Matches syntax issues?

help
1

Hi, I am not sure what to search for but I didn't find anything.
I want to check if an enum field equals some parameter
if !matches!(&args[0].0, &vc.script_context.return_type)
but it complains about the first . after vc

error: no rules expected the token `.`
    |         if !matches!(&args[0].0, &vc.script_context.return_type)
    |                                     ^ no rules expected this token in macro call
    |
    = note: while trying to match sequence start

I don't understand why it cannot parse this, it should in my opinion.
So my workaround is to reference vc.script_context.return_type into a variable:

let value_type = &vc.script_context.return_type;
if !matches!(&args[0].0, value_type)

which compiles fine. But it gives me this non-sensical warning:

warning: unused variable: `value_type`
711 |         let value_type = &vc.script_context.return_type;
    |             ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_value_type`
    |
    = note: `#[warn(unused_variables)]` on by default
warning: unused variable: `value_type`
    |
712 |         if !matches!(&args[0].0, value_type)
    |                                  ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_value_type`

it claims that the variable that I am using here is unused, which is just wrong.
Am I missing something? Or is this a bug?
Thanks in advance

2

matches! is a shorthand sugar for rust pattern match, it's not something like regex match.

3

The second argument of matches is a pattern, not an expression. It seem like you want == instead.

3 Likes