Since GHC-9.0.2 I see such warnings despite the import is actually used.
<no location info>: warning: [-Wunused-imports]
The qualified import of ‘GHC.Stack’ is redundant
except perhaps to import instances from ‘GHC.Stack’
To import instances alone, use: import GHC.Stack()
Since GHC-9.0.2 I see such warnings despite the import is actually used.