Requested feature overview description.
If a user would try to request an alias or implication with a specific tag type combination, display a warning to the user and ask them to confirm again before submission.
Concerning warnings for specific tag type combinations, this would apply to most combinations of different types. As for more specific examples, consider the following.

• alias non-artist and non-general → artist: Unless the former tag is an artist tag typed as a "general" tag, as is occasionally the case for new artists, this should never happen.
• alias non-character and non-general → character: Similarly, unless the former is a character tag typed as a "general" tag, this should never happen.
• alias character → series (or vice versa): Ask the user if they meant to submit an implication instead. Repeat as appropriate for any other tag type which would usually appear as an implication rather than an alias.
• imply character → non-copyright: Characters usually only imply copyright tags, but they never imply species or gender, as has been suggested previously.
• imply copyright → non-copyright: Copyright tags typically only imply other copyright tags. For example, consider all the properties owned by Nintendo.
• imply non-artist (and non-character?) → artist: I don't recall what the policy for characters implying their owners is, if there is any, but there's no reason for any of the other types to imply an artist tag.

Nevertheless, depending on which error was triggered, show to the user something like this:
Warning: "tag A" is a character tag, and "tag B" is a species tag. Characters should never imply species. Please confirm that you still want to do this.
Adjust the text as appropriate, naturally. Disable the submission button so long as the warning is displayed and has not yet been acknowledged by the user.

Why would it be useful?
It's fewer unnecessary aliases or implications being requested. Beyond that, the process is often enough that the first reply to these sorts of suggestions immediately points out the problem, and the warnings can be formatted as such that they provide explanations for why certain tag type combos don't get implied/aliased (such as e621:tag_what_you_see_(explained) for character → gender/species.)

What part(s) of the site page(s) are affected?
Suggestion pages for new aliases and implications.

Meh, seems like a lot of work for little benefit. I'm not saying it's bad, just that our little techy-newt has more important stuff to do than implementing this, since the problem isn't that common imo.

actually just could ask for a different box to fill, instead to try to identify if the tag is a free tag or a character/species tag,
in all honestly that i dont use tags a lot but this kind of features could give more control over the upload.

Aliases and implications are still handled manually, so if it's blatantly wrong then it's simply denied. Also as janitor, I have seen users doing some really dumb tag type changes in high volume, so making alias/implication to depent on tag type would only make users to deliberately change the tag types to be wrong before hitting submit.

Character tag types are occasionally incorrect. Since anyone can change a tag' type with only a few posts on it, sometimes, a tag will change back and forth.

For example.. let's say that white_lion only had a few posts... someone uploads art by artist_white_lion. Someone tags some pale lions as species_white_lion. Someone says that white lions are a color morph, not a species, and changes it to gen:white_lion. then some person comes along with White_lion the character...

etc etc etc. its' easy for a tag's type to be wrong. And the artist and character both don't make the intent behind white lion implies lion incorrect

SnowWolf said:
its' easy for a tag's type to be wrong.

Which is why this would only be a warning, and not an automatic rejection of the changes.

I know I would like to know which tags are invalid before a submission is uploaded then having to remove invalid_tag after the submission is mad and left wondering which one it was.

Or even just some feedback about which tags were automatically added or changed.