xhash/asert: remove redundant MaxTarget constant in favor of two256m1

Author: andrepatta

consensus/xhash/asert_test.go

@@ -319,3 +319,17 @@ func TestASERTNextTarget_BCHNVectors(t *testing.T) {
 		})
 	}
 }
+
+func TestASERTMaxTargetConsistency(t *testing.T) {
+	d1 := big.NewInt(1)
+	targetFromDiff := difficultyToTarget(d1)
+
+	if targetFromDiff.Cmp(two256m1) != 0 {
+		t.Fatalf("expected target for difficulty=1 to be two256m1, got %v", targetFromDiff)
+	}
+
+	roundTrip := targetToDifficulty(targetFromDiff)
+	if roundTrip.Cmp(d1) != 0 {
+		t.Fatalf("roundtrip diff→target→diff failed: want 1, got %v", roundTrip)
+	}
+}

consensus/xhash/consensus.go

@@ -46,8 +46,6 @@ var (
 	InitialBlockRewardWei = new(big.Int).Mul(big.NewInt(50), big.NewInt(1e18))
 	// A reserved system address to store maturity schedules in the state trie.
 	lockboxAddress = common.HexToAddress("0x0000000000000000000000000000000000000042")
-
-	MaxTarget = new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(1))
 )
 
 // Various error messages to mark blocks invalid. These should be private to
@@ -329,7 +327,7 @@ func (xhash *XHash) CalcDifficulty(chain consensus.ChainHeaderReader, time uint6
 		xhash.asertAnchorTarget,
 		evalHeight,
 		evalTime,
-		MaxTarget,
+		two256m1,
 	)
 
 	return targetToDifficulty(nextTarget)