[Catch-All Issue] More diagnostics

[JCWasmx86]

This is a catch-all issue for listing/brainstorming ideas for new diagnostics/checks.

Reassignment of loop variables

Disabled by default.

foreach xyz : some_list
  # ... some code ...
  xyz = 2 # Warning: Reassignment of loop variable
  # ... some more code ...
endforeach

Use of loop variable after loop

Disabled by default.

foreach xyz : some_list
  # ... code ...
endforeach

message(xyz) # Use of loop variable after loop