error message suggests variables in a pattern

In this reddit thread the OP posts some code with a confusing error message.

The relevant code is:

import qualified Data.Map as Map

instance Functor (Map.Map k) where
  fmap f (Map.Map k v) = undefined

For which GHC 8.10.4 produces the error message:

MapAsFunctor.hs:4:11: error:
    Not in scope: data constructor ‘Map.Map’
    Perhaps you meant variable ‘Map.map’ (imported from Data.Map)
    Module ‘Data.Map’ does not export ‘Map’.
  |
4 |   fmap f (Map.Map k v) = undefined
  |           ^^^^^^^

Clearly Map.map cannot be used in this pattern so this is a bad suggestion. GHC should only suggest constructors and pattern synonyms in this case.