diff --git a/src/llvm b/src/llvm
index b55be285d18..ab9efdacc29 160000
--- a/src/llvm
+++ b/src/llvm
@@ -1 +1 @@
-Subproject commit b55be285d18e9b3537fc9d29af44e83be2171326
+Subproject commit ab9efdacc290b24955561eda222363217578a908
diff --git a/src/rustc/driver/session.rs b/src/rustc/driver/session.rs
index 10c0f283525..2f7badd49d1 100644
--- a/src/rustc/driver/session.rs
+++ b/src/rustc/driver/session.rs
@@ -189,7 +189,7 @@ impl session {
     }
     // This exists to help with refactoring to eliminate impossible
     // cases later on
-    fn impossible_case(sp: span, msg: ~str) -> ! {
+    fn impossible_case(sp: span, msg: &str) -> ! {
         self.span_bug(sp, #fmt("Impossible case reached: %s", msg));
     }
     fn ppregions() -> bool { self.debugging_opt(ppregions) }
diff --git a/src/rustc/middle/trans/alt.rs b/src/rustc/middle/trans/alt.rs
index af7c2dcb9ba..b67e490863d 100644
--- a/src/rustc/middle/trans/alt.rs
+++ b/src/rustc/middle/trans/alt.rs
@@ -305,10 +305,10 @@ fn extract_variant_args(bcx: block, pat_id: ast::node_id,
    {vals: ~[ValueRef], bcx: block} {
     let _icx = bcx.insn_ctxt("alt::extract_variant_args");
     let ccx = bcx.fcx.ccx;
-    let enum_ty_substs = match check ty::get(node_id_type(bcx, pat_id))
+    let enum_ty_substs = match ty::get(node_id_type(bcx, pat_id))
         .struct {
-
       ty::ty_enum(id, substs) => { assert id == vdefs.enm; substs.tps }
+      _ => bcx.sess().bug(~"extract_variant_args: pattern has non-enum type")
     };
     let mut blobptr = val;
     let variants = ty::enum_variants(ccx.tcx, vdefs.enm);
@@ -667,11 +667,13 @@ fn compile_submatch(bcx: block, m: match_, vals: ~[ValueRef],
             match kind {
               single => Br(bcx, opt_cx.llbb),
               switch => {
-                match check trans_opt(bcx, opt) {
+                match trans_opt(bcx, opt) {
                   single_result(r) => {
                     llvm::LLVMAddCase(sw, r.val, opt_cx.llbb);
                     bcx = r.bcx;
                   }
+                  _ => bcx.sess().bug(~"in compile_submatch, expected \
+                         trans_opt to return a single_result")
                 }
               }
               compare => {
@@ -892,7 +894,8 @@ fn trans_alt_inner(scope_cx: block, expr: @ast::expr, arms: ~[ast::arm],
                 let arm_dest = dup_for_join(dest);
                 vec::push(arm_dests, arm_dest);
                 let mut arm_cx = trans_block(body_cx, a.body, arm_dest);
-                arm_cx = trans_block_cleanups(arm_cx, body_cx);
+                arm_cx = trans_block_cleanups(arm_cx,
+                                              block_cleanups(body_cx));
                 vec::push(arm_cxs, arm_cx);
             }
         }
diff --git a/src/rustc/middle/trans/base.rs b/src/rustc/middle/trans/base.rs
index fe0d49a3532..02f3c74972a 100644
--- a/src/rustc/middle/trans/base.rs
+++ b/src/rustc/middle/trans/base.rs
@@ -1962,7 +1962,7 @@ fn trans_if(cx: block, cond: @ast::expr, thn: ast::blk,
     let else_cx = scope_block(bcx, els.info(), ~"else");
     CondBr(bcx, cond_val, then_cx.llbb, else_cx.llbb);
     let then_bcx = trans_block(then_cx, thn, then_dest);
-    let then_bcx = trans_block_cleanups(then_bcx, then_cx);
+    let then_bcx = trans_block_cleanups(then_bcx, block_cleanups(then_cx));
     // Calling trans_block directly instead of trans_expr
     // because trans_expr will create another scope block
     // context for the block, but we've already got the
@@ -1983,7 +1983,7 @@ fn trans_if(cx: block, cond: @ast::expr, thn: ast::blk,
       }
       _ => else_cx
     };
-    let else_bcx = trans_block_cleanups(else_bcx, else_cx);
+    let else_bcx = trans_block_cleanups(else_bcx, block_cleanups(else_cx));
     return join_returns(cx,
                      ~[then_bcx, else_bcx], ~[then_dest, else_dest], dest);
 }
@@ -1998,7 +1998,8 @@ fn trans_while(cx: block, cond: @ast::expr, body: ast::blk)
     Br(cx, loop_cx.llbb);
     Br(loop_cx, cond_cx.llbb);
     let cond_res = trans_temp_expr(cond_cx, cond);
-    let cond_bcx = trans_block_cleanups(cond_res.bcx, cond_cx);
+    let cond_bcx = trans_block_cleanups(cond_res.bcx,
+                                        block_cleanups(cond_cx));
     CondBr(cond_bcx, cond_res.val, body_cx.llbb, next_cx.llbb);
     let body_end = trans_block(body_cx, body, ignore);
     cleanup_and_Br(body_end, body_cx, cond_cx.llbb);
@@ -2113,19 +2114,19 @@ fn make_mono_id(ccx: @crate_ctxt, item: ast::def_id, substs: ~[ty::t],
                   _ => ()
                 }
             }
-            mono_precise(subst, if v.len() > 0u { some(v) } else { none })
+            (subst, if v.len() > 0u { some(v) } else { none })
         })
       }
       none => {
-        vec::map(substs, |subst| mono_precise(subst, none))
+        vec::map(substs, |subst| (subst, none))
       }
     };
     let param_ids = match param_uses {
       some(uses) => {
         vec::map2(precise_param_ids, uses, |id, uses| {
-            match check id {
-              mono_precise(_, some(_)) => id,
-              mono_precise(subst, none) => {
+            match id {
+                (a, b@some(_)) => mono_precise(a, b),
+              (subst, none) => {
                 if uses == 0u { mono_any }
                 else if uses == type_use::use_repr &&
                         !ty::type_needs_drop(ccx.tcx, subst) {
@@ -2137,12 +2138,13 @@ fn make_mono_id(ccx: @crate_ctxt, item: ast::def_id, substs: ~[ty::t],
                     if size == 1u && ty::type_is_nil(subst) {
                         mono_repr(0u, 0u)
                     } else { mono_repr(size, align) }
-                } else { id }
+                } else { mono_precise(subst, none) }
               }
             }
         })
       }
-      none => precise_param_ids
+      none => precise_param_ids.map(|x| { let (a, b) = x;
+                mono_precise(a, b) })
     };
     @{def: item, params: param_ids}
 }
@@ -2367,7 +2369,7 @@ fn maybe_instantiate_inline(ccx: @crate_ctxt, fn_id: ast::def_id)
           csearch::found_parent(parent_id, ast::ii_item(item)) => {
             ccx.external.insert(parent_id, some(item.id));
             let mut my_id = 0;
-            match check item.node {
+            match item.node {
               ast::item_enum(_, _) => {
                 let vs_here = ty::enum_variants(ccx.tcx, local_def(item.id));
                 let vs_there = ty::enum_variants(ccx.tcx, parent_id);
@@ -2376,6 +2378,8 @@ fn maybe_instantiate_inline(ccx: @crate_ctxt, fn_id: ast::def_id)
                     ccx.external.insert(there.id, some(here.id.node));
                 }
               }
+              _ => ccx.sess.bug(~"maybe_instantiate_inline: item has a \
+                    non-enum parent")
             }
             trans_item(ccx, *item);
             local_def(my_id)
@@ -2756,7 +2760,7 @@ fn trans_lval(cx: block, e: @ast::expr) -> lval_result {
             let ccx = cx.ccx();
             let sub = trans_temp_expr(cx, base);
             let t = expr_ty(cx, base);
-            let val = match check ty::get(t).struct {
+            let val = match ty::get(t).struct {
               ty::ty_box(_) => {
                 let non_gc_val = non_gc_box_cast(sub.bcx, sub.val);
                 GEPi(sub.bcx, non_gc_val, ~[0u, abi::box_field_body])
@@ -2770,7 +2774,9 @@ fn trans_lval(cx: block, e: @ast::expr) -> lval_result {
                 let ellty = T_ptr(type_of(ccx, ety));
                 PointerCast(sub.bcx, sub.val, ellty)
               }
-              ty::ty_ptr(_) | ty::ty_rptr(_,_) => sub.val
+              ty::ty_ptr(_) | ty::ty_rptr(_,_) => sub.val,
+              _ => cx.sess().impossible_case(e.span, #fmt("unary operand \
+                may not have type %s", cx.ty_to_str(t)))
             };
             return lval_owned(sub.bcx, val);
           }
@@ -2917,22 +2923,13 @@ fn trans_cast(cx: block, e: @ast::expr, id: ast::node_id,
     return store_in_dest(e_res.bcx, newval, dest);
 }
 
