Useless diagnostics from procmacro expansion

[SomeoneToIgnore]

rust-analyzer version: rust-analyzer version: 0.4.1834-standalone (c48f145 2024-02-07)
rustc version: rustc 1.75.0 (82e1608df 2023-12-21)

Open Zed, wait for r-a to load it and produce diagnostics in this file:

https://github.com/zed-industries/zed/blob/bde509fa749da60beb4ac378afd3ade15297bb91/crates/editor/src/display_map.rs#L1685
or
https://github.com/zed-industries/zed/blob/bde509fa749da60beb4ac378afd3ade15297bb91/crates/multi_buffer/src/multi_buffer.rs#L4764

this diagnostic is very volatile, but usually appears around those files, sometimes producing dozens of errors, sometimes a couple.
Inside #[gpui::test] macro expansion there's indeed a let mut ... binding that does not need to be mutable, but

• rustc/cargo does not emit such warnings
• what the end procmacro user is supposed to do about it?

[SomeoneToIgnore]

Found a very minimalistic example:

thread_local! {
    static TEST: bool = false;
}

produces the remove unnecessary else block diagnostics that is totally useless

[pacak]

FWIW the problem is not limited to proc macros. I'm getting an unhelpful diagnostic from anyhow::bail!. It's not like I can do anything about it.

H anyhow::bail!("no rmeta?"); ■ replace return <expr>; with <expr>