* main:
  [red-knot] fix collapsing literal and its negation to object (#17605)
  [red-knot] Add more tests for protocols (#17603)
  [red-knot] Ban direct instantiations of `Protocol` classes (#17597)
  [`pyupgrade`] Preserve parenthesis when fixing native literals containing newlines (`UP018`) (#17220)
  [`airflow`] fix typos (`AIR302`, `AIR312`) (#17574)
  [red-knot] Special case `@abstractmethod` for function type (#17591)
  [red-knot] Emit diagnostics for isinstance() and issubclass() calls where a non-runtime-checkable protocol is the second argument (#17561)
  [red-knot] Infer the members of a protocol class (#17556)
  [red-knot] Add `FunctionType::to_overloaded` (#17585)
  [red-knot] Add mdtests for `global` statement (#17563)
  [syntax-errors] Make duplicate parameter names a semantic error (#17131)

… syntax error (#17637)

Summary
--

This PR resolves both the typing-related and syntax error TODOs added in
#17563 by tracking a set of `global` bindings for each scope. As
discussed below, we avoid the additional AST traversal from ruff by
collecting `Name`s from `global` statements while building the semantic
index and emit a syntax error if the `Name` is already bound in the
current scope at the point of the `global` statement. This has the
downside of separating the error from the `SemanticSyntaxChecker`, but I
plan to explore using this approach in the `SemanticSyntaxChecker`
itself as a follow-up. It seems like this may be a better approach for
ruff as well.

Test Plan
--

Updated all of the related mdtests to remove the TODOs (and add quotes I
forgot on the messages).

There is one remaining TODO, but it requires `nonlocal` support, which
isn't even incorporated into the `SemanticSyntaxChecker` yet.

---------

Co-authored-by: Alex Waygood <[email protected]>
Co-authored-by: Carl Meyer <[email protected]>