Haskell 在Quipper中编译GHC程序时出错

我正在尝试用Quipper编译一个程序，Quipper是本网站的官方量子编程语言：

我在编译它时遇到了麻烦，我认为这一定是与GHC或Haskell有关的问题，因为Quipper本身没有突出的bug

我使用以下命令编译程序：

cd ~/quipper-0.8/quipper/scripts/
sudo ./quipper ~/quipper-0.8/tests/name.hs

我收到的错误如下所示：

[13 of 21] Compiling Quipper.QData    ( ../../quipper/Quipper/QData.hs, ../../quipper/Quipper/QData.o )

../../quipper/Quipper/QData.hs:965:20:
Could not deduce (QCType Bool Bool s0
                  ~ QCType Int Bool (QCType Bit Bit s))
from the context (QData s)
  bound by the type signature for
             qdata_promote_c :: QData s =>
                                BType s -> CType s -> ErrMsg -> BType s
  at ../../quipper/Quipper/QData.hs:965:20-71
NB: ‘QCType’ is a type function, and may not be injective
The type variable ‘s0’ is ambiguous
Expected type: BType s -> CType s -> ErrMsg -> BType s
  Actual type: BType s0 -> CType s0 -> ErrMsg -> BType s0
In the ambiguity check for the type signature for ‘qdata_promote_c’:
  qdata_promote_c :: forall s.
                     QData s =>
                     BType s -> CType s -> ErrMsg -> BType s
To defer the ambiguity check to use sites, enable AllowAmbiguousTypes
In the type signature for ‘qdata_promote_c’:
  qdata_promote_c :: (QData s) =>
                     BType s -> CType s -> ErrMsg -> BType s

-- | Like 'qdata_promote', except take a piece of classical data.
qdata_promote_c :: (QData s) => BType s -> CType s -> ErrMsg -> BType s
qdata_promote_c b c s = qdata_promote b q s where
q = qdata_map (shapetype_c c) map_qubit c

map_qubit :: Bit -> Qubit
map_qubit = const qubit

QData.hs

中引用的代码行如下所示：

[13 of 21] Compiling Quipper.QData    ( ../../quipper/Quipper/QData.hs, ../../quipper/Quipper/QData.o )

../../quipper/Quipper/QData.hs:965:20:
Could not deduce (QCType Bool Bool s0
                  ~ QCType Int Bool (QCType Bit Bit s))
from the context (QData s)
  bound by the type signature for
             qdata_promote_c :: QData s =>
                                BType s -> CType s -> ErrMsg -> BType s
  at ../../quipper/Quipper/QData.hs:965:20-71
NB: ‘QCType’ is a type function, and may not be injective
The type variable ‘s0’ is ambiguous
Expected type: BType s -> CType s -> ErrMsg -> BType s
  Actual type: BType s0 -> CType s0 -> ErrMsg -> BType s0
In the ambiguity check for the type signature for ‘qdata_promote_c’:
  qdata_promote_c :: forall s.
                     QData s =>
                     BType s -> CType s -> ErrMsg -> BType s
To defer the ambiguity check to use sites, enable AllowAmbiguousTypes
In the type signature for ‘qdata_promote_c’:
  qdata_promote_c :: (QData s) =>
                     BType s -> CType s -> ErrMsg -> BType s

-- | Like 'qdata_promote', except take a piece of classical data.
qdata_promote_c :: (QData s) => BType s -> CType s -> ErrMsg -> BType s
qdata_promote_c b c s = qdata_promote b q s where
q = qdata_map (shapetype_c c) map_qubit c

map_qubit :: Bit -> Qubit
map_qubit = const qubit

显然，这是它在

QData.hs

中遇到问题的代码的唯一部分，但当我对它进行注释时，我得到了以下错误：

[13 of 21] Compiling Quipper.QData    ( ../../quipper/Quipper/QData.hs, ../../quipper/Quipper/QData.o )
[14 of 21] Compiling Quipper.Generic  ( ../../quipper/Quipper/Generic.hs, ../../quipper/Quipper/Generic.o )

../../quipper/Quipper/Generic.hs:257:13:
Not in scope: ‘qdata_promote_c’
Perhaps you meant one of these:
  ‘qdata_promote’ (imported from Quipper.QData),
  ‘qcdata_promote’ (imported from Quipper.QData)

正如您所看到的，这次它接受了

[13/21]

，但在14日中断，因为它依赖于我注释掉的函数。当我尝试按照它的建议添加AllowAmbigUstypes时：

sudo ./quipper ~/quipper-0.8/tests/name.hs -XAllowAmbiguousTypes

我得到了更多的错误：

[13 of 21] Compiling Quipper.QData    ( ../../quipper/Quipper/QData.hs, ../../quipper/Quipper/QData.o )

../../quipper/Quipper/QData.hs:966:25:
Could not deduce (QCType
                    Bool Bool (QCType Qubit Qubit (QCType Qubit Qubit s0))
                  ~ QCType Int Bool (QCType Bit Bit s))
from the context (QData s)
  bound by the type signature for
             qdata_promote_c :: QData s =>
                                BType s -> CType s -> ErrMsg -> BType s
  at ../../quipper/Quipper/QData.hs:965:20-71
NB: ‘QCType’ is a type function, and may not be injective
The type variable ‘s0’ is ambiguous
Expected type: BType s
  Actual type: BType (HType Qubit s0)
Relevant bindings include
  q :: HType Qubit s0 (bound at ../../quipper/Quipper/QData.hs:967:3)
  c :: CType s (bound at ../../quipper/Quipper/QData.hs:966:19)
  b :: BType s (bound at ../../quipper/Quipper/QData.hs:966:17)
  qdata_promote_c :: BType s -> CType s -> ErrMsg -> BType s
    (bound at ../../quipper/Quipper/QData.hs:966:1)
In the expression: qdata_promote b q s
In an equation for ‘qdata_promote_c’:
    qdata_promote_c b c s
      = qdata_promote b q s
      where
          q = qdata_map (shapetype_c c) map_qubit c
          map_qubit :: Bit -> Qubit
          map_qubit = const qubit

