Merge #9402

9402: internal: add cloning macro fixture r=matklad a=matklad

bors r+
🤖

Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>

crates/proc_macro_srv/src/tests/mod.rs

@@ -42,6 +42,19 @@ fn test_fn_like_macro() {
     );
 }
 
+#[test]
+fn test_fn_like_macro2() {
+    assert_expand(
+        "fn_like_clone_tokens",
+        r#"ident, []"#,
+        expect![[r#"
+            SUBTREE $
+              IDENT   ident 4294967295
+              PUNCH   , [alone] 4294967295
+              SUBTREE [] 4294967295"#]],
+    );
+}
+
 #[test]
 fn test_attr_macro() {
     // Corresponds to
@@ -70,6 +83,7 @@ fn list_test_macros() {
         fn_like_noop [FuncLike]
         fn_like_panic [FuncLike]
         fn_like_error [FuncLike]
+        fn_like_clone_tokens [FuncLike]
         attr_noop [Attr]
         attr_panic [Attr]
         attr_error [Attr]

crates/proc_macro_test/imp/src/lib.rs

@@ -1,6 +1,6 @@
 //! Exports a few trivial procedural macros for testing.
 
-use proc_macro::TokenStream;
+use proc_macro::{Group, Ident, Punct, TokenStream, TokenTree};
 
 #[proc_macro]
 pub fn fn_like_noop(args: TokenStream) -> TokenStream {
@@ -17,6 +17,11 @@ pub fn fn_like_error(args: TokenStream) -> TokenStream {
     format!("compile_error!(\"fn_like_error!({})\");", args).parse().unwrap()
 }
 
+#[proc_macro]
+pub fn fn_like_clone_tokens(args: TokenStream) -> TokenStream {
+    clone_stream(args)
+}
+
 #[proc_macro_attribute]
 pub fn attr_noop(_args: TokenStream, item: TokenStream) -> TokenStream {
     item
@@ -46,3 +51,24 @@ pub fn derive_panic(item: TokenStream) -> TokenStream {
 pub fn derive_error(item: TokenStream) -> TokenStream {
     format!("compile_error!(\"#[derive(DeriveError)] {}\");", item).parse().unwrap()
 }
+
+fn clone_stream(ts: TokenStream) -> TokenStream {
+    ts.into_iter().map(clone_tree).collect()
+}
+
+fn clone_tree(t: TokenTree) -> TokenTree {
+    match t {
+        TokenTree::Group(orig) => {
+            let mut new = Group::new(orig.delimiter(), clone_stream(orig.stream()));
+            new.set_span(orig.span());
+            TokenTree::Group(new)
+        }
+        TokenTree::Ident(orig) => TokenTree::Ident(Ident::new(&orig.to_string(), orig.span())),
+        TokenTree::Punct(orig) => {
+            let mut new = Punct::new(orig.as_char(), orig.spacing());
+            new.set_span(orig.span());
+            TokenTree::Punct(new)
+        }
+        TokenTree::Literal(_orig) => unimplemented!(),
+    }
+}