Error on unsafe on non-unsafe attribute

compiler/rustc_passes/src/errors.rs

@@ -4,7 +4,7 @@ use std::{
 };
 
 use crate::fluent_generated as fluent;
-use rustc_ast::Label;
+use rustc_ast::{ast, Label};
 use rustc_errors::{
     codes::*, Applicability, Diag, DiagCtxt, DiagSymbolList, Diagnostic, EmissionGuarantee, Level,
     MultiSpan, SubdiagMessageOp, Subdiagnostic,
@@ -863,6 +863,15 @@ pub struct InvalidAttrAtCrateLevel {
     pub item: Option<ItemFollowingInnerAttr>,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_invalid_attr_unsafe)]
+#[note]
+pub struct InvalidAttrUnsafe {
+    #[primary_span]
+    pub span: Span,
+    pub name: ast::Path,
+}
+
 #[derive(Clone, Copy)]
 pub struct ItemFollowingInnerAttr {
     pub span: Span,