../../quipper/Quipper/QData.hs:967:30:
Could not deduce (QCType Bit Bit s0 ~ QCType Bit Bit s)
from the context (QData s)
  bound by the type signature for
             qdata_promote_c :: QData s =>
                                BType s -> CType s -> ErrMsg -> BType s
  at ../../quipper/Quipper/QData.hs:965:20-71
NB: ‘QCType’ is a type function, and may not be injective
The type variable ‘s0’ is ambiguous
Expected type: CType s0
  Actual type: CType s
Relevant bindings include
  q :: HType Qubit s0 (bound at ../../quipper/Quipper/QData.hs:967:3)
  c :: CType s (bound at ../../quipper/Quipper/QData.hs:966:19)
  b :: BType s (bound at ../../quipper/Quipper/QData.hs:966:17)
  qdata_promote_c :: BType s -> CType s -> ErrMsg -> BType s
    (bound at ../../quipper/Quipper/QData.hs:966:1)
In the first argument of ‘shapetype_c’, namely ‘c’
In the first argument of ‘qdata_map’, namely ‘(shapetype_c c)’

../../quipper/Quipper/QData.hs:967:43:
Could not deduce (QCType Bit Bit (QCType Qubit Qubit s0)
                  ~ QCType Bit Bit s)
from the context (QData s)
  bound by the type signature for
             qdata_promote_c :: QData s =>
                                BType s -> CType s -> ErrMsg -> BType s
  at ../../quipper/Quipper/QData.hs:965:20-71
NB: ‘QCType’ is a type function, and may not be injective
The type variable ‘s0’ is ambiguous
Expected type: HType Bit s0
  Actual type: CType s
Relevant bindings include
  q :: HType Qubit s0 (bound at ../../quipper/Quipper/QData.hs:967:3)
  c :: CType s (bound at ../../quipper/Quipper/QData.hs:966:19)
  b :: BType s (bound at ../../quipper/Quipper/QData.hs:966:17)
  qdata_promote_c :: BType s -> CType s -> ErrMsg -> BType s
    (bound at ../../quipper/Quipper/QData.hs:966:1)
In the third argument of ‘qdata_map’, namely ‘c’
In the expression: qdata_map (shapetype_c c) map_qubit c

所有这些都源于我上面引用的

QData.hs

中的同一行。注意这些错误显然都与我自己在

name.hs

中的代码无关

我注意到这个网站没有Quipper的直接帮助（我已经给Quipper的负责人发了电子邮件，但没有回复），但我很确定这是我编译它的方式造成的问题，因为这些错误消息不是来自Quipper，而是来自GHC或Haskell

所以不管怎样，如果有人能帮我弄清真相，我们将不胜感激，

---

Nathan

您使用的是什么版本的GHC？Quipper使用了很多高级类型级别的机器，这对于GHC版本来说有点脆弱。我记得我试着给Quipper打补丁，让它在7.10上运行，我的错误与之类似。好吧，7.10 simple不适用于Quipper…我对Quipper一无所知，但错误建议在

q_data\u promotec

中添加

Proxy s

arg可能会有所帮助。或者，您可以使用含糊不清的类型，但这也需要使用TypeApplications在每个使用站点上指定含糊不清的类型。根据整个代码体的外观，其中一个可能更方便您。Alec我的版本显然是7.10.3:

ghc:amd64/xenial 7.10.3-7 Update

。我按照上的说明运行了安装了ghc 8.0.2的

堆栈设置
。但当上述问题持续存在时，当我再次检查GHC版本时，它仍然显示为7.10.3 WTH？！User24这是我第一次在haskell中编程，所以我不完全确定在哪里添加argto@NathanGoedeke不幸的是，如果您不熟悉Haskell的一些更高级的类型级别特性（当然，要熟悉这些特性，您必须熟悉基础知识）你会发现使用这样一个高级类型级特性的库非常困难。你使用的是什么版本的GHC？Quipper使用了很多高级类型级别的机器，这对于GHC版本来说有点脆弱。我记得我试着给Quipper打补丁，让它在7.10上运行，我的错误与之类似。好吧，7.10 simple不适用于Quipper…我对Quipper一无所知，但错误建议在
q_data\u promotec
中添加
Proxy s
arg可能会有所帮助。或者，您可以使用含糊不清的类型，但这也需要使用TypeApplications在每个使用站点上指定含糊不清的类型。根据整个代码体的外观，其中一个可能更方便您。Alec我的版本显然是7.10.3:
ghc:amd64/xenial 7.10.3-7 Update
。我按照上的说明运行了安装了ghc 8.0.2的
堆栈设置
。但当上述问题持续存在时，当我再次检查GHC版本时，它仍然显示为7.10.3 WTH？！User24这是我第一次在haskell中编程，所以我不完全确定在哪里添加argto@NathanGoedeke不幸的是，如果您不熟悉Haskell的一些更高级的类型级别特性（当然，要熟悉这些特性，您必须熟悉基础知识）您会发现使用一个利用了这种高级类型级别特性的库是非常困难的。