I am considering "literals" as more like constants embedded in the program, using a constant pool, where changing a value would have bizarre effects, like changing the value of "123456" everywhere in the program. Literal strings in C programs are often combined in this way.

The {} and [] operators are defined to produce distinct mutable aggregates every time they are evaluated. In this sense, they are not literals.

I am unsure how this behavior of replacing the reference itself is actually useful, but nor do I see any harm here.