core: improved bad block error reporting (#3320)

params/config.go

@@ -17,6 +17,7 @@
 package params
 
 import (
+	"fmt"
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -66,6 +67,19 @@ type ChainConfig struct {
 	EIP158Block *big.Int `json:"eip158Block"` // EIP158 HF block
 }
 
+// String implements the Stringer interface.
+func (c *ChainConfig) String() string {
+	return fmt.Sprintf("{ChainID: %v Homestead: %v DAO: %v DAOSupport: %v EIP150: %v EIP155: %v EIP158: %v}",
+		c.ChainId,
+		c.HomesteadBlock,
+		c.DAOForkBlock,
+		c.DAOForkSupport,
+		c.EIP150Block,
+		c.EIP155Block,
+		c.EIP158Block,
+	)
+}
+
 var (
 	TestChainConfig = &ChainConfig{big.NewInt(1), new(big.Int), new(big.Int), true, new(big.Int), common.Hash{}, new(big.Int), new(big.Int)}
 	TestRules       = TestChainConfig.Rules(new(big.Int))