error: invalid `struct` delimiters or `fn` call arguments --> $DIR/issue-44406.rs:3:9 | LL | bar(baz: $rest) | ^^^^^^^^^^^^^^^ ... LL | foo!(true); | ---------- in this macro invocation | = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info) help: if `bar` is a struct, use braces as delimiters | LL | bar { baz: $rest } | ~ ~ help: if `bar` is a function, use the arguments directly | LL - bar(baz: $rest) LL + bar(: $rest) | error: aborting due to previous error