Rename Red Knot (#17820)

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

@@ -0,0 +1,57 @@
+# Unbound
+
+## Unbound class variable
+
+Name lookups within a class scope fall back to globals, but lookups of class attributes don't.
+
+```py
+def coinflip() -> bool:
+    return True
+
+flag = coinflip()
+x = 1
+
+class C:
+    y = x
+    if flag:
+        x = 2
+
+# error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C]` is possibly unbound"
+reveal_type(C.x)  # revealed: Unknown | Literal[2]
+reveal_type(C.y)  # revealed: Unknown | Literal[1]
+```
+
+## Possibly unbound in class and global scope
+
+```py
+def coinflip() -> bool:
+    return True
+
+if coinflip():
+    x = "abc"
+
+class C:
+    if coinflip():
+        x = 1
+
+    # error: [possibly-unresolved-reference]
+    y = x
+
+reveal_type(C.y)  # revealed: Unknown | Literal[1, "abc"]
+```
+
+## Unbound function local
+
+An unbound function local that has definitions in the scope does not fall back to globals.
+
+```py
+x = 1
+
+def f():
+    # error: [unresolved-reference]
+    # revealed: Unknown
+    reveal_type(x)
+    x = 2
+    # revealed: Literal[2]
+    reveal_type(x)
+```