-fn trans_loop_body(bcx: block, e: @ast::expr, ret_flag: option<ValueRef>,
+fn trans_loop_body(bcx: block, id: ast::node_id,
+                   decl: ast::fn_decl, body: ast::blk,
+                   proto: ty::fn_proto, cap: ast::capture_clause,
+                   ret_flag: option<ValueRef>,
                    dest: dest) -> block {
-    match check e.node {
-      ast::expr_loop_body(b@@{
-        node: ast::expr_fn_block(decl, body, cap),
-        _
-      }) => {
-        match check ty::get(expr_ty(bcx, e)).struct {
-          ty::ty_fn({proto, _}) => {
-            closure::trans_expr_fn(bcx, proto, decl, body, b.id,
-                                   cap, some(ret_flag),
-                                   dest)
-          }
-        }
-      }
-    }
+    closure::trans_expr_fn(bcx, proto, decl, body, id,
+                           cap, some(ret_flag), dest)
 }
 
 // temp_cleanups: cleanups that should run only if failure occurs before the
@@ -2950,12 +2947,21 @@ fn trans_arg_expr(cx: block, arg: ty::arg, lldestty: TypeRef, e: @ast::expr,
     // translate the arg expr as an lvalue
     let lv = match ret_flag {
       // If there is a ret_flag, this *must* be a loop body
-      some(_) => match check e.node {
-        ast::expr_loop_body(blk) => {
+      some(_) => match e.node {
+          ast::expr_loop_body(blk@@{node:
+                  ast::expr_fn_block(decl, body, cap),_}) => {
             let scratch = alloc_ty(cx, expr_ty(cx, blk));
-            let bcx = trans_loop_body(cx, e, ret_flag, save_in(scratch));
+            let proto = match ty::get(expr_ty(cx, e)).struct {
+                ty::ty_fn({proto, _}) => proto,
+                _ => cx.sess().impossible_case(e.span, ~"Loop body has \
+                       non-fn ty")
+            };
+            let bcx = trans_loop_body(cx, blk.id, decl, body, proto,
+                                      cap, ret_flag, save_in(scratch));
             {bcx: bcx, val: scratch, kind: lv_temporary}
         }
+        _ => cx.sess().impossible_case(e.span, ~"ret_flag with non-loop-\
+              body expr")
       },
       none => {
         trans_temp_lval(cx, e)
@@ -3462,21 +3468,25 @@ fn trans_tup(bcx: block, elts: ~[@ast::expr], dest: dest) -> block {
 
 fn trans_rec(bcx: block, fields: ~[ast::field],
              base: option<@ast::expr>, id: ast::node_id,
-             dest: dest) -> block {
+             // none = ignore; some(x) = save_in(x)
+             dest: option<ValueRef>) -> block {
     let _icx = bcx.insn_ctxt("trans_rec");
     let t = node_id_type(bcx, id);
     let mut bcx = bcx;
-    let addr = match check dest {
-      ignore => {
+    let addr = match dest {
+      none => {
         for vec::each(fields) |fld| {
             bcx = trans_expr(bcx, fld.node.expr, ignore);
         }
         return bcx;
       }
-      save_in(pos) => pos
+      some(pos) => pos
     };
 
