GHC incorrectly suggests a data constructor is in scope in 8.2

After commit 343cb32d (the fix for #13568 (closed)), which debuted in GHC 8.2, GHC thinks that out-of-scope identifiers are actually in-scope!

module Bug where

f :: T
f = undefined

In GHC 8.2.1-rc3, the error message is:

$ /opt/ghc/8.2.1/bin/ghc Bug.hs
[1 of 1] Compiling Bug              ( Bug.hs, Bug.o )

Bug.hs:3:6: error:
    Not in scope: type constructor or class ‘T’
    A data constructor of that name is in scope; did you mean DataKinds?
  |
3 | f :: T
  |      ^

Compare this to GHC 8.0.2, which gives a more sensible error message:

$ /opt/ghc/8.0.2/bin/ghc Bug.hs
[1 of 1] Compiling Bug              ( Bug.hs, Bug.o )

Bug.hs:3:6: error: Not in scope: type constructor or class ‘T’

Trac metadata

Trac field	Value
Version	8.2.1-rc2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	mrkgnao
Operating system
Architecture