{"ast_node_type":"function","tokens":[{"end":97,"kind":"keyword","start":0,"text":"pub"}]}
    pub fn env_var<K: ?Sized + AsRef<OsStr>>(self, key: &'tcx K) -> Result<&'tcx str, VarError> {
    /// UTF-8 like [`std::env::var`].
        match self.env_var_os(key.as_ref()) {