Solana: BN type argument can be assigned to u64 type parameter

Here is an example of an article based on your code snippet:

Error message analysis: Solana Vote application test file

A common error occurs when trying to initialize the poll' structure in the test file for the Solana voting application. The problem arises when you try to assign an argument type to a parameter of type "u64", for example, the value "BN" (a large number). In this article, we will analyze the code and consider possible causes.

#![resolve(clippy::result_large_err)]


// Attempt to initialize the poll structure with the BN argument

#[test]

fn test_poll_init() {

    // ...

    let result = survey.init();

}

• Type Incompatibility: The BNtype provided by thesolana-type-aliasblock may be incompatible with theu64parameter of thepollstructure.

• Incorrect use of type aliases: TheBNtype alias should be used in a context where it can be safely displayed asu64. If not, consider using a type that is more appropriate for your case.

• You have imported the required types from thesolana-type-alias’ field.

• The alias type BN is correctly defined and available in the test file.

• You are using the correct syntax to assign an argument of type u64 to the parameter of the poll structure.

Here is an updated example:

#![resolve(clippy::result_large_err)]


use solana_type_alias::{BN, u64};


#[test]

fn test_poll_init() {

    // ...

    let poll = Poll::new();

    let result = survey.init();

}

In this refactoring example, “u64” is imported from the “solana-type-alias” block and used as the “u64” type parameter in the “init()” function.

Conclusion

The error message indicates that an attempt was made to assign a value of type “BN” of type “u64” to a parameter of type “u64”. Analyzing the code, it becomes clear that the problem arises from the incorrect use or import of types. To solve this problem, make sure you use the correct types and syntax in your test file.

Best Practice

To avoid such problems in the future:

• Check if the alias type BN is imported correctly.

• Ensure that the “u64” parameter of the “poll” structure has access to the valid value “u64”.

• Use the correct syntax to assign an argument of type ‘u64’ to a parameter of type ‘u64’.

By following these guidelines, you’ll be able to write more reliable and error-free test code for your Solana voting application.