From d5fef7950cf94f5c278b3f668d2f410ed29250bd Mon Sep 17 00:00:00 2001
From: Maximilian Langenfeld <15726643+ezdac@users.noreply.github.com>
Date: Mon, 5 Aug 2024 12:00:29 +0200
Subject: [PATCH] Add comment for nil fee-currency code path

---
 common/celo_types.go | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/common/celo_types.go b/common/celo_types.go
index 44c59e857d..533c2416a5 100644
--- a/common/celo_types.go
+++ b/common/celo_types.go
@@ -21,12 +21,16 @@ func MaxAllowedIntrinsicGasCost(i IntrinsicGasCosts, feeCurrency *Address) (uint
 	if !ok {
 		return 0, false
 	}
-	// allow the contract to overshoot 2 times the deducted intrinsic gas
-	// during execution
+	// Allow the contract to overshoot 2 times the deducted intrinsic gas
+	// during execution.
+	// If the feeCurrency is nil, then the max allowed intrinsic gas cost
+	// is 0 (i.e. not allowed) for a fee-currency specific EVM call within the STF.
 	return intrinsicGas * 3, true
 }
 
 func CurrencyIntrinsicGasCost(i IntrinsicGasCosts, feeCurrency *Address) (uint64, bool) {
+	// the additional intrinsic gas cost for a non fee-currency
+	// transaction is 0
 	if feeCurrency == nil {
 		return 0, true
 	}