Rework rustc_dump_vtable

compiler/rustc_feature/src/builtin_attrs.rs

@@ -1136,7 +1136,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ),
     rustc_attr!(
         TEST, rustc_dump_vtable, Normal, template!(Word),
-        WarnFollowing, EncodeCrossCrate::Yes
+        WarnFollowing, EncodeCrossCrate::No
     ),
     rustc_attr!(
         TEST, rustc_dummy, Normal, template!(Word /* doesn't matter*/),

compiler/rustc_hir_analysis/src/collect/dump.rs

@@ -1,7 +1,8 @@
+use rustc_hir as hir;
 use rustc_hir::def_id::{CRATE_DEF_ID, LocalDefId};
 use rustc_hir::intravisit;
 use rustc_middle::hir::nested_filter;
-use rustc_middle::ty::TyCtxt;
+use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt};
 use rustc_span::sym;
 
 pub(crate) fn opaque_hidden_types(tcx: TyCtxt<'_>) {
@@ -87,3 +88,82 @@ pub(crate) fn def_parents(tcx: TyCtxt<'_>) {
         }
     }
 }
+
+pub(crate) fn vtables<'tcx>(tcx: TyCtxt<'tcx>) {
+    for id in tcx.hir().items() {
+        let def_id = id.owner_id.def_id;
+
+        let Some(attr) = tcx.get_attr(def_id, sym::rustc_dump_vtable) else {
+            continue;
+        };
+
+        let vtable_entries = match tcx.hir().item(id).kind {
+            hir::ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) => {
+                let trait_ref = tcx.impl_trait_ref(def_id).unwrap().instantiate_identity();
+                if trait_ref.has_non_region_param() {
+                    tcx.dcx().span_err(
+                        attr.span,
+                        "`rustc_dump_vtable` must be applied to non-generic impl",
+                    );
+                    continue;
+                }
+                if !tcx.is_dyn_compatible(trait_ref.def_id) {
+                    tcx.dcx().span_err(
+                        attr.span,
+                        "`rustc_dump_vtable` must be applied to dyn-compatible trait",
+                    );
+                    continue;
+                }
+                let Ok(trait_ref) = tcx
+                    .try_normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), trait_ref)
+                else {
+                    tcx.dcx().span_err(
+                        attr.span,
+                        "`rustc_dump_vtable` applied to impl header that cannot be normalized",
+                    );
+                    continue;
+                };
+                tcx.vtable_entries(ty::Binder::dummy(trait_ref))
+            }
+            hir::ItemKind::TyAlias(_, _) => {
+                let ty = tcx.type_of(def_id).instantiate_identity();
+                if ty.has_non_region_param() {
+                    tcx.dcx().span_err(
+                        attr.span,
+                        "`rustc_dump_vtable` must be applied to non-generic type",
+                    );
+                    continue;
+                }
+                let Ok(ty) =
+                    tcx.try_normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), ty)
+                else {
+                    tcx.dcx().span_err(
+                        attr.span,
+                        "`rustc_dump_vtable` applied to type alias that cannot be normalized",
+                    );
+                    continue;
+                };
+                let ty::Dynamic(data, _, _) = *ty.kind() else {
+                    tcx.dcx().span_err(attr.span, "`rustc_dump_vtable` to type alias of dyn type");
+                    continue;
+                };
+                if let Some(principal) = data.principal() {
+                    tcx.vtable_entries(
+                        principal.map_bound(|principal| principal.with_self_ty(tcx, ty)),
+                    )
+                } else {
+                    TyCtxt::COMMON_VTABLE_ENTRIES
+                }
+            }
+            _ => {
+                tcx.dcx().span_err(
+                    attr.span,
+                    "`rustc_dump_vtable` only applies to impl, or type alias of dyn type",
+                );
+                continue;
+            }
+        };
+
+        tcx.dcx().span_err(tcx.def_span(def_id), format!("vtable entries: {vtable_entries:#?}"));
+    }
+}

