Revert "Remove usages of case(_) { fail; } since the compiler does this automatically". When we have exhaustiveness checking, "case(_) { fail; }" will be useful to silence warnings.

This reverts commit 92a716d.

Author: pcwalton

src/comp/middle/trans.rs

@@ -1789,6 +1789,7 @@ fn variant_types(@crate_ctxt cx, &ast.variant v) -> vec[@ty.t] {
             }
         }
         case (ty.ty_tag(_, _)) { /* nothing */ }
+        case (_) { fail; }
     }
     ret tys;
 }
@@ -2001,6 +2002,7 @@ fn iter_structural_ty_full(@block_ctxt cx,
                                 j += 1;
                             }
                         }
+                        case (_) { fail; }
                     }
 
                     variant_cx.build.Br(next_cx.llbb);
@@ -2167,6 +2169,7 @@ fn iter_sequence(@block_ctxt cx,
             auto et = plain_ty(ty.ty_machine(common.ty_u8));
             ret iter_sequence_body(cx, v, et, f, true);
         }
+        case (_) { fail; }
     }
     cx.fcx.ccx.sess.bug("bad type in trans.iter_sequence");
     fail;

src/comp/middle/typeck.rs

@@ -1861,6 +1861,9 @@ fn check_expr(&@fn_ctxt fcx, @ast.expr expr) -> @ast.expr {
                 case (ty.ty_chan(?it)) {
                     item_t = it;
                 }
+                case (_) {
+                    fail;
+                }
             }
             auto rhs_1 = demand_expr(fcx, item_t, rhs_0);
 
@@ -1881,6 +1884,9 @@ fn check_expr(&@fn_ctxt fcx, @ast.expr expr) -> @ast.expr {
                 case (ty.ty_port(?it)) {
                     item_t = it;
                 }
+                case (_) {
+                    fail;
+                }
             }
             auto lhs_1 = demand_expr(fcx, item_t, lhs_0);
 

src/lib/deque.rs

@@ -47,6 +47,7 @@ fn create[T]() -> t[T] {
     fn get[T](vec[cell[T]] elts, uint i) -> T {
         alt (elts.(i)) {
             case (option.some[T](?t)) { ret t; }
+            case (_) { fail; }
         }
         fail;   // FIXME: remove me when exhaustiveness checking works
     }

src/lib/map.rs

@@ -176,6 +176,7 @@ fn mk_hashmap[K, V](&hashfn[K] hasher, &eqfn[K] eqer) -> hashmap[K, V] {
             fn get(&K key) -> V {
                 alt (find_common[K, V](hasher, eqer, bkts, nbkts, key)) {
                     case (option.some[V](?val)) { ret val; }
+                    case (_) { fail; }
                 }
                 fail;   // FIXME: remove me when exhaustiveness checking works
             }