How to Understand the “No Function or Associated Item with Name Create_Type” Error in Solana
As a developer building applications on the Solana blockchain, it’s not uncommon to encounter errors related to smart contract development. One such error is the “No Function or Associated Item with Name Create_Type” error, which can occur when attempting to use a custom type defined in the Solana program.
The Problem: Error E0599
In the provided code snippet:
use solana_program::program_error::{error, ErrorKind};
use solana_program:: pubkey::Pubkey;
use solana_type::create_type;
// Define your custom type here
pub fn main() -> Result<(), error::Error> {
// Your program logic here...
// Create a new transaction with the custom type
let tx = create_type!(T) as &_, 10u64; // T is your custom type and "as &_"
}
The error occurs because the create_type! function does not exist in the Solana SDK. Instead, you should use program_error::ErrorKind::CustomType to handle this specific error.
Fix bug
To fix the error, you need to define a custom type and then use it when creating transactions. Here is an updated version of the code:
use solana_program::program_error::{error, ErrorKind};
use solana_program:: pubkey::Pubkey;
use std::mem;
// Define your custom type here
pub fn main() -> Result<(), error::Error> {
// Create a new transaction with the custom type
let tx = create_type!(T) as &_, 10u64; // T is your custom type and "as &_"
// Check if the transaction was created correctly
match tx {
Ok(_) => println!("Transaction created successfully"),
Err(err) => error!("Error creating transaction", err),
}
}
Understanding Custom Types
In Solana, you can define custom types using the create_type! macro. This macro is used to generate code to create custom types.
Here is an example of a basic custom type:
use solana_type::create_type;
public type MyCustomType = u8;
With this definition, we can use it when creating transactions:
pub fn create_transaction() -> ProgramResult {
// Create a new transaction with the custom type
let tx = MyCustomType::new(10);
Ok(())
}
Conclusion
In this article, we saw how to fix the “no function or associated element with name create_type” error in Solana. By defining your own custom types and using them when creating transactions, you can create more complex applications on the blockchain.
Always remember to consult the official Solana documentation for the most up-to-date information about programming languages and types.