diff --git a/library/init/lean/expr.lean b/library/init/lean/expr.lean
index f90ecee012..58e99c69d3 100644
--- a/library/init/lean/expr.lean
+++ b/library/init/lean/expr.lean
@@ -69,15 +69,11 @@ args.foldl expr.app fn
 def mk_capp (fn : name) (args : list expr) : expr :=
 mk_app (expr.const fn []) args
 
--- Mark as opaque
 @[extern "lean_expr_hash"]
-protected def hash (n : @& expr) : usize :=
-0 -- dummy implementation
+constant hash (n : @& expr) : usize := default usize
 
--- Mark as opaque
 @[extern "lean_expr_dbg_to_string"]
-protected def dbg_to_string (e : @& expr) : string :=
-"" -- dummy implementation
+constant dbg_to_string (e : @& expr) : string := default string
 
 end expr
 
diff --git a/library/init/lean/level.lean b/library/init/lean/level.lean
index 9cd2191e03..883ef2011b 100644
--- a/library/init/lean/level.lean
+++ b/library/init/lean/level.lean
@@ -71,10 +71,8 @@ def level.instantiate (s : name → option level) : level → level
    | none    := l)
 | l                  := l
 
--- Mark as opaque
 @[extern "lean_level_hash"]
-protected def level.hash (n : @& level) : usize :=
-0 -- dummy implementation
+constant level.hash (n : @& level) : usize := default usize
 
 /- level to format -/
 namespace level_to_format
diff --git a/library/init/lean/name.lean b/library/init/lean/name.lean
index c28bba0587..3742af4cbd 100644
--- a/library/init/lean/name.lean
+++ b/library/init/lean/name.lean
@@ -32,15 +32,8 @@ instance string_to_name : has_coe string name :=
 ⟨mk_simple_name⟩
 
 namespace name
-private def hash_aux : name → usize → usize
-| anonymous        r := r
-| (mk_string n s)  r := hash_aux n (mix_hash r (hash s))
-| (mk_numeral n k) r := hash_aux n (mix_hash r (hash k))
-
--- TODO: mark as opaque
 @[extern "lean_name_hash_usize"]
-protected def hash (n : @& name) : usize :=
-hash_aux n 11
+constant hash (n : @& name) : usize := default usize
 
 instance : hashable name :=
 ⟨name.hash⟩
diff --git a/src/boot/init/lean/name.cpp b/src/boot/init/lean/name.cpp
index 09015fa1ee..613fbee5aa 100644
--- a/src/boot/init/lean/name.cpp
+++ b/src/boot/init/lean/name.cpp
@@ -26,7 +26,6 @@ obj* l_lean_name_decidable__eq;
 obj* l_lean_mk__str__name(obj*, obj*);
 obj* l_rbnode_ins___main___at_lean_name__map_insert___spec__3___boxed(obj*);
 obj* l_rbnode_insert___at_lean_name__map_insert___spec__2___rarg___boxed(obj*, obj*, obj*, obj*);
-obj* l___private_init_lean_name_1__hash__aux___main___boxed(obj*, obj*);
 obj* l_lean_name_components_x_27(obj*);
 obj* l_lean_name__map_find___rarg___boxed(obj*, obj*);
 obj* l_lean_name_quick__lt__core___main___boxed(obj*, obj*);
@@ -82,7 +81,6 @@ obj* l_lean_name_append___main(obj*, obj*);
 obj* l_lean_name_to__string__with__sep(obj*, obj*);
 obj* l_lean_name_to__string__with__sep___main___boxed(obj*, obj*);
 obj* l_lean_name_dec__eq___boxed(obj*, obj*);
-usize l___private_init_lean_name_1__hash__aux(obj*, usize);
 obj* l_rbnode_ins___main___at_lean_name__set_insert___spec__4(obj*, obj*, obj*, obj*);
 obj* l_rbmap_insert___main___at_lean_name__map_insert___spec__1___boxed(obj*);
 obj* l_lean_name__map_insert___boxed(obj*);
@@ -108,17 +106,12 @@ obj* l_lean_mk__num__name(obj*, obj*);
 uint8 l_lean_name_quick__lt(obj*, obj*);
 obj* l_lean_mk__simple__name(obj*);
 obj* l_lean_name_lean_has__to__format(obj*);
-namespace lean {
-usize usize_of_nat(obj*);
-}
 obj* l_rbnode_balance1___main___rarg(obj*, obj*);
-obj* l___private_init_lean_name_1__hash__aux___boxed(obj*, obj*);
 obj* l_lean_name_to__string__with__sep___boxed(obj*, obj*);
 obj* l_lean_name__map_find(obj*);
 obj* l_lean_name_update__prefix___main(obj*, obj*);
 obj* l_lean_name_get__prefix(obj*);
 obj* l_rbnode_ins___main___at_lean_name__map_insert___spec__3___rarg(obj*, obj*, obj*, obj*);
-usize l___private_init_lean_name_1__hash__aux___main(obj*, usize);
 obj* l_rbmap_find___main___at_lean_name__map_find___spec__1___rarg___boxed(obj*, obj*);
 extern "C" obj* lean_name_mk_numeral(obj*, obj*);
 obj* l_nat_repr(obj*);
@@ -184,56 +177,6 @@ x_0 = lean::alloc_closure(reinterpret_cast<void*>(l_lean_mk__simple__name), 1, 0
 return x_0;
 }
 }
-usize l___private_init_lean_name_1__hash__aux___main(obj* x_0, usize x_1) {
-_start:
-{
-switch (lean::obj_tag(x_0)) {
-case 0:
-{
-return x_1;
-}
-default:
-{
-obj* x_2; usize x_3; 
-x_2 = lean::cnstr_get(x_0, 0);
-x_3 = 0;
-x_0 = x_2;
-x_1 = x_3;
-goto _start;
-}
-}
-}
-}
-obj* l___private_init_lean_name_1__hash__aux___main___boxed(obj* x_0, obj* x_1) {
-_start:
-{
-usize x_2; usize x_3; obj* x_4; 
-x_2 = lean::unbox_size_t(x_1);
-x_3 = l___private_init_lean_name_1__hash__aux___main(x_0, x_2);
-x_4 = lean::box_size_t(x_3);
-lean::dec(x_0);
-return x_4;
-}
-}
-usize l___private_init_lean_name_1__hash__aux(obj* x_0, usize x_1) {
-_start:
-{
-usize x_2; 
-x_2 = l___private_init_lean_name_1__hash__aux___main(x_0, x_1);
-return x_2;
-}
-}
-obj* l___private_init_lean_name_1__hash__aux___boxed(obj* x_0, obj* x_1) {
-_start:
-{
-usize x_2; usize x_3; obj* x_4; 
-x_2 = lean::unbox_size_t(x_1);
-x_3 = l___private_init_lean_name_1__hash__aux(x_0, x_2);
-x_4 = lean::box_size_t(x_3);
-lean::dec(x_0);
-return x_4;
-}
-}
 obj* l_lean_name_hash___boxed(obj* x_0) {
 _start:
 {