diff --git a/src/comp/front/test.rs b/src/comp/front/test.rs
index db1718ad645..38afc23b32a 100644
--- a/src/comp/front/test.rs
+++ b/src/comp/front/test.rs
@@ -192,7 +192,7 @@ fn mk_tests(cx: test_ctxt) -> @ast::item {
          il: ast::il_normal,
          cf: ast::return_val,
          constraints: []};
-    let proto = ast::proto_shared;
+    let proto = ast::proto_bare;
 
     // The vector of test_descs for this crate
     let test_descs = mk_test_desc_vec(cx);
@@ -214,7 +214,7 @@ fn mk_tests(cx: test_ctxt) -> @ast::item {
 }
 
 fn empty_fn_ty() -> ast::ty {
-    let proto = ast::proto_shared;
+    let proto = ast::proto_bare;
     let input_ty = [];
     let ret_ty = @nospan(ast::ty_nil);
     let cf = ast::return_val;
diff --git a/src/comp/metadata/tydecode.rs b/src/comp/metadata/tydecode.rs
index 255ab320aa0..0129c91f00c 100644
--- a/src/comp/metadata/tydecode.rs
+++ b/src/comp/metadata/tydecode.rs
@@ -242,7 +242,8 @@ fn parse_ty(st: @pstate, sd: str_def) -> ty::t {
       }
       'F' {
         let func = parse_ty_fn(st, sd);
-        ret ty::mk_fn(st.tcx, ast::proto_shared, func.args, func.ty, func.cf,
+        ret ty::mk_fn(st.tcx, ast::proto_shared(ast::sugar_normal),
+                      func.args, func.ty, func.cf,
                       func.cs);
       }
       'f' {
diff --git a/src/comp/metadata/tyencode.rs b/src/comp/metadata/tyencode.rs
index 6f03f3f7e35..6f8d7b3b3de 100644
--- a/src/comp/metadata/tyencode.rs
+++ b/src/comp/metadata/tyencode.rs
@@ -195,7 +195,7 @@ fn enc_sty(w: io::writer, cx: @ctxt, st: ty::sty) {
 fn enc_proto(w: io::writer, proto: proto) {
     alt proto {
       proto_iter. { w.write_char('W'); }
-      proto_shared. { w.write_char('F'); }
+      proto_shared(_) { w.write_char('F'); }
       proto_block. { w.write_char('B'); }
       proto_bare. { w.write_char('f'); }
     }
diff --git a/src/comp/middle/alias.rs b/src/comp/middle/alias.rs
index 3314fb890a2..9d170a68480 100644
--- a/src/comp/middle/alias.rs
+++ b/src/comp/middle/alias.rs
@@ -71,7 +71,7 @@ fn visit_fn(cx: @ctx, f: ast::_fn, _tp: [ast::ty_param], sp: span,
 
     let bs = alt f.proto {
       // Blocks need to obey any restrictions from the enclosing scope.
-      ast::proto_block. | ast::proto_closure. { sc.bs }
+      ast::proto_block. | ast::proto_shared(_) { sc.bs }
       // Non capturing functions start out fresh.
       _ { [] }
     };
diff --git a/src/comp/middle/freevars.rs b/src/comp/middle/freevars.rs
index ea6d57e351b..1bd4f8f0f15 100644
--- a/src/comp/middle/freevars.rs
+++ b/src/comp/middle/freevars.rs
@@ -36,7 +36,8 @@ fn collect_freevars(def_map: resolve::def_map, walker: fn@(visit::vt<int>)) ->
             alt expr.node {
               ast::expr_fn(f) {
                 if f.proto == ast::proto_block ||
-                       f.proto == ast::proto_closure {
+                    f.proto == ast::proto_shared(ast::sugar_normal) ||
+                    f.proto == ast::proto_shared(ast::sugar_sexy) {
                     visit::visit_expr(expr, depth + 1, v);
                 }
               }
diff --git a/src/comp/middle/resolve.rs b/src/comp/middle/resolve.rs
index e287cc4ec77..2d3fcb46406 100644
--- a/src/comp/middle/resolve.rs
+++ b/src/comp/middle/resolve.rs
@@ -595,7 +595,6 @@ fn lookup_in_scope_strict(e: env, sc: scopes, sp: span, name: ident,
 fn scope_is_fn(sc: scope) -> bool {
     ret alt sc {
           scope_fn(_, ast::proto_iter., _) |
-          scope_fn(_, ast::proto_shared., _) |
           scope_fn(_, ast::proto_bare., _) |
           scope_native_item(_) {
             true
@@ -607,7 +606,7 @@ fn scope_is_fn(sc: scope) -> bool {
 fn scope_closes(sc: scope) -> option::t<bool> {
     alt sc {
       scope_fn(_, ast::proto_block., _) | scope_loop(_, true) { some(true) }
-      scope_fn(_, ast::proto_closure., _) { some(false) }
+      scope_fn(_, ast::proto_shared(_), _) { some(false) }
       _ { none }
     }
 }
diff --git a/src/comp/middle/trans.rs b/src/comp/middle/trans.rs
index 471fd4b2094..de5c3cb5398 100644
--- a/src/comp/middle/trans.rs
+++ b/src/comp/middle/trans.rs
@@ -2250,10 +2250,12 @@ fn trans_expr_fn(bcx: @block_ctxt, f: ast::_fn, sp: span,
     let s = mangle_internal_name_by_path(ccx, sub_cx.path);
     let llfn = decl_internal_cdecl_fn(ccx.llmod, s, llfnty);
 
