Unary unboxed tuple field causes interface file error

Compiling this code under 8.2 or HEAD (but not 8.0), I get an error.

{-# language UnboxedTuples #-}
module Reccy where

data Foo a = Foo (# a #)

Reccy.hs:1:1: error:
    Can't find interface-file declaration for variable GHC.Types.$tcUnit#
      Probable cause: bug in .hi-boot file, or inconsistent .hi file
      Use -ddump-if-trace to get an idea of which file caused the error
  |
1 | -- {-# language GADTs, TypeOperators #-}
  | ^

Trac metadata

Trac field	Value
Version	8.2.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Compiler
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