Improper warning about useless_let_if_seq

[wdanilo]

Hi, the following code:

        let mut changed = false;
        if self.transform_dirty.check() {
            ...
            changed = true;
        }
        if self.projection_dirty.check() {
            ...
            changed = true;
        }
        if changed {
            ...
        }

gives a warning:

help: it is more idiomatic to write: `let <mut> changed = if self.transform_dirty.check() { ..; true } else { false };`

Which I believe could not be applied here.

[ghost]

Duplicate of #3769