hlist_pat can trigger #[warn(non_shorthand_field_patterns)]

[ExpHP]

let hlist_pat![head, ...tail] = list;

warning: the `head:` in this pattern is redundant
  --> src/main.rs:5:18
   |
5  |     => { HCons { head: $a, tail: $b }};
   |                  ^^^^ help: remove this
...
10 |     let hlist_pat!(head, tail) = list;
   |         ---------------------- in this macro invocation
   |
   = note: #[warn(non_shorthand_field_patterns)] on by default

warning: the `tail:` in this pattern is redundant
  --> src/main.rs:5:28
   |
5  |     => { HCons { head: $a, tail: $b }};
   |                            ^^^^ help: remove this
...
10 |     let hlist_pat!(head, tail) = list;
   |         ---------------------- in this macro invocation

    Finished dev [unoptimized + debuginfo] target(s) in 0.50 secs
     Running `target/debug/playground`

I don't see any solution so I opened this thread as a call for help.

[lloydmeta]

Nice; we'll see what the community says :)

[ExpHP]

So yesterday I tried working around this, and came to the conclusion that doing so is possible but outrageously difficult. I came to this conclusion when the macro was at a length of about 16 rules with a 150-line test suite, and was still incorrect for the edge case of [mut head, ...mut tail], which would have required rewriting the recursive case as an incremental muncher and doubling the size of the test suite.

https://github.com/rust-lang/rust/pull/49614 is coming to the rescue.

[lloydmeta]

rust-lang/rust#49614 is coming to the rescue.

Totally fine with waiting on that :)

[ExpHP]

Fixed as of rustc stable 1.28.0.