Get rid of cast on every self reference.

Author: msullivan

src/librustc/middle/trans/base.rs

@@ -1683,21 +1683,20 @@ pub fn copy_args_to_allocas(fcx: fn_ctxt,
 
     match fcx.llself {
       Some(slf) => {
-        // We really should do this regardless of whether self is owned, but
-        // it doesn't work right with default method impls yet. (FIXME: #2794)
-        if slf.is_owned {
-            let self_val = if datum::appropriate_mode(slf.t).is_by_value() {
-                let tmp = BitCast(bcx, slf.v, type_of(bcx.ccx(), slf.t));
-                let alloc = alloc_ty(bcx, slf.t);
-                Store(bcx, tmp, alloc);
-                alloc
-            } else {
-                PointerCast(bcx, slf.v, type_of(bcx.ccx(), slf.t).ptr_to())
-            };
-
-            fcx.llself = Some(ValSelfData {v: self_val, ..slf});
-            add_clean(bcx, self_val, slf.t);
-        }
+          let self_val = if slf.is_owned
+                  && datum::appropriate_mode(slf.t).is_by_value() {
+              let tmp = BitCast(bcx, slf.v, type_of(bcx.ccx(), slf.t));
+              let alloc = alloc_ty(bcx, slf.t);
+              Store(bcx, tmp, alloc);
+              alloc
+          } else {
+              PointerCast(bcx, slf.v, type_of(bcx.ccx(), slf.t).ptr_to())
+          };
+
+          fcx.llself = Some(ValSelfData {v: self_val, ..slf});
+          if slf.is_owned {
+              add_clean(bcx, self_val, slf.t);
+          }
       }
       _ => {}
     }

src/librustc/middle/trans/expr.rs

@@ -1051,14 +1051,8 @@ pub fn trans_local_var(bcx: block, def: ast::def) -> Datum {
             debug!("def_self() reference, self_info.t=%s",
                    self_info.t.repr(bcx.tcx()));
 
-            // This cast should not be necessary. We should cast self *once*,
-            // but right now this conflicts with default methods.
-            let real_self_ty = monomorphize_type(bcx, self_info.t);
-            let llselfty = type_of::type_of(bcx.ccx(), real_self_ty).ptr_to();
-
-            let casted_val = PointerCast(bcx, self_info.v, llselfty);
             Datum {
-                val: casted_val,
+                val: self_info.v,
                 ty: self_info.t,
                 mode: ByRef(ZeroMem)
             }

src/librustc/middle/trans/meth.rs

@@ -103,8 +103,8 @@ pub fn trans_method(ccx: @mut CrateContext,
         let self_ty = ty::node_id_to_type(ccx.tcx, method.self_id);
         let self_ty = match param_substs {
             None => self_ty,
-            Some(@param_substs {tys: ref tys, _}) => {
-                ty::subst_tps(ccx.tcx, *tys, None, self_ty)
+            Some(@param_substs {tys: ref tys, self_ty: ref self_sub, _}) => {
+                ty::subst_tps(ccx.tcx, *tys, *self_sub, self_ty)
             }
         };
         debug!("calling trans_fn with self_ty %s",