Boot file problem

Here are two modules and a boot file. Compile by

ghc -c Foo.hs-boot; ghc -c Bar.hs; ghc -c Foo.hs

and observe this error message

Foo.hs:12:1:
    Type constructor `Foo' has conflicting definitions in the module
    and its hs-boot file
    Main module: data Foo = Foo {x :: {-# UNPACK #-} !Int}
    Boot file:   data Foo = Foo {x :: !Int}

But the definitions are not conflicting, they are identical.

Foo.hs-boot:

module Foo where
data Foo = Foo { x :: {-# UNPACK #-} !Int }

Foo.hs:

module Foo where
import Bar
data Foo = Foo { x :: {-# UNPACK #-} !Int }

Bar.hs:

module Bar where
import {-# SOURCE #-} Foo

Removing the unbox pragma gives the even more perplexing:

Foo.hs:3:1:
    Type constructor `Foo' has conflicting definitions in the module
    and its hs-boot file
    Main module: data Foo = Foo {x :: !Int}
    Boot file:   data Foo = Foo {x :: !Int}

Trac metadata

Trac field	Value
Version	7.8.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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