Class DebugFileKey

crates/rustc_codegen_spirv/src/builder_spirv.rs:325–325

`HashMap` key type (for `debug_file_cache` in `BuilderSpirv`), which is equivalent to a whole `rustc` `SourceFile`, but has O(1) `Eq` and `Hash` implementations (i.e. not involving the path or the contents of the file). This is possible because we can compare `Lrc `s by equality, as `rustc`'s `SourceMap` already ensures that only one `SourceFile` will be allocated for some given file.

/// allocated for some given file. For hashing, we could hash the address, or
///
struct DebugFileKey(Lrc<SourceFile>);

impl PartialEq for DebugFileKey {
    fn eq(&self, other: &Self) -> bool {