-    let ty_fields = match check ty::get(t).struct { ty::ty_rec(f) => f };
+    let ty_fields = match ty::get(t).struct {
+        ty::ty_rec(f) => f,
+        _ => bcx.sess().bug(~"trans_rec: record has non-record type")
+    };
 
     let mut temp_cleanups = ~[];
     for fields.each |fld| {
@@ -3797,7 +3807,13 @@ fn trans_expr(bcx: block, e: @ast::expr, dest: dest) -> block {
             };
           }
           ast::expr_rec(args, base) => {
-            return trans_rec(bcx, args, base, e.id, dest);
+              let d = match dest {
+                  ignore => none,
+                  save_in(p) => some(p),
+                  _ => bcx.sess().impossible_case(e.span,
+                        "trans_expr::unrooted: can't pass a record by val")
+              };
+            return trans_rec(bcx, args, base, e.id, d);
           }
           ast::expr_struct(_, fields, base) => {
             return trans_struct(bcx, e.span, fields, base, e.id, dest);
@@ -3849,7 +3865,7 @@ fn trans_expr(bcx: block, e: @ast::expr, dest: dest) -> block {
                                           dest);
           }
           ast::expr_fn_block(decl, body, cap_clause) => {
-            match check ty::get(expr_ty(bcx, e)).struct {
+            match ty::get(expr_ty(bcx, e)).struct {
               ty::ty_fn({proto, _}) => {
                 debug!("translating fn_block %s with type %s",
                        expr_to_str(e, tcx.sess.intr()),
@@ -3857,10 +3873,25 @@ fn trans_expr(bcx: block, e: @ast::expr, dest: dest) -> block {
                 return closure::trans_expr_fn(bcx, proto, decl, body,
                                            e.id, cap_clause, none, dest);
               }
+              _ =>  bcx.sess().impossible_case(e.span, "fn_block has \
+                         body with a non-fn type")
             }
           }
-          ast::expr_loop_body(_) => {
-            return trans_loop_body(bcx, e, none, dest);
+          ast::expr_loop_body(blk) => {
+              match ty::get(expr_ty(bcx, e)).struct {
+                  ty::ty_fn({proto, _}) => {
+                      match blk.node {
+                          ast::expr_fn_block(decl, body, cap) =>
+                            return trans_loop_body(bcx, blk.id, decl, body,
+                                                   proto, cap, none, dest),
+                          _ => bcx.sess().impossible_case(e.span, "loop_body \
+                                 has the wrong kind of contents")
+                      }
+
+                  }
+                  _ => bcx.sess().impossible_case(e.span, "loop_body has \
+                         body with a non-fn type")
+              }
           }
           ast::expr_do_body(blk) => {
             return trans_expr(bcx, blk, dest);
@@ -4436,19 +4467,18 @@ fn raw_block(fcx: fn_ctxt, is_lpad: bool, llbb: BasicBlockRef) -> block {
 // need to make sure those variables go out of scope when the block ends.  We
 // do that by running a 'cleanup' function for each variable.
 // trans_block_cleanups runs all the cleanup functions for the block.
-fn trans_block_cleanups(bcx: block, cleanup_cx: block) -> block {
-    trans_block_cleanups_(bcx, cleanup_cx, false)
+fn trans_block_cleanups(bcx: block, +cleanups: ~[cleanup]) -> block {
+    trans_block_cleanups_(bcx, cleanups, false)
 }
 
-fn trans_block_cleanups_(bcx: block, cleanup_cx: block, is_lpad: bool) ->
+fn trans_block_cleanups_(bcx: block,
+                         +cleanups: ~[cleanup],
+                         /* cleanup_cx: block, */ is_lpad: bool) ->
    block {
     let _icx = bcx.insn_ctxt("trans_block_cleanups");
     if bcx.unreachable { return bcx; }
     let mut bcx = bcx;
-    match check cleanup_cx.kind {
-      block_scope({cleanups, _}) => {
-        let cleanups = copy cleanups;
-        do vec::riter(cleanups) |cu| {
+    do vec::riter(cleanups) |cu| {
             match cu {
               clean(cfn, cleanup_type) | clean_temp(_, cfn, cleanup_type) => {
                 // Some types don't need to be cleaned up during
@@ -4458,9 +4488,7 @@ fn trans_block_cleanups_(bcx: block, cleanup_cx: block, is_lpad: bool) ->
                 }
               }
             }
-        }
-      }
-    }
+            }
     return bcx;
 }
 
@@ -4491,7 +4519,7 @@ fn cleanup_and_leave(bcx: block, upto: option<BasicBlockRef>,
             let sub_cx = sub_block(bcx, ~"cleanup");
             Br(bcx, sub_cx.llbb);
             vec::push(inf.cleanup_paths, {target: leave, dest: sub_cx.llbb});
-            bcx = trans_block_cleanups_(sub_cx, cur, is_lpad);
+            bcx = trans_block_cleanups_(sub_cx, block_cleanups(cur), is_lpad);
           }
           _ => ()
         }
@@ -4906,8 +4934,9 @@ fn trans_enum_variant(ccx: @crate_ctxt,
         // If this argument to this function is a enum, it'll have come in to
         // this function as an opaque blob due to the way that type_of()
         // works. So we have to cast to the destination's view of the type.
-        let llarg = match check fcx.llargs.find(va.id) {
-          some(local_mem(x)) => x
+        let llarg = match fcx.llargs.find(va.id) {
+            some(local_mem(x)) => x,
+            _ => fail ~"trans_enum_variant: how do we know this works?",
         };
         let arg_ty = arg_tys[i].ty;
         memmove_ty(bcx, lldestptr, llarg, arg_ty);
@@ -5052,8 +5081,10 @@ fn trans_enum_def(ccx: @crate_ctxt, enum_definition: ast::enum_def,
 
