chore: remove old frontend leftovers

src/Init/System/IO.lean

@@ -480,8 +480,4 @@ instance {α : Type} [HasEval α] : HasEval (IO α) :=
 @[noinline, nospecialize] def runEval {α : Type u} [HasEval α] (a : Unit → α) : IO (String × Except IO.Error Unit) :=
   IO.FS.withIsolatedStreams (HasEval.eval a false)
 
--- TODO: delete aux function old frontend
-def runEvalOld {α : Type u} [HasEval α] (a : α) : IO (String × Except IO.Error Unit) :=
-  runEval (fun _ => a)
-
 end Lean

src/Lean/Attributes.lean

@@ -31,9 +31,6 @@ instance : MonadResolveName AttrM := {
   getOpenDecls     := do pure (← read).openDecls
 }
 
--- TODO: after we delete the old frontend, we should use `EIO` with a richer exception kind at AttributeImpl.
--- We must perform a similar modification at `PersistentEnvExtension`
-
 structure AttributeImplCore :=
   (name : Name)
   (descr : String)

src/Lean/Elab/Quotation.lean

@@ -10,16 +10,6 @@ import Lean.Syntax
 import Lean.ResolveName
 import Lean.Elab.Term
 
-/- TODO
-
-Quotations are currently integrated hackily into the old frontend. This implies the following restrictions:
-* quotations have to fit in a single line, because that's how the old scanner works :)
-* `open` commands are not respected (but `export`, `namespace` are)
-* antiquotation terms have to be trivial (locals, consts (w/ projections), and apps, basically)
-
-After removing the old frontend, quotations in this and other files should be cleaned up.
--/
-
 namespace Lean.Elab.Term.Quotation
 
 open Lean.Syntax (isQuot isAntiquot)

src/Lean/Environment.lean

@@ -209,32 +209,6 @@ unsafe def imp : EnvExtensionInterface := {
   mkInitialExtStates := mkInitialExtStates
 }
 
-/- Auxiliary code for supporting old frontend. It will be deleted -/
-namespace OldFrontend
-/- It is not safe to use "extract closed term" optimization in the following code because of `unsafeIO`.
-   If `compiler.extract_closed` is set to true, then the compiler will cache the result of
-   `exts ← envExtensionsRef.get` during initialization which is incorrect. -/
-set_option compiler.extract_closed false
-@[export lean_register_extension]
-unsafe def registerCPPExtension (initial : EnvExtensionState) : Option Nat :=
-  Except.toOption $ unsafeIO do
-    let ext ← registerExt (pure initial)
-    pure ext.idx
-
-@[export lean_set_extension]
-unsafe def setCPPExtensionState (env : Environment) (idx : Nat) (s : EnvExtensionState) : Option Environment :=
-  Except.toOption $ unsafeIO do
-    let exts ← envExtensionsRef.get
-    pure $ setState (exts.get! idx) env s
-
-@[export lean_get_extension]
-unsafe def getCPPExtensionState (env : Environment) (idx : Nat) : Option EnvExtensionState :=
-  Except.toOption $ unsafeIO do
-    let exts ← envExtensionsRef.get
-    pure $ getState (exts.get! idx) env
-
-end OldFrontend
-
 end EnvExtensionInterfaceUnsafe
 
 @[implementedBy EnvExtensionInterfaceUnsafe.imp]

src/Lean/Server/Snapshots.lean

@@ -15,7 +15,6 @@ each command. Importantly, we allow (re)starting compilation from any
 snapshot/position in the file for interactive editing purposes. -/
 
 namespace Lean
-namespace Elab end Elab -- Hack for old frontend
 namespace Server
 namespace Snapshots
 

src/kernel/environment.cpp

@@ -243,56 +243,6 @@ extern "C" object * lean_add_decl(object * env, object * decl) {
         });
 }
 
-static void env_ext_finalizer(void * ext) {
-    delete static_cast<environment_extension*>(ext);
-}
-
-static void env_ext_foreach(void * /* ext */, b_obj_arg /* fn */) {
-    /* The foreach combinator is used by `mark_mt` when marking values as "multi-threaded".
-       Moreover, it is invoked even when we don't use threads because of global
-       IO.Ref is considered to be "multi-threaded".
-
-       So, we just ignore this issue for now.
-       This is not critical since eventually all environment extensions will be implemented in Lean,
-       and we will be able to delete this code.
-    */
-}
-
-static external_object_class * g_env_ext_class = nullptr;
-
-static environment_extension const & to_env_ext(b_obj_arg o) {
-    lean_assert(external_class(o) == g_env_ext_class);
-    return *static_cast<environment_extension *>(external_data(o));
-}
-
-static obj_res to_object(environment_extension * ext) {
-    return alloc_external(g_env_ext_class, ext);
-}
-
-unsigned environment::register_extension(environment_extension * initial) {
-    object * r = lean_register_extension(to_object(initial));
-    if (is_scalar(r)) { throw exception("error creating empty environment"); }
-    unsigned idx = unbox(cnstr_get(r, 0));
-    dec(r);
-    return idx;
-}
-
-environment_extension const & environment::get_extension(unsigned id) const {
-    object * r = lean_get_extension(to_obj_arg(), box(id));
-    if (is_scalar(r)) { throw exception("invalid extension id"); }
-    object * ext = cnstr_get(r, 0);
-    dec(r);
-    return to_env_ext(ext);
-}
-
-environment environment::update(unsigned id, environment_extension * ext) const {
-    object * r = lean_set_extension(to_obj_arg(), box(id), to_object(ext));
-    if (is_scalar(r)) { throw exception("invalid extension id"); }
-    environment env(cnstr_get(r, 0), true);
-    dec(r);
-    return env;
-}
-
 void environment::for_each_constant(std::function<void(constant_info const & d)> const & f) const {
     smap_foreach(cnstr_get(raw(), 1), [&](object *, object * v) {
             constant_info cinfo(v, true);
@@ -307,7 +257,6 @@ void environment::display_stats() const {
 }
 
 void initialize_environment() {
-    g_env_ext_class = register_external_object_class(env_ext_finalizer, env_ext_foreach);
 }
 
 void finalize_environment() {

src/kernel/environment.h

@@ -74,23 +74,6 @@ public:
     /** \brief Extends the current environment with the given declaration */
     environment add(declaration const & d, bool check = true) const;
 
-    /** \brief Register an environment extension. Every environment
-        object may contain this extension. The argument \c initial is
-        the initial value for the new extensions. The extension object
-        can be retrieved using the given token (unsigned integer) returned
-        by this method.
-
-        \remark The extension objects are created on demand.
-
-        \see get_extension */
-    static unsigned register_extension(environment_extension * initial);
-
-    /** \brief Return the extension with the given id. */
-    environment_extension const & get_extension(unsigned extid) const;
-
-    /** \brief Update the environment extension with the given id. */
-    environment update(unsigned extid, environment_extension * ext) const;
-
     /** \brief Apply the function \c f to each constant */
     void for_each_constant(std::function<void(constant_info const & d)> const & f) const;