Illegal instance declaration for `Show Doc'

I can't install hmatrix-syntax because template-haskell has errors.

$ cabal install hmatrix-syntax
Resolving dependencies...
Downloading template-haskell-2.7.0.0...
Configuring template-haskell-2.7.0.0...
Preprocessing library template-haskell-2.7.0.0...
Building template-haskell-2.7.0.0...
[1 of 7] Compiling Language.Haskell.TH.Syntax.Internals ( Language/Haskell/TH/Syntax/Internals.hs, dist/build/Language/Haskell/TH/Syntax/Internals.o )
[2 of 7] Compiling Language.Haskell.TH.Syntax ( Language/Haskell/TH/Syntax.hs, dist/build/Language/Haskell/TH/Syntax.o )
[3 of 7] Compiling Language.Haskell.TH.PprLib ( Language/Haskell/TH/PprLib.hs, dist/build/Language/Haskell/TH/PprLib.o )

Language/Haskell/TH/PprLib.hs:55:10:
    Illegal instance declaration for `Show Doc'
      (All instance types must be of the form (T t1 ... tn)
       where T is not a synonym.
       Use -XTypeSynonymInstances if you want to disable this.)
    In the instance declaration for `Show Doc'
cabal: Error: some packages failed to install:
haskell-src-meta-0.5.1 depends on template-haskell-2.7.0.0 which failed to
install.
hmatrix-syntax-0.1 depends on template-haskell-2.7.0.0 which failed to
install.
template-haskell-2.7.0.0 failed during the building phase. The exception was:
ExitFailure 1
th-lift-0.5.5 depends on template-haskell-2.7.0.0 which failed to install.

Trac metadata

Trac field	Value
Version	7.4.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
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