-    let copying = f.proto == ast::proto_closure;
+    let copying =
+        f.proto == ast::proto_shared(ast::sugar_normal)
+        || f.proto == ast::proto_shared(ast::sugar_sexy);
     let env;
     alt f.proto {
-      ast::proto_block. | ast::proto_closure. {
+      ast::proto_block. | ast::proto_shared(_) {
         let upvars = get_freevars(ccx.tcx, id);
         let env_r = build_closure(bcx, upvars, copying);
         env = env_r.ptr;
@@ -5349,7 +5351,8 @@ fn trans_res_ctor(cx: @local_ctxt, sp: span, dtor: ast::_fn,
     }
     let fcx = new_fn_ctxt(cx, sp, llctor_decl);
     let ret_t = ty::ret_ty_of_fn(cx.ccx.tcx, ctor_id);
-    create_llargs_for_fn_args(fcx, ast::proto_shared, none::<ty::t>, ret_t,
+    create_llargs_for_fn_args(fcx, ast::proto_shared(ast::sugar_normal),
+                              none::<ty::t>, ret_t,
                               dtor.decl.inputs, ty_params);
     let bcx = new_top_block_ctxt(fcx);
     let lltop = bcx.llbb;
@@ -5409,7 +5412,8 @@ fn trans_tag_variant(cx: @local_ctxt, tag_id: ast::node_id,
       }
     }
     let fcx = new_fn_ctxt(cx, variant.span, llfndecl);
-    create_llargs_for_fn_args(fcx, ast::proto_shared, none::<ty::t>,
+    create_llargs_for_fn_args(fcx, ast::proto_shared(ast::sugar_normal),
+                              none::<ty::t>,
                               ty::ret_ty_of_fn(cx.ccx.tcx, variant.node.id),
                               fn_args, ty_params);
     let ty_param_substs: [ty::t] = [];
@@ -5616,7 +5620,8 @@ fn create_main_wrapper(ccx: @crate_ctxt, sp: span, main_llfn: ValueRef,
         let nt = ty::mk_nil(ccx.tcx);
         check non_ty_var(ccx, nt);
 
