unused_doc_comments warning reported for each doc comment line on macro invocation, unlike on other expressions

[camelid]

Other expressions work as expected: it reports just one error, for the whole sequence of doc comment lines.

macro_rules! foo { () => {}; }

fn main() {
    /// line1
    /// line2
    /// line3
    foo!();
}

(Playground)

Errors:

   Compiling playground v0.0.1 (/playground)
warning: unused doc comment
 --> src/main.rs:4:5
  |
4 |     /// line1
  |     ^^^^^^^^^ rustdoc does not generate documentation for macro invocations
  |
  = note: `#[warn(unused_doc_comments)]` on by default
  = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion

warning: unused doc comment
 --> src/main.rs:5:5
  |
5 |     /// line2
  |     ^^^^^^^^^ rustdoc does not generate documentation for macro invocations
  |
  = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion

warning: unused doc comment
 --> src/main.rs:6:5
  |
6 |     /// line3
  |     ^^^^^^^^^ rustdoc does not generate documentation for macro invocations
  |
  = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion

warning: 3 warnings emitted

    Finished dev [unoptimized + debuginfo] target(s) in 1.65s
     Running `target/debug/playground`

[jyn514]

(unused_doc_comments is a rustc lint.)

[camelid]

(unused_doc_comments is a rustc lint.)

True, but I added T-rustdoc as well since it's a rustdoc-related lint.