From dfb11a8a265d967e55c5515e78e741dfdba4db4d Mon Sep 17 00:00:00 2001
From: Oli Scherer <github35764891676564198441@oli-obk.de>
Date: Tue, 10 Aug 2021 11:12:11 +0000
Subject: [PATCH] Add helper function to `InferCtxt` that generates inference
vars for unresolved associated types
---
compiler/rustc_infer/src/infer/mod.rs | 1 +
compiler/rustc_infer/src/infer/projection.rs | 33 +++++++++++++++++++
.../src/traits/project.rs | 12 +------
3 files changed, 35 insertions(+), 11 deletions(-)
create mode 100644 compiler/rustc_infer/src/infer/projection.rs
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index 354b8e26d53..43d3730c049 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -64,6 +64,7 @@ mod lub;
pub mod nll_relate;
pub mod opaque_types;
pub mod outlives;
+mod projection;
pub mod region_constraints;
pub mod resolve;
mod sub;
diff --git a/compiler/rustc_infer/src/infer/projection.rs b/compiler/rustc_infer/src/infer/projection.rs
new file mode 100644
index 00000000000..aa0fddf9b6f
--- /dev/null
+++ b/compiler/rustc_infer/src/infer/projection.rs
@@ -0,0 +1,33 @@
+use rustc_middle::traits::ObligationCause;
+use rustc_middle::ty::{self, ToPredicate, Ty};
+
+use crate::traits::{Obligation, PredicateObligation};
+
+use super::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
+use super::InferCtxt;
+
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
+ pub fn infer_projection(
+ &self,
+ param_env: ty::ParamEnv<'tcx>,
+ projection_ty: ty::ProjectionTy<'tcx>,
+ cause: ObligationCause<'tcx>,
+ recursion_depth: usize,
+ obligations: &mut Vec<PredicateObligation<'tcx>>,
+ ) -> Ty<'tcx> {
+ let def_id = projection_ty.item_def_id;
+ let ty_var = self.next_ty_var(TypeVariableOrigin {
+ kind: TypeVariableOriginKind::NormalizeProjectionType,
+ span: self.tcx.def_span(def_id),
+ });
+ let projection = ty::Binder::dummy(ty::ProjectionPredicate { projection_ty, ty: ty_var });
+ let obligation = Obligation::with_depth(
+ cause,
+ recursion_depth,
+ param_env,
+ projection.to_predicate(self.tcx),
+ );
+ obligations.push(obligation);
+ ty_var
+ }
+}
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index 4f22543950c..873c058c55c 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -810,17 +810,7 @@ pub fn normalize_projection_type<'a, 'b, 'tcx>(
// and a deferred predicate to resolve this when more type
// information is available.
- let tcx = selcx.infcx().tcx;
- let def_id = projection_ty.item_def_id;
- let ty_var = selcx.infcx().next_ty_var(TypeVariableOrigin {
- kind: TypeVariableOriginKind::NormalizeProjectionType,
- span: tcx.def_span(def_id),
- });
- let projection = ty::Binder::dummy(ty::ProjectionPredicate { projection_ty, ty: ty_var });
- let obligation =
- Obligation::with_depth(cause, depth + 1, param_env, projection.to_predicate(tcx));
- obligations.push(obligation);
- ty_var
+ selcx.infcx().infer_projection(param_env, projection_ty, cause, depth + 1, obligations)
})
}