Use global error

Author: StephenButtolph

trie/proof.go

@@ -489,7 +489,7 @@ func VerifyRangeProof(rootHash common.Hash, firstKey []byte, keys [][]byte, valu
 	for i := 0; i < len(keys)-1; i++ {
 		// See: https://github.com/ava-labs/coreth/issues/907
 		if len(keys[i]) != len(keys[i+1]) {
-			return false, errors.New("keys do not have constant length")
+			return false, errKeysHaveDifferentLengths
 		}
 		if bytes.Compare(keys[i], keys[i+1]) >= 0 {
 			return false, errors.New("range is not monotonically increasing")

trie/proof.libevm.go

@@ -0,0 +1,23 @@
+// Copyright 2025 the libevm authors.
+//
+// The libevm additions to go-ethereum are free software: you can redistribute
+// them and/or modify them under the terms of the GNU Lesser General Public License
+// as published by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// The libevm additions are distributed in the hope that they will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+// General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package trie
+
+import (
+	"errors"
+)
+
+var errKeysHaveDifferentLengths = errors.New("keys have different lengths")

trie/proof.libevm_test.go

@@ -19,6 +19,8 @@ package trie
 import (
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	"github.com/ava-labs/libevm/common"
 )
 
@@ -42,7 +44,5 @@ func TestRangeProofKeysWithDifferentLengths(t *testing.T) {
 		values,
 		nil, // force it to use stacktrie
 	)
-	if err == nil {
-		t.Fatalf("unexpectedly verified invalid range proof: %v", err)
-	}
+	require.ErrorIs(t, err, errKeysHaveDifferentLengths)
 }