Kotlin, 90 bytes source, 177416 bytes (173 KB) compiled JVM binary
inline fun a(x:(Int)->Any){x(0);x(1)} fun b()=a{a{a{a{a{a{a{a{a{a{a{println(it)}}}}}}}}}}} Technically, you could make this even longer by nesting the expression further. However, the compiler crashes with a StackOverflow error if you increase the recursion. Note that this also compiles to a 4428966 bytes (4.22 MB) javascript file.