diff options
Diffstat (limited to 'src/libsyntax_ext')
| -rw-r--r-- | src/libsyntax_ext/concat_idents.rs | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/src/libsyntax_ext/concat_idents.rs b/src/libsyntax_ext/concat_idents.rs index 544b1410d3d..b8345e7cf40 100644 --- a/src/libsyntax_ext/concat_idents.rs +++ b/src/libsyntax_ext/concat_idents.rs @@ -31,6 +31,11 @@ pub fn expand_syntax_ext<'cx>(cx: &'cx mut ExtCtxt, return base::DummyResult::expr(sp); } + if tts.is_empty() { + cx.span_err(sp, "concat_idents! takes 1 or more arguments."); + return DummyResult::expr(sp); + } + let mut res_str = String::new(); for (i, e) in tts.iter().enumerate() { if i & 1 == 1 { |