gh-146401: add BuiltinImporter.discover() to find built-in modules

Lib/importlib/_bootstrap.py

@@ -938,6 +938,14 @@ def is_package(cls, fullname):
         """Return False as built-in modules are never packages."""
         return False
 
+    @classmethod
+    def discover(cls, spec=None):
+        if spec is not None: # assume that built-in modules have no submodule
+            return
+        for i in sys.builtin_module_names:
+            if i_spec := cls.find_spec(i):
+                yield i_spec
+
 
 class FrozenImporter:
 

Lib/test/test_traceback.py

@@ -5004,6 +5004,26 @@ def func():
         actual = self.get_suggestion(func)
         self.assertIn("forget to import '_io'", actual)
 
+    def test_import_builtin_module_typo_suggestion(self):
+        def func():
+            import itertool # noqa: F401
+
+        actual = self.get_suggestion(func)
+        self.assertIn("Did you mean: 'itertools'?", actual)
+
+    def test_import_file_module_typo_suggestion(self):
+        def func():
+            import abs # noqa: F401
+
+        actual = self.get_suggestion(func)
+        self.assertIn("Did you mean: 'abc'?", actual)
+
+    def test_import_submodule_typo_suggestion(self):
+        def func():
+            import multiprocessing.dumy # noqa: F401
+
+        actual = self.get_suggestion(func)
+        self.assertIn("Did you mean: 'multiprocessing.dummy'?", actual)
 
 
 class PurePythonSuggestionFormattingTests(