From c9ff21d30a2d4b0b9d7b6c6586bd64bd53b60c91 Mon Sep 17 00:00:00 2001
From: Harpo Reder <roederharpo@protonmail.ch>
Date: Sun, 15 Jul 2018 05:47:50 +0000
Subject: [PATCH 1/2] cherrypick unsafeSqlCastAs

---
 src/Database/Esqueleto/Internal/Sql.hs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/Database/Esqueleto/Internal/Sql.hs b/src/Database/Esqueleto/Internal/Sql.hs
index 528d140..63c801c 100644
--- a/src/Database/Esqueleto/Internal/Sql.hs
+++ b/src/Database/Esqueleto/Internal/Sql.hs
@@ -33,6 +33,7 @@ module Database.Esqueleto.Internal.Sql
   , unsafeSqlBinOp
   , unsafeSqlBinOpComposite
   , unsafeSqlValue
+  , unsafeSqlCastAs
   , unsafeSqlFunction
   , unsafeSqlExtractSubField
   , UnsafeSqlFunctionArgument
@@ -766,6 +767,13 @@ unsafeSqlFunctionParens name arg =
     in (name <> parens argsTLB, argsVals)
 
 
+-- | explicit cast using CAST(value as type)
+unsafeSqlCastAs :: T.Text -> SqlExpr (Value a) -> SqlExpr (Value b)
+unsafeSqlCastAs t (ERaw p f) =
+  ERaw Never $ \info ->
+    let (b, v) = f info
+    in ("CAST" <> parens ( parensM p b <> " AS " <> TLB.fromText t), v )
+
 class UnsafeSqlFunctionArgument a where
   toArgList :: a -> [SqlExpr (Value ())]
 instance (a ~ Value b) => UnsafeSqlFunctionArgument (SqlExpr a) where

From 2e16c72154d8c2200afeea0f295e935967bd8f4b Mon Sep 17 00:00:00 2001
From: Harpo Reder <roederharpo@protonmail.ch>
Date: Sun, 15 Jul 2018 06:08:23 +0000
Subject: [PATCH 2/2] add SqlCast composite key error

---
 src/Database/Esqueleto/Internal/Sql.hs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Database/Esqueleto/Internal/Sql.hs b/src/Database/Esqueleto/Internal/Sql.hs
index 63c801c..e13877a 100644
--- a/src/Database/Esqueleto/Internal/Sql.hs
+++ b/src/Database/Esqueleto/Internal/Sql.hs
@@ -102,6 +102,7 @@ data CompositeKeyError =
   | FoldHelpError
   | SqlCaseError
   | SqlBinOpError
+  | SqlCastAsError
   | MakeOnClauseError
   | MakeExcError
   | MakeSetError
@@ -766,13 +767,14 @@ unsafeSqlFunctionParens name arg =
           uncommas' $ map (\(ERaw p f) -> first (parensM p) (f info)) $ toArgList arg
     in (name <> parens argsTLB, argsVals)
 
-
--- | explicit cast using CAST(value as type)
+-- | (Internal) An explicit SQL type cast using CAST(value as type).
+-- See 'unsafeSqlBinOp' for warnings.
 unsafeSqlCastAs :: T.Text -> SqlExpr (Value a) -> SqlExpr (Value b)
 unsafeSqlCastAs t (ERaw p f) =
   ERaw Never $ \info ->
     let (b, v) = f info
     in ("CAST" <> parens ( parensM p b <> " AS " <> TLB.fromText t), v )
+unsafeSqlCastAs _ (ECompositeKey _) = throw (CompositeKeyErr SqlCastAsError)
 
 class UnsafeSqlFunctionArgument a where
   toArgList :: a -> [SqlExpr (Value ())]