Rollup merge of #115578 - ouz-a:rustc_clarify, r=oli-obk

Clarify cryptic comments

Clarifies some unclear comments that lurked in the compiler.

r? ``@oli-obk``

Author: matthiaskrgr

compiler/rustc_lint/src/traits.rs

@@ -96,7 +96,7 @@ impl<'tcx> LateLintPass<'tcx> for DropTraitConstraints {
             };
             let def_id = trait_predicate.trait_ref.def_id;
             if cx.tcx.lang_items().drop_trait() == Some(def_id) {
-                // Explicitly allow `impl Drop`, a drop-guards-as-Voldemort-type pattern.
+                // Explicitly allow `impl Drop`, a drop-guards-as-unnameable-type pattern.
                 if trait_predicate.trait_ref.self_ty().is_impl_trait() {
                     continue;
                 }

compiler/rustc_lint_defs/src/builtin.rs

@@ -4363,7 +4363,7 @@ declare_lint! {
     ///     pub struct S;
     /// }
     ///
-    /// pub fn get_voldemort() -> m::S { m::S }
+    /// pub fn get_unnameable() -> m::S { m::S }
     /// # fn main() {}
     /// ```
     ///

compiler/rustc_middle/src/ty/sty.rs

@@ -2857,7 +2857,7 @@ impl<'tcx> Ty<'tcx> {
             | ty::Uint(..)
             | ty::Float(..) => true,
 
-            // The voldemort ZSTs are fine.
+            // ZST which can't be named are fine.
             ty::FnDef(..) => true,
 
             ty::Array(element_ty, _len) => element_ty.is_trivially_pure_clone_copy(),

tests/ui/drop-bounds/drop-bounds-impl-drop.rs

@@ -2,13 +2,13 @@
 #![deny(drop_bounds)]
 // As a special exemption, `impl Drop` in the return position raises no error.
 // This allows a convenient way to return an unnamed drop guard.
-fn voldemort_type() -> impl Drop {
-  struct Voldemort;
-  impl Drop for Voldemort {
+fn unnameable_type() -> impl Drop {
+  struct Unnameable;
+  impl Drop for Unnameable {
     fn drop(&mut self) {}
   }
-  Voldemort
+  Unnameable
 }
 fn main() {
-  let _ = voldemort_type();
+  let _ = unnameable_type();
 }

tests/ui/privacy/unnameable_types.rs

@@ -20,10 +20,10 @@ mod m {
     }
 }
 
-pub trait Voldemort<T> {}
+pub trait Unnameable<T> {}
 
-impl Voldemort<m::PubStruct> for i32 {}
-impl Voldemort<m::PubE> for i32 {}
-impl<T> Voldemort<T> for u32 where T: m::PubTr {}
+impl Unnameable<m::PubStruct> for i32 {}
+impl Unnameable<m::PubE> for i32 {}
+impl<T> Unnameable<T> for u32 where T: m::PubTr {}
 
 fn main() {}