diff --git a/artiq/master/worker_impl.py b/artiq/master/worker_impl.py
index 29ec4e427..50896a946 100644
--- a/artiq/master/worker_impl.py
+++ b/artiq/master/worker_impl.py
@@ -20,6 +20,8 @@ from sipyco import pipe_ipc, pyon
 from sipyco.packed_exceptions import raise_packed_exc
 from sipyco.logging_tools import multiline_log_config
 
+from nac3artiq import CompileError
+
 import artiq
 from artiq import tools
 from artiq.master.worker_db import DeviceManager, DatasetManager, DummyDevice
@@ -27,9 +29,7 @@ from artiq.language.environment import (
     is_public_experiment, TraceArgumentManager, ProcessArgumentManager
 )
 from artiq.language.core import set_watchdog_factory, TerminationRequested
-from artiq.language.types import TBool
 from artiq.language import import_cache
-from artiq.coredevice.core import CompileError, host_only, _render_diagnostic
 from artiq import __version__ as artiq_version
 
 
@@ -98,13 +98,13 @@ class Scheduler:
         self.priority = priority
 
     pause_noexc = staticmethod(make_parent_action("pause"))
-    @host_only
+
     def pause(self):
         if self.pause_noexc():
             raise TerminationRequested
 
     _check_pause = staticmethod(make_parent_action("scheduler_check_pause"))
-    def check_pause(self, rid=None) -> TBool:
+    def check_pause(self, rid=None) -> bool:
         if rid is None:
             rid = self.rid
         return self._check_pause(rid)
@@ -182,31 +182,6 @@ def examine(device_mgr, dataset_mgr, file):
             del sys.modules[key]
 
 
-def setup_diagnostics(experiment_file, repository_path):
-    def render_diagnostic(self, diagnostic):
-        message = "While compiling {}\n".format(experiment_file) + \
-                    _render_diagnostic(diagnostic, colored=False)
-        if repository_path is not None:
-            message = message.replace(repository_path, "<repository>")
-
-        if diagnostic.level == "warning":
-            logging.warning(message)
-        else:
-            logging.error(message)
-
-    # This is kind of gross, but 1) we do not have any explicit connection
-    # between the worker and a coredevice.core.Core instance at all,
-    # and 2) the diagnostic engine really ought to be per-Core, since
-    # that's what uses it and the repository path is per-Core.
-    # So I don't know how to implement this properly for now.
-    #
-    # This hack is as good or bad as any other solution that involves
-    # putting inherently local objects (the diagnostic engine) into
-    # global slots, and there isn't any point in making it prettier by
-    # wrapping it in layers of indirection.
-    artiq.coredevice.core._DiagnosticEngine.render_diagnostic = \
-        render_diagnostic
-
 
 def put_completed():
     put_object({"action": "completed"})
@@ -278,7 +253,6 @@ def main():
                 else:
                     experiment_file = expid["file"]
                     repository_path = None
-                setup_diagnostics(experiment_file, repository_path)
                 exp = get_experiment(experiment_file, expid["class_name"])
                 device_mgr.virtual_devices["scheduler"].set_run_info(
                     rid, obj["pipeline_name"], expid, obj["priority"])