+
+/// Parses the input token tree as comma separated plain paths.
+pub fn parse_tt_as_comma_sep_paths(input: ast::TokenTree) -> Option<Vec<ast::Path>> {
+ let r_paren = input.r_paren_token();
+ let tokens =
+ input.syntax().children_with_tokens().skip(1).map_while(|it| match it.into_token() {
+ // seeing a keyword means the attribute is unclosed so stop parsing here
+ Some(tok) if tok.kind().is_keyword() => None,
+ // don't include the right token tree parenthesis if it exists
+ tok @ Some(_) if tok == r_paren => None,
+ // only nodes that we can find are other TokenTrees, those are unexpected in this parse though
+ None => None,
+ Some(tok) => Some(tok),
+ });
+ let input_expressions = tokens.into_iter().group_by(|tok| tok.kind() == T![,]);
+ let paths = input_expressions
+ .into_iter()
+ .filter_map(|(is_sep, group)| (!is_sep).then(|| group))
+ .filter_map(|mut tokens| {
+ syntax::hacks::parse_expr_from_str(&tokens.join("")).and_then(|expr| match expr {
+ ast::Expr::PathExpr(it) => it.path(),
+ _ => None,
+ })
+ })
+ .collect();
+ Some(paths)
+}