retrieve outlives constraints from inferctxt

Author: csmoe

src/librustc_infer/infer/region_constraints/mod.rs

@@ -13,7 +13,7 @@ use rustc_hir::def_id::DefId;
 use rustc_index::vec::IndexVec;
 use rustc_middle::ty::ReStatic;
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_middle::ty::{ReLateBound, ReVar};
+use rustc_middle::ty::{OutlivesPredicate, ReLateBound, ReVar, RegionKind};
 use rustc_middle::ty::{Region, RegionVid};
 use rustc_span::Span;
 
@@ -137,14 +137,23 @@ pub enum Constraint<'tcx> {
     RegSubReg(Region<'tcx>, Region<'tcx>),
 }
 
-impl Constraint<'_> {
+impl<'tcx> Constraint<'tcx> {
     pub fn involves_placeholders(&self) -> bool {
         match self {
             Constraint::VarSubVar(_, _) => false,
             Constraint::VarSubReg(_, r) | Constraint::RegSubVar(r, _) => r.is_placeholder(),
             Constraint::RegSubReg(r, s) => r.is_placeholder() || s.is_placeholder(),
         }
     }
+
+    pub fn to_region_outlives_predicate(self) -> OutlivesPredicate<RegionKind, RegionKind> {
+        match self {
+            Self::VarSubVar(a, b) => OutlivesPredicate(RegionKind::ReVar(a), RegionKind::ReVar(b)),
+            Self::RegSubVar(a, b) => OutlivesPredicate(*a, RegionKind::ReVar(b)),
+            Self::VarSubReg(a, b) => OutlivesPredicate(RegionKind::ReVar(a), *b),
+            Self::RegSubReg(a, b) => OutlivesPredicate(*a, *b),
+        }
+    }
 }
 
 /// `VerifyGenericBound(T, _, R, RS)`: the parameter type `T` (or

src/librustc_typeck/check/generator_interior.rs

@@ -188,6 +188,16 @@ pub fn resolve_interior<'a, 'tcx>(
 
     // Extract type components to build the witness type.
     let type_list = fcx.tcx.mk_type_list(type_causes.iter().map(|cause| cause.ty));
+    let _region_constraints = visitor.fcx.with_region_constraints(|constraints_data| {
+        constraints_data
+            .constraints
+            .keys()
+            .map(|constraints| constraints.to_region_outlives_predicate())
+            .collect::<Vec<_>>()
+    });
+
+    debug!("region outlives inside generator: {:?}", _region_constraints);
+
     let witness = fcx.tcx.mk_generator_witness(ty::Binder::bind(type_list));
 
     // Store the generator types and spans into the tables for this generator.