Fixed subscripts of unimportable types not being handled correctly

Fixes #336.

docs/versionhistory.rst

@@ -3,6 +3,11 @@ Version history
 
 This library adheres to `Semantic Versioning 2.0 <https://semver.org/#semantic-versioning-200>`_.
 
+**UNRELEASED**
+
+- Fixed imports guarded by ``if TYPE_CHECKING:`` when used with subscripts
+  (``SomeType[...]``) being replaced with ``Any[...]`` instead of just ``Any``
+
 **4.0.0rc3** (2023-04-10)
 
 - Fixed ``typing.Literal`` subscript contents being evaluated as forward references

src/typeguard/_transformer.py

@@ -370,6 +370,12 @@ def visit_Attribute(self, node: Attribute) -> Any:
         return node
 
     def visit_Subscript(self, node: Subscript) -> Any:
+        if self._memo.is_ignored_name(node.value):
+            if self.level > 0:
+                return self.transformer._get_import("typing", "Any")
+            else:
+                return None
+
         self.level += 1
 
         # The subscript of typing(_extensions).Literal can be any arbitrary string, so

tests/dummymodule.py

@@ -316,11 +316,25 @@ def typed_variable_args(
 
 
 @typechecked
-def guarded_type_hint(x: "Imaginary") -> "Imaginary":
+def guarded_type_hint_plain(x: "Imaginary") -> "Imaginary":
     y: Imaginary = x
     return y
 
 
+@typechecked
+def guarded_type_hint_subscript_toplevel(x: "Imaginary[int]") -> "Imaginary[int]":
+    y: Imaginary[int] = x
+    return y
+
+
+@typechecked
+def guarded_type_hint_subscript_nested(
+    x: List["Imaginary[int]"],
+) -> List["Imaginary[int]"]:
+    y: List[Imaginary[int]] = x
+    return y
+
+
 @typechecked
 def literal(x: Literal["foo"]) -> Literal["foo"]:
     y: Literal["foo"] = x

tests/test_instrumentation.py

@@ -332,8 +332,15 @@ def test_kwargs_fail(self, dummymodule):
             dummymodule.typed_variable_args("foo", "bar", a="baz")
 
 
-def test_guarded_type(dummymodule):
-    assert dummymodule.guarded_type_hint("foo") == "foo"
+class TestGuardedType:
+    def test_plain(self, dummymodule):
+        assert dummymodule.guarded_type_hint_plain("foo") == "foo"
+
+    def test_subscript_toplevel(self, dummymodule):
+        assert dummymodule.guarded_type_hint_subscript_toplevel("foo") == "foo"
+
+    def test_subscript_nested(self, dummymodule):
+        assert dummymodule.guarded_type_hint_subscript_nested(["foo"]) == ["foo"]
 
 
 def test_literal(dummymodule):