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-rw-r--r--crates/ra_hir_ty/src/infer/unify.rs55
1 files changed, 40 insertions, 15 deletions
diff --git a/crates/ra_hir_ty/src/infer/unify.rs b/crates/ra_hir_ty/src/infer/unify.rs
index 269495ca0..2e895d911 100644
--- a/crates/ra_hir_ty/src/infer/unify.rs
+++ b/crates/ra_hir_ty/src/infer/unify.rs
@@ -9,7 +9,7 @@ use test_utils::mark;
9use super::{InferenceContext, Obligation}; 9use super::{InferenceContext, Obligation};
10use crate::{ 10use crate::{
11 BoundVar, Canonical, DebruijnIndex, GenericPredicate, InEnvironment, InferTy, Substs, Ty, 11 BoundVar, Canonical, DebruijnIndex, GenericPredicate, InEnvironment, InferTy, Substs, Ty,
12 TypeCtor, TypeWalk, 12 TyKind, TypeCtor, TypeWalk,
13}; 13};
14 14
15impl<'a> InferenceContext<'a> { 15impl<'a> InferenceContext<'a> {
@@ -86,10 +86,20 @@ where
86 } 86 }
87 87
88 fn into_canonicalized<T>(self, result: T) -> Canonicalized<T> { 88 fn into_canonicalized<T>(self, result: T) -> Canonicalized<T> {
89 Canonicalized { 89 let kinds = self
90 value: Canonical { value: result, num_vars: self.free_vars.len() }, 90 .free_vars
91 free_vars: self.free_vars, 91 .iter()
92 } 92 .map(|v| match v {
93 // mapping MaybeNeverTypeVar to the same kind as general ones
94 // should be fine, because as opposed to int or float type vars,
95 // they don't restrict what kind of type can go into them, they
96 // just affect fallback.
97 InferTy::TypeVar(_) | InferTy::MaybeNeverTypeVar(_) => TyKind::General,
98 InferTy::IntVar(_) => TyKind::Integer,
99 InferTy::FloatVar(_) => TyKind::Float,
100 })
101 .collect();
102 Canonicalized { value: Canonical { value: result, kinds }, free_vars: self.free_vars }
93 } 103 }
94 104
95 pub(crate) fn canonicalize_ty(mut self, ty: Ty) -> Canonicalized<Ty> { 105 pub(crate) fn canonicalize_ty(mut self, ty: Ty) -> Canonicalized<Ty> {
@@ -131,26 +141,41 @@ impl<T> Canonicalized<T> {
131 ty 141 ty
132 } 142 }
133 143
134 pub fn apply_solution(&self, ctx: &mut InferenceContext<'_>, solution: Canonical<Vec<Ty>>) { 144 pub fn apply_solution(&self, ctx: &mut InferenceContext<'_>, solution: Canonical<Substs>) {
135 // the solution may contain new variables, which we need to convert to new inference vars 145 // the solution may contain new variables, which we need to convert to new inference vars
136 let new_vars = Substs((0..solution.num_vars).map(|_| ctx.table.new_type_var()).collect()); 146 let new_vars = Substs(
147 solution
148 .kinds
149 .iter()
150 .map(|k| match k {
151 TyKind::General => ctx.table.new_type_var(),
152 TyKind::Integer => ctx.table.new_integer_var(),
153 TyKind::Float => ctx.table.new_float_var(),
154 })
155 .collect(),
156 );
137 for (i, ty) in solution.value.into_iter().enumerate() { 157 for (i, ty) in solution.value.into_iter().enumerate() {
138 let var = self.free_vars[i]; 158 let var = self.free_vars[i];
139 // eagerly replace projections in the type; we may be getting types 159 // eagerly replace projections in the type; we may be getting types
140 // e.g. from where clauses where this hasn't happened yet 160 // e.g. from where clauses where this hasn't happened yet
141 let ty = ctx.normalize_associated_types_in(ty.subst_bound_vars(&new_vars)); 161 let ty = ctx.normalize_associated_types_in(ty.clone().subst_bound_vars(&new_vars));
142 ctx.table.unify(&Ty::Infer(var), &ty); 162 ctx.table.unify(&Ty::Infer(var), &ty);
143 } 163 }
144 } 164 }
145} 165}
146 166
147pub fn unify(ty1: &Canonical<Ty>, ty2: &Canonical<Ty>) -> Option<Substs> { 167pub fn unify(tys: &Canonical<(Ty, Ty)>) -> Option<Substs> {
148 let mut table = InferenceTable::new(); 168 let mut table = InferenceTable::new();
149 let num_vars = ty1.num_vars.max(ty2.num_vars); 169 let vars = Substs(
150 let vars = 170 tys.kinds
151 Substs::builder(num_vars).fill(std::iter::repeat_with(|| table.new_type_var())).build(); 171 .iter()
152 let ty1_with_vars = ty1.value.clone().subst_bound_vars(&vars); 172 // we always use type vars here because we want everything to
153 let ty2_with_vars = ty2.value.clone().subst_bound_vars(&vars); 173 // fallback to Unknown in the end (kind of hacky, as below)
174 .map(|_| table.new_type_var())
175 .collect(),
176 );
177 let ty1_with_vars = tys.value.0.clone().subst_bound_vars(&vars);
178 let ty2_with_vars = tys.value.1.clone().subst_bound_vars(&vars);
154 if !table.unify(&ty1_with_vars, &ty2_with_vars) { 179 if !table.unify(&ty1_with_vars, &ty2_with_vars) {
155 return None; 180 return None;
156 } 181 }
@@ -162,7 +187,7 @@ pub fn unify(ty1: &Canonical<Ty>, ty2: &Canonical<Ty>) -> Option<Substs> {
162 } 187 }
163 } 188 }
164 Some( 189 Some(
165 Substs::builder(ty1.num_vars) 190 Substs::builder(tys.kinds.len())
166 .fill(vars.iter().map(|v| table.resolve_ty_completely(v.clone()))) 191 .fill(vars.iter().map(|v| table.resolve_ty_completely(v.clone())))
167 .build(), 192 .build(),
168 ) 193 )