-        let llfty = type_of_fn(ccx, sp, ast::proto_shared, false, false,
+        let llfty = type_of_fn(ccx, sp, ast::proto_shared(ast::sugar_normal),
+                               false, false,
                                [vecarg_ty], nt, 0u);
         let llfdecl = decl_fn(ccx.llmod, "_rust_main",
                               lib::llvm::LLVMCCallConv, llfty);
@@ -5729,7 +5734,8 @@ fn native_fn_wrapper_type(cx: @crate_ctxt, sp: span, ty_param_count: uint,
     alt ty::struct(cx.tcx, x) {
       ty::ty_native_fn(abi, args, out) {
         check non_ty_var(cx, out);
-        ret type_of_fn(cx, sp, ast::proto_shared, false, false, args, out,
+        ret type_of_fn(cx, sp, ast::proto_shared(ast::sugar_normal),
+                       false, false, args, out,
                        ty_param_count);
       }
     }
diff --git a/src/comp/middle/trans_common.rs b/src/comp/middle/trans_common.rs
index d7357c9a2f4..4caa38a7421 100644
--- a/src/comp/middle/trans_common.rs
+++ b/src/comp/middle/trans_common.rs
@@ -340,7 +340,8 @@ fn get_res_dtor(ccx: @crate_ctxt, sp: span, did: ast::def_id, inner_t: ty::t)
     let nil_res = ty::mk_nil(ccx.tcx);
     // FIXME: Silly check -- mk_nil should have a postcondition
     check non_ty_var(ccx, nil_res);
-    let f_t = type_of_fn(ccx, sp, ast::proto_shared, false, false,
+    let f_t = type_of_fn(ccx, sp, ast::proto_shared(ast::sugar_normal),
+                         false, false,
                          [{mode: ast::by_ref, ty: inner_t}],
                          nil_res, params);
     ret trans::get_extern_const(ccx.externs, ccx.llmod,
diff --git a/src/comp/middle/trans_objects.rs b/src/comp/middle/trans_objects.rs
index 5a1209d0f08..6103e3ec455 100644
--- a/src/comp/middle/trans_objects.rs
+++ b/src/comp/middle/trans_objects.rs
@@ -52,7 +52,8 @@ fn trans_obj(cx: @local_ctxt, sp: span, ob: ast::_obj, ctor_id: ast::node_id,
     let lltop = bcx.llbb;
 
     // Both regular arguments and type parameters are handled here.
-    create_llargs_for_fn_args(fcx, ast::proto_shared, none::<ty::t>,
+    create_llargs_for_fn_args(fcx, ast::proto_shared(ast::sugar_normal),
+                              none::<ty::t>,
                               ty::ret_ty_of_fn(ccx.tcx, ctor_id), fn_args,
                               ty_params);
     let arg_tys: [ty::arg] = arg_tys_of_fn(ccx, ctor_id);
diff --git a/src/comp/middle/ty.rs b/src/comp/middle/ty.rs
index 950e91c275b..47bfa483e4d 100644
--- a/src/comp/middle/ty.rs
+++ b/src/comp/middle/ty.rs
@@ -1012,8 +1012,7 @@ fn type_kind(cx: ctxt, ty: t) -> ast::kind {
         result = alt proto {
           ast::proto_iter. { ast::kind_shared }
           ast::proto_block. { ast::kind_pinned }
-          ast::proto_closure. { ast::kind_shared }
-          ast::proto_shared. { ast::kind_shared }
+          ast::proto_shared(_) { ast::kind_shared }
           ast::proto_bare. { ast::kind_unique }
         };
       }
@@ -1616,7 +1615,10 @@ fn ty_fn_args(cx: ctxt, fty: t) -> [arg] {
 fn ty_fn_proto(cx: ctxt, fty: t) -> ast::proto {
     alt struct(cx, fty) {
       ty::ty_fn(p, _, _, _, _) { ret p; }
-      ty::ty_native_fn(_, _, _) { ret ast::proto_shared; }
+      ty::ty_native_fn(_, _, _) {
+        // FIXME: This should probably be proto_bare
+        ret ast::proto_shared(ast::sugar_normal);
+      }
       _ { cx.sess.bug("ty_fn_proto() called on non-fn type"); }
     }
 }
@@ -2031,7 +2033,7 @@ mod unify {
                 // Every function type is a subtype of block
                 false
               }
-              ast::proto_closure. | ast::proto_shared. {
+              ast::proto_shared(_) {
                 a_proto == ast::proto_block
               }
               ast::proto_bare. {
diff --git a/src/comp/middle/typeck.rs b/src/comp/middle/typeck.rs
index 66663ea251e..389bc3e6722 100644
--- a/src/comp/middle/typeck.rs
+++ b/src/comp/middle/typeck.rs
@@ -477,10 +477,9 @@ mod write {
 // code. This is needed because fn and lambda have fn type while iter
 // has iter type and block has block type. This may end up changing.
 fn proto_to_ty_proto(proto: ast::proto) -> ast::proto {
-    ret alt proto {
-          ast::proto_iter. | ast::proto_block. | ast::proto_bare. { proto }
-          _ { ast::proto_shared }
-        };
+    // FIXME: This is no longer needed since fn@ and lambda have
+    // the same type
+    proto
 }
 
