AtnNn/haskell-rethinkdb — pull request #19 by prettynatty (2014-05-13 13:14:41+00:00)
Title: Fixed compilation error

Fixes the following error:
```
[21 of 28] Compiling Database.RethinkDB.ReQL ( Database/RethinkDB/ReQL.hs, dist/dist-sandbox-8cf38cea/build/Database/RethinkDB/ReQL.o )

Database/RethinkDB/ReQL.hs:329:14:
No instance for (Expr t0) arising from a use of `op'
The type variable `t0' is ambiguous
Possible fix: add a type signature that fixes these type variable(s)
Note: there are several potential instances:
instance (Expr a, Expr b, Expr c, Expr d, Expr e) =>
Expr (a, b, c, d, e)
-- Defined at Database/RethinkDB/ReQL.hs:480:10
instance (Expr a, Expr b, Expr c, Expr d) => Expr (a, b, c, d)
-- Defined at Database/RethinkDB/ReQL.hs:477:10
instance (Expr a, Expr b, Expr c) => Expr (a, b, c)
-- Defined at Database/RethinkDB/ReQL.hs:474:10
...plus 24 others
In the expression: op SUB (0, a) ()
In an equation for `negate': negate a = op SUB (0, a) ()
In the instance declaration for `Num ReQL'

Database/RethinkDB/ReQL.hs:329:22:
No instance for (Num t0) arising from the literal `0'
The type variable `t0' is ambiguous
Possible fix: add a type signature that fixes these type variable(s)
Note: there are several potential instances:
instance Num ReQL -- Defined at Database/RethinkDB/ReQL.hs:324:10
instance Num EnumCode -- Defined in `Text.ProtocolBuffers.Basic'
instance Num FieldId -- Defined in `Text.ProtocolBuffers.Basic'
...plus 16 others
In the expression: 0
In the second argument of `op', namely `(0, a)'
In the expression: op SUB (0, a) ()
```