Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/infer/expr.rs')
| -rw-r--r-- | crates/hir-ty/src/infer/expr.rs | 776 |
1 files changed, 491 insertions, 285 deletions
diff --git a/crates/hir-ty/src/infer/expr.rs b/crates/hir-ty/src/infer/expr.rs index 175fded8cc..535189ff02 100644 --- a/crates/hir-ty/src/infer/expr.rs +++ b/crates/hir-ty/src/infer/expr.rs @@ -15,7 +15,6 @@ use hir_def::{ generics::TypeOrConstParamData, lang_item::LangItem, path::{GenericArg, GenericArgs}, - resolver::resolver_for_expr, ConstParamId, FieldId, ItemContainerId, Lookup, }; use hir_expand::name::{name, Name}; @@ -25,7 +24,9 @@ use syntax::ast::RangeOp; use crate::{ autoderef::{self, Autoderef}, consteval, - infer::{coerce::CoerceMany, find_continuable, BreakableKind}, + infer::{ + coerce::CoerceMany, find_continuable, pat::contains_explicit_ref_binding, BreakableKind, + }, lower::{ const_or_path_to_chalk, generic_arg_to_chalk, lower_to_chalk_mutability, ParamLoweringMode, }, @@ -39,8 +40,8 @@ use crate::{ }; use super::{ - coerce::auto_deref_adjust_steps, find_breakable, BindingMode, BreakableContext, Diverges, - Expectation, InferenceContext, InferenceDiagnostic, TypeMismatch, + coerce::auto_deref_adjust_steps, find_breakable, BreakableContext, Diverges, Expectation, + InferenceContext, InferenceDiagnostic, TypeMismatch, }; impl<'a> InferenceContext<'a> { @@ -58,6 +59,10 @@ impl<'a> InferenceContext<'a> { ty } + pub(crate) fn infer_expr_no_expect(&mut self, tgt_expr: ExprId) -> Ty { + self.infer_expr_inner(tgt_expr, &Expectation::None) + } + /// Infer type of expression with possibly implicit coerce to the expected type. /// Return the type after possible coercion. pub(super) fn infer_expr_coerce(&mut self, expr: ExprId, expected: &Expectation) -> Ty { @@ -78,6 +83,30 @@ impl<'a> InferenceContext<'a> { } } + pub(super) fn infer_expr_coerce_never(&mut self, expr: ExprId, expected: &Expectation) -> Ty { + let ty = self.infer_expr_inner(expr, expected); + // While we don't allow *arbitrary* coercions here, we *do* allow + // coercions from ! to `expected`. + if ty.is_never() { + if let Some(adjustments) = self.result.expr_adjustments.get(&expr) { + return if let [Adjustment { kind: Adjust::NeverToAny, target }] = &**adjustments { + target.clone() + } else { + self.err_ty() + }; + } + + let adj_ty = self.table.new_type_var(); + self.write_expr_adj( + expr, + vec![Adjustment { kind: Adjust::NeverToAny, target: adj_ty.clone() }], + ); + adj_ty + } else { + ty + } + } + fn infer_expr_inner(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty { self.db.unwind_if_cancelled(); @@ -85,7 +114,7 @@ impl<'a> InferenceContext<'a> { Expr::Missing => self.err_ty(), &Expr::If { condition, then_branch, else_branch } => { let expected = &expected.adjust_for_branches(&mut self.table); - self.infer_expr( + self.infer_expr_coerce_never( condition, &Expectation::HasType(self.result.standard_types.bool_.clone()), ); @@ -97,59 +126,39 @@ impl<'a> InferenceContext<'a> { both_arms_diverge &= mem::replace(&mut self.diverges, Diverges::Maybe); let mut coerce = CoerceMany::new(expected.coercion_target_type(&mut self.table)); coerce.coerce(self, Some(then_branch), &then_ty); - let else_ty = match else_branch { - Some(else_branch) => self.infer_expr_inner(else_branch, expected), - None => TyBuilder::unit(), - }; + match else_branch { + Some(else_branch) => { + let else_ty = self.infer_expr_inner(else_branch, expected); + coerce.coerce(self, Some(else_branch), &else_ty); + } + None => { + coerce.coerce_forced_unit(self); + } + } both_arms_diverge &= self.diverges; - // FIXME: create a synthetic `else {}` so we have something to refer to here instead of None? - coerce.coerce(self, else_branch, &else_ty); self.diverges = condition_diverges | both_arms_diverge; - coerce.complete() + coerce.complete(self) } &Expr::Let { pat, expr } => { let input_ty = self.infer_expr(expr, &Expectation::none()); - self.infer_pat(pat, &input_ty, BindingMode::default()); + self.infer_top_pat(pat, &input_ty); self.result.standard_types.bool_.clone() } Expr::Block { statements, tail, label, id: _ } => { - let old_resolver = mem::replace( - &mut self.resolver, - resolver_for_expr(self.db.upcast(), self.owner, tgt_expr), - ); - let ty = match label { - Some(_) => { - let break_ty = self.table.new_type_var(); - let (breaks, ty) = self.with_breakable_ctx( - BreakableKind::Block, - break_ty.clone(), - *label, - |this| { - this.infer_block( - tgt_expr, - statements, - *tail, - &Expectation::has_type(break_ty), - ) - }, - ); - breaks.unwrap_or(ty) - } - None => self.infer_block(tgt_expr, statements, *tail, expected), - }; - self.resolver = old_resolver; - ty + self.infer_block(tgt_expr, statements, *tail, *label, expected) + } + Expr::Unsafe { id: _, statements, tail } => { + self.infer_block(tgt_expr, statements, *tail, None, expected) } - Expr::Unsafe { body } => self.infer_expr(*body, expected), - Expr::Const { body } => { - self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| { - this.infer_expr(*body, expected) + Expr::Const { id: _, statements, tail } => { + self.with_breakable_ctx(BreakableKind::Border, None, None, |this| { + this.infer_block(tgt_expr, statements, *tail, None, expected) }) .1 } - Expr::TryBlock { body } => { + Expr::TryBlock { id: _, statements, tail } => { // The type that is returned from the try block let try_ty = self.table.new_type_var(); if let Some(ty) = expected.only_has_type(&mut self.table) { @@ -160,28 +169,41 @@ impl<'a> InferenceContext<'a> { let ok_ty = self.resolve_associated_type(try_ty.clone(), self.resolve_ops_try_output()); - self.with_breakable_ctx(BreakableKind::Block, ok_ty.clone(), None, |this| { - this.infer_expr(*body, &Expectation::has_type(ok_ty)); - }); - + self.infer_block( + tgt_expr, + statements, + *tail, + None, + &Expectation::has_type(ok_ty.clone()), + ); try_ty } - Expr::Async { body } => { + Expr::Async { id: _, statements, tail } => { let ret_ty = self.table.new_type_var(); let prev_diverges = mem::replace(&mut self.diverges, Diverges::Maybe); let prev_ret_ty = mem::replace(&mut self.return_ty, ret_ty.clone()); + let prev_ret_coercion = + mem::replace(&mut self.return_coercion, Some(CoerceMany::new(ret_ty.clone()))); let (_, inner_ty) = - self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| { - this.infer_expr_coerce(*body, &Expectation::has_type(ret_ty)) + self.with_breakable_ctx(BreakableKind::Border, None, None, |this| { + this.infer_block( + tgt_expr, + statements, + *tail, + None, + &Expectation::has_type(ret_ty), + ) }); self.diverges = prev_diverges; self.return_ty = prev_ret_ty; + self.return_coercion = prev_ret_coercion; // Use the first type parameter as the output type of future. // existential type AsyncBlockImplTrait<InnerType>: Future<Output = InnerType> - let impl_trait_id = crate::ImplTraitId::AsyncBlockTypeImplTrait(self.owner, *body); + let impl_trait_id = + crate::ImplTraitId::AsyncBlockTypeImplTrait(self.owner, tgt_expr); let opaque_ty_id = self.db.intern_impl_trait_id(impl_trait_id).into(); TyKind::OpaqueType(opaque_ty_id, Substitution::from1(Interner, inner_ty)) .intern(Interner) @@ -191,7 +213,7 @@ impl<'a> InferenceContext<'a> { // let ty = expected.coercion_target_type(&mut self.table); let ty = self.table.new_type_var(); let (breaks, ()) = - self.with_breakable_ctx(BreakableKind::Loop, ty, label, |this| { + self.with_breakable_ctx(BreakableKind::Loop, Some(ty), label, |this| { this.infer_expr(body, &Expectation::HasType(TyBuilder::unit())); }); @@ -204,7 +226,7 @@ impl<'a> InferenceContext<'a> { } } &Expr::While { condition, body, label } => { - self.with_breakable_ctx(BreakableKind::Loop, self.err_ty(), label, |this| { + self.with_breakable_ctx(BreakableKind::Loop, None, label, |this| { this.infer_expr( condition, &Expectation::HasType(this.result.standard_types.bool_.clone()), @@ -220,11 +242,13 @@ impl<'a> InferenceContext<'a> { let iterable_ty = self.infer_expr(iterable, &Expectation::none()); let into_iter_ty = self.resolve_associated_type(iterable_ty, self.resolve_into_iter_item()); - let pat_ty = - self.resolve_associated_type(into_iter_ty, self.resolve_iterator_item()); + let pat_ty = self + .resolve_associated_type(into_iter_ty.clone(), self.resolve_iterator_item()); + + self.result.type_of_for_iterator.insert(tgt_expr, into_iter_ty); - self.infer_pat(pat, &pat_ty, BindingMode::default()); - self.with_breakable_ctx(BreakableKind::Loop, self.err_ty(), label, |this| { + self.infer_top_pat(pat, &pat_ty); + self.with_breakable_ctx(BreakableKind::Loop, None, label, |this| { this.infer_expr(body, &Expectation::HasType(TyBuilder::unit())); }); @@ -298,20 +322,24 @@ impl<'a> InferenceContext<'a> { // Now go through the argument patterns for (arg_pat, arg_ty) in args.iter().zip(sig_tys) { - self.infer_pat(*arg_pat, &arg_ty, BindingMode::default()); + self.infer_top_pat(*arg_pat, &arg_ty); } + // FIXME: lift these out into a struct let prev_diverges = mem::replace(&mut self.diverges, Diverges::Maybe); let prev_ret_ty = mem::replace(&mut self.return_ty, ret_ty.clone()); + let prev_ret_coercion = + mem::replace(&mut self.return_coercion, Some(CoerceMany::new(ret_ty.clone()))); let prev_resume_yield_tys = mem::replace(&mut self.resume_yield_tys, resume_yield_tys); - self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| { - this.infer_expr_coerce(*body, &Expectation::has_type(ret_ty)); + self.with_breakable_ctx(BreakableKind::Border, None, None, |this| { + this.infer_return(*body); }); self.diverges = prev_diverges; self.return_ty = prev_ret_ty; + self.return_coercion = prev_ret_coercion; self.resume_yield_tys = prev_resume_yield_tys; ty @@ -348,7 +376,13 @@ impl<'a> InferenceContext<'a> { } (params, ret_ty) } - None => (Vec::new(), self.err_ty()), // FIXME diagnostic + None => { + self.result.diagnostics.push(InferenceDiagnostic::ExpectedFunction { + call_expr: tgt_expr, + found: callee_ty.clone(), + }); + (Vec::new(), self.err_ty()) + } }; let indices_to_skip = self.check_legacy_const_generics(derefed_callee, args); self.register_obligations_for_call(&callee_ty); @@ -381,92 +415,109 @@ impl<'a> InferenceContext<'a> { Expr::Match { expr, arms } => { let input_ty = self.infer_expr(*expr, &Expectation::none()); - let expected = expected.adjust_for_branches(&mut self.table); - - let result_ty = if arms.is_empty() { + if arms.is_empty() { + self.diverges = Diverges::Always; self.result.standard_types.never.clone() } else { - expected.coercion_target_type(&mut self.table) - }; - let mut coerce = CoerceMany::new(result_ty); - - let matchee_diverges = self.diverges; - let mut all_arms_diverge = Diverges::Always; - - for arm in arms.iter() { - self.diverges = Diverges::Maybe; - let _pat_ty = self.infer_pat(arm.pat, &input_ty, BindingMode::default()); - if let Some(guard_expr) = arm.guard { - self.infer_expr( - guard_expr, - &Expectation::HasType(self.result.standard_types.bool_.clone()), - ); + let matchee_diverges = mem::replace(&mut self.diverges, Diverges::Maybe); + let mut all_arms_diverge = Diverges::Always; + for arm in arms.iter() { + let input_ty = self.resolve_ty_shallow(&input_ty); + self.infer_top_pat(arm.pat, &input_ty); } - let arm_ty = self.infer_expr_inner(arm.expr, &expected); - all_arms_diverge &= self.diverges; - coerce.coerce(self, Some(arm.expr), &arm_ty); - } + let expected = expected.adjust_for_branches(&mut self.table); + let result_ty = match &expected { + // We don't coerce to `()` so that if the match expression is a + // statement it's branches can have any consistent type. + Expectation::HasType(ty) if *ty != self.result.standard_types.unit => { + ty.clone() + } + _ => self.table.new_type_var(), + }; + let mut coerce = CoerceMany::new(result_ty); + + for arm in arms.iter() { + if let Some(guard_expr) = arm.guard { + self.diverges = Diverges::Maybe; + self.infer_expr_coerce_never( + guard_expr, + &Expectation::HasType(self.result.standard_types.bool_.clone()), + ); + } + self.diverges = Diverges::Maybe; + + let arm_ty = self.infer_expr_inner(arm.expr, &expected); + all_arms_diverge &= self.diverges; + coerce.coerce(self, Some(arm.expr), &arm_ty); + } - self.diverges = matchee_diverges | all_arms_diverge; + self.diverges = matchee_diverges | all_arms_diverge; - coerce.complete() + coerce.complete(self) + } } Expr::Path(p) => { - // FIXME this could be more efficient... - let resolver = resolver_for_expr(self.db.upcast(), self.owner, tgt_expr); - self.infer_path(&resolver, p, tgt_expr.into()).unwrap_or_else(|| self.err_ty()) + let g = self.resolver.update_to_inner_scope(self.db.upcast(), self.owner, tgt_expr); + let ty = self.infer_path(p, tgt_expr.into()).unwrap_or_else(|| self.err_ty()); + self.resolver.reset_to_guard(g); + ty } Expr::Continue { label } => { if let None = find_continuable(&mut self.breakables, label.as_ref()) { self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop { expr: tgt_expr, is_break: false, + bad_value_break: false, }); }; self.result.standard_types.never.clone() } Expr::Break { expr, label } => { let val_ty = if let Some(expr) = *expr { - self.infer_expr(expr, &Expectation::none()) + let opt_coerce_to = match find_breakable(&mut self.breakables, label.as_ref()) { + Some(ctxt) => match &ctxt.coerce { + Some(coerce) => coerce.expected_ty(), + None => { + self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop { + expr: tgt_expr, + is_break: true, + bad_value_break: true, + }); + self.err_ty() + } + }, + None => self.err_ty(), + }; + self.infer_expr_inner(expr, &Expectation::HasType(opt_coerce_to)) } else { TyBuilder::unit() }; match find_breakable(&mut self.breakables, label.as_ref()) { - Some(ctxt) => { - // avoiding the borrowck - let mut coerce = mem::replace( - &mut ctxt.coerce, - CoerceMany::new(expected.coercion_target_type(&mut self.table)), - ); - - // FIXME: create a synthetic `()` during lowering so we have something to refer to here? - coerce.coerce(self, *expr, &val_ty); - - let ctxt = find_breakable(&mut self.breakables, label.as_ref()) - .expect("breakable stack changed during coercion"); - ctxt.coerce = coerce; - ctxt.may_break = true; - } + Some(ctxt) => match ctxt.coerce.take() { + Some(mut coerce) => { + coerce.coerce(self, *expr, &val_ty); + + // Avoiding borrowck + let ctxt = find_breakable(&mut self.breakables, label.as_ref()) + .expect("breakable stack changed during coercion"); + ctxt.may_break = true; + ctxt.coerce = Some(coerce); + } + None => ctxt.may_break = true, + }, None => { self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop { expr: tgt_expr, is_break: true, + bad_value_break: false, }); } } self.result.standard_types.never.clone() } - Expr::Return { expr } => { - if let Some(expr) = expr { - self.infer_expr_coerce(*expr, &Expectation::has_type(self.return_ty.clone())); - } else { - let unit = TyBuilder::unit(); - let _ = self.coerce(Some(tgt_expr), &unit, &self.return_ty.clone()); - } - self.result.standard_types.never.clone() - } + &Expr::Return { expr } => self.infer_expr_return(expr), Expr::Yield { expr } => { if let Some((resume_ty, yield_ty)) = self.resume_yield_tys.clone() { if let Some(expr) = expr { @@ -483,7 +534,7 @@ impl<'a> InferenceContext<'a> { } Expr::Yeet { expr } => { if let &Some(expr) = expr { - self.infer_expr_inner(expr, &Expectation::None); + self.infer_expr_no_expect(expr); } self.result.standard_types.never.clone() } @@ -524,71 +575,7 @@ impl<'a> InferenceContext<'a> { } ty } - Expr::Field { expr, name } => { - let receiver_ty = self.infer_expr_inner(*expr, &Expectation::none()); - - let mut autoderef = Autoderef::new(&mut self.table, receiver_ty); - let mut private_field = None; - let ty = autoderef.by_ref().find_map(|(derefed_ty, _)| { - let (field_id, parameters) = match derefed_ty.kind(Interner) { - TyKind::Tuple(_, substs) => { - return name.as_tuple_index().and_then(|idx| { - substs - .as_slice(Interner) - .get(idx) - .map(|a| a.assert_ty_ref(Interner)) - .cloned() - }); - } - TyKind::Adt(AdtId(hir_def::AdtId::StructId(s)), parameters) => { - let local_id = self.db.struct_data(*s).variant_data.field(name)?; - let field = FieldId { parent: (*s).into(), local_id }; - (field, parameters.clone()) - } - TyKind::Adt(AdtId(hir_def::AdtId::UnionId(u)), parameters) => { - let local_id = self.db.union_data(*u).variant_data.field(name)?; - let field = FieldId { parent: (*u).into(), local_id }; - (field, parameters.clone()) - } - _ => return None, - }; - let is_visible = self.db.field_visibilities(field_id.parent)[field_id.local_id] - .is_visible_from(self.db.upcast(), self.resolver.module()); - if !is_visible { - if private_field.is_none() { - private_field = Some(field_id); - } - return None; - } - // can't have `write_field_resolution` here because `self.table` is borrowed :( - self.result.field_resolutions.insert(tgt_expr, field_id); - let ty = self.db.field_types(field_id.parent)[field_id.local_id] - .clone() - .substitute(Interner, ¶meters); - Some(ty) - }); - let ty = match ty { - Some(ty) => { - let adjustments = auto_deref_adjust_steps(&autoderef); - self.write_expr_adj(*expr, adjustments); - let ty = self.insert_type_vars(ty); - let ty = self.normalize_associated_types_in(ty); - ty - } - _ => { - // Write down the first private field resolution if we found no field - // This aids IDE features for private fields like goto def - if let Some(field) = private_field { - self.result.field_resolutions.insert(tgt_expr, field); - self.result - .diagnostics - .push(InferenceDiagnostic::PrivateField { expr: tgt_expr, field }); - } - self.err_ty() - } - }; - ty - } + Expr::Field { expr, name } => self.infer_field_access(tgt_expr, *expr, name), Expr::Await { expr } => { let inner_ty = self.infer_expr_inner(*expr, &Expectation::none()); self.resolve_associated_type(inner_ty, self.resolve_future_future_output()) @@ -611,7 +598,7 @@ impl<'a> InferenceContext<'a> { Expr::Cast { expr, type_ref } => { let cast_ty = self.make_ty(type_ref); // FIXME: propagate the "castable to" expectation - let _inner_ty = self.infer_expr_inner(*expr, &Expectation::None); + let _inner_ty = self.infer_expr_no_expect(*expr); // FIXME check the cast... cast_ty } @@ -807,49 +794,7 @@ impl<'a> InferenceContext<'a> { TyKind::Tuple(tys.len(), Substitution::from_iter(Interner, tys)).intern(Interner) } - Expr::Array(array) => { - let elem_ty = - match expected.to_option(&mut self.table).as_ref().map(|t| t.kind(Interner)) { - Some(TyKind::Array(st, _) | TyKind::Slice(st)) => st.clone(), - _ => self.table.new_type_var(), - }; - let mut coerce = CoerceMany::new(elem_ty.clone()); - - let expected = Expectation::has_type(elem_ty.clone()); - let len = match array { - Array::ElementList { elements, .. } => { - for &expr in elements.iter() { - let cur_elem_ty = self.infer_expr_inner(expr, &expected); - coerce.coerce(self, Some(expr), &cur_elem_ty); - } - consteval::usize_const(Some(elements.len() as u128)) - } - &Array::Repeat { initializer, repeat } => { - self.infer_expr_coerce(initializer, &Expectation::has_type(elem_ty)); - self.infer_expr( - repeat, - &Expectation::HasType( - TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(Interner), - ), - ); - - if let Some(g_def) = self.owner.as_generic_def_id() { - let generics = generics(self.db.upcast(), g_def); - consteval::eval_to_const( - repeat, - ParamLoweringMode::Placeholder, - self, - || generics, - DebruijnIndex::INNERMOST, - ) - } else { - consteval::usize_const(None) - } - } - }; - - TyKind::Array(coerce.complete(), len).intern(Interner) - } + Expr::Array(array) => self.infer_expr_array(array, expected), Expr::Literal(lit) => match lit { Literal::Bool(..) => self.result.standard_types.bool_.clone(), Literal::String(..) => { @@ -859,7 +804,11 @@ impl<'a> InferenceContext<'a> { Literal::ByteString(bs) => { let byte_type = TyKind::Scalar(Scalar::Uint(UintTy::U8)).intern(Interner); - let len = consteval::usize_const(Some(bs.len() as u128)); + let len = consteval::usize_const( + self.db, + Some(bs.len() as u128), + self.resolver.krate(), + ); let array_type = TyKind::Array(byte_type, len).intern(Interner); TyKind::Ref(Mutability::Not, static_lifetime(), array_type).intern(Interner) @@ -904,6 +853,97 @@ impl<'a> InferenceContext<'a> { ty } + fn infer_expr_array( + &mut self, + array: &Array, + expected: &Expectation, + ) -> chalk_ir::Ty<Interner> { + let elem_ty = match expected.to_option(&mut self.table).as_ref().map(|t| t.kind(Interner)) { + Some(TyKind::Array(st, _) | TyKind::Slice(st)) => st.clone(), + _ => self.table.new_type_var(), + }; + + let krate = self.resolver.krate(); + + let expected = Expectation::has_type(elem_ty.clone()); + let (elem_ty, len) = match array { + Array::ElementList { elements, .. } if