 // Item collection - a pair of bootstrap passes:
@@ -612,7 +611,8 @@ mod collect {
         }
 
         let t_fn =
-            ty::mk_fn(cx.tcx, ast::proto_shared, t_inputs, t_obj.ty,
+            ty::mk_fn(cx.tcx, ast::proto_shared(ast::sugar_normal),
+                      t_inputs, t_obj.ty,
                       ast::return_val, []);
         let tpt = {kinds: ty_param_kinds(ty_params), ty: t_fn};
         cx.tcx.tcache.insert(local_def(ctor_id), tpt);
@@ -723,7 +723,8 @@ mod collect {
                 let tag_t = ty::mk_tag(cx.tcx, tag_id, ty_param_tys);
                 // FIXME: this will be different for constrained types
                 result_ty =
-                    ty::mk_fn(cx.tcx, ast::proto_shared, args, tag_t,
+                    ty::mk_fn(cx.tcx, ast::proto_shared(ast::sugar_normal),
+                              args, tag_t,
                               ast::return_val, []);
             }
             let tpt = {kinds: ty_param_kinds(ty_params), ty: result_ty};
@@ -793,10 +794,12 @@ mod collect {
                 ty::mk_res(cx.tcx, local_def(it.id), t_arg.ty,
                            mk_ty_params(cx, tps));
             let t_ctor =
-                ty::mk_fn(cx.tcx, ast::proto_shared, [t_arg], t_res,
+                ty::mk_fn(cx.tcx, ast::proto_shared(ast::sugar_normal),
+                          [t_arg], t_res,
                           ast::return_val, []);
             let t_dtor =
-                ty::mk_fn(cx.tcx, ast::proto_shared, [t_arg],
+                ty::mk_fn(cx.tcx, ast::proto_shared(ast::sugar_normal),
+                          [t_arg],
                           ty::mk_nil(cx.tcx),
                           ast::return_val, []);
             write::ty_only(cx.tcx, it.id, t_res);
@@ -2092,7 +2095,7 @@ fn check_expr_with_unifier(fcx: @fn_ctxt, expr: @ast::expr, unify: unifier,
             constrs = constrs_;
           }
           ty::ty_native_fn(_, arg_tys_, rt_) {
-            proto = ast::proto_shared;
+            proto = ast::proto_shared(ast::sugar_normal);
             arg_tys = arg_tys_;
             rt = rt_;
             cf = ast::return_val;
@@ -2117,7 +2120,7 @@ fn check_expr_with_unifier(fcx: @fn_ctxt, expr: @ast::expr, unify: unifier,
         fn lower_bound_proto(proto: ast::proto) -> ast::proto {
             // FIXME: This is right for bare fns, possibly not others
             alt proto {
-              ast::proto_bare. { ast::proto_shared }
+              ast::proto_bare. { ast::proto_shared(ast::sugar_normal) }
               _ { proto }
             }
         }
@@ -2568,7 +2571,7 @@ fn check_const(ccx: @crate_ctxt, _sp: span, e: @ast::expr, id: ast::node_id) {
     let fcx: @fn_ctxt =
         @{ret_ty: rty,
           purity: ast::pure_fn,
-          proto: ast::proto_shared,
+          proto: ast::proto_shared(ast::sugar_normal),
           var_bindings: ty::unify::mk_var_bindings(),
           locals: new_int_hash::<int>(),
           local_names: new_int_hash::<ast::ident>(),
diff --git a/src/comp/syntax/ast.rs b/src/comp/syntax/ast.rs
index 8ec411cff5e..80d6e7cb754 100644
--- a/src/comp/syntax/ast.rs
+++ b/src/comp/syntax/ast.rs
@@ -103,13 +103,16 @@ tag kind { kind_pinned; kind_shared; kind_unique; }
 
 tag _auth { auth_unsafe; }
 
+tag proto_sugar {
+    sugar_normal;
+    sugar_sexy;
+}
+
 tag proto {
     proto_iter;
-    proto_shared;
-    proto_block;
-    // FIXME: Merge with proto_shared
-    proto_closure;
     proto_bare;
+    proto_shared(proto_sugar);
+    proto_block;
 }
 
