::Polarity::Positive,
720 }; 730 };
721 let impl_datum = ImplDatum { binders: make_binders(impl_datum_bound, num_args as usize + 1) };
722 Some(Arc::new(impl_datum)) 731 Some(Arc::new(impl_datum))
723} 732}
724 733
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-15 14:53:23 +0100