From a87579500a2c35597071efd0ad6983927f0c1815 Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Wed, 27 Nov 2019 17:46:02 +0300 Subject: Move Ty --- crates/ra_hir_ty/src/infer/pat.rs | 186 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 186 insertions(+) create mode 100644 crates/ra_hir_ty/src/infer/pat.rs (limited to 'crates/ra_hir_ty/src/infer/pat.rs') diff --git a/crates/ra_hir_ty/src/infer/pat.rs b/crates/ra_hir_ty/src/infer/pat.rs new file mode 100644 index 000000000..1ebb36239 --- /dev/null +++ b/crates/ra_hir_ty/src/infer/pat.rs @@ -0,0 +1,186 @@ +//! Type inference for patterns. + +use std::iter::repeat; +use std::sync::Arc; + +use hir_def::{ + expr::{BindingAnnotation, Pat, PatId, RecordFieldPat}, + path::Path, + type_ref::Mutability, +}; +use hir_expand::name::Name; +use test_utils::tested_by; + +use super::{BindingMode, InferenceContext}; +use crate::{db::HirDatabase, utils::variant_data, Substs, Ty, TypeCtor, TypeWalk}; + +impl<'a, D: HirDatabase> InferenceContext<'a, D> { + fn infer_tuple_struct_pat( + &mut self, + path: Option<&Path>, + subpats: &[PatId], + expected: &Ty, + default_bm: BindingMode, + ) -> Ty { + let (ty, def) = self.resolve_variant(path); + let var_data = def.map(|it| variant_data(self.db, it)); + self.unify(&ty, expected); + + let substs = ty.substs().unwrap_or_else(Substs::empty); + + let field_tys = def.map(|it| self.db.field_types(it.into())).unwrap_or_default(); + + for (i, &subpat) in subpats.iter().enumerate() { + let expected_ty = var_data + .as_ref() + .and_then(|d| d.field(&Name::new_tuple_field(i))) + .map_or(Ty::Unknown, |field| field_tys[field].clone()) + .subst(&substs); + let expected_ty = self.normalize_associated_types_in(expected_ty); + self.infer_pat(subpat, &expected_ty, default_bm); + } + + ty + } + + fn infer_record_pat( + &mut self, + path: Option<&Path>, + subpats: &[RecordFieldPat], + expected: &Ty, + default_bm: BindingMode, + id: PatId, + ) -> Ty { + let (ty, def) = self.resolve_variant(path); + let var_data = def.map(|it| variant_data(self.db, it)); + if let Some(variant) = def { + self.write_variant_resolution(id.into(), variant); + } + + self.unify(&ty, expected); + + let substs = ty.substs().unwrap_or_else(Substs::empty); + + let field_tys = def.map(|it| self.db.field_types(it.into())).unwrap_or_default(); + for subpat in subpats { + let matching_field = var_data.as_ref().and_then(|it| it.field(&subpat.name)); + let expected_ty = + matching_field.map_or(Ty::Unknown, |field| field_tys[field].clone()).subst(&substs); + let expected_ty = self.normalize_associated_types_in(expected_ty); + self.infer_pat(subpat.pat, &expected_ty, default_bm); + } + + ty + } + + pub(super) fn infer_pat( + &mut self, + pat: PatId, + mut expected: &Ty, + mut default_bm: BindingMode, + ) -> Ty { + let body = Arc::clone(&self.body); // avoid borrow checker problem + + let is_non_ref_pat = match &body[pat] { + Pat::Tuple(..) + | Pat::TupleStruct { .. } + | Pat::Record { .. } + | Pat::Range { .. } + | Pat::Slice { .. } => true, + // FIXME: Path/Lit might actually evaluate to ref, but inference is unimplemented. + Pat::Path(..) | Pat::Lit(..) => true, + Pat::Wild | Pat::Bind { .. } | Pat::Ref { .. } | Pat::Missing => false, + }; + if is_non_ref_pat { + while let Some((inner, mutability)) = expected.as_reference() { + expected = inner; + default_bm = match default_bm { + BindingMode::Move => BindingMode::Ref(mutability), + BindingMode::Ref(Mutability::Shared) => BindingMode::Ref(Mutability::Shared), + BindingMode::Ref(Mutability::Mut) => BindingMode::Ref(mutability), + } + } + } else if let Pat::Ref { .. } = &body[pat] { + tested_by!(match_ergonomics_ref); + // When you encounter a `&pat` pattern, reset to Move. + // This is so that `w` is by value: `let (_, &w) = &(1, &2);` + default_bm = BindingMode::Move; + } + + // Lose mutability. + let default_bm = default_bm; + let expected = expected; + + let ty = match &body[pat] { + Pat::Tuple(ref args) => { + let expectations = match expected.as_tuple() { + Some(parameters) => &*parameters.0, + _ => &[], + }; + let expectations_iter = expectations.iter().chain(repeat(&Ty::Unknown)); + + let inner_tys = args + .iter() + .zip(expectations_iter) + .map(|(&pat, ty)| self.infer_pat(pat, ty, default_bm)) + .collect(); + + Ty::apply(TypeCtor::Tuple { cardinality: args.len() as u16 }, Substs(inner_tys)) + } + Pat::Ref { pat, mutability } => { + let expectation = match expected.as_reference() { + Some((inner_ty, exp_mut)) => { + if *mutability != exp_mut { + // FIXME: emit type error? + } + inner_ty + } + _ => &Ty::Unknown, + }; + let subty = self.infer_pat(*pat, expectation, default_bm); + Ty::apply_one(TypeCtor::Ref(*mutability), subty) + } + Pat::TupleStruct { path: p, args: subpats } => { + self.infer_tuple_struct_pat(p.as_ref(), subpats, expected, default_bm) + } + Pat::Record { path: p, args: fields } => { + self.infer_record_pat(p.as_ref(), fields, expected, default_bm, pat) + } + Pat::Path(path) => { + // FIXME use correct resolver for the surrounding expression + let resolver = self.resolver.clone(); + self.infer_path(&resolver, &path, pat.into()).unwrap_or(Ty::Unknown) + } + Pat::Bind { mode, name: _, subpat } => { + let mode = if mode == &BindingAnnotation::Unannotated { + default_bm + } else { + BindingMode::convert(*mode) + }; + let inner_ty = if let Some(subpat) = subpat { + self.infer_pat(*subpat, expected, default_bm) + } else { + expected.clone() + }; + let inner_ty = self.insert_type_vars_shallow(inner_ty); + + let bound_ty = match mode { + BindingMode::Ref(mutability) => { + Ty::apply_one(TypeCtor::Ref(mutability), inner_ty.clone()) + } + BindingMode::Move => inner_ty.clone(), + }; + let bound_ty = self.resolve_ty_as_possible(&mut vec![], bound_ty); + self.write_pat_ty(pat, bound_ty); + return inner_ty; + } + _ => Ty::Unknown, + }; + // use a new type variable if we got Ty::Unknown here + let ty = self.insert_type_vars_shallow(ty); + self.unify(&ty, expected); + let ty = self.resolve_ty_as_possible(&mut vec![], ty); + self.write_pat_ty(pat, ty.clone()); + ty + } +} -- cgit v1.2.3