PatternSynonyms error gives wrong source locations

Using an example from the GHC user's guide but omitting the argument to Maybe

{-# LANGUAGE PatternSynonyms #-}

data Type = App String [Type]

pattern Maybe = App "Maybe" [t]

gives the following error without the correct source locations

ghci> :load /tmp/failure.hs 
[1 of 1] Compiling Main             ( /tmp/failure.hs, interpreted )

/tmp/failure.hs:1:1:
    Right-hand side of bidirectional pattern synonym cannot be used as an expression
      App "Maybe" [t]
Failed, modules loaded: none.

Trac metadata

Trac field	Value
Version	7.8.1-rc2
Type	Bug
TypeOfFailure	OtherFailure
Priority	low
Resolution	Unresolved
Component	Compiler
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