error: expected identifier, found keyword `true`
  --> $DIR/issue-44406.rs:8:10
   |
LL |     foo!(true);
   |          ^^^^ expected identifier, found keyword
help: you can escape reserved keywords to use them as identifiers
   |
LL |     foo!(r#true);
   |          ^^^^^^

error: expected type, found keyword `true`
  --> $DIR/issue-44406.rs:8:10
   |
LL |         bar(baz: $rest)
   |                - help: try using a semicolon: `;`
...
LL |     foo!(true);
   |          ^^^^ expecting a type here because of type ascription

error: aborting due to 2 previous errors