Prior to this change, references or pointers could be mutated. In practice, we do not require this capability in the codebase except in zipAttrsWith. This cleans up all easy sites in preparation to have a smarter representation of attribute sets albeit one that requires constant references. Change-Id: I2be20cce040a9228bde9e5f7b42c0499fba9550b Signed-off-by: Raito Bezarius <raito@lix.systems> Co-authored-by: Sergei Zimmerman <sergei@zimmerman.foo>