Error on non-literal expressions in doc attributes on macro calls

compiler/rustc_attr_parsing/src/interface.rs

@@ -334,20 +334,6 @@ impl<'sess> AttributeParser<'sess> {
                 }
             }
 
-            fn is_doc_non_lit_expr(attr: &ast::Attribute) -> bool {
-                if !attr.has_name(sym::doc) {
-                    return false;
-                }
-                let ast::AttrKind::Normal(n) = &attr.kind else { return false };
-                let ast::AttrArgs::Eq { expr, .. } = &n.item.args else { return false };
-                !matches!(expr.kind, ast::ExprKind::Lit(_))
-            }
-
-            // FIXME accidentally allowed on Stable Rust
-            if target == Target::MacroCall && is_doc_non_lit_expr(attr) {
-                continue;
-            }
-
             let attr_span = lower_span(attr.span);
             match &attr.kind {
                 ast::AttrKind::DocComment(comment_kind, symbol) => {

tests/ui/attributes/attr-on-mac-call.rs

@@ -113,12 +113,19 @@ fn main() {
     #[deprecated = concat!("woah", "dude")]
     //~^ ERROR attribute value must be a literal
     #[doc = concat!("woah", "dude")]
+    //~^ ERROR attribute value must be a literal
     unreachable!();
     #[doc = {
         let a = 1;
         let b = 1;
         let sum = a + b;
         assert_eq!(sum, 2);
     }]
+    //~^^^^^^ ERROR attribute value must be a literal
+    unreachable!();
+    #[doc = {
+        let expressions @ r#in @ doc @ attributes @ at = home;
+    }]
+    //~^^^ ERROR attribute value must be a literal
     unreachable!();
 }

tests/ui/attributes/attr-on-mac-call.stderr

@@ -44,6 +44,33 @@ error: attribute value must be a literal
 LL |     #[deprecated = concat!("woah", "dude")]
    |                    ^^^^^^^^^^^^^^^^^^^^^^^
 
+error: attribute value must be a literal
+  --> $DIR/attr-on-mac-call.rs:115:13
+   |
+LL |     #[doc = concat!("woah", "dude")]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: attribute value must be a literal
+  --> $DIR/attr-on-mac-call.rs:118:13
+   |
+LL |       #[doc = {
+   |  _____________^
+LL | |         let a = 1;
+LL | |         let b = 1;
+LL | |         let sum = a + b;
+LL | |         assert_eq!(sum, 2);
+LL | |     }]
+   | |_____^
+
+error: attribute value must be a literal
+  --> $DIR/attr-on-mac-call.rs:126:13
+   |
+LL |       #[doc = {
+   |  _____________^
+LL | |         let expressions @ r#in @ doc @ attributes @ at = home;
+LL | |     }]
+   | |_____^
+
 warning: the `export_name` attribute cannot be used on macro calls
   --> $DIR/attr-on-mac-call.rs:8:7
    |
@@ -347,6 +374,6 @@ LL |     #[repr(Rust)]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: placing this attribute on a macro invocation does nothing even if the macro expands to what would be a valid target for the attribute
 
-error: aborting due to 5 previous errors; 30 warnings emitted
+error: aborting due to 8 previous errors; 30 warnings emitted
 
 For more information about this error, try `rustc --explain E0658`.

tests/ui/lint/unused/unused-doc-comments-for-macros.rs

@@ -23,5 +23,6 @@ fn main() {
         assert_eq!(sum, 2);
     }]
     //~^^^^^^ ERROR: unused doc comment
+    //~| ERROR attribute value must be a literal
     foo!();
 }

tests/ui/lint/unused/unused-doc-comments-for-macros.stderr

@@ -1,3 +1,15 @@
+error: attribute value must be a literal
+  --> $DIR/unused-doc-comments-for-macros.rs:19:13
+   |
+LL |       #[doc = {
+   |  _____________^
+LL | |         let a = 1;
+LL | |         let b = 1;
+LL | |         let sum = a + b;
+LL | |         assert_eq!(sum, 2);
+LL | |     }]
+   | |_____^
+
 error: unused doc comment
   --> $DIR/unused-doc-comments-for-macros.rs:7:5
    |
@@ -40,5 +52,5 @@ LL | |     }]
    |
    = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors