From 2e96484a3494016d280c0adefe4d2c71a56826fb Mon Sep 17 00:00:00 2001
From: Johannes Lund <johannes.lund@iohk.io>
Date: Mon, 13 Sep 2021 19:04:12 +0200
Subject: [PATCH] Expose unsafeNaturalToCoin with guards

This should be safer than using the `Coin` constructor.
---
 lib/core/src/Cardano/Wallet/Primitive/Types/Coin.hs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/core/src/Cardano/Wallet/Primitive/Types/Coin.hs b/lib/core/src/Cardano/Wallet/Primitive/Types/Coin.hs
index 3801544c385..bf24f050ef4 100644
--- a/lib/core/src/Cardano/Wallet/Primitive/Types/Coin.hs
+++ b/lib/core/src/Cardano/Wallet/Primitive/Types/Coin.hs
@@ -16,6 +16,7 @@ module Cardano.Wallet.Primitive.Types.Coin
     , coinQuantity
     , coinToInteger
     , coinToNatural
+    , unsafeNaturalToCoin
 
       -- * Checks
     , isValidCoin
@@ -125,7 +126,10 @@ coinToNatural :: Coin -> Natural
 coinToNatural = fromIntegral . unCoin
 
 unsafeNaturalToCoin :: Natural -> Coin
-unsafeNaturalToCoin = Coin . fromIntegral
+unsafeNaturalToCoin x | x <= maxBoundNatural = Coin $ fromIntegral x
+                      | otherwise = error "unsafeNaturalToCoin: overflow"
+  where
+    maxBoundNatural = fromIntegral . unCoin $ maxBound @Coin
 
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