elements.is_empty() => { + (elem_ty, consteval::usize_const(self.db, Some(0), krate)) + } + Array::ElementList { elements, .. } => { + let mut coerce = CoerceMany::new(elem_ty.clone()); + for &expr in elements.iter() { + let cur_elem_ty = self.infer_expr_inner(expr, &expected); + coerce.coerce(self, Some(expr), &cur_elem_ty); + } + ( + coerce.complete(self), + consteval::usize_const(self.db, Some(elements.len() as u128), krate), + ) + } + &Array::Repeat { initializer, repeat } => { + self.infer_expr_coerce(initializer, &Expectation::has_type(elem_ty.clone())); + self.infer_expr( + repeat, + &Expectation::HasType( + TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(Interner), + ), + ); + + ( + elem_ty, + if let Some(g_def) = self.owner.as_generic_def_id() { + let generics = generics(self.db.upcast(), g_def); + consteval::eval_to_const( + repeat, + ParamLoweringMode::Placeholder, + self, + || generics, + DebruijnIndex::INNERMOST, + ) + } else { + consteval::usize_const(self.db, None, krate) + }, + ) + } + }; + + TyKind::Array(elem_ty, len).intern(Interner) + } + + pub(super) fn infer_return(&mut self, expr: ExprId) { + let ret_ty = self + .return_coercion + .as_mut() + .expect("infer_return called outside function body") + .expected_ty(); + let return_expr_ty = self.infer_expr_inner(expr, &Expectation::HasType(ret_ty)); + let mut coerce_many = self.return_coercion.take().unwrap(); + coerce_many.coerce(self, Some(expr), &return_expr_ty); + self.return_coercion = Some(coerce_many); + } + + fn infer_expr_return(&mut self, expr: Option<ExprId>) -> Ty { + match self.return_coercion { + Some(_) => { + if let Some(expr) = expr { + self.infer_return(expr); + } else { + let mut coerce = self.return_coercion.take().unwrap(); + coerce.coerce_forced_unit(self); + self.return_coercion = Some(coerce); + } + } + None => { + // FIXME: diagnose return outside of function + if let Some(expr) = expr { + self.infer_expr_no_expect(expr); + } + } + } + self.result.standard_types.never.clone() + } + fn infer_expr_box(&mut self, inner_expr: ExprId, expected: &Expectation) -> Ty { if let Some(box_id) = self.resolve_boxed_box() { let table = &mut self.table; @@ -982,8 +1022,11 @@ impl<'a> InferenceContext<'a> { // type and length). This should not be just an error type, // because we are to compute the unifiability of this type and // `rhs_ty` in the end of this function to issue type mismatches. - _ => TyKind::Array(self.err_ty(), crate::consteval::usize_const(None)) - .intern(Interner), + _ => TyKind::Array( + self.err_ty(), + crate::consteval::usize_const(self.db, None, self.resolver.krate()), + ) + .intern(Interner), } } Expr::RecordLit { path, fields, .. } => { @@ -1123,65 +1166,211 @@ impl<'a> InferenceContext<'a> { expr: ExprId, statements: &[Statement], tail: Option<ExprId>, + label: Option<LabelId>, expected: &Expectation, ) -> Ty { - for stmt in statements { - match stmt { - Statement::Let { pat, type_ref, initializer, else_branch } => { - let decl_ty = type_ref - .as_ref() - .map(|tr| self.make_ty(tr)) - .unwrap_or_else(|| self.err_ty()); - - // Always use the declared type when specified - let mut ty = decl_ty.clone(); - - if let Some(expr) = initializer { - let actual_ty = - self.infer_expr_coerce(*expr, &Expectation::has_type(decl_ty.clone())); - if decl_ty.is_unknown() { - ty = actual_ty; + let coerce_ty = expected.coercion_target_type(&mut self.table); + let g = self.resolver.update_to_inner_scope(self.db.upcast(), self.owner, expr); + + let (break_ty, ty) = + self.with_breakable_ctx(BreakableKind::Block, Some(coerce_ty.clone()), label, |this| { + for stmt in statements { + match stmt { + Statement::Let { pat, type_ref, initializer, else_branch } => { + let decl_ty = type_ref + .as_ref() + .map(|tr| this.make_ty(tr)) + .unwrap_or_else(|| this.table.new_type_var()); + + let ty = if let Some(expr) = initializer { + let ty = if contains_explicit_ref_binding(&this.body, *pat) { + this.infer_expr(*expr, &Expectation::has_type(decl_ty.clone())) + } else { + this.infer_expr_coerce( + *expr, + &Expectation::has_type(decl_ty.clone()), + ) + }; + if type_ref.is_some() { + decl_ty + } else { + ty + } + } else { + decl_ty + }; + + this.infer_top_pat(*pat, &ty); + + if let Some(expr) = else_branch { + let previous_diverges = + mem::replace(&mut this.diverges, Diverges::Maybe); + this.infer_expr_coerce( + *expr, + &Expectation::HasType(this.result.standard_types.never.clone()), + ); + this.diverges = previous_diverges; + } + } + &Statement::Expr { expr, has_semi } => { + if has_semi { + this.infer_expr(expr, &Expectation::none()); + } else { + this.infer_expr_coerce( + expr, + &Expectation::HasType(this.result.standard_types.unit.clone()), + ); + } } } + } - if let Some(expr) = else_branch { - self.infer_expr_coerce( - *expr, - &Expectation::HasType(self.result.standard_types.never.clone()), - ); + // FIXME: This should make use of the breakable CoerceMany + if let Some(expr) = tail { + this.infer_expr_coerce(expr, expected) + } else { + // Citing rustc: if there is no explicit tail expression, + // that is typically equivalent to a tail expression + // of `()` -- except if the block diverges. In that + // case, there is no value supplied from the tail + // expression (assuming there are no other breaks, + // this implies that the type of the block will be + // `!`). + if this.diverges.is_always() { + // we don't even make an attempt at coercion + this.table.new_maybe_never_var() + } else if let Some(t) = expected.only_has_type(&mut this.table) { + if this + .coerce(Some(expr), &this.result.standard_types.unit.clone(), &t) + .is_err() + { + this.result.type_mismatches.insert( + expr.into(), + TypeMismatch { + expected: t.clone(), + actual: this.result.standard_types.unit.clone(), + }, + ); + } + t + } else { + this.result.standard_types.unit.clone() } + } + }); + self.resolver.reset_to_guard(g); + + break_ty.unwrap_or(ty) + } - self.infer_pat(*pat, &ty, BindingMode::default()); + fn lookup_field( + &mut self, + receiver_ty: &Ty, + name: &Name, + ) -> Option<(Ty, Option<FieldId>, Vec<Adjustment>, bool)> { + let mut autoderef = Autoderef::new(&mut self.table, receiver_ty.clone()); + let mut private_field = None; + let res = autoderef.by_ref().find_map(|(derefed_ty, _)| { + let (field_id, parameters) = match derefed_ty.kind(Interner) { + TyKind::Tuple(_, substs) => { + return name.as_tuple_index().and_then(|idx| { + substs + .as_slice(Interner) + .get(idx) + .map(|a| a.assert_ty_ref(Interner)) + .cloned() + .map(|ty| (None, ty)) + }); } - Statement::Expr { expr, .. } => { - self.infer_expr(*expr, &Expectation::none()); + TyKind::Adt(AdtId(hir_def::AdtId::StructId(s)), parameters) => { + let local_id = self.db.struct_data(*s).variant_data.field(name)?; + let field = FieldId { parent: (*s).into(), local_id }; + (field, parameters.clone()) } + TyKind::Adt(AdtId(hir_def::AdtId::UnionId(u)), parameters) => { + let local_id = self.db.union_data(*u).variant_data.field(name)?; + let field = FieldId { parent: (*u).into(), local_id }; + (field, parameters.clone()) + } + _ => return None, + }; + let is_visible = self.db.field_visibilities(field_id.parent)[field_id.local_id] + .is_visible_from(self.db.upcast(), self.resolver.module()); + if !is_visible { + if private_field.is_none() { + private_field = Some((field_id, parameters)); + } + return None; } - } + let ty = self.db.field_types(field_id.parent)[field_id.local_id] + .clone() + .substitute(Interner, ¶meters); + Some((Some(field_id), ty)) + }); - if let Some(expr) = tail { - self.infer_expr_coerce(expr, expected) - } else { - // Citing rustc: if there is no explicit tail expression, - // that is typically equivalent to a tail expression - // of `()` -- except if the block diverges. In that - // case, there is no value supplied from the tail - // expression (assuming there are no other breaks, - // this implies that the type of the block will be - // `!