compiler/rustc_hir_analysis/src/lib.rs

@@ -152,11 +152,14 @@ pub fn check_crate(tcx: TyCtxt<'_>) {
     });
 
     if tcx.features().rustc_attrs() {
-        tcx.sess.time("outlives_dumping", || outlives::dump::inferred_outlives(tcx));
-        tcx.sess.time("variance_dumping", || variance::dump::variances(tcx));
-        collect::dump::opaque_hidden_types(tcx);
-        collect::dump::predicates_and_item_bounds(tcx);
-        collect::dump::def_parents(tcx);
+        tcx.sess.time("dumping_rustc_attr_data", || {
+            outlives::dump::inferred_outlives(tcx);
+            variance::dump::variances(tcx);
+            collect::dump::opaque_hidden_types(tcx);
+            collect::dump::predicates_and_item_bounds(tcx);
+            collect::dump::def_parents(tcx);
+            collect::dump::vtables(tcx);
+        });
     }
 
     // Make sure we evaluate all static and (non-associated) const items, even if unused.

compiler/rustc_trait_selection/messages.ftl

@@ -148,8 +148,6 @@ trait_selection_dtcs_has_req_note = the used `impl` has a `'static` requirement
 trait_selection_dtcs_introduces_requirement = calling this method introduces the `impl`'s `'static` requirement
 trait_selection_dtcs_suggestion = consider relaxing the implicit `'static` requirement
 
-trait_selection_dump_vtable_entries = vtable entries for `{$trait_ref}`: {$entries}
-
 trait_selection_empty_on_clause_in_rustc_on_unimplemented = empty `on`-clause in `#[rustc_on_unimplemented]`
     .label = empty on-clause here
 

compiler/rustc_trait_selection/src/errors.rs

@@ -12,7 +12,7 @@ use rustc_hir::intravisit::{Visitor, VisitorExt, walk_ty};
 use rustc_hir::{self as hir, AmbigArg, FnRetTy, GenericParamKind, Node};
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_middle::ty::print::{PrintTraitRefExt as _, TraitRefPrintOnlyTraitPath};
-use rustc_middle::ty::{self, Binder, ClosureKind, FnSig, PolyTraitRef, Region, Ty, TyCtxt};
+use rustc_middle::ty::{self, Binder, ClosureKind, FnSig, Region, Ty, TyCtxt};
 use rustc_span::{BytePos, Ident, Span, Symbol, kw};
 
 use crate::error_reporting::infer::ObligationCauseAsDiagArg;
@@ -22,15 +22,6 @@ use crate::fluent_generated as fluent;
 
 pub mod note_and_explain;
 
-#[derive(Diagnostic)]
-#[diag(trait_selection_dump_vtable_entries)]
-pub struct DumpVTableEntries<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub trait_ref: PolyTraitRef<'a>,
-    pub entries: String,
-}
-
 #[derive(Diagnostic)]
 #[diag(trait_selection_unable_to_construct_constant_value)]
 pub struct UnableToConstructConstantValue<'a> {

compiler/rustc_trait_selection/src/traits/vtable.rs

@@ -11,11 +11,10 @@ use rustc_middle::query::Providers;
 use rustc_middle::ty::{
     self, GenericArgs, GenericParamDefKind, Ty, TyCtxt, TypeVisitableExt, Upcast, VtblEntry,
 };
-use rustc_span::{DUMMY_SP, Span, sym};
+use rustc_span::DUMMY_SP;
 use smallvec::{SmallVec, smallvec};
 use tracing::debug;
 
-use crate::errors::DumpVTableEntries;
 use crate::traits::{ObligationCtxt, impossible_predicates, is_vtable_safe_method};
 
 #[derive(Clone, Debug)]
@@ -192,15 +191,6 @@ fn maybe_iter<I: Iterator>(i: Option<I>) -> impl Iterator<Item = I::Item> {
     i.into_iter().flatten()
 }
 