 fn trans_item(ccx: @crate_ctxt, item: ast::item) {
     let _icx = ccx.insn_ctxt("trans_item");
-    let path = match check ccx.tcx.items.get(item.id) {
-      ast_map::node_item(_, p) => p
+    let path = match ccx.tcx.items.get(item.id) {
+        ast_map::node_item(_, p) => p,
+        // tjc: ?
+        _ => fail ~"trans_item",
     };
     match item.node {
       ast::item_fn(decl, purity, tps, body) => {
@@ -5288,8 +5319,10 @@ fn fill_fn_pair(bcx: block, pair: ValueRef, llfn: ValueRef,
 
 fn item_path(ccx: @crate_ctxt, i: @ast::item) -> path {
     vec::append(
-        *match check ccx.tcx.items.get(i.id) {
-            ast_map::node_item(_, p) => p
+        *match ccx.tcx.items.get(i.id) {
+            ast_map::node_item(_, p) => p,
+                // separate map for paths?
+            _ => fail ~"item_path"
         },
         ~[path_name(i.ident)])
 }
@@ -5340,7 +5373,7 @@ fn get_item_val(ccx: @crate_ctxt, id: ast::node_id) -> ValueRef {
         let val = match ccx.tcx.items.get(id) {
           ast_map::node_item(i, pth) => {
             let my_path = vec::append(*pth, ~[path_name(i.ident)]);
-            match check i.node {
+            match i.node {
               ast::item_const(_, _) => {
                 let typ = ty::node_id_to_type(ccx.tcx, i.id);
                 let s = mangle_exported_name(ccx, my_path, typ);
@@ -5359,6 +5392,7 @@ fn get_item_val(ccx: @crate_ctxt, id: ast::node_id) -> ValueRef {
                 set_inline_hint_if_appr(i.attrs, llfn);
                 llfn
               }
+              _ => fail ~"get_item_val: weird result in table"
             }
           }
           ast_map::node_trait_method(trait_method, _, pth) => {
@@ -5417,10 +5451,11 @@ fn get_item_val(ccx: @crate_ctxt, id: ast::node_id) -> ValueRef {
                     let pth = vec::append(*pth,
                                           ~[path_name(enm.ident),
                                             path_name(v.node.name)]);
-                    llfn = match check enm.node {
+                    llfn = match enm.node {
                       ast::item_enum(_, _) => {
                         register_fn(ccx, v.span, pth, id)
                       }
+                      _ => fail ~"node_variant, shouldn't happen"
                     };
                 }
                 ast::struct_variant_kind(_) => {
@@ -5733,11 +5768,11 @@ fn crate_ctxt_to_encode_parms(cx: @crate_ctxt)
         for cx.exp_map.each |exp_id, defs| {
             for defs.each |def| {
                 if !def.reexp { again; }
-                let path = match check cx.tcx.items.get(exp_id) {
-                    ast_map::node_export(_, path) => {
-                        ast_map::path_to_str(*path,
-                                             cx.sess.parse_sess.interner)
-                    }
+                let path = match cx.tcx.items.get(exp_id) {
+                  ast_map::node_export(_, path) => {
+                      ast_map::path_to_str(*path, cx.sess.parse_sess.interner)
+                  }
+                  _ => fail ~"reexports"
                 };
                 vec::push(reexports, (path, def.id));
             }
diff --git a/src/rustc/middle/trans/common.rs b/src/rustc/middle/trans/common.rs
index e397dd5c113..f5ba581e3fe 100644
--- a/src/rustc/middle/trans/common.rs
+++ b/src/rustc/middle/trans/common.rs
@@ -368,6 +368,13 @@ fn revoke_clean(cx: block, val: ValueRef) {
     }
 }
 
