Whether the variable definition holder surely holds a value one of origins created, following plain copies (e2 <- e) and replacements (e$f <- v keeps what e held).
holder
origins
e2 <- e
e$f <- v
e
Whether the variable definition
holdersurely holds a value one oforiginscreated, following plain copies (e2 <- e) and replacements (e$f <- vkeeps whateheld).