def test_trivial_expr(self):
        """
        Ensure even a non-nested expression is rewritten, as it can enable
        scalar optimizations such as rewriting `x ** 2`.
        """
        ns = self._test_cube_function()
        self._assert_total_rewrite(ns.control_pipeline.state.func_ir.blocks,
                                   ns.test_pipeline.state.func_ir.blocks,
                                   trivial=True)

        Ensure even a non-nested expression is rewritten, as it can enable
        scalar optimizations such as rewriting `x ** 2`.
        
numba/tests/test_array_exprs.py