It's more nuanced, because the shadowing is block-local, so when the lexical scope exits the prior bindings are restored. I think in practice this is the ideal

It's more nuanced, because the shadowing is block-local, so when the lexical scope exits the prior bindings are restored. I think in practice this is the ideal middle ground of convenience (putting version numbers at the end of variables being annoying), but retaining mostly sane semantics and reuse of prior intermediate results.