Keep allowing invalid metaitem syntax in diagnostic attributes

Author: mejrs

compiler/rustc_attr_parsing/src/parser.rs

@@ -113,8 +113,9 @@ impl ArgParser {
         Some(match value {
             AttrArgs::Empty => Self::NoArgs,
             AttrArgs::Delimited(args) => {
-                // The arguments of rustc_dummy are not validated if the arguments are delimited
-                if parts == &[sym::rustc_dummy] {
+                // The arguments of rustc_dummy and diagnostic attributes are not validated
+                // if the arguments are delimited
+                if parts == &[sym::rustc_dummy] || parts[0] == sym::diagnostic {
                     return Some(ArgParser::List(MetaItemListParser {
                         sub_parsers: ThinVec::new(),
                         span: args.dspan.entire(),

tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.current.stderr

@@ -1,22 +1,28 @@
 warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
-  --> $DIR/does_not_acccept_args.rs:11:1
+  --> $DIR/does_not_acccept_args.rs:12:1
    |
 LL | #[diagnostic::do_not_recommend(not_accepted)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `#[warn(malformed_diagnostic_attributes)]` (part of `#[warn(unknown_or_malformed_diagnostic_attributes)]`) on by default
 
 warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
-  --> $DIR/does_not_acccept_args.rs:15:1
+  --> $DIR/does_not_acccept_args.rs:16:1
    |
 LL | #[diagnostic::do_not_recommend(not_accepted = "foo")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
-  --> $DIR/does_not_acccept_args.rs:19:1
+  --> $DIR/does_not_acccept_args.rs:20:1
    |
 LL | #[diagnostic::do_not_recommend(not_accepted(42))]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-warning: 3 warnings emitted
+warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
+  --> $DIR/does_not_acccept_args.rs:24:1
+   |
+LL | #[diagnostic::do_not_recommend(x = y + z)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 4 warnings emitted
 

tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.next.stderr

@@ -1,22 +1,28 @@
 warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
-  --> $DIR/does_not_acccept_args.rs:11:1
+  --> $DIR/does_not_acccept_args.rs:12:1
    |
 LL | #[diagnostic::do_not_recommend(not_accepted)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `#[warn(malformed_diagnostic_attributes)]` (part of `#[warn(unknown_or_malformed_diagnostic_attributes)]`) on by default
 
 warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
-  --> $DIR/does_not_acccept_args.rs:15:1
+  --> $DIR/does_not_acccept_args.rs:16:1
    |
 LL | #[diagnostic::do_not_recommend(not_accepted = "foo")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
-  --> $DIR/does_not_acccept_args.rs:19:1
+  --> $DIR/does_not_acccept_args.rs:20:1
    |
 LL | #[diagnostic::do_not_recommend(not_accepted(42))]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-warning: 3 warnings emitted
+warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
+  --> $DIR/does_not_acccept_args.rs:24:1
+   |
+LL | #[diagnostic::do_not_recommend(x = y + z)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 4 warnings emitted
 

tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.rs

@@ -7,6 +7,7 @@
 trait Foo {}
 trait Bar {}
 trait Baz {}
+trait Boo {}
 
 #[diagnostic::do_not_recommend(not_accepted)]
 //~^ WARNING `#[diagnostic::do_not_recommend]` does not expect any arguments
@@ -20,4 +21,8 @@ impl<T> Bar for T where T: Send {}
 //~^ WARNING `#[diagnostic::do_not_recommend]` does not expect any arguments
 impl<T> Baz for T where T: Send {}
 
+#[diagnostic::do_not_recommend(x = y + z)]
+//~^ WARNING `#[diagnostic::do_not_recommend]` does not expect any arguments
+impl<T> Boo for T where T: Send {}
+
 fn main() {}