Implicit grouping of macro fragments not working

[m-ou-se]

use assert2::assert;

fn main() {
	macro_rules! bla {
		($e:expr) => {
			assert!($e * $e == 4);
		}
	}
	bla!(1 + 1);
}

This test should pass, but fails.

Assertion failed at example.rs:9:2:
  assert!( 1 + 1 * 1 + 1 == 4 )
with expansion:
  3 == 4

It somehow evaluates 1 + 1 * 1 + 1 instead of (1 + 1) * (1 + 1), as if we're using a C preprocessor instead of Rust. 👀