`). - if self.diverges.is_always() { - // we don't even make an attempt at coercion - self.table.new_maybe_never_var() - } else if let Some(t) = expected.only_has_type(&mut self.table) { - if self.coerce(Some(expr), &TyBuilder::unit(), &t).is_err() { - self.result.type_mismatches.insert( - expr.into(), - TypeMismatch { expected: t.clone(), actual: TyBuilder::unit() }, - ); + Some(match res { + Some((field_id, ty)) => { + let adjustments = auto_deref_adjust_steps(&autoderef); + let ty = self.insert_type_vars(ty); + let ty = self.normalize_associated_types_in(ty); + + (ty, field_id, adjustments, true) + } + None => { + let (field_id, subst) = private_field?; + let adjustments = auto_deref_adjust_steps(&autoderef); + let ty = self.db.field_types(field_id.parent)[field_id.local_id] + .clone() + .substitute(Interner, &subst); + let ty = self.insert_type_vars(ty); + let ty = self.normalize_associated_types_in(ty); + + (ty, Some(field_id), adjustments, false) + } + }) + } + + fn infer_field_access(&mut self, tgt_expr: ExprId, receiver: ExprId, name: &Name) -> Ty { + let receiver_ty = self.infer_expr_inner(receiver, &Expectation::none()); + match self.lookup_field(&receiver_ty, name) { + Some((ty, field_id, adjustments, is_public)) => { + self.write_expr_adj(receiver, adjustments); + if let Some(field_id) = field_id { + self.result.field_resolutions.insert(tgt_expr, field_id); } - t - } else { - TyBuilder::unit() + if !is_public { + if let Some(field) = field_id { + // FIXME: Merge this diagnostic into UnresolvedField? + self.result + .diagnostics + .push(InferenceDiagnostic::PrivateField { expr: tgt_expr, field }); + } + } + ty + } + None => { + // no field found, + let method_with_same_name_exists = { + self.get_traits_in_scope(); + + let canonicalized_receiver = self.canonicalize(receiver_ty.clone()); + method_resolution::lookup_method( + self.db, + &canonicalized_receiver.value, + self.trait_env.clone(), + self.get_traits_in_scope().as_ref().left_or_else(|&it| it), + VisibleFromModule::Filter(self.resolver.module()), + name, + ) + .is_some() + }; + self.result.diagnostics.push(InferenceDiagnostic::UnresolvedField { + expr: tgt_expr, + receiver: receiver_ty, + name: name.clone(), + method_with_same_name_exists, + }); + self.err_ty() } } } @@ -1198,13 +1387,11 @@ impl<'a> InferenceContext<'a> { let receiver_ty = self.infer_expr(receiver, &Expectation::none()); let canonicalized_receiver = self.canonicalize(receiver_ty.clone()); - let traits_in_scope = self.resolver.traits_in_scope(self.db.upcast()); - let resolved = method_resolution::lookup_method( self.db, &canonicalized_receiver.value, self.trait_env.clone(), - &traits_in_scope, + self.get_traits_in_scope().as_ref().left_or_else(|&it| it), VisibleFromModule::Filter(self.resolver.module()), method_name, ); @@ -1223,11 +1410,30 @@ impl<'a> InferenceContext<'a> { } (ty, self.db.value_ty(func.into()), substs) } - None => ( - receiver_ty, - Binders::empty(Interner, self.err_ty()), - Substitution::empty(Interner), - ), + None => { + let field_with_same_name_exists = match self.lookup_field(&receiver_ty, method_name) + { + Some((ty, field_id, adjustments, _public)) => { + self.write_expr_adj(receiver, adjustments); + if let Some(field_id) = field_id { + self.result.field_resolutions.insert(tgt_expr, field_id); + } + Some(ty) + } + None => None, + }; + self.result.diagnostics.push(InferenceDiagnostic::UnresolvedMethodCall { + expr: tgt_expr, + receiver: receiver_ty.clone(), + name: method_name.clone(), + field_with_same_name: field_with_same_name_exists, + }); + ( + receiver_ty, + Binders::empty(Interner, self.err_ty()), + Substitution::empty(Interner), + ) + } }; let method_ty = method_ty.substitute(Interner, &substs); self.register_obligations_for_call(&method_ty); @@ -1636,16 +1842,16 @@ impl<'a> InferenceContext<'a> { fn with_breakable_ctx<T>( &mut self, kind: BreakableKind, - ty: Ty, + ty: Option<Ty>, label: Option<LabelId>, cb: impl FnOnce(&mut Self) -> T, ) -> (Option<Ty>, T) { self.breakables.push({ let label = label.map(|label| self.body[label].name.clone()); - BreakableContext { kind, may_break: false, coerce: CoerceMany::new(ty), label } + BreakableContext { kind, may_break: false, coerce: ty.map(CoerceMany::new), label } }); let res = cb(self); let ctx = self.breakables.pop().expect("breakable stack broken"); - (ctx.may_break.then(|| ctx.coerce.complete()), res) + (if ctx.may_break { ctx.coerce.map(|ctx| ctx.complete(self)) } else { None }, res) } } |