 tag binop {
diff --git a/src/comp/syntax/parse/parser.rs b/src/comp/syntax/parse/parser.rs
index 0f2c93756b7..4d48fd3c653 100644
--- a/src/comp/syntax/parse/parser.rs
+++ b/src/comp/syntax/parse/parser.rs
@@ -842,7 +842,7 @@ fn parse_bottom_expr(p: parser) -> @ast::expr {
     } else if eat_word(p, "block") {
         ret parse_fn_expr(p, ast::proto_block);
     } else if eat_word(p, "lambda") {
-        ret parse_fn_expr(p, ast::proto_closure);
+        ret parse_fn_expr(p, ast::proto_shared(ast::sugar_sexy));
     } else if eat_word(p, "unchecked") {
         ret parse_block_expr(p, lo, ast::unchecked_blk);
     } else if eat_word(p, "unsafe") {
@@ -1901,7 +1901,8 @@ fn parse_item_res(p: parser, attrs: [ast::attribute]) -> @ast::item {
          il: ast::il_normal,
          cf: ast::return_val,
          constraints: []};
-    let f = {decl: decl, proto: ast::proto_shared, body: dtor};
+    let f = {decl: decl, proto: ast::proto_shared(ast::sugar_normal),
+             body: dtor};
     ret mk_item(p, lo, dtor.span.hi, ident,
                 ast::item_res(f, p.get_id(), ty_params, p.get_id()), attrs);
 }
@@ -2140,7 +2141,7 @@ fn parse_fn_item_proto(p: parser) -> ast::proto {
         ast::proto_bare
     } else if p.peek() == token::AT {
         p.bump();
-        ast::proto_shared
+        ast::proto_shared(ast::sugar_normal)
     } else {
         ast::proto_bare
     }
@@ -2152,7 +2153,7 @@ fn parse_fn_ty_proto(p: parser) -> ast::proto {
         ast::proto_bare
     } else if p.peek() == token::AT {
         p.bump();
-        ast::proto_shared
+        ast::proto_shared(ast::sugar_normal)
     } else {
         ast::proto_bare
     }
@@ -2164,7 +2165,7 @@ fn parse_fn_anon_proto(p: parser) -> ast::proto {
         ast::proto_bare
     } else if p.peek() == token::AT {
         p.bump();
-        ast::proto_shared
+        ast::proto_shared(ast::sugar_normal)
     } else {
         ast::proto_bare
     }
diff --git a/src/comp/syntax/print/pprust.rs b/src/comp/syntax/print/pprust.rs
index 4c4b66c59fe..76a2fd1d843 100644
--- a/src/comp/syntax/print/pprust.rs
+++ b/src/comp/syntax/print/pprust.rs
@@ -1643,11 +1643,11 @@ fn ast_fn_constrs_str(decl: ast::fn_decl, constrs: [@ast::constr]) -> str {
 
 fn proto_to_str(p: ast::proto) -> str {
     ret alt p {
-          ast::proto_shared. { "fn@" }
           ast::proto_iter. { "iter" }
-          ast::proto_block. { "block" }
-          ast::proto_closure. { "lambda" }
           ast::proto_bare. { "fn" }
+          ast::proto_block. { "block" }
+          ast::proto_shared(ast::sugar_normal.) { "fn@" }
+          ast::proto_shared(ast::sugar_sexy.) { "lambda" }
         };
 }
 
diff --git a/src/comp/util/ppaux.rs b/src/comp/util/ppaux.rs
index 6640bc37f2d..b9197f1a63f 100644
--- a/src/comp/util/ppaux.rs
+++ b/src/comp/util/ppaux.rs
@@ -129,7 +129,7 @@ fn ty_to_str(cx: ctxt, typ: t) -> str {
             fn_to_str(cx, proto, none, inputs, output, cf, constrs)
           }
           ty_native_fn(_, inputs, output) {
-            fn_to_str(cx, ast::proto_shared, none, inputs, output,
+            fn_to_str(cx, ast::proto_bare, none, inputs, output,
                       ast::return_val, [])
           }
           ty_obj(meths) {