use usize for self instead of ty

Author: nikomatsakis

src/librustc_typeck/outlives/implicit_infer.rs

@@ -12,7 +12,7 @@ use rustc::hir;
 use rustc::hir::def_id::DefId;
 use rustc::hir::itemlikevisit::ItemLikeVisitor;
 use rustc::ty::subst::{Kind, Subst, UnpackedKind};
-use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};
+use rustc::ty::{self, Ty, TyCtxt};
 use rustc::util::nodemap::FxHashMap;
 
 use super::explicit::ExplicitPredicatesMap;
@@ -191,43 +191,35 @@ fn insert_required_predicates_to_be_wf<'tcx>(
                     substs,
                     required_predicates,
                     explicit_map,
-                    false,
+                    IgnoreSelfTy(false),
                 );
             }
 
             ty::Dynamic(obj, ..) => {
                 // This corresponds to `dyn Trait<..>`. In this case, we should
                 // use the explicit predicates as well.
 
-                // We are passing type `ty` as a placeholder value with the function
-                // `with_self_ty`, since there is no concrete type `Self` for a
-                // `dyn Trait` at this stage. Therefore when checking explicit
-                // predicates in `check_explicit_predicates` we need to ignore
-                // checking the explicit_map for Self type.
                 debug!("Dynamic");
                 debug!("field_ty = {}", &field_ty);
                 debug!("ty in field = {}", &ty);
                 if let Some(ex_trait_ref) = obj.principal() {
-                    // The method `has_escaping_regions` checks if
-                    // there are any late-bound regions, which is
-                    // the lifetime `'r`. It is safe to ignore
-                    // these since `'r` is not in scope for `Foo`.
-                    //
-                    // ```
-                    // struct Foo {
-                    //   bar: for<'r> Fn(usize, &'r FnMut())
-                    // }
-                    // ```
-                    if !ty.has_escaping_regions() {
-                        check_explicit_predicates(
-                            tcx,
-                            &ex_trait_ref.skip_binder().def_id,
-                            ex_trait_ref.with_self_ty(tcx, ty).skip_binder().substs,
-                            required_predicates,
-                            explicit_map,
-                            true,
-                        );
-                    }
+                    // Here, we are passing the type `usize` as a
+                    // placeholder value with the function
+                    // `with_self_ty`, since there is no concrete type
+                    // `Self` for a `dyn Trait` at this
+                    // stage. Therefore when checking explicit
+                    // predicates in `check_explicit_predicates` we
+                    // need to ignore checking the explicit_map for
+                    // Self type.
+                    let substs = ex_trait_ref.with_self_ty(tcx, tcx.types.usize).skip_binder().substs;
+                    check_explicit_predicates(
+                        tcx,
+                        &ex_trait_ref.skip_binder().def_id,
+                        substs,
+                        required_predicates,
+                        explicit_map,
+                        IgnoreSelfTy(true),
+                    );
                 }
             }
 
@@ -241,7 +233,7 @@ fn insert_required_predicates_to_be_wf<'tcx>(
                     obj.substs,
                     required_predicates,
                     explicit_map,
-                    false,
+                    IgnoreSelfTy(false),
                 );
             }
 
@@ -250,6 +242,8 @@ fn insert_required_predicates_to_be_wf<'tcx>(
     }
 }
 
+pub struct IgnoreSelfTy(bool);
+
 /// We also have to check the explicit predicates
 /// declared on the type.
 ///
@@ -271,7 +265,7 @@ pub fn check_explicit_predicates<'tcx>(
     substs: &[Kind<'tcx>],
     required_predicates: &mut RequiredPredicates<'tcx>,
     explicit_map: &mut ExplicitPredicatesMap<'tcx>,
-    ignore_self_ty: bool,
+    ignore_self_ty: IgnoreSelfTy,
 ) {
     debug!("def_id = {:?}", &def_id);
     debug!("substs = {:?}", &substs);
@@ -309,7 +303,7 @@ pub fn check_explicit_predicates<'tcx>(
         // to apply the substs, and not filter this predicate, we might then falsely
         // conclude that e.g. `X: 'x` was a reasonable inferred requirement.
         if let UnpackedKind::Type(ty) = outlives_predicate.0.unpack() {
-            if ty.is_self() && ignore_self_ty {
+            if ty.is_self() && ignore_self_ty.0 {
                 debug!("skipping self ty = {:?}", &ty);
                 continue;
             }
@@ -319,5 +313,4 @@ pub fn check_explicit_predicates<'tcx>(
         debug!("predicate = {:?}", &predicate);
         insert_outlives_predicate(tcx, predicate.0.into(), predicate.1, required_predicates);
     }
-    // }
 }