exit trap defined in function body isn't triggered

[Oğuz]

Consider this:

bash <<EOF
foo() {
  trap 'echo exit' EXIT
}
foo &
EOF

After trap is set, the subshell exits and `echo exit` should be run,
but it won't. If you set a RETURN trap instead it works though. This
is reproducible on bash4 and bash5

-- 
Oğuz