Only use first matching constructor

Author: dcreager

crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md

@@ -361,8 +361,7 @@ class C(Generic[T]):
     def __init__(self, x: str | bytes | int) -> None: ...
 
 reveal_type(C("string"))  # revealed: C[str]
-# TODO: revealed: C[bytes]
-reveal_type(C(b"bytes"))  # revealed: C[bytes | int]
+reveal_type(C(b"bytes"))  # revealed: C[bytes]
 reveal_type(C(12))  # revealed: C[Unknown]
 
 C[str]("string")

crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md

@@ -299,8 +299,7 @@ class C[T]:
     def __init__(self, x: str | bytes | int) -> None: ...
 
 reveal_type(C("string"))  # revealed: C[str]
-# TODO: revealed: C[bytes]
-reveal_type(C(b"bytes"))  # revealed: C[bytes | int]
+reveal_type(C(b"bytes"))  # revealed: C[bytes]
 reveal_type(C(12))  # revealed: C[Unknown]
 
 C[str]("string")

crates/ty_python_semantic/src/types.rs

@@ -4663,32 +4663,25 @@ impl<'db> Type<'db> {
                     }
                 }
 
-                fn combine_binding_specialization<'db>(
-                    db: &'db dyn Db,
-                    binding: &CallableBinding<'db>,
-                ) -> Option<Specialization<'db>> {
-                    binding
-                        .matching_overloads()
-                        .map(|(_, binding)| binding.inherited_specialization())
-                        .reduce(|acc, specialization| {
-                            combine_specializations(db, acc, specialization)
-                        })
-                        .flatten()
-                }
-
                 let new_specialization = new_call_outcome
                     .and_then(Result::ok)
                     .as_ref()
                     .and_then(Bindings::single_element)
-                    .and_then(|binding| combine_binding_specialization(db, binding))
+                    .into_iter()
+                    .flat_map(CallableBinding::matching_overloads)
+                    .next()
+                    .and_then(|(_, binding)| binding.inherited_specialization())
                     .filter(|specialization| {
                         Some(specialization.generic_context(db)) == generic_context
                     });
                 let init_specialization = init_call_outcome
                     .and_then(Result::ok)
                     .as_ref()
                     .and_then(Bindings::single_element)
-                    .and_then(|binding| combine_binding_specialization(db, binding))
+                    .into_iter()
+                    .flat_map(CallableBinding::matching_overloads)
+                    .next()
+                    .and_then(|(_, binding)| binding.inherited_specialization())
                     .filter(|specialization| {
                         Some(specialization.generic_context(db)) == generic_context
                     });