Reject constant modifier on the fallback function

libsolidity/interface/InterfaceHandler.cpp

@@ -81,7 +81,6 @@ string InterfaceHandler::abiInterface(ContractDefinition const& _contractDef)
 		solAssert(!!externalFunctionType, "");
 		Json::Value method;
 		method["type"] = "fallback";
-		method["constant"] = externalFunctionType->isConstant();
 		method["payable"] = externalFunctionType->isPayable();
 		abi.append(method);
 	}