1 files changed, 23 insertions, 0 deletions
diff --git a/rust/macros/concat_idents.rs b/rust/macros/concat_idents.rs
new file mode 100644
index 000000000000..7e4b450f3a50
--- /dev/null
+++ b/rust/macros/concat_idents.rs
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use proc_macro::{token_stream, Ident, TokenStream, TokenTree};
+
+use crate::helpers::expect_punct;
+
+fn expect_ident(it: &mut token_stream::IntoIter) -> Ident {
+    if let Some(TokenTree::Ident(ident)) = it.next() {
+        ident
+    } else {
+        panic!("Expected Ident")
+    }
+}
+
+pub(crate) fn concat_idents(ts: TokenStream) -> TokenStream {
+    let mut it = ts.into_iter();
+    let a = expect_ident(&mut it);
+    assert_eq!(expect_punct(&mut it), ',');
+    let b = expect_ident(&mut it);
+    assert!(it.next().is_none(), "only two idents can be concatenated");
+    let res = Ident::new(&format!("{a}{b}"), b.span());
+    TokenStream::from_iter([TokenTree::Ident(res)])
+}