Don't allow the #[pointee] attribute where it doesn't belong

Author: Brezak

compiler/rustc_hir/src/lib.rs

@@ -26,7 +26,7 @@ pub mod intravisit;
 pub mod lang_items;
 pub mod pat_util;
 mod stable_hash_impls;
-mod target;
+pub mod target;
 pub mod weak_lang_items;
 
 #[cfg(test)]

compiler/rustc_passes/messages.ftl

@@ -584,6 +584,10 @@ passes_pass_by_value =
     `pass_by_value` attribute should be applied to a struct, enum or type alias
     .label = is not a struct, enum or type alias
 
+passes_pointee_on_non_generic_ty =
+    attribute should be applied to generic type parameters
+    .label = not a generic type parameter
+
 passes_proc_macro_bad_sig = {$kind} has incorrect signature
 
 passes_remove_fields =

compiler/rustc_passes/src/check_attr.rs

@@ -242,6 +242,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 [sym::coroutine, ..] => {
                     self.check_coroutine(attr, target);
                 }
+                [sym::pointee, ..] => {
+                    self.check_pointee(attr, target);
+                }
                 [
                     // ok
                     sym::allow
@@ -253,7 +256,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     // need to be fixed
                     | sym::cfi_encoding // FIXME(cfi_encoding)
                     | sym::may_dangle // FIXME(dropck_eyepatch)
-                    | sym::pointee // FIXME(derive_smart_pointer)
                     | sym::linkage // FIXME(linkage)
                     | sym::no_sanitize // FIXME(no_sanitize)
                     | sym::omit_gdb_pretty_printer_section // FIXME(omit_gdb_pretty_printer_section)
@@ -2343,6 +2345,15 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             }
         }
     }
+
+    fn check_pointee(&self, attr: &Attribute, target: Target) {
+        match target {
+            Target::GenericParam(hir::target::GenericParamKind::Type) => return,
+            _ => {
+                self.dcx().emit_err(errors::PointeeOnNonGenericTy { attr_span: attr.span });
+            }
+        }
+    }
 }
 
 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {

compiler/rustc_passes/src/errors.rs

@@ -643,6 +643,13 @@ pub struct CoroutineOnNonClosure {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_pointee_on_non_generic_ty)]
+pub struct PointeeOnNonGenericTy {
+    #[primary_span]
+    pub attr_span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(passes_empty_confusables)]
 pub(crate) struct EmptyConfusables {

tests/ui/deriving/deriving-smart-pointer-pointee-in-strange-places.rs

@@ -0,0 +1,35 @@
+#![feature(derive_smart_pointer)]
+
+#[pointee]
+//~^ ERROR: attribute should be applied to generic type parameters
+struct AStruct<
+    #[pointee]
+    //~^ ERROR: attribute should be applied to generic type parameters
+    'lifetime,
+    #[pointee]
+    //~^ ERROR: attribute should be applied to generic type parameters
+    const CONST: usize
+> {
+    #[pointee]
+    //~^ ERROR: attribute should be applied to generic type parameters
+    val: &'lifetime ()
+}
+
+#[pointee]
+//~^ ERROR: attribute should be applied to generic type parameters
+enum AnEnum {
+    #[pointee]
+    //~^ ERROR: attribute should be applied to generic type parameters
+    AVariant
+}
+
+#[pointee]
+//~^ ERROR: attribute should be applied to generic type parameters
+mod AModule {}
+
+#[pointee]
+//~^ ERROR: attribute should be applied to generic type parameters
+fn a_function(
+) {}
+
+fn main() {}

tests/ui/deriving/deriving-smart-pointer-pointee-in-strange-places.stderr

@@ -0,0 +1,50 @@
+error: attribute should be applied to generic type parameters
+  --> $DIR/deriving-smart-pointer-pointee-in-strange-places.rs:3:1
+   |
+LL | #[pointee]
+   | ^^^^^^^^^^
+
+error: attribute should be applied to generic type parameters
+  --> $DIR/deriving-smart-pointer-pointee-in-strange-places.rs:6:5
+   |
+LL |     #[pointee]
+   |     ^^^^^^^^^^
+
+error: attribute should be applied to generic type parameters
+  --> $DIR/deriving-smart-pointer-pointee-in-strange-places.rs:9:5
+   |
+LL |     #[pointee]
+   |     ^^^^^^^^^^
+
+error: attribute should be applied to generic type parameters
+  --> $DIR/deriving-smart-pointer-pointee-in-strange-places.rs:13:5
+   |
+LL |     #[pointee]
+   |     ^^^^^^^^^^
+
+error: attribute should be applied to generic type parameters
+  --> $DIR/deriving-smart-pointer-pointee-in-strange-places.rs:18:1
+   |
+LL | #[pointee]
+   | ^^^^^^^^^^
+
+error: attribute should be applied to generic type parameters
+  --> $DIR/deriving-smart-pointer-pointee-in-strange-places.rs:21:5
+   |
+LL |     #[pointee]
+   |     ^^^^^^^^^^
+
+error: attribute should be applied to generic type parameters
+  --> $DIR/deriving-smart-pointer-pointee-in-strange-places.rs:26:1
+   |
+LL | #[pointee]
+   | ^^^^^^^^^^
+
+error: attribute should be applied to generic type parameters
+  --> $DIR/deriving-smart-pointer-pointee-in-strange-places.rs:30:1
+   |
+LL | #[pointee]
+   | ^^^^^^^^^^
+
+error: aborting due to 8 previous errors
+