rustdoc: `generate-macro-expansion` produces incorrect expansion for macros in type position

[el-ev]

Code

macro_rules! foo {
    () => {
        ()
    };
    ($baz:expr) => {
        [(); 1]
    };
}

fn bar() {
    let _: foo!();
    let _: foo!(42);
}

Reproduction Steps

rustdoc -Zunstable-options --generate-macro-expansion thefile.rs

Expected Outcome

1. foo!() should expand to ().
2. foo!(42) should expand to [(); 1].

Actual Output

1. let _: foo!(); does not show an expansion toggle at all.
2. let _: foo!(42); expands to let _: 1;

Version

rustdoc 1.94.0-nightly (806c2a3 2025-12-19)

Additional Details

Tracking issue: #148222
Found while working on #150154

@rustbot label +A-macros +A-rustdoc-ui +B-unstable

[rustbot]

Error: Label B-unstable can only be set by Rust team members

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