Stepping with "next" in a debugger skips past end-of-scope drops

[saethlin]

I am trying to re-enable a lot of disabled debuginfo tests, and in doing that I learned that tests/debuginfo/drop-locations https://github.com/rust-lang/rust/blob/c9bd03cb724e13cca96ad320733046cbdb16fbbe/tests/debuginfo/drop-locations.rs was broken at some point in the past 6 years. No idea when, I will not be doing a bisection.

The bug is that in code like this:

{
    let s = String::from("s");
}

stepping through this with the gdb command next should step from the String::from call to the close brace. But gdb never stops on the close brace, even though there is indeed a call to drop_in_place for the String, and the debuginfo for the call correctly points at the close brace.