Summary

The fix in #15017 is incomplete and only handles the particular issue that was reported. The problem is that brackets are needed in the general case to create a scope which will restrict the lifetime of created values.

Reproducer

I tried this code:

fn main() {
    let a = 10;
    match 11 {
        a => { println!("a = {a}"); }
    }
    println!("a = {a}");
}

Before autofix, this code prints:

a = 11
a = 10

After autofix, the code prints:

a = 11
a = 11

because the autofix, even with #15017 applied, reads:

fn main() {
    let a = 10;
    let a = 11;
    { println!("a = {a}"); }
    println!("a = {a}");
}

Version

Clippy master as of 9e7782b8

Additional Labels

@rustbot label +I-suggestion-causes-bug