Rollup merge of #40678 - michaelwoerister:dmi-prep, r=nikomatsakis

Some preparations for directly computing the ICH of crate-metadata.

This PR contains some small fixes in preparation for direct metadata hashing. It mostly just moves stuff into places where it will be needed (making the module structure slightly cleaner along the way) and it fixes some omissions in the MIR region eraser.

r? @nikomatsakis

1 files changed, 27 insertions, 1 deletions

diff --git a/src/librustc_mir/transform/erase_regions.rs b/src/librustc_mir/transform/erase_regions.rs
index cebd9dd9668..0f869e7ed02 100644
--- a/src/librustc_mir/transform/erase_regions.rs
+++ b/src/librustc_mir/transform/erase_regions.rs
@@ -13,7 +13,7 @@
 //! care erasing regions all over the place.
 
 use rustc::ty::subst::Substs;
-use rustc::ty::{Ty, TyCtxt};
+use rustc::ty::{Ty, TyCtxt, ReErased, ClosureSubsts};
 use rustc::mir::*;
 use rustc::mir::visit::MutVisitor;
 use rustc::mir::transform::{MirPass, MirSource, Pass};
@@ -39,6 +39,32 @@ impl<'a, 'tcx> MutVisitor<'tcx> for EraseRegionsVisitor<'a, 'tcx> {
     fn visit_substs(&mut self, substs: &mut &'tcx Substs<'tcx>) {
         *substs = self.tcx.erase_regions(&{*substs});
     }
+
+    fn visit_rvalue(&mut self, rvalue: &mut Rvalue<'tcx>, location: Location) {
+        match *rvalue {
+            Rvalue::Ref(ref mut r, _, _) => {
+                *r = self.tcx.mk_region(ReErased);
+            }
+            Rvalue::Use(..) |
+            Rvalue::Repeat(..) |
+            Rvalue::Len(..) |
+            Rvalue::Cast(..) |
+            Rvalue::BinaryOp(..) |
+            Rvalue::CheckedBinaryOp(..) |
+            Rvalue::UnaryOp(..) |
+            Rvalue::Discriminant(..) |
+            Rvalue::Box(..) |
+            Rvalue::Aggregate(..) => {
+                // These variants don't contain regions.
+            }
+        }
+        self.super_rvalue(rvalue, location);
+    }
+
+    fn visit_closure_substs(&mut self,
+                            substs: &mut ClosureSubsts<'tcx>) {
+        *substs = self.tcx.erase_regions(substs);
+    }
 }
 
 pub struct EraseRegions;