extend param_env with predicates from generator_witness

Author: csmoe

src/librustc/ty/walk.rs

@@ -13,7 +13,9 @@ 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::{OutlivesPredicate, ReLateBound, ReVar, RegionKind, RegionOutlivesPredicate};
+use rustc_middle::ty::{
+    OutlivesPredicate, ReLateBound, ReVar, RegionKind, RegionOutlivesPredicate,
+};
 use rustc_middle::ty::{Region, RegionVid};
 use rustc_span::Span;
 

src/librustc_infer/infer/region_constraints/mod.rs

@@ -2335,7 +2335,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
     fn collect_predicates_for_types(
         &mut self,
-        param_env: ty::ParamEnv<'tcx>,
+        mut param_env: ty::ParamEnv<'tcx>,
         cause: ObligationCause<'tcx>,
         recursion_depth: usize,
         trait_def_id: DefId,
@@ -2359,6 +2359,23 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             .skip_binder()
             .iter()
             .flat_map(|ty| {
+                let param_env = if let ty::GeneratorWitness(_, predicates) = ty.kind {
+                    let predicates: Vec<_> = param_env
+                        .caller_bounds
+                        .to_vec()
+                        .into_iter()
+                        .chain(
+                            predicates
+                                .skip_binder()
+                                .into_iter()
+                                .map(|&p| ty::Binder::bind(p).to_predicate()),
+                        )
+                        .collect();
+                    param_env.caller_bounds = self.infcx.tcx.mk_predicates(predicates.iter());
+                    param_env
+                } else {
+                    param_env
+                };
                 // binder moved -\
                 let ty: ty::Binder<Ty<'tcx>> = ty::Binder::bind(ty); // <----/
 

src/librustc_trait_selection/traits/select.rs

@@ -107,7 +107,7 @@ where
 
                         let witness = substs.witness();
                         let interior_tys = match &witness.kind {
-                            ty::GeneratorWitness(tys) => tcx.erase_late_bound_regions(tys),
+                            ty::GeneratorWitness(tys, _) => tcx.erase_late_bound_regions(tys),
                             _ => bug!(),
                         };
 

src/librustc_ty/needs_drop.rs

@@ -11,7 +11,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::{Expr, ExprKind, Pat, PatKind};
 use rustc_middle::middle::region::{self, YieldData};
-use rustc_middle::ty::{self, ToPredicate, Ty};
+use rustc_middle::ty::{self, Ty};
 use rustc_span::Span;
 
 struct InteriorVisitor<'a, 'tcx> {