From 45b565cbb5b21e16ef58d1c649f7bb1f96cbad24 Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Thu, 12 Dec 2024 11:50:34 +0000
Subject: [PATCH] [red-knot] `Any` cannot be parameterized (#14933)

---
 .../resources/mdtest/annotations/any.md              | 12 ++++++++++++
 crates/red_knot_python_semantic/src/types/infer.rs   | 12 +++++++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/crates/red_knot_python_semantic/resources/mdtest/annotations/any.md b/crates/red_knot_python_semantic/resources/mdtest/annotations/any.md
index 17e5a99b2a..86320c030a 100644
--- a/crates/red_knot_python_semantic/resources/mdtest/annotations/any.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/annotations/any.md
@@ -69,3 +69,15 @@ y: int = Subclass()  # error: [invalid-assignment]
 def _(s: Subclass):
     reveal_type(s)  # revealed: Subclass
 ```
+
+## Invalid
+
+`Any` cannot be parameterized:
+
+```py
+from typing import Any
+
+# error: [invalid-type-parameter] "Type `typing.Any` expected no type parameter"
+def f(x: Any[int]):
+    reveal_type(x)  # revealed: Unknown
+```
diff --git a/crates/red_knot_python_semantic/src/types/infer.rs b/crates/red_knot_python_semantic/src/types/infer.rs
index 432cc6de87..f50d4219ef 100644
--- a/crates/red_knot_python_semantic/src/types/infer.rs
+++ b/crates/red_knot_python_semantic/src/types/infer.rs
@@ -4863,7 +4863,17 @@ impl<'db> TypeInferenceBuilder<'db> {
             }
             KnownInstanceType::Type => self.infer_subclass_of_type_expression(parameters),
             KnownInstanceType::Tuple => self.infer_tuple_type_expression(parameters),
-            KnownInstanceType::Any => Type::Any,
+            KnownInstanceType::Any => {
+                self.diagnostics.add_lint(
+                    &INVALID_TYPE_PARAMETER,
+                    subscript.into(),
+                    format_args!(
+                        "Type `{}` expected no type parameter",
+                        known_instance.repr(self.db)
+                    ),
+                );
+                Type::Unknown
+            }
         }
     }