[ty] more cases for the class body global fallback

crates/ty_python_semantic/resources/mdtest/narrow/assignment.md

@@ -75,7 +75,7 @@ class _:
 
     if cond():
         a = A()
-    reveal_type(a.x)  # revealed: int | None
+    reveal_type(a.x)  # revealed: int | None | Unknown
     reveal_type(a.y)  # revealed: Unknown | None
     reveal_type(a.z)  # revealed: Unknown | None
 

crates/ty_python_semantic/resources/mdtest/scopes/global.md

@@ -269,6 +269,8 @@ If we try to access a variable in a class before it has been defined, the lookup
 global.
 
 ```py
+import secrets
+
 x: str = "a"
 
 def f(x: int, y: int):
@@ -286,4 +288,23 @@ def f(x: int, y: int):
         # error: [unresolved-reference]
         reveal_type(y)  # revealed: Unknown
         y = None
+
+    # Declarations count as definitions, even if there's no binding.
+    class F:
+        reveal_type(x)  # revealed: str
+        x: int
+        reveal_type(x)  # revealed: str
+
+    # Explicitly `nonlocal` variables don't count, even if they're bound.
+    class G:
+        nonlocal x
+        reveal_type(x)  # revealed: int
+        x = 42
+        reveal_type(x)  # revealed: Literal[42]
+
+    # Possibly-unbound variables get unioned with the fallback lookup.
+    class H:
+        if secrets.randbelow(2):
+            x = None
+        reveal_type(x)  # revealed: None | str
 ```

crates/ty_python_semantic/resources/mdtest/scopes/unbound.md

@@ -34,7 +34,7 @@ class C:
     if coinflip():
         x = 1
 
-    # error: [possibly-unresolved-reference]
+    # Possibly unbound variables in enclosing scopes are considered bound.
     y = x
 
 reveal_type(C.y)  # revealed: Unknown | Literal[1, "abc"]