diff --git a/jedi/inference/compiled/subprocess/functions.py b/jedi/inference/compiled/subprocess/functions.py
index fe2c4d18..39181993 100644
--- a/jedi/inference/compiled/subprocess/functions.py
+++ b/jedi/inference/compiled/subprocess/functions.py
@@ -1,10 +1,13 @@
 from __future__ import print_function
 import sys
 import os
+import re
+import inspect
 
 from jedi._compatibility import find_module, cast_path, force_unicode, \
-    all_suffixes
+    all_suffixes, scandir
 from jedi.inference.compiled import access
+from jedi import debug
 from jedi import parser_utils
 
 
@@ -77,3 +80,37 @@ def _get_init_path(directory_path):
 
 def safe_literal_eval(inference_state, value):
     return parser_utils.safe_literal_eval(value)
+
+
+def iter_module_names(*args, **kwargs):
+    return list(_iter_module_names(*args, **kwargs))
+    return sorted(set(_iter_module_names(*args, **kwargs)))
+
+
+def _iter_module_names(inference_state, paths):
+    # Python modules/packages
+    for path in paths:
+        try:
+            dirs = scandir(path)
+        except OSError:
+            # The file might not exist or reading it might lead to an error.
+            debug.warning("Not possible to list directory: %s", path)
+            continue
+        for dir_entry in dirs:
+            name = dir_entry.name
+            # First Namespaces then modules/stubs
+            if dir_entry.is_dir():
+                # pycache is obviously not an interestin namespace. Also the
+                # name must be a valid identifier.
+                # TODO use str.isidentifier, once Python 2 is removed
+                if name != '__pycache__' and not re.search(r'\W|^\d', name):
+                    yield name
+            else:
+                if name.endswith('.pyi'):  # Stub files
+                    modname = name[:-4]
+                else:
+                    modname = inspect.getmodulename(name)
+
+                if modname and '.' not in modname:
+                    if modname != '__init__':
+                        yield modname
diff --git a/jedi/inference/imports.py b/jedi/inference/imports.py
index 2ae6b498..926d05ef 100644
--- a/jedi/inference/imports.py
+++ b/jedi/inference/imports.py
@@ -31,7 +31,6 @@ from jedi.inference.names import ImportName, SubModuleName
 from jedi.inference.base_value import ValueSet, NO_VALUES
 from jedi.inference.gradual.typeshed import import_module_decorator, \
     create_stub_module, parse_stub_module
-from jedi.inference.value.module import iter_module_names as module_iter_module_names
 from jedi.plugins import plugin_manager
 
 
@@ -560,5 +559,5 @@ def iter_module_names(inference_state, module_context, search_path,
         for name in inference_state.compiled_subprocess.get_builtin_module_names():
             yield module_cls(module_context, name)
 
-    for name in module_iter_module_names(inference_state, search_path):
+    for name in inference_state.compiled_subprocess.iter_module_names(search_path):
         yield module_cls(module_context, name)
diff --git a/jedi/inference/value/module.py b/jedi/inference/value/module.py
index 72048ff7..51cc5863 100644
--- a/jedi/inference/value/module.py
+++ b/jedi/inference/value/module.py
@@ -1,8 +1,5 @@
-import re
 import os
 
-from jedi._compatibility import scandir
-from jedi import debug
 from jedi.inference.cache import inference_state_method_cache
 from jedi.inference.names import AbstractNameDefinition, ModuleName
 from jedi.inference.filters import GlobalNameFilter, ParserTreeFilter, DictFilter, MergedFilter
@@ -38,38 +35,6 @@ class _ModuleAttributeName(AbstractNameDefinition):
         return compiled.get_string_value_set(self.parent_context.inference_state)
 
 
-def iter_module_names(*args, **kwargs):
-    return sorted(set(iter_module_names(*args, **kwargs)))
-
-
-def iter_module_names(inference_state, paths):
-    # Python modules/packages
-    for path in paths:
-        try:
-            dirs = scandir(path)
-        except OSError:
-            # The file might not exist or reading it might lead to an error.
-            debug.warning("Not possible to list directory: %s", path)
-            continue
-        for dir_entry in dirs:
-            name = dir_entry.name
-            # First Namespaces then modules/stubs
-            if dir_entry.is_dir():
-                # pycache is obviously not an interestin namespace. Also the
-                # name must be a valid identifier.
-                # TODO use str.isidentifier, once Python 2 is removed
-                if name != '__pycache__' and not re.search(r'\W|^\d', name):
-                    yield name
-            else:
-                if name.endswith('.py'):
-                    if name != '__init__.py':
-                        yield name[:-3]
-                # Stub files
-                elif name.endswith('.pyi'):
-                    if name != '__init__.pyi':
-                        yield name[:-4]
-
-
 class SubModuleDictMixin(object):
     @inference_state_method_cache()
     def sub_modules_dict(self):
@@ -79,7 +44,9 @@ class SubModuleDictMixin(object):
         """
         names = {}
         if self.is_package():
-            mods = iter_module_names(self.inference_state, self.py__path__())
+            mods = self.inference_state.compiled_subprocess.iter_module_names(
+                self.py__path__()
+            )
             for name in mods:
                 # It's obviously a relative import to the current module.
                 names[name] = SubModuleName(self.as_context(), name)
diff --git a/test/completion/on_import.py b/test/completion/on_import.py
index 76984b12..ddf04151 100644
--- a/test/completion/on_import.py
+++ b/test/completion/on_import.py
@@ -12,6 +12,8 @@ def from_names_goto():
 def builtin_test():
     #? ['math']
     import math
+    #? ['mmap']
+    import mmap
 
 # -----------------
 # completions within imports