Why I can not attempted to repeat an expression

[3442853561]

This can run:

macro_rules! foo {
    ($name: ident) => {
        macro_rules! $name {
            ($x: tt) => {
                println!($x);
            }
        }
    }
}

fn main() {
    foo!(bar);
    bar!("test");
}

However, this can not:

macro_rules! foo {
    ($name: ident) => {
        macro_rules! $name {
            ($($x: tt),*) => {
                println!($($x),*);
            }
        }
    }
}

fn main() {
    foo!(bar);
    bar!("test");
}

[TimNN]

This is a known limitation of macro_rules!: The macro parse thinks that the pattern in $name is a replacement in foo, in which case the error message would be correct.

Closing as a duplicate of #35853.