Don't crash if we're raising an attribute as an exception.

Fixes nhoad#9.

Author: nhoad

flake8_unused_arguments.py

@@ -176,14 +176,18 @@ def is_stub_function(function: FunctionTypes) -> bool:
         return True
 
     if isinstance(statement, ast.Raise):
+        # raise NotImplementedError()
         if (
             isinstance(statement.exc, ast.Call)
+            and hasattr(statement.exc.func, "id")
             and statement.exc.func.id == "NotImplementedError"  # type: ignore
         ):
             return True
 
+        # raise NotImplementedError
         elif (
             isinstance(statement.exc, ast.Name)
+            and hasattr(statement.exc, "id")
             and statement.exc.id == "NotImplementedError"
         ):
             return True

test_unused_arguments.py

@@ -121,6 +121,10 @@ def test_get_decorator_names(function, expected_result):
         ("def foo(): raise NotImplementedError()", True),
         ("def foo(): raise NotImplementedError", True),
         ("def foo(): raise SomethingElse()", False),
+        ("def foo(): raise object.error()", False),
+        ("def foo(): raise object.error", False),
+        ("def foo(): raise value", False),
+        ("def foo(): raise 'cool string'", False),
         ("def foo(): raise", False),
         ("lambda: ...", True),
         ("lambda: 5", False),