Remnant of the future

https://www.facebook.com/groups/2166033293623124/posts/4074111876148580
"the only trace of [the Latin future tense] is one form, in one
language, with a different function, namely Spanish eres ‘you are’
(sing.), "

Fascinating! What about Portuguese 'es'? Is it an exact copy of the
Latin word, or also eris or eres with a later elided r?
https://en.wiktionary.org/wiki/eres#Spanish