Function resolve_import_path 

pub fn resolve_import_path(
    current_file: &Path,
    import_path: &str,
) -> Option<PathBuf>

Resolve an import string relative to the importing file.

Returns the path as-constructed (not canonicalized) so callers that compare against their own PathBuf::join result get matching values. The module graph canonicalizes internally via normalize_path when keying modules, so call-site canonicalization is not required for dedup.

std/<module> imports resolve to a virtual path (<std>/<module>) backed by the embedded stdlib sources in [stdlib]. This lets the module graph model stdlib symbols even though they have no on-disk location.