error[E0609]: no field `trace` on type `&T`
  --> $DIR/issue-31011.rs:3:17
   |
LL |         if $ctx.trace {
   |                 ^^^^^ unknown field
...
LL | fn wrap<T>(context: &T) -> ()
   |         - type parameter 'T' declared here
LL | {
LL |     log!(context, "entered wrapper");
   |     -------------------------------- in this macro invocation
   |
   = note: this error originates in the macro `log` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0609`.