From a1127f8f9d5dede6c314961ff1b2f12fc6e30849 Mon Sep 17 00:00:00 2001
From: Marcio Diaz <marcio.diaz@gmail.com>
Date: Wed, 6 May 2020 17:37:02 +0200
Subject: [PATCH] Fix saturating_mul (#5925)

---
 substrate/primitives/arithmetic/src/traits.rs | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/substrate/primitives/arithmetic/src/traits.rs b/substrate/primitives/arithmetic/src/traits.rs
index 6b5e324464..4201a41364 100644
--- a/substrate/primitives/arithmetic/src/traits.rs
+++ b/substrate/primitives/arithmetic/src/traits.rs
@@ -123,7 +123,7 @@ pub trait Saturating {
 	fn saturating_pow(self, exp: usize) -> Self;
 }
 
-impl<T: Clone + One + CheckedMul + Bounded + num_traits::Saturating> Saturating for T {
+impl<T: Clone + Zero + One + PartialOrd + CheckedMul + Bounded + num_traits::Saturating> Saturating for T {
 	fn saturating_add(self, o: Self) -> Self {
 		<Self as num_traits::Saturating>::saturating_add(self, o)
 	}
@@ -133,7 +133,14 @@ impl<T: Clone + One + CheckedMul + Bounded + num_traits::Saturating> Saturating
 	}
 
 	fn saturating_mul(self, o: Self) -> Self {
-		self.checked_mul(&o).unwrap_or_else(Bounded::max_value)
+		self.checked_mul(&o)
+			.unwrap_or_else(||
+				if (self < T::zero()) != (o < T::zero()) {
+					Bounded::min_value()
+				} else {
+					Bounded::max_value()
+				}
+			)
 	}
 
 	fn saturating_pow(self, exp: usize) -> Self {