Error/syntax highlighting not working

[v1nsai]

I have installed just rls-vscode by itself to avoid conflicts, and am using all default settings but still can't get linting or syntax highlighting of any kind to work. For example, the following code shows no errors in vscode but obviously cannot actually build:

fn main() {
    my_macro!(); jkfjdkjfkdjk
}

I checked the console and there is only one error

console.ts:137 [Extension Host] (node:44686) [DEP0005] DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.
t.log @ console.ts:137

but I'm not so sure its related, it seems to just be a warning instead of an error.

It does appear that RLS is updating and starting properly as I see entries in the log to indicate:

[Extension Host] Using active channel: stable-x86_64-unknown-linux-gnu
console.ts:137 [Extension Host] running with rustup: rls
console.ts:137 [Extension Host] will use a rustup-installed RLS; ensuring present
console.ts:137 [Extension Host] ApplicationInsights:CorrelationIdManager Array(1)
t.log @ console.ts:137
console.ts:137 [Extension Host] ApplicationInsights:CorrelationIdManager Array(1)
t.log @ console.ts:137
console.ts:137 [Extension Host] ApplicationInsights:CorrelationIdManager Array(1)
t.log @ console.ts:137
console.ts:137 [Extension Host] Setting sysroot to /home/doctor_ew/.rustup/toolchains/stable-x86_64-unknown-linux-gnu

And that is all of the logs I get in the Console. I'm really not sure what else to check but am happy to do/try anything else that I've missed. I've seen nearly identical results when running on my MacBook and on my Linux (Ubuntu) machine.