Revert change to deprecated_parameter

cirq-core/cirq/_compat.py

@@ -283,9 +283,7 @@ def deprecated_parameter(
     ] = None,
 ) -> Callable[[Callable], Callable]:
     """Marks a function parameter as deprecated.
-
     Also handles rewriting the deprecated parameter into the new signature.
-
     Args:
         deadline: The version where the function will be deleted. It should be a minor version
             (e.g. "v0.7").
@@ -302,41 +300,30 @@ def deprecated_parameter(
             rewrite is called.
         rewrite: Returns new args/kwargs that don't use the deprecated
             parameter. Defaults to making no changes.
-
     Returns:
         A decorator that decorates functions with a parameter deprecation
             warning.
     """
     _validate_deadline(deadline)
 
-    def invoke(func, *args, **kwargs):
-        if match(args, kwargs):
-            if rewrite is not None:
-                args, kwargs = rewrite(args, kwargs)
-
-            qualname = func.__qualname__ if func_name is None else func_name
-            _warn_or_error(
-                f'The {parameter_desc} parameter of {qualname} was used but is deprecated.\n'
-                f'It will be removed in cirq {deadline}.\n'
-                f'{fix}\n'
-            )
-        return func(*args, **kwargs)
-
     def decorator(func: Callable) -> Callable:
-        if inspect.iscoroutinefunction(func):
-
-            @functools.wraps(func)
-            async def decorated_func(*args, **kwargs) -> Any:
-                return await invoke(func, *args, **kwargs)
+        @functools.wraps(func)
+        def decorated_func(*args, **kwargs) -> Any:
+            if match(args, kwargs):
+                if rewrite is not None:
+                    args, kwargs = rewrite(args, kwargs)
 
-            return decorated_func
-        else:
+                qualname = func.__qualname__ if func_name is None else func_name
+                _warn_or_error(
+                    f'The {parameter_desc} parameter of {qualname} was '
+                    f'used but is deprecated.\n'
+                    f'It will be removed in cirq {deadline}.\n'
+                    f'{fix}\n'
+                )
 
-            @functools.wraps(func)
-            def decorated_func(*args, **kwargs) -> Any:
-                return invoke(func, *args, **kwargs)
+            return func(*args, **kwargs)
 
-            return decorated_func
+        return decorated_func
 
     return decorator