There is also an issue when doing something like `declare -n r=a' in a function if the same has been done in a higher scope. Instead of creating a new variable r in the function's scope, it modifies the local `a' to be a self-referencing nameref..
$ declare -nt r=a; f() { declare a; declare -n r=a; declare -p a r; }; f
declare -n a="a" # ??
declare -nt r="a" # note the -t. this is the outer $r, a new one was not created
In a slightly different version, with `declare -n r; r=a', the function exits with code 1 after the `r=a' statement:
$ declare -nt r=a; f() { declare a; declare -n r; r=a; declare -p a r; }; f; echo $?
1