move method to function so it can be used in map iterators without borrowing self

src/interpreter/mod.rs

@@ -285,11 +285,6 @@ pub fn load_mir(&self, def_id: DefId) -> EvalResult<'tcx, MirRef<'tcx>> {
         }
     }
 
-    pub fn monomorphize_field_ty(&self, f: ty::FieldDef<'tcx>, substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
-        let substituted = &f.ty(self.tcx, substs);
-        self.tcx.normalize_associated_type(&substituted)
-    }
-
     pub fn monomorphize(&self, ty: Ty<'tcx>, substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
         let substituted = ty.subst(self.tcx, substs);
         self.tcx.normalize_associated_type(&substituted)
@@ -1511,8 +1506,8 @@ fn unsize_into(
 
                 let iter = src_fields.zip(dst_fields).enumerate();
                 for (i, (src_f, dst_f)) in iter {
-                    let src_fty = self.monomorphize_field_ty(src_f, substs_a);
-                    let dst_fty = self.monomorphize_field_ty(dst_f, substs_b);
+                    let src_fty = monomorphize_field_ty(self.tcx, src_f, substs_a);
+                    let dst_fty = monomorphize_field_ty(self.tcx, dst_f, substs_b);
                     if self.type_size(dst_fty) == 0 {
                         continue;
                     }
@@ -1729,3 +1724,9 @@ fn size(self) -> Size {
         }
     }
 }
+
+
+pub fn monomorphize_field_ty<'a, 'tcx:'a >(tcx: TyCtxt<'a, 'tcx, 'tcx>, f: ty::FieldDef<'tcx>, substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
+    let substituted = &f.ty(tcx, substs);
+    tcx.normalize_associated_type(&substituted)
+}