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Description
I use the derive macro provided by the clap crate in my code, and then call the in_external_macro function in the context of a custom lint diagnostic code. The function determines that the code derived from the derive macro is local code.
I tried this code:
fn main() {
let _a = 1;
}
use clap::Args;
#[derive(Args)]
pub struct ToFrom {
#[arg(long = "workspace")]
a: i32,
}dependency is clap = { version = "=4.2.0", features = ["derive"] }
My lint code is:
fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx Block<'_>) {
let res = in_external_macro(cx.sess(), block.span);
info!("check block in_external_macro res {:?}", res);
if res == false {
info!("check block {:?}", block);
}
}I expected to see this happen: I think all code generated by derived macros should belong to external macros derived from external crates.
Instead, this happened: Some of the code generated by the derived macro is considered to be local code
The error macro code is expanded as follows.
The blocks inside the .arg function are considered native code.
.arg({
#[allow(deprecated)]
let arg = clap::Arg::new("a")
.value_name("A")
.required(true && clap::ArgAction::Set.takes_values())
.value_parser({
use ::clap_builder::builder::via_prelude::*;
let auto = ::clap_builder::builder::_AutoValueParser::<
i32,
>::new();
(&&&&&&auto).value_parser()
})
.action(clap::ArgAction::Set);
let arg = arg.long("workspace");
let arg = arg.required(false);
arg
});rustc --version --verbose:
+nightly-2024-03-07