From 2b806a974aa30ff8ae79bab4aa9bd44528126e51 Mon Sep 17 00:00:00 2001
From: Matthew Mckee <matthewmckee04@yahoo.co.uk>
Date: Tue, 3 Jun 2025 17:02:14 +0100
Subject: [PATCH 1/2] Add generic inference for dataclasses

---
 .../mdtest/generics/legacy/classes.md          | 18 ++++++++++++++++++
 .../mdtest/generics/pep695/classes.md          | 15 +++++++++++++++
 .../resources/mdtest/named_tuple.md            |  4 +---
 crates/ty_python_semantic/src/types/class.rs   |  3 ++-
 4 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md b/crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md
index ad1fe65958a2a5..ab6f8f2004f0ed 100644
--- a/crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md
+++ b/crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md
@@ -379,6 +379,24 @@ C[None](b"bytes")  # error: [no-matching-overload]
 C[None](12)
 ```
 
+### Synthesized methods with dataclasses
+
+```py
+from dataclasses import dataclass
+from typing import Generic, TypeVar
+
+T = TypeVar("T")
+
+@dataclass
+class A(Generic[T]):
+    x: T
+
+class B(A[T], Generic[T]): ...
+
+reveal_type(A(x=1))  # revealed: A[int]
+reveal_type(B(x=1))  # revealed: B[int]
+```
+
 ## Generic subclass
 
 When a generic subclass fills its superclass's type parameter with one of its own, the actual types
diff --git a/crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md b/crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md
index 1d3fee229bace0..796f861f39bf33 100644
--- a/crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md
+++ b/crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md
@@ -354,6 +354,21 @@ C[None](b"bytes")  # error: [no-matching-overload]
 C[None](12)
 ```
 
+### Synthesized methods with dataclasses
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class A[T]:
+    x: T
+
+class B[T](A[T]): ...
+
+reveal_type(A(x=1))  # revealed: A[int]
+reveal_type(B(x=1))  # revealed: B[int]
+```
+
 ## Generic subclass
 
 When a generic subclass fills its superclass's type parameter with one of its own, the actual types
diff --git a/crates/ty_python_semantic/resources/mdtest/named_tuple.md b/crates/ty_python_semantic/resources/mdtest/named_tuple.md
index 8c5a79d62f9095..dfc81a73f0e77f 100644
--- a/crates/ty_python_semantic/resources/mdtest/named_tuple.md
+++ b/crates/ty_python_semantic/resources/mdtest/named_tuple.md
@@ -134,9 +134,7 @@ class Property[T](NamedTuple):
     name: str
     value: T
 
-# TODO: this should be supported (no error, revealed type of `Property[float]`)
-# error: [invalid-argument-type]
-reveal_type(Property("height", 3.4))  # revealed: Property[Unknown]
+reveal_type(Property("height", 3.4))  # revealed: Property[float]
 ```
 
 ## Attributes on `NamedTuple`
diff --git a/crates/ty_python_semantic/src/types/class.rs b/crates/ty_python_semantic/src/types/class.rs
index 94158e653cd489..8056b9ef784cac 100644
--- a/crates/ty_python_semantic/src/types/class.rs
+++ b/crates/ty_python_semantic/src/types/class.rs
@@ -1372,7 +1372,8 @@ impl<'db> ClassLiteral<'db> {
                 parameters.push(parameter);
             }
 
-            let signature = Signature::new(Parameters::new(parameters), Some(Type::none(db)));
+            let mut signature = Signature::new(Parameters::new(parameters), Some(Type::none(db)));
+            signature.inherited_generic_context = self.generic_context(db);
             Some(CallableType::function_like(db, signature))
         };
 

From e1c0eca7b43b25381f95d9b986b975675764b061 Mon Sep 17 00:00:00 2001
From: Matthew Mckee <matthewmckee04@yahoo.co.uk>
Date: Tue, 3 Jun 2025 17:32:20 +0100
Subject: [PATCH 2/2] Remove unsupporeted tests

---
 .../resources/mdtest/generics/legacy/classes.md                | 3 ---
 .../resources/mdtest/generics/pep695/classes.md                | 3 ---
 2 files changed, 6 deletions(-)

diff --git a/crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md b/crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md
index ab6f8f2004f0ed..5e8858bf7b716d 100644
--- a/crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md
+++ b/crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md
@@ -391,10 +391,7 @@ T = TypeVar("T")
 class A(Generic[T]):
     x: T
 
-class B(A[T], Generic[T]): ...
-
 reveal_type(A(x=1))  # revealed: A[int]
-reveal_type(B(x=1))  # revealed: B[int]
 ```
 
 ## Generic subclass
diff --git a/crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md b/crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md
index 796f861f39bf33..9726dbae542250 100644
--- a/crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md
+++ b/crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md
@@ -363,10 +363,7 @@ from dataclasses import dataclass
 class A[T]:
     x: T
 
-class B[T](A[T]): ...
-
 reveal_type(A(x=1))  # revealed: A[int]
-reveal_type(B(x=1))  # revealed: B[int]
 ```
 
 ## Generic subclass