+fn block_cleanups(bcx: block) -> ~[cleanup] {
+    match bcx.kind {
+       block_non_scope  => ~[],
+       block_scope(inf) => inf.cleanups
+    }
+}
+
 enum block_kind {
     // A scope at the end of which temporary values created inside of it are
     // cleaned up. May correspond to an actual block in the language, but also
diff --git a/src/rustc/middle/trans/debuginfo.rs b/src/rustc/middle/trans/debuginfo.rs
index 42b8274d78c..8a2ac2ae156 100644
--- a/src/rustc/middle/trans/debuginfo.rs
+++ b/src/rustc/middle/trans/debuginfo.rs
@@ -399,7 +399,7 @@ fn create_record(cx: @crate_ctxt, t: ty::t, fields: ~[ast::ty_field],
                                line_from_span(cx.sess.codemap,
                                               span) as int);
     for fields.each |field| {
-        let field_t = ty::get_field(t, field.node.ident).mt.ty;
+        let field_t = ty::get_field(cx.tcx, t, field.node.ident).mt.ty;
         let ty_md = create_ty(cx, field_t, field.node.mt.ty);
         let (size, align) = size_and_align_of(cx, field_t);
         add_member(scx, cx.sess.str_of(field.node.ident),
diff --git a/src/rustc/middle/trans/foreign.rs b/src/rustc/middle/trans/foreign.rs
index efcdc644104..8f7881a4d7a 100644
--- a/src/rustc/middle/trans/foreign.rs
+++ b/src/rustc/middle/trans/foreign.rs
@@ -925,8 +925,9 @@ fn trans_intrinsic(ccx: @crate_ctxt, decl: ValueRef, item: @ast::foreign_item,
         let tp_sz = shape::llsize_of_real(ccx, lltp_ty),
             out_sz = shape::llsize_of_real(ccx, llout_ty);
         if tp_sz != out_sz {
-            let sp = match check ccx.tcx.items.get(option::get(ref_id)) {
-              ast_map::node_expr(e) => e.span
+            let sp = match ccx.tcx.items.get(option::get(ref_id)) {
+              ast_map::node_expr(e) => e.span,
+              _ => fail ~"reinterpret_cast or forget has non-expr arg"
             };
             ccx.sess.span_fatal(
                 sp, fmt!("reinterpret_cast called on types \
@@ -981,6 +982,8 @@ fn trans_intrinsic(ccx: @crate_ctxt, decl: ValueRef, item: @ast::foreign_item,
                                arg_vals(~[frameaddress_val]), ignore);
       }
       _ => {
+      // Could we make this an enum rather than a string? does it get
+      // checked earlier?
           ccx.sess.span_bug(item.span, ~"unknown intrinsic");
       }
     }
@@ -1171,8 +1174,10 @@ fn register_foreign_fn(ccx: @crate_ctxt, sp: span,
 fn abi_of_foreign_fn(ccx: @crate_ctxt, i: @ast::foreign_item)
     -> ast::foreign_abi {
     match attr::first_attr_value_str_by_name(i.attrs, ~"abi") {
-      none => match check ccx.tcx.items.get(i.id) {
-        ast_map::node_foreign_item(_, abi, _) => abi
+      none => match ccx.tcx.items.get(i.id) {
+        ast_map::node_foreign_item(_, abi, _) => abi,
+        // ??
+        _ => fail ~"abi_of_foreign_fn: not foreign"
       },
       some(_) => match attr::foreign_abi(i.attrs) {
         either::Right(abi) => abi,
diff --git a/src/rustc/middle/trans/impl.rs b/src/rustc/middle/trans/impl.rs
index 2c927d2cc5d..20e5bee4305 100644
--- a/src/rustc/middle/trans/impl.rs
+++ b/src/rustc/middle/trans/impl.rs
@@ -125,12 +125,14 @@ fn trans_method_callee(bcx: block, callee_id: ast::node_id,
       }
       typeck::method_param({trait_id:trait_id, method_num:off,
                             param_num:p, bound_num:b}) => {
-        match check bcx.fcx.param_substs {
+        match bcx.fcx.param_substs {
           some(substs) => {
             let vtbl = find_vtable_in_fn_ctxt(substs, p, b);
             trans_monomorphized_callee(bcx, callee_id, self, mentry,
                                        trait_id, off, vtbl)
           }
+          // how to get rid of this?
+          none => fail ~"trans_method_callee: missing param_substs"
         }
       }
       typeck::method_trait(_, off) => {
@@ -150,10 +152,11 @@ fn trans_static_method_callee(bcx: block, method_id: ast::def_id,
     let ccx = bcx.ccx();
 
     let mname = if method_id.crate == ast::local_crate {
-        match check bcx.tcx().items.get(method_id.node) {
+        match bcx.tcx().items.get(method_id.node) {
           ast_map::node_trait_method(trait_method, _, _) => {
             ast_util::trait_method_to_ty_method(*trait_method).ident
           }
+          _ => fail ~"callee is not a trait method"
         }
     } else {
         let path = csearch::get_item_path(bcx.tcx(), method_id);
@@ -200,7 +203,7 @@ fn method_from_methods(ms: ~[@ast::method], name: ast::ident)
 fn method_with_name(ccx: @crate_ctxt, impl_id: ast::def_id,
                     name: ast::ident) -> ast::def_id {
     if impl_id.crate == ast::local_crate {
-        match check ccx.tcx.items.get(impl_id.node) {
+        match ccx.tcx.items.get(impl_id.node) {
           ast_map::node_item(@{node: ast::item_impl(_, _, _, ms), _}, _) => {
             method_from_methods(ms, name)
           }
@@ -208,6 +211,7 @@ fn method_with_name(ccx: @crate_ctxt, impl_id: ast::def_id,
               ast::item_class(struct_def, _), _}, _) => {
             method_from_methods(struct_def.methods, name)
           }
+          _ => fail ~"method_with_name"
         }
     } else {
         csearch::get_impl_method(ccx.sess.cstore, impl_id, name)
@@ -217,8 +221,9 @@ fn method_with_name(ccx: @crate_ctxt, impl_id: ast::def_id,
 fn method_ty_param_count(ccx: @crate_ctxt, m_id: ast::def_id,
                          i_id: ast::def_id) -> uint {
     if m_id.crate == ast::local_crate {
-        match check ccx.tcx.items.get(m_id.node) {
+        match ccx.tcx.items.get(m_id.node) {
           ast_map::node_method(m, _, _) => vec::len(m.tps),
+          _ => fail ~"method_ty_param_count"
         }
     } else {
         csearch::get_type_param_count(ccx.sess.cstore, m_id) -
@@ -321,10 +326,11 @@ fn resolve_vtable_in_fn_ctxt(fcx: fn_ctxt, vt: typeck::vtable_origin)
                               resolve_vtables_in_fn_ctxt(fcx, sub))
       }
       typeck::vtable_param(n_param, n_bound) => {
-        match check fcx.param_substs {
+        match fcx.param_substs {
           some(substs) => {
             find_vtable_in_fn_ctxt(substs, n_param, n_bound)
           }
+          _ => fail ~"resolve_vtable_in_fn_ctxt: no substs"
         }
       }
       _ => vt
@@ -332,7 +338,7 @@ fn resolve_vtable_in_fn_ctxt(fcx: fn_ctxt, vt: typeck::vtable_origin)
 }
 
 fn vtable_id(ccx: @crate_ctxt, origin: typeck::vtable_origin) -> mono_id {
-    match check origin {
+    match origin {
       typeck::vtable_static(impl_id, substs, sub_vtables) => {
         make_mono_id(ccx, impl_id, substs,
                      if (*sub_vtables).len() == 0u { none }
@@ -342,6 +348,8 @@ fn vtable_id(ccx: @crate_ctxt, origin: typeck::vtable_origin) -> mono_id {
         @{def: trait_id,
           params: vec::map(substs, |t| mono_precise(t, none))}
       }
+      // can't this be checked at the callee?
+      _ => fail ~"vtable_id"
     }
 }
 
