Don't allow unsafe statics outside of extern blocks

compiler/rustc_ast_passes/messages.ftl

@@ -264,6 +264,9 @@ ast_passes_unsafe_negative_impl = negative impls cannot be unsafe
     .negative = negative because of this
     .unsafe = unsafe because of this
 
+ast_passes_unsafe_static =
+    static items cannot be declared with `unsafe` safety qualifier outside of `extern` block
+
 ast_passes_visibility_not_permitted =
     visibility qualifiers are not permitted here
     .enum_variant = enum variants and their fields always share the visibility of the enum they are in

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -1161,11 +1161,17 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     });
                 }
             }
-            ItemKind::Static(box StaticItem { expr: None, .. }) => {
-                self.dcx().emit_err(errors::StaticWithoutBody {
-                    span: item.span,
-                    replace_span: self.ending_semi_or_hi(item.span),
-                });
+            ItemKind::Static(box StaticItem { expr, safety, .. }) => {
+                if matches!(safety, Safety::Unsafe(_)) {
+                    self.dcx().emit_err(errors::UnsafeStatic { span: item.span });
+                }
+
+                if expr.is_none() {
+                    self.dcx().emit_err(errors::StaticWithoutBody {
+                        span: item.span,
+                        replace_span: self.ending_semi_or_hi(item.span),
+                    });
+                }
             }
             ItemKind::TyAlias(
                 ty_alias @ box TyAlias { defaultness, bounds, where_clauses, ty, .. },

compiler/rustc_ast_passes/src/errors.rs

@@ -225,6 +225,13 @@ pub struct InvalidSafetyOnExtern {
     pub block: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(ast_passes_unsafe_static)]
+pub struct UnsafeStatic {
+    #[primary_span]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(ast_passes_bound_in_context)]
 pub struct BoundInContext<'a> {

tests/ui/rust-2024/safe-outside-extern.gated.stderr

@@ -0,0 +1,8 @@
+error: static items cannot be declared with `unsafe` safety qualifier outside of `extern` block
+  --> $DIR/safe-outside-extern.rs:6:1
+   |
+LL | unsafe static LOL: u8 = 0;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+

tests/ui/rust-2024/safe-outside-extern.rs

@@ -0,0 +1,9 @@
+//@ revisions: gated ungated
+
+// Very pared down version of the same named test on nightly, since we only want
+// to validate that `unsafe static` is not being accidentally accepted by the parser.
+
+unsafe static LOL: u8 = 0;
+//~^ ERROR: static items cannot be declared with `unsafe` safety qualifier outside of `extern` block
+
+fn main() {}

tests/ui/rust-2024/safe-outside-extern.ungated.stderr

@@ -0,0 +1,8 @@
+error: static items cannot be declared with `unsafe` safety qualifier outside of `extern` block
+  --> $DIR/safe-outside-extern.rs:6:1
+   |
+LL | unsafe static LOL: u8 = 0;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+