diff options
Diffstat (limited to 'src/tools/rust-analyzer/crates/hir-ty/src/infer/pat.rs')
| -rw-r--r-- | src/tools/rust-analyzer/crates/hir-ty/src/infer/pat.rs | 312 |
1 files changed, 188 insertions, 124 deletions
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/infer/pat.rs b/src/tools/rust-analyzer/crates/hir-ty/src/infer/pat.rs index f154dac8e..5f839fc30 100644 --- a/src/tools/rust-analyzer/crates/hir-ty/src/infer/pat.rs +++ b/src/tools/rust-analyzer/crates/hir-ty/src/infer/pat.rs @@ -4,22 +4,57 @@ use std::iter::repeat_with; use chalk_ir::Mutability; use hir_def::{ - expr::{BindingAnnotation, Expr, Literal, Pat, PatId}, + body::Body, + expr::{Binding, BindingAnnotation, BindingId, Expr, ExprId, ExprOrPatId, Literal, Pat, PatId}, path::Path, - type_ref::ConstScalar, }; use hir_expand::name::Name; use crate::{ - consteval::intern_const_scalar, + consteval::{try_const_usize, usize_const}, infer::{BindingMode, Expectation, InferenceContext, TypeMismatch}, lower::lower_to_chalk_mutability, primitive::UintTy, - static_lifetime, ConcreteConst, ConstValue, Interner, Scalar, Substitution, Ty, TyBuilder, - TyExt, TyKind, + static_lifetime, Interner, Scalar, Substitution, Ty, TyBuilder, TyExt, TyKind, }; -use super::PatLike; +/// Used to generalize patterns and assignee expressions. +pub(super) trait PatLike: Into<ExprOrPatId> + Copy { + type BindingMode: Copy; + + fn infer( + this: &mut InferenceContext<'_>, + id: Self, + expected_ty: &Ty, + default_bm: Self::BindingMode, + ) -> Ty; +} + +impl PatLike for ExprId { + type BindingMode = (); + + fn infer( + this: &mut InferenceContext<'_>, + id: Self, + expected_ty: &Ty, + (): Self::BindingMode, + ) -> Ty { + this.infer_assignee_expr(id, expected_ty) + } +} + +impl PatLike for PatId { + type BindingMode = BindingMode; + + fn infer( + this: &mut InferenceContext<'_>, + id: Self, + expected_ty: &Ty, + default_bm: Self::BindingMode, + ) -> Ty { + this.infer_pat(id, expected_ty, default_bm) + } +} impl<'a> InferenceContext<'a> { /// Infers type for tuple struct pattern or its corresponding assignee expression. @@ -112,6 +147,7 @@ impl<'a> InferenceContext<'a> { ellipsis: Option<usize>, subs: &[T], ) -> Ty { + let expected = self.resolve_ty_shallow(expected); let expectations = match expected.as_tuple() { Some(parameters) => &*parameters.as_slice(Interner), _ => &[], @@ -145,12 +181,11 @@ impl<'a> InferenceContext<'a> { .intern(Interner) } - pub(super) fn infer_pat( - &mut self, - pat: PatId, - expected: &Ty, - mut default_bm: BindingMode, - ) -> Ty { + pub(super) fn infer_top_pat(&mut self, pat: PatId, expected: &Ty) { + self.infer_pat(pat, expected, BindingMode::default()); + } + + fn infer_pat(&mut self, pat: PatId, expected: &Ty, mut default_bm: BindingMode) -> Ty { let mut expected = self.resolve_ty_shallow(expected); if is_non_ref_pat(self.body, pat) { @@ -185,30 +220,17 @@ impl<'a> InferenceContext<'a> { self.infer_tuple_pat_like(&expected, default_bm, *ellipsis, args) } Pat::Or(pats) => { - if let Some((first_pat, rest)) = pats.split_first() { - let ty = self.infer_pat(*first_pat, &expected, default_bm); - for pat in rest { - self.infer_pat(*pat, &expected, default_bm); - } - ty - } else { - self.err_ty() + for pat in pats.iter() { + self.infer_pat(*pat, &expected, default_bm); } + expected.clone() } - Pat::Ref { pat, mutability } => { - let mutability = lower_to_chalk_mutability(*mutability); - let expectation = match expected.as_reference() { - Some((inner_ty, _lifetime, exp_mut)) => { - if mutability != exp_mut { - // FIXME: emit type error? - } - inner_ty.clone() - } - _ => self.result.standard_types.unknown.clone(), - }; - let subty = self.infer_pat(*pat, &expectation, default_bm); - TyKind::Ref(mutability, static_lifetime(), subty).intern(Interner) - } + &Pat::Ref { pat, mutability } => self.infer_ref_pat( + pat, + lower_to_chalk_mutability(mutability), + &expected, + default_bm, + ), Pat::TupleStruct { path: p, args: subpats, ellipsis } => self .infer_tuple_struct_pat_like( p.as_deref(), @@ -223,72 +245,14 @@ impl<'a> InferenceContext<'a> { self.infer_record_pat_like(p.as_deref(), &expected, default_bm, pat, subs) } Pat::Path(path) => { - // FIXME use correct resolver for the surrounding expression - let resolver = self.resolver.clone(); - self.infer_path(&resolver, path, pat.into()).unwrap_or_else(|| self.err_ty()) + // FIXME update resolver for the surrounding expression + self.infer_path(path, pat.into()).unwrap_or_else(|| self.err_ty()) } - Pat::Bind { mode, name: _, subpat } => { - let mode = if mode == &BindingAnnotation::Unannotated { - default_bm - } else { - BindingMode::convert(*mode) - }; - self.result.pat_binding_modes.insert(pat, mode); - - let inner_ty = match subpat { - Some(subpat) => self.infer_pat(*subpat, &expected, default_bm), - None => expected, - }; - let inner_ty = self.insert_type_vars_shallow(inner_ty); - - let bound_ty = match mode { - BindingMode::Ref(mutability) => { - TyKind::Ref(mutability, static_lifetime(), inner_ty.clone()) - .intern(Interner) - } - BindingMode::Move => inner_ty.clone(), - }; - self.write_pat_ty(pat, bound_ty); - return inner_ty; + Pat::Bind { id, subpat } => { + return self.infer_bind_pat(pat, *id, default_bm, *subpat, &expected); } Pat::Slice { prefix, slice, suffix } => { - let elem_ty = match expected.kind(Interner) { - TyKind::Array(st, _) | TyKind::Slice(st) => st.clone(), - _ => self.err_ty(), - }; - - for &pat_id in prefix.iter().chain(suffix.iter()) { - self.infer_pat(pat_id, &elem_ty, default_bm); - } - - if let &Some(slice_pat_id) = slice { - let rest_pat_ty = match expected.kind(Interner) { - TyKind::Array(_, length) => { - let len = match length.data(Interner).value { - ConstValue::Concrete(ConcreteConst { - interned: ConstScalar::UInt(len), - }) => len.checked_sub((prefix.len() + suffix.len()) as u128), - _ => None, - }; - TyKind::Array( - elem_ty.clone(), - intern_const_scalar( - len.map_or(ConstScalar::Unknown, |len| ConstScalar::UInt(len)), - TyBuilder::usize(), - ), - ) - } - _ => TyKind::Slice(elem_ty.clone()), - } - .intern(Interner); - self.infer_pat(slice_pat_id, &rest_pat_ty, default_bm); - } - - match expected.kind(Interner) { - TyKind::Array(_, const_) => TyKind::Array(elem_ty, const_.clone()), - _ => TyKind::Slice(elem_ty), - } - .intern(Interner) + self.infer_slice_pat(&expected, prefix, slice, suffix, default_bm) } Pat::Wild => expected.clone(), Pat::Range { start, end } => { @@ -296,27 +260,10 @@ impl<'a> InferenceContext<'a> { self.infer_expr(*end, &Expectation::has_type(start_ty)) } &Pat::Lit(expr) => { - // FIXME: using `Option` here is a workaround until we can use if-let chains in stable. - let mut pat_ty = None; - - // Like slice patterns, byte string patterns can denote both `&[u8; N]` and `&[u8]`. - if let Expr::Literal(Literal::ByteString(_)) = self.body[expr] { - if let Some((inner, ..)) = expected.as_reference() { - let inner = self.resolve_ty_shallow(inner); - if matches!(inner.kind(Interner), TyKind::Slice(_)) { - let elem_ty = TyKind::Scalar(Scalar::Uint(UintTy::U8)).intern(Interner); - let slice_ty = TyKind::Slice(elem_ty).intern(Interner); - let ty = TyKind::Ref(Mutability::Not, static_lifetime(), slice_ty) - .intern(Interner); - self.write_expr_ty(expr, ty.clone()); - pat_ty = Some(ty); - } - } - } - - pat_ty.unwrap_or_else(|| { - self.infer_expr(expr, &Expectation::has_type(expected.clone())) - }) + // Don't emit type mismatches again, the expression lowering already did that. + let ty = self.infer_lit_pat(expr, &expected); + self.write_pat_ty(pat, ty.clone()); + return ty; } Pat::Box { inner } => match self.resolve_boxed_box() { Some(box_adt) => { @@ -345,7 +292,8 @@ impl<'a> InferenceContext<'a> { }; // use a new type variable if we got error type here let ty = self.insert_type_vars_shallow(ty); - if !self.unify(&ty, &expected) { + // FIXME: This never check is odd, but required with out we do inference right now + if !expected.is_never() && !self.unify(&ty, &expected) { self.result .type_mismatches .insert(pat.into(), TypeMismatch { expected, actual: ty.clone() }); @@ -353,6 +301,111 @@ impl<'a> InferenceContext<'a> { self.write_pat_ty(pat, ty.clone()); ty } + + fn infer_ref_pat( + &mut self, + pat: PatId, + mutability: Mutability, + expected: &Ty, + default_bm: BindingMode, + ) -> Ty { + let expectation = match expected.as_reference() { + Some((inner_ty, _lifetime, _exp_mut)) => inner_ty.clone(), + _ => self.result.standard_types.unknown.clone(), + }; + let subty = self.infer_pat(pat, &expectation, default_bm); + TyKind::Ref(mutability, static_lifetime(), subty).intern(Interner) + } + + fn infer_bind_pat( + &mut self, + pat: PatId, + binding: BindingId, + default_bm: BindingMode, + subpat: Option<PatId>, + expected: &Ty, + ) -> Ty { + let Binding { mode, .. } = self.body.bindings[binding]; + let mode = if mode == BindingAnnotation::Unannotated { + default_bm + } else { + BindingMode::convert(mode) + }; + self.result.pat_binding_modes.insert(pat, mode); + + let inner_ty = match subpat { + Some(subpat) => self.infer_pat(subpat, &expected, default_bm), + None => expected.clone(), + }; + let inner_ty = self.insert_type_vars_shallow(inner_ty); + + let bound_ty = match mode { + BindingMode::Ref(mutability) => { + TyKind::Ref(mutability, static_lifetime(), inner_ty.clone()).intern(Interner) + } + BindingMode::Move => inner_ty.clone(), + }; + self.write_pat_ty(pat, bound_ty.clone()); + self.write_binding_ty(binding, bound_ty); + return inner_ty; + } + + fn infer_slice_pat( + &mut self, + expected: &Ty, + prefix: &[PatId], + slice: &Option<PatId>, + suffix: &[PatId], + default_bm: BindingMode, + ) -> Ty { + let elem_ty = match expected.kind(Interner) { + TyKind::Array(st, _) | TyKind::Slice(st) => st.clone(), + _ => self.err_ty(), + }; + + for &pat_id in prefix.iter().chain(suffix.iter()) { + self.infer_pat(pat_id, &elem_ty, default_bm); + } + + if let &Some(slice_pat_id) = slice { + let rest_pat_ty = match expected.kind(Interner) { + TyKind::Array(_, length) => { + let len = try_const_usize(length); + let len = + len.and_then(|len| len.checked_sub((prefix.len() + suffix.len()) as u128)); + TyKind::Array(elem_ty.clone(), usize_const(self.db, len, self.resolver.krate())) + } + _ => TyKind::Slice(elem_ty.clone()), + } + .intern(Interner); + self.infer_pat(slice_pat_id, &rest_pat_ty, default_bm); + } + + match expected.kind(Interner) { + TyKind::Array(_, const_) => TyKind::Array(elem_ty, const_.clone()), + _ => TyKind::Slice(elem_ty), + } + .intern(Interner) + } + + fn infer_lit_pat(&mut self, expr: ExprId, expected: &Ty) -> Ty { + // Like slice patterns, byte string patterns can denote both `&[u8; N]` and `&[u8]`. + if let Expr::Literal(Literal::ByteString(_)) = self.body[expr] { + if let Some((inner, ..)) = expected.as_reference() { + let inner = self.resolve_ty_shallow(inner); + if matches!(inner.kind(Interner), TyKind::Slice(_)) { + let elem_ty = TyKind::Scalar(Scalar::Uint(UintTy::U8)).intern(Interner); + let slice_ty = TyKind::Slice(elem_ty).intern(Interner); + let ty = + TyKind::Ref(Mutability::Not, static_lifetime(), slice_ty).intern(Interner); + self.write_expr_ty(expr, ty.clone()); + return ty; + } + } + } + + self.infer_expr(expr, &Expectation::has_type(expected.clone())) + } } fn is_non_ref_pat(body: &hir_def::body::Body, pat: PatId) -> bool { @@ -369,11 +422,22 @@ fn is_non_ref_pat(body: &hir_def::body::Body, pat: PatId) -> bool { Pat::Lit(expr) => { !matches!(body[*expr], Expr::Literal(Literal::String(..) | Literal::ByteString(..))) } - Pat::Bind { - mode: BindingAnnotation::Mutable | BindingAnnotation::Unannotated, - subpat: Some(subpat), - .. - } => is_non_ref_pat(body, *subpat), + Pat::Bind { id, subpat: Some(subpat), .. } + if matches!( + body.bindings[*id].mode, + BindingAnnotation::Mutable | BindingAnnotation::Unannotated + ) => + { + is_non_ref_pat(body, *subpat) + } Pat::Wild | Pat::Bind { .. } | Pat::Ref { .. } | Pat::Box { .. } | Pat::Missing => false, } } + +pub(super) fn contains_explicit_ref_binding(body: &Body, pat_id: PatId) -> bool { + let mut res = false; + body.walk_pats(pat_id, &mut |pat| { + res |= matches!(pat, Pat::Bind { id, .. } if body.bindings[*id].mode == BindingAnnotation::Ref); + }); + res +} |