Rule expansions in return statement yielding incorrect values

[Dominic Martinez]

Rule expansions in return statements cause the return value to be incorrect. Below is an MRE:

rule Identity x : y
{
    return $(x) $(y) ;
}

rule Two x
{
    local var = 2 ;
    return [ Identity $(x) : $(var) ] ;
}

rule One
{
    local var = 1 ;
    return [ Two $(var) ] ;
}

Echo [ One ] ;
-
$ jam
1 2
$ ham
2