Handle extended key value attr in mbe

crates/mbe/src/tests/expand.rs

@@ -940,6 +940,24 @@ fn test_meta_doc_comments() {
     );
 }
 
+#[test]
+fn test_meta_extended_key_value_attributes() {
+    parse_macro(
+        r#"
+macro_rules! foo {
+    (#[$i:meta]) => (
+        #[$ i]
+        fn bar() {}
+    )
+}
+"#,
+    )
+    .assert_expand_items(
+        r#"foo! { #[doc = concat!("The `", "bla", "` lang item.")] }"#,
+        r#"# [doc = concat ! ("The `" , "bla" , "` lang item.")] fn bar () {}"#,
+    );
+}
+
 #[test]
 fn test_meta_doc_comments_non_latin() {
     parse_macro(

crates/parser/src/grammar.rs

@@ -76,42 +76,7 @@ pub(crate) mod fragments {
 
     // Parse a meta item , which excluded [], e.g : #[ MetaItem ]
     pub(crate) fn meta_item(p: &mut Parser) {
-        fn is_delimiter(p: &mut Parser) -> bool {
+        attributes::meta(p);
-            matches!(p.current(), T!['{'] | T!['('] | T!['['])
-        }
-
-        if is_delimiter(p) {
-            items::token_tree(p);
-            return;
-        }
-
-        let m = p.start();
-        while !p.at(EOF) {
-            if is_delimiter(p) {
-                items::token_tree(p);
-                break;
-            } else {
-                // https://doc.rust-lang.org/reference/attributes.html
-                // https://doc.rust-lang.org/reference/paths.html#simple-paths
-                // The start of an meta must be a simple path
-                match p.current() {
-                    IDENT | T![super] | T![self] | T![crate] => p.bump_any(),
-                    T![=] => {
-                        p.bump_any();
-                        match p.current() {
-                            c if c.is_literal() => p.bump_any(),
-                            T![true] | T![false] => p.bump_any(),
-                            _ => {}
-                        }
-                        break;
-                    }
-                    _ if p.at(T![::]) => p.bump(T![::]),
-                    _ => break,
-                }
-            }
-        }
-
-        m.complete(p, TOKEN_TREE);
     }
 
     pub(crate) fn item(p: &mut Parser) {

crates/parser/src/grammar/attributes.rs

@@ -14,17 +14,7 @@ pub(super) fn outer_attrs(p: &mut Parser) {
     }
 }
 
-fn attr(p: &mut Parser, inner: bool) {
+pub(super) fn meta(p: &mut Parser) {
-    let attr = p.start();
-    assert!(p.at(T![#]));
-    p.bump(T![#]);
-
-    if inner {
-        assert!(p.at(T![!]));
-        p.bump(T![!]);
-    }
-
-    if p.eat(T!['[']) {
     paths::use_path(p);
 
     match p.current() {
@@ -37,6 +27,20 @@ fn attr(p: &mut Parser, inner: bool) {
         T!['('] | T!['['] | T!['{'] => items::token_tree(p),
         _ => {}
     }
+}
+
+fn attr(p: &mut Parser, inner: bool) {
+    let attr = p.start();
+    assert!(p.at(T![#]));
+    p.bump(T![#]);
+
+    if inner {
+        assert!(p.at(T![!]));
+        p.bump(T![!]);
+    }
+
+    if p.eat(T!['[']) {
+        meta(p);
 
         if !p.eat(T![']']) {
             p.error("expected `]`");