Incorrect handling of parameter names that are also macros in trait member generation

[fennewald]

Using rust-analyzer 1.92.0-nightly (be0ade2 2025-10-11), and the following snippet:

trait Foo {
    fn foo(&self, vec: usize);
}

struct Bar;

impl Foo for Bar {}

Select Foo in the impl Foo for Bar, and choose "Implement missing members". rust-analyzer will produce this snippet:

impl Foo for Bar {
    fn foo(&self, std::vec: usize) {
        todo!()
    }
}

The argument named vec for foo was incorrectly inserted as std::vec.

Notably, this behavior does not occur for other, similar std::... names. I tested:

• alloc
• any
• arch
• array
• box

[fennewald]

Wait a second, I think I've figured it out.

The error also occurs for format (it is inserted as std::format), panic and assert_eq -- it looks like all parameter names that happen to be global macros exhibits the behavior.

Notably, creating a module and defined a macro manually does not trigger the behavior.

[fennewald]

I've tried to reproduce this in an internal test, but it isn't triggering :/

I tried adding a vec minicore flag with appropiate macros, but I still couldn't trigger the issue. Maybe I was unsuccessful because minicore doesn't use the std prefix the same?

[ChayimFriedman2]

If I had to guess, this is related to #[macro_export] macros and perhaps the prelude imports. So you need to add a #[macro_export] macro to minicore.