diff --git a/src/Database/Esqueleto/Internal/Sql.hs b/src/Database/Esqueleto/Internal/Sql.hs
index e76fe3b..63f17dc 100644
--- a/src/Database/Esqueleto/Internal/Sql.hs
+++ b/src/Database/Esqueleto/Internal/Sql.hs
@@ -30,6 +30,7 @@ module Database.Esqueleto.Internal.Sql
   , Mode(..)
   , Escape
   , SqlSelect
+  , veryUnsafeCoerceSqlExprValue
   ) where
 
 import Control.Applicative (Applicative(..), (<$>))
@@ -343,6 +344,13 @@ unsafeSqlBinOp op (ERaw p1 f1) (ERaw p2 f2) = ERaw Parens f
                , vals1 <> vals2 )
 
 
+-- | (Internal) Coerce a type of a 'SqlExpr (Value a)' into
+-- another 'SqlExpr (Value b)'.  You should /not/ use this
+-- function unless you know what you're doing!
+veryUnsafeCoerceSqlExprValue :: SqlExpr (Value a) -> SqlExpr (Value b)
+veryUnsafeCoerceSqlExprValue (ERaw p f) = ERaw p f
+
+
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