`&raw const`/`&raw mut` is not syntax-highlighted in all files

[RalfJung]

When opening a file that is not in the current project (i.e. RA cannot do its full semantic analysis), syntax highlighting of &raw is broken:

Note that raw is not in the same style as mut.
raw is not a keyword, but its role as a contextual keyword in these expressions is entirely syntactic so this does not seem to me like it should require full type information to be properly highlighted.

rust-analyzer version: rust-analyzer version: 0.3.2337-standalone (5e7dd31 2025-03-09) [/home/r/.vscode-oss/extensions/rust-lang.rust-analyzer-0.3.2337-linux-x64/server/rust-analyzer]

editor or extension: VSCodium, extension v0.3.2337

code snippet to reproduce:

fn main() {
    let x = &raw mut 5;
}

[Veykril]

Technically that's an issue with the textmate grammar vscode ships. Though our semantic highlighting infra should handle this either way (which would fix it here)

[Veykril]

Oh actually this should already work but does not because of

rust-analyzer/crates/ide/src/syntax_highlighting.rs

Line 227 in 185f9de

None => return hl.to_vec(),

early returning
We should make that krate an Option and actually generate the highlighting

[Shourya742]

@rustbot claim