From 44858012f430c203f9fbedb96e288268a3543fcf Mon Sep 17 00:00:00 2001
From: youknowdot <dot@youknowone.org>
Date: Sat, 10 Oct 2026 14:05:21 -0700
Subject: [PATCH] Preserve missing caller modules in eager type aliases (#9073)

Only lazy aliases may obtain their module from the evaluation function. Eager aliases without a caller __name__ must not inspect their stored value.

Assisted-by: OpenAI Codex:model identifier unavailable
---
 crates/vm/src/stdlib/_typing.rs       |  4 +++-
 extra_tests/snippets/stdlib_typing.py | 21 +++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/crates/vm/src/stdlib/_typing.rs b/crates/vm/src/stdlib/_typing.rs
index 863dd8367..fad43d8eb 100644
--- a/crates/vm/src/stdlib/_typing.rs
+++ b/crates/vm/src/stdlib/_typing.rs
@@ -321,7 +321,9 @@ pub(crate) mod decl {
                 return module.clone();
             }
             // Fall back to compute_value's __module__ (like PyFunction_GetModule)
-            if let Ok(module) = self.compute_value.get_attr("__module__", vm) {
+            if self.is_lazy
+                && let Ok(module) = self.compute_value.get_attr("__module__", vm)
+            {
                 return module;
             }
             vm.ctx.none()
diff --git a/extra_tests/snippets/stdlib_typing.py b/extra_tests/snippets/stdlib_typing.py
index 4082d683f..8ba64844c 100644
--- a/extra_tests/snippets/stdlib_typing.py
+++ b/extra_tests/snippets/stdlib_typing.py
@@ -63,3 +63,24 @@ try:
     repr(nested)
 except RecursionError:
     pass
+
+
+# Eager aliases without a caller module never inspect their aliased value.
+alias_module_lookups = []
+
+
+class AliasModuleValue:
+    @property
+    def __module__(self):
+        alias_module_lookups.append(True)
+        return "unexpected_value_module"
+
+
+for alias_value in (int, AliasModuleValue()):
+    alias_namespace = {"value": alias_value}
+    exec(
+        "from typing import TypeAliasType; alias = TypeAliasType('Alias', value)",
+        alias_namespace,
+    )
+    assert alias_namespace["alias"].__module__ is None
+assert alias_module_lookups == []