@@ -350,10 +358,11 @@ fn get_vtable(ccx: @crate_ctxt, origin: typeck::vtable_origin)
     let hash_id = vtable_id(ccx, origin);
     match ccx.vtables.find(hash_id) {
       some(val) => val,
-      none => match check origin {
+      none => match origin {
         typeck::vtable_static(id, substs, sub_vtables) => {
             make_impl_vtable(ccx, id, substs, sub_vtables)
         }
+        _ => fail ~"get_vtable: expected a static origin"
       }
     }
 }
diff --git a/src/rustc/middle/trans/type_of.rs b/src/rustc/middle/trans/type_of.rs
index f6cd78e3015..0e5997a0d3a 100644
--- a/src/rustc/middle/trans/type_of.rs
+++ b/src/rustc/middle/trans/type_of.rs
@@ -95,13 +95,13 @@ fn type_of(cx: @crate_ctxt, t: ty::t) -> TypeRef {
       ty::ty_estr(ty::vstore_uniq) => {
         T_unique_ptr(T_unique(cx, T_vec(cx, T_i8())))
       }
-      ty::ty_enum(*) => {
+      ty::ty_enum(did, substs) => {
         // Only create the named struct, but don't fill it in. We
         // fill it in *after* placing it into the type cache. This
         // avoids creating more than one copy of the enum when one
         // of the enum's variants refers to the enum itself.
 
-        common::T_named_struct(llvm_type_name(cx, t))
+        common::T_named_struct(llvm_type_name(cx, an_enum, did, substs.tps))
       }
       ty::ty_estr(ty::vstore_box) => {
         T_box_ptr(T_box(cx, T_vec(cx, T_i8())))
@@ -158,12 +158,12 @@ fn type_of(cx: @crate_ctxt, t: ty::t) -> TypeRef {
         T_struct(tys)
       }
       ty::ty_opaque_closure_ptr(_) => T_opaque_box_ptr(cx),
-      ty::ty_class(*) => {
+      ty::ty_class(did, substs) => {
         // Only create the named struct, but don't fill it in. We fill it
         // in *after* placing it into the type cache. This prevents
         // infinite recursion with recursive class types.
 
-        common::T_named_struct(llvm_type_name(cx, t))
+        common::T_named_struct(llvm_type_name(cx, a_class, did, substs.tps))
       }
       ty::ty_self => cx.tcx.sess.unimpl(~"type_of: ty_self"),
       ty::ty_var(_) => cx.tcx.sess.bug(~"type_of with ty_var"),
@@ -223,14 +223,18 @@ fn fill_type_of_enum(cx: @crate_ctxt, did: ast::def_id, t: ty::t,
     common::set_struct_body(llty, lltys);
 }
 
-fn llvm_type_name(cx: @crate_ctxt, t: ty::t) -> ~str {
-    let (name, did, tps) = match check ty::get(t).struct {
-      ty::ty_enum(did, substs) => (~"enum", did, substs.tps),
-      ty::ty_class(did, substs) => (~"class", did, substs.tps)
-    };
+// Want refinements! (Or case classes, I guess
+enum named_ty { a_class, an_enum }
+
+fn llvm_type_name(cx: @crate_ctxt,
+                  what: named_ty,
+                  did: ast::def_id,
+                  tps: ~[ty::t]
+                  ) -> ~str {
+    let name = match what { a_class => { "~class" } an_enum => { "~enum" } };
     return fmt!(
         "%s %s[#%d]",
-        name,
+          name,
         util::ppaux::parameterized(
             cx.tcx,
             ty::item_path_str(cx.tcx, did),
diff --git a/src/rustc/middle/trans/type_use.rs b/src/rustc/middle/trans/type_use.rs
index 2b527bb9682..9b8f6cb96e0 100644
--- a/src/rustc/middle/trans/type_use.rs
+++ b/src/rustc/middle/trans/type_use.rs
@@ -97,6 +97,7 @@ fn type_uses_for(ccx: @crate_ctxt, fn_id: def_id, n_tps: uint)
               ~"visit_tydesc" | ~"forget" | ~"addr_of" => {
                 0u
               }
+              // would be cool to make these an enum instead of strings!
               _ => fail ~"unknown intrinsic in type_use"
             };
             for uint::range(0u, n_tps) |n| { cx.uses[n] |= flags;}
@@ -255,8 +256,8 @@ fn mark_for_expr(cx: ctx, e: @expr) {
             }
         })
       }
-      expr_match(_, _, _) | expr_block(_) | expr_if(_, _, _) |
-      expr_while(_, _) | expr_fail(_) | expr_break(_) | expr_again(_) |
+      expr_match(*) | expr_block(_) | expr_if(*) |
+      expr_while(*) | expr_fail(_) | expr_break(_) | expr_again(_) |
       expr_unary(_, _) | expr_lit(_) | expr_assert(_) |
       expr_mac(_) | expr_addr_of(_, _) |
       expr_ret(_) | expr_loop(_, _) |
diff --git a/src/rustc/middle/ty.rs b/src/rustc/middle/ty.rs
index 9bdf2074ba1..5cda414f3a9 100644
--- a/src/rustc/middle/ty.rs
+++ b/src/rustc/middle/ty.rs
@@ -2503,15 +2503,20 @@ fn field_idx(id: ast::ident, fields: ~[field]) -> option<uint> {
     return none;
 }
 
-fn get_field(rec_ty: t, id: ast::ident) -> field {
-    match check vec::find(get_fields(rec_ty), |f| f.ident == id) {
-      some(f) => f
+fn get_field(tcx: ctxt, rec_ty: t, id: ast::ident) -> field {
+    match vec::find(get_fields(rec_ty), |f| f.ident == id) {
+      some(f) => f,
+      // Do we only call this when we know the field is legit?
+      none => fail (#fmt("get_field: ty doesn't have a field %s",
+                         tcx.sess.str_of(id)))
     }
 }
 
 fn get_fields(rec_ty:t) -> ~[field] {
-    match check get(rec_ty).struct {
-      ty_rec(fields) => fields
+    match get(rec_ty).struct {
+      ty_rec(fields) => fields,
+      // Can we check at the caller?
+      _ => fail ~"get_fields: not a record type"
     }
 }
 
