Merge #8550

8550: Handle extended key value attributes in mbe r=edwin0cheng a=edwin0cheng

fixes #8544

bors r+

Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>

crates/mbe/src/tests/expand.rs

@@ -940,6 +940,24 @@ fn bar() {}
     );
 }
 
+#[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) fn opt_visibility(p: &mut Parser) {
 
     // Parse a meta item , which excluded [], e.g : #[ MetaItem ]
     pub(crate) fn meta_item(p: &mut Parser) {
-        fn is_delimiter(p: &mut Parser) -> bool {
-            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);
+        attributes::meta(p);
     }
 
     pub(crate) fn item(p: &mut Parser) {

crates/parser/src/grammar/attributes.rs

@@ -14,6 +14,21 @@ pub(super) fn outer_attrs(p: &mut Parser) {
     }
 }
 
+pub(super) fn meta(p: &mut Parser) {
+    paths::use_path(p);
+
+    match p.current() {
+        T![=] => {
+            p.bump(T![=]);
+            if expressions::expr(p).0.is_none() {
+                p.error("expected expression");
+            }
+        }
+        T!['('] | T!['['] | T!['{'] => items::token_tree(p),
+        _ => {}
+    }
+}
+
 fn attr(p: &mut Parser, inner: bool) {
     let attr = p.start();
     assert!(p.at(T![#]));
@@ -25,18 +40,7 @@ fn attr(p: &mut Parser, inner: bool) {
     }
 
     if p.eat(T!['[']) {
-        paths::use_path(p);
-
-        match p.current() {
-            T![=] => {
-                p.bump(T![=]);
-                if expressions::expr(p).0.is_none() {
-                    p.error("expected expression");
-                }
-            }
-            T!['('] | T!['['] | T!['{'] => items::token_tree(p),
-            _ => {}
-        }
+        meta(p);
 
         if !p.eat(T![']']) {
             p.error("expected `]`");