From 819186184014e4bde68572360231f2046c87957d Mon Sep 17 00:00:00 2001
From: Eric Traut <eric@traut.com>
Date: Fri, 6 Sep 2024 11:18:28 -0700
Subject: [PATCH] Changed behavior to allow a value with type `_AnnotatedAlias`
 to be used with an implicit `__getitem__` call even though this type is not
 documented or declared in typeshed. This addresses #8916.

---
 packages/pyright-internal/src/analyzer/typeEvaluator.ts   | 8 ++++++++
 packages/pyright-internal/src/tests/samples/annotated1.py | 1 +
 packages/pyright-internal/src/tests/samples/typeAlias1.py | 2 +-
 packages/pyright-internal/src/tests/samples/typeForm4.py  | 2 +-
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/packages/pyright-internal/src/analyzer/typeEvaluator.ts b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
index 965dda1bc589..38ce7af828b9 100644
--- a/packages/pyright-internal/src/analyzer/typeEvaluator.ts
+++ b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
@@ -4776,6 +4776,14 @@ export function createTypeEvaluator(
             return type;
         }
 
+        // If this is a type alias and we are not supposed to specialize it, return it as is.
+        if ((flags & EvalFlags.NoSpecialize) !== 0 && type.props?.typeAliasInfo) {
+            // Special-case TypeAliasType which should be converted in this case.
+            if (!ClassType.isBuiltIn(type.props.specialForm, 'TypeAliasType')) {
+                return type;
+            }
+        }
+
         if (type.props?.typeForm) {
             return TypeBase.cloneWithTypeForm(type.props.specialForm, type.props.typeForm);
         }
diff --git a/packages/pyright-internal/src/tests/samples/annotated1.py b/packages/pyright-internal/src/tests/samples/annotated1.py
index 7014ea361a80..98c088ed33eb 100644
--- a/packages/pyright-internal/src/tests/samples/annotated1.py
+++ b/packages/pyright-internal/src/tests/samples/annotated1.py
@@ -54,6 +54,7 @@ def func2(a: TypeWithStringArg):
 Param = Annotated[_T, "x"]
 
 x1: Param[int] = 3
+print(Param[int])
 
 
 class A:
diff --git a/packages/pyright-internal/src/tests/samples/typeAlias1.py b/packages/pyright-internal/src/tests/samples/typeAlias1.py
index 2328686cd05e..57df5ff52be2 100644
--- a/packages/pyright-internal/src/tests/samples/typeAlias1.py
+++ b/packages/pyright-internal/src/tests/samples/typeAlias1.py
@@ -23,7 +23,7 @@ class A:
     Value2 = 1
 
 
-reveal_type(A.Value1, expected_text="type[Literal]")
+reveal_type(A.Value1, expected_text="type[Literal[1]]")
 reveal_type(A.Value2, expected_text="int")
 
 
diff --git a/packages/pyright-internal/src/tests/samples/typeForm4.py b/packages/pyright-internal/src/tests/samples/typeForm4.py
index 682b9deb5e08..297faf7bcc5a 100644
--- a/packages/pyright-internal/src/tests/samples/typeForm4.py
+++ b/packages/pyright-internal/src/tests/samples/typeForm4.py
@@ -48,7 +48,7 @@ def func1():
 
     t10: TypeForm = TA2[str]
     t11: TypeForm[TA2[str]] = TA2[str]
-    t12: TypeForm[list[Any]] = TA2[str]
+    t12: TypeForm[list[Any] | str] = TA2[str]
 
     t13: TypeForm = TA2