@@ -2805,6 +2810,9 @@ fn trait_methods(cx: ctxt, id: ast::def_id) -> @~[method] {
     }
 }
 
+/*
+  Could this return a list of (def_id, substs) pairs?
+ */
 fn impl_traits(cx: ctxt, id: ast::def_id) -> ~[t] {
     if id.crate == ast::local_crate {
         debug!("(impl_traits) searching for trait impl %?", id);
diff --git a/src/rustc/middle/typeck/check.rs b/src/rustc/middle/typeck/check.rs
index b8ee661b1b0..9563163c706 100644
--- a/src/rustc/middle/typeck/check.rs
+++ b/src/rustc/middle/typeck/check.rs
@@ -177,10 +177,12 @@ fn check_bare_fn(ccx: @crate_ctxt,
                  id: ast::node_id,
                  self_info: option<self_info>) {
     let fty = ty::node_id_to_type(ccx.tcx, id);
-    match check ty::get(fty).struct {
+    match ty::get(fty).struct {
         ty::ty_fn(ref fn_ty) => {
             check_fn(ccx, self_info, fn_ty, decl, body, false, none)
         }
+        _ => ccx.tcx.sess.impossible_case(body.span,
+                                 "check_bare_fn: function type expected")
     }
 }
 
@@ -803,7 +805,7 @@ fn impl_self_ty(fcx: @fn_ctxt,
 
     let {n_tps, region_param, raw_ty} = if did.crate == ast::local_crate {
         let region_param = fcx.tcx().region_paramd_items.find(did.node);
-        match check tcx.items.find(did.node) {
+        match tcx.items.find(did.node) {
           some(ast_map::node_item(@{node: ast::item_impl(ts, _, st, _),
                                   _}, _)) => {
             {n_tps: ts.len(),
@@ -1597,7 +1599,7 @@ fn check_expr_with_unifier(fcx: @fn_ctxt,
         fcx.write_ty(id, ty::mk_nil(tcx));
         bot = !may_break(body);
       }
-      ast::expr_match(discrim, arms, _) => {
+      ast::expr_match(discrim, arms, mode) => {
         bot = alt::check_alt(fcx, expr, discrim, arms);
       }
       ast::expr_fn(proto, decl, body, cap_clause) => {
@@ -1640,7 +1642,7 @@ fn check_expr_with_unifier(fcx: @fn_ctxt,
                                             type");
           }
         };
-        match check b.node {
+        match b.node {
           ast::expr_fn_block(decl, body, cap_clause) => {
             check_expr_fn(fcx, b, none,
                           decl, body, true,
@@ -1648,14 +1650,17 @@ fn check_expr_with_unifier(fcx: @fn_ctxt,
             demand::suptype(fcx, b.span, inner_ty, fcx.expr_ty(b));
             capture::check_capture_clause(tcx, b.id, cap_clause);
           }
+          // argh
+          _ => fail ~"expr_fn_block"
         }
         let block_ty = structurally_resolved_type(
             fcx, expr.span, fcx.node_ty(b.id));
-        match check ty::get(block_ty).struct {
+        match ty::get(block_ty).struct {
           ty::ty_fn(fty) => {
             fcx.write_ty(expr.id, ty::mk_fn(tcx, {output: ty::mk_bool(tcx)
                                                   with fty}));
           }
+          _ => fail ~"expected fn type"
         }
       }
       ast::expr_do_body(b) => {
@@ -1670,7 +1675,7 @@ fn check_expr_with_unifier(fcx: @fn_ctxt,
               passed to a `do` function");
           }
         };
-        match check b.node {
+        match b.node {
           ast::expr_fn_block(decl, body, cap_clause) => {
             check_expr_fn(fcx, b, none,
                           decl, body, true,
@@ -1678,13 +1683,16 @@ fn check_expr_with_unifier(fcx: @fn_ctxt,
             demand::suptype(fcx, b.span, inner_ty, fcx.expr_ty(b));
             capture::check_capture_clause(tcx, b.id, cap_clause);
           }
+          // argh
+          _ => fail ~"expected fn ty"
         }
         let block_ty = structurally_resolved_type(
             fcx, expr.span, fcx.node_ty(b.id));
-        match check ty::get(block_ty).struct {
+        match ty::get(block_ty).struct {
           ty::ty_fn(fty) => {
             fcx.write_ty(expr.id, ty::mk_fn(tcx, fty));
           }
+          _ => fail ~"expected fn ty"
         }
       }
       ast::expr_block(b) => {
diff --git a/src/rustc/middle/typeck/check/method.rs b/src/rustc/middle/typeck/check/method.rs
index b8139b181cd..6e254958539 100644
--- a/src/rustc/middle/typeck/check/method.rs
+++ b/src/rustc/middle/typeck/check/method.rs
@@ -222,8 +222,9 @@ struct lookup {
 
     fn report_static_candidate(idx: uint, did: ast::def_id) {
         let span = if did.crate == ast::local_crate {
-            match check self.tcx().items.get(did.node) {
+            match self.tcx().items.get(did.node) {
               ast_map::node_method(m, _, _) => m.span,
+              _ => fail ~"report_static_candidate: bad item"
             }
         } else {
             self.expr.span
@@ -297,8 +298,9 @@ struct lookup {
                 again; /* ok */
               }
               ty::bound_trait(bound_t) => {
-                match check ty::get(bound_t).struct {
-                  ty::ty_trait(i, substs, _) => (i, substs)
+                match ty::get(bound_t).struct {
+                  ty::ty_trait(i, substs, _) => (i, substs),
+                  _ => fail ~"add_candidates_from_param: non-trait bound"
                 }
               }
             };
@@ -402,11 +404,12 @@ struct lookup {
     }
 
     fn ty_from_did(did: ast::def_id) -> ty::t {
-        match check ty::get(ty::lookup_item_type(self.tcx(), did).ty).struct {
+        match ty::get(ty::lookup_item_type(self.tcx(), did).ty).struct {
           ty::ty_fn(fty) => {
             ty::mk_fn(self.tcx(),
                       {proto: ty::proto_vstore(ty::vstore_box) with fty})
           }
+          _ => fail ~"ty_from_did: not function ty"
         }
         /*
         if did.crate == ast::local_crate {
diff --git a/src/rustc/middle/typeck/check/regionmanip.rs b/src/rustc/middle/typeck/check/regionmanip.rs
index b879e4b8fed..fc177c6c8b8 100644
--- a/src/rustc/middle/typeck/check/regionmanip.rs
+++ b/src/rustc/middle/typeck/check/regionmanip.rs
@@ -15,9 +15,9 @@ fn replace_bound_regions_in_fn_ty(
 
