[FIXED] What is the Rust compiler saying here?

Issue

error[E0621]: explicit lifetime required in the type of `is`
  --> src/bee.rs:76:45
   |
75 | fn compute_instruction_set<'a>(is: &'a mut InstructionSet) {
   |                                    ---------------------- help: add explicit lifetime `'a` to the type of `is`: `&'a mut [OpCode<'a>; 255]`
76 |     let mut isb = InstructionSetBuilder{is: is, pos: 0};
   |                                             ^^ lifetime `'a` required

This is the code:

type InstructionSet<'a> = [OpCode<'a>; 0xff];
...
struct InstructionSetBuilder<'a> {
    is: &'a mut [OpCode<'a>],
    pos: usize,
}
...
fn compute_instruction_set<'a>(is: &'a mut InstructionSet) {
    let mut isb = InstructionSetBuilder{is: is, pos: 0};
...
}

Why do I need to set yet another 'a lifetime param?

Where?

I tried several combinations, all broke the syntax...

Solution

type InstructionSet<'a> = [OpCode<'a>; 0xff];

This type alias is generic over a lifetime 'a. So you must specify it. Try this instead.

fn compute_instruction_set<'a>(is: &'a mut InstructionSet<'a>) {
    let mut isb = InstructionSetBuilder{is: is, pos: 0};
...
}

Answered By - Aleksander Krauze

Answer Checked By - Robin (PHPFixing Admin)