Syntax restrictions for lazy imports

Lib/test/test_syntax.py

@@ -3394,6 +3394,119 @@ def test_ifexp_body_stmt_else_stmt(self):
         ]:
             self._check_error(f"x = {lhs_stmt} if 1 else {rhs_stmt}", msg)
 
+
+class LazyImportRestrictionTestCase(SyntaxErrorTestCase):
+    """Test syntax restrictions for lazy imports."""
+
+    def test_lazy_import_in_try_block(self):
+        """Test that lazy imports are not allowed inside try blocks."""
+        self._check_error("""\
+try:
+    lazy import os
+except:
+    pass
+""", "lazy import not allowed inside try/except blocks")
+
+        self._check_error("""\
+try:
+    lazy from sys import path
+except ImportError:
+    pass
+""", "lazy from ... import not allowed inside try/except blocks")
+
+    def test_lazy_import_in_trystar_block(self):
+        """Test that lazy imports are not allowed inside try* blocks."""
+        self._check_error("""\
+try:
+    lazy import json
+except* Exception:
+    pass
+""", "lazy import not allowed inside try/except blocks")
+
+        self._check_error("""\
+try:
+    lazy from collections import defaultdict
+except* ImportError:
+    pass
+""", "lazy from ... import not allowed inside try/except blocks")
+
+    def test_lazy_import_in_function(self):
+        """Test that lazy imports are not allowed inside functions."""
+        self._check_error("""\
+def func():
+    lazy import math
+""", "lazy import not allowed inside functions")
+
+        self._check_error("""\
+def func():
+    lazy from datetime import datetime
+""", "lazy from ... import not allowed inside functions")
+
+    def test_lazy_import_in_async_function(self):
+        """Test that lazy imports are not allowed inside async functions."""
+        self._check_error("""\
+async def async_func():
+    lazy import asyncio
+""", "lazy import not allowed inside functions")
+
+        self._check_error("""\
+async def async_func():
+    lazy from json import loads
+""", "lazy from ... import not allowed inside functions")
+
+    def test_lazy_import_in_class(self):
+        """Test that lazy imports are not allowed inside classes."""
+        self._check_error("""\
+class MyClass:
+    lazy import typing
+""", "lazy import not allowed inside classes")
+
+        self._check_error("""\
+class MyClass:
+    lazy from abc import ABC
+""", "lazy from ... import not allowed inside classes")
+
+    def test_lazy_import_star_forbidden(self):
+        """Test that 'lazy from ... import *' is forbidden everywhere."""
+        # At module level should also be forbidden
+        self._check_error("lazy from os import *",
+                         "lazy from ... import \\* is not allowed")
+
+        # Inside function should give lazy function error first
+        self._check_error("""\
+def func():
+    lazy from sys import *
+""", "lazy from ... import not allowed inside functions")
+
+    def test_lazy_import_nested_scopes(self):
+        """Test lazy imports in nested scopes."""
+        self._check_error("""\
+class Outer:
+    def method(self):
+        lazy import sys
+""", "lazy import not allowed inside functions")
+
+        self._check_error("""\
+def outer():
+    class Inner:
+        lazy import json
+""", "lazy import not allowed inside classes")
+
+        self._check_error("""\
+def outer():
+    def inner():
+        lazy from collections import deque
+""", "lazy from ... import not allowed inside functions")
+
+    def test_lazy_import_valid_cases(self):
+        """Test that lazy imports work at module level."""
+        # These should compile without errors
+        compile("lazy import os", "<test>", "exec")
+        compile("lazy from sys import path", "<test>", "exec")
+        compile("lazy import json as j", "<test>", "exec")
+        compile("lazy from datetime import datetime as dt", "<test>", "exec")
+
+
 def load_tests(loader, tests, pattern):
     tests.addTest(doctest.DocTestSuite())
     return tests