     // Take self_info apart; the self_ty part is the only one we want
     // to update here.
-    let self_ty = match self_info {
-      some(s) => some(s.self_ty),
-      none => none
+    let (self_ty, rebuild_self_info) = match self_info {
+      some(s) => (some(s.self_ty), |t| some({self_ty: t with s})),
+      none => (none, |_t| none)
     };
 
     let mut all_tys = ty::tys_in_fn_ty(fn_ty);
@@ -59,22 +59,15 @@ fn replace_bound_regions_in_fn_ty(
 
 
     // Glue updated self_ty back together with its original def_id.
-    let new_self_info = match self_info {
-        some(s) => {
-            match t_self {
-                some(t) => some({self_ty: t with s}),
-                none => {
-                    tcx.sess.bug(~"unexpected t_self in \
-                                   replace_bound_regions_in_fn_ty()");
-                }
-            }
-        },
-        none => none
+    let new_self_info: option<self_info> = match t_self {
+      none    => none,
+      some(t) => rebuild_self_info(t)
     };
 
     return {isr: isr,
          self_info: new_self_info,
-         fn_ty: match check ty::get(t_fn).struct { ty::ty_fn(o) => o }};
+         fn_ty: match ty::get(t_fn).struct { ty::ty_fn(o) => o,
+          _ => tcx.sess.bug(~"replace_bound_regions_in_fn_ty: impossible")}};
 
 
     // Takes `isr`, a (possibly empty) mapping from in-scope region
diff --git a/src/rustc/middle/typeck/check/vtable.rs b/src/rustc/middle/typeck/check/vtable.rs
index 930bb3480b9..e10d7b5c140 100644
--- a/src/rustc/middle/typeck/check/vtable.rs
+++ b/src/rustc/middle/typeck/check/vtable.rs
@@ -59,8 +59,9 @@ fn fixup_substs(fcx: @fn_ctxt, expr: @ast::expr,
     // use a dummy type just to package up the substs that need fixing up
     let t = ty::mk_trait(tcx, id, substs, ty::vstore_slice(ty::re_static));
     do fixup_ty(fcx, expr, t, is_early).map |t_f| {
-        match check ty::get(t_f).struct {
+        match ty::get(t_f).struct {
           ty::ty_trait(_, substs_f, _) => substs_f,
+          _ => fail ~"t_f should be a trait"
         }
     }
 }
@@ -88,8 +89,10 @@ fn lookup_vtable(fcx: @fn_ctxt,
     let _i = indenter();
 
     let tcx = fcx.ccx.tcx;
-    let (trait_id, trait_substs) = match check ty::get(trait_ty).struct {
-      ty::ty_trait(did, substs, _) => (did, substs)
+    let (trait_id, trait_substs) = match ty::get(trait_ty).struct {
+      ty::ty_trait(did, substs, _) => (did, substs),
+      _ => tcx.sess.impossible_case(expr.span, "lookup_vtable: \
+             don't know how to handle a non-trait ty")
     };
     let ty = match fixup_ty(fcx, expr, ty, is_early) {
       some(ty) => ty,
@@ -105,7 +108,7 @@ fn lookup_vtable(fcx: @fn_ctxt,
 
     match ty::get(ty).struct {
       ty::ty_param({idx: n, def_id: did}) => {
-        let mut n_bound = 0u;
+        let mut n_bound = 0;
         for vec::each(*tcx.ty_param_bounds.get(did.node)) |bound| {
             match bound {
               ty::bound_send | ty::bound_copy | ty::bound_const |
@@ -113,7 +116,7 @@ fn lookup_vtable(fcx: @fn_ctxt,
                 /* ignore */
               }
               ty::bound_trait(ity) => {
-                match check ty::get(ity).struct {
+                match ty::get(ity).struct {
                   ty::ty_trait(idid, substs, _) => {
                     if trait_id == idid {
                         debug!("(checking vtable) @0 relating ty to trait ty
@@ -122,6 +125,9 @@ fn lookup_vtable(fcx: @fn_ctxt,
                         return vtable_param(n, n_bound);
                     }
                   }
+                  _ => tcx.sess.impossible_case(expr.span,
+                         "lookup_vtable: in loop, \
+                         don't know how to handle a non-trait ity")
                 }
                 n_bound += 1u;
               }
@@ -277,11 +283,13 @@ fn connect_trait_tps(fcx: @fn_ctxt, expr: @ast::expr, impl_tys: ~[ty::t],
     let trait_ty = ty::subst_tps(tcx, impl_tys, ity);
     debug!("(connect trait tps) trait type is %?, impl did is %?",
            ty::get(trait_ty).struct, impl_did);
-    match check ty::get(trait_ty).struct {
-      ty::ty_trait(_, substs, _) => {
+    match ty::get(trait_ty).struct {
+     ty::ty_trait(_, substs, _) => {
         vec::iter2(substs.tps, trait_tys,
                    |a, b| demand::suptype(fcx, expr.span, a, b));
       }
+     _ => tcx.sess.impossible_case(expr.span, "connect_trait_tps: \
+            don't know how to handle a non-trait ty")
     }
 }