-fn dump_vtable_entries<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    sp: Span,
-    trait_ref: ty::PolyTraitRef<'tcx>,
-    entries: &[VtblEntry<'tcx>],
-) {
-    tcx.dcx().emit_err(DumpVTableEntries { span: sp, trait_ref, entries: format!("{entries:#?}") });
-}
-
 fn has_own_existential_vtable_entries(tcx: TyCtxt<'_>, trait_def_id: DefId) -> bool {
     own_existential_vtable_entries_iter(tcx, trait_def_id).next().is_some()
 }
@@ -317,11 +307,6 @@ fn vtable_entries<'tcx>(
 
     let _ = prepare_vtable_segments(tcx, trait_ref, vtable_segment_callback);
 
-    if tcx.has_attr(trait_ref.def_id(), sym::rustc_dump_vtable) {
-        let sp = tcx.def_span(trait_ref.def_id());
-        dump_vtable_entries(tcx, sp, trait_ref, &entries);
-    }
-
     tcx.arena.alloc_from_iter(entries)
 }
 

src/doc/rustc-dev-guide/src/compiler-debugging.md

@@ -275,7 +275,7 @@ Here are some notable ones:
 | `rustc_dump_def_parents` | Dumps the chain of `DefId` parents of certain definitions. |
 | `rustc_dump_item_bounds` | Dumps the [`item_bounds`] of an item. |
 | `rustc_dump_predicates` | Dumps the [`predicates_of`] an item. |
-| `rustc_dump_vtable` |  |
+| `rustc_dump_vtable` | Dumps the vtable layout of an impl, or a type alias of a dyn type. |
 | `rustc_hidden_type_of_opaques` | Dumps the [hidden type of each opaque types][opaq] in the crate. |
 | `rustc_layout` | [See this section](#debugging-type-layouts). |
 | `rustc_object_lifetime_default` | Dumps the [object lifetime defaults] of an item. |

tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder-vtable.rs

@@ -0,0 +1,25 @@
+#![feature(rustc_attrs)]
+
+trait Supertrait<T> {
+    fn _print_numbers(&self, mem: &[usize; 100]) {
+    }
+}
+impl<T> Supertrait<T> for () {}
+
+trait Trait<T, U>: Supertrait<T> + Supertrait<U> {
+    fn say_hello(&self, _: &usize) {
+    }
+}
+impl<T, U> Trait<T, U> for () {}
+
+// We should observe compatibility between these two vtables.
+
+#[rustc_dump_vtable]
+type First = dyn for<'a> Trait<&'static (), &'a ()>;
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
+type Second = dyn Trait<&'static (), &'static ()>;
+//~^ ERROR vtable entries
+
+fn main() {}

tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-binder-vtable.stderr

@@ -0,0 +1,28 @@
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<dyn for<'a> Trait<&(), &'a ()> as Supertrait<&()>>::_print_numbers - shim(reify)),
+           Method(<dyn for<'a> Trait<&(), &'a ()> as Supertrait<&()>>::_print_numbers - shim(reify)),
+           TraitVPtr(for<'a> <dyn for<'a> Trait<&(), &'a ()> as Supertrait<&'a ()>>),
+           Method(<dyn for<'a> Trait<&(), &'a ()> as Trait<&(), &()>>::say_hello - shim(reify)),
+       ]
+  --> $DIR/multiple-supertraits-modulo-binder-vtable.rs:18:1
+   |
+LL | type First = dyn for<'a> Trait<&'static (), &'a ()>;
+   | ^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<dyn Trait<&(), &()> as Supertrait<&()>>::_print_numbers - shim(reify)),
+           Method(<dyn Trait<&(), &()> as Trait<&(), &()>>::say_hello - shim(reify)),
+       ]
+  --> $DIR/multiple-supertraits-modulo-binder-vtable.rs:22:1
+   |
+LL | type Second = dyn Trait<&'static (), &'static ()>;
+   | ^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+

tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization-vtable.rs

@@ -0,0 +1,36 @@
+#![feature(rustc_attrs)]
+
+#![feature(trait_upcasting)]
+
+trait Supertrait<T> {
+    fn _print_numbers(&self, mem: &[usize; 100]) {
+        println!("{mem:?}");
+    }
+}
+impl<T> Supertrait<T> for () {}
+
+trait Identity {
+    type Selff;
+}
+impl<Selff> Identity for Selff {
+    type Selff = Selff;
+}
+
+trait Middle<T>: Supertrait<()> + Supertrait<T> {
+    fn say_hello(&self, _: &usize) {
+        println!("Hello!");
+    }
+}
+impl<T> Middle<T> for () {}
+
+trait Trait: Middle<<() as Identity>::Selff> {}
+
+#[rustc_dump_vtable]
+impl Trait for () {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
+type Virtual = dyn Middle<()>;
+//~^ ERROR vtable entries
+
+fn main() {}

tests/ui/traits/trait-upcasting/multiple-supertraits-modulo-normalization-vtable.stderr

@@ -0,0 +1,28 @@
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<() as Supertrait<()>>::_print_numbers),
+           Method(<() as Supertrait<()>>::_print_numbers),
+           TraitVPtr(<() as Supertrait<<() as Identity>::Selff>>),
+           Method(<() as Middle<()>>::say_hello),
+       ]
+  --> $DIR/multiple-supertraits-modulo-normalization-vtable.rs:29:1
+   |
+LL | impl Trait for () {}
+   | ^^^^^^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<dyn Middle<()> as Supertrait<()>>::_print_numbers - shim(reify)),
+           Method(<dyn Middle<()> as Middle<()>>::say_hello - shim(reify)),
+       ]
+  --> $DIR/multiple-supertraits-modulo-normalization-vtable.rs:33:1
+   |
+LL | type Virtual = dyn Middle<()>;
+   | ^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+

tests/ui/traits/vtable/multiple-markers.rs

@@ -2,8 +2,7 @@
 //
 // This test makes sure that multiple marker (method-less) traits can reuse the
 // same pointer for upcasting.
-//
-//@ build-fail
+
 #![crate_type = "lib"]
 #![feature(rustc_attrs)]
 
@@ -17,17 +16,13 @@ trait T {
     fn method(&self) {}
 }
 
-#[rustc_dump_vtable]
-trait A: M0 + M1 + M2 + T {} //~ error: vtable entries for `<S as A>`:
+trait A: M0 + M1 + M2 + T {}
 
-#[rustc_dump_vtable]
-trait B: M0 + M1 + T + M2 {} //~ error: vtable entries for `<S as B>`:
+trait B: M0 + M1 + T + M2 {}
 
-#[rustc_dump_vtable]
-trait C: M0 + T + M1 + M2 {} //~ error: vtable entries for `<S as C>`:
+trait C: M0 + T + M1 + M2 {}
 
-#[rustc_dump_vtable]
-trait D: T + M0 + M1 + M2 {} //~ error: vtable entries for `<S as D>`:
+trait D: T + M0 + M1 + M2 {}
 
 struct S;
 
@@ -35,13 +30,21 @@ impl M0 for S {}
 impl M1 for S {}
 impl M2 for S {}
 impl T for S {}
+
+#[rustc_dump_vtable]
 impl A for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl B for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl C for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl D for S {}
+//~^ ERROR vtable entries
 
-pub fn require_vtables() {
-    fn require_vtables(_: &dyn A, _: &dyn B, _: &dyn C, _: &dyn D) {}
-
-    require_vtables(&S, &S, &S, &S)
-}
+fn main() {}

tests/ui/traits/vtable/multiple-markers.stderr

@@ -1,46 +1,46 @@
-error: vtable entries for `<S as A>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as T>::method),
        ]
-  --> $DIR/multiple-markers.rs:21:1
+  --> $DIR/multiple-markers.rs:35:1
    |
-LL | trait A: M0 + M1 + M2 + T {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | impl A for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as B>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as T>::method),
        ]
-  --> $DIR/multiple-markers.rs:24:1
+  --> $DIR/multiple-markers.rs:39:1
    |
-LL | trait B: M0 + M1 + T + M2 {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | impl B for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as C>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as T>::method),
        ]
-  --> $DIR/multiple-