accounts/abi/bind/backends/simulated.go

@@ -527,7 +527,7 @@ func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMs
 		available := new(big.Int).Set(balance)
 		if call.Value != nil {
 			if call.Value.Cmp(available) >= 0 {
-				return 0, errors.New("insufficient funds for transfer")
+				return 0, core.ErrInsufficientFundsForTransfer
 			}
 			available.Sub(available, call.Value)
 		}

internal/ethapi/api.go

@@ -1098,7 +1098,7 @@ func DoEstimateGas(ctx context.Context, b Backend, args TransactionArgs, blockNr
 		available := new(big.Int).Set(balance)
 		if args.Value != nil {
 			if args.Value.ToInt().Cmp(available) >= 0 {
-				return 0, errors.New("insufficient funds for transfer")
+				return 0, core.ErrInsufficientFundsForTransfer
 			}
 			available.Sub(available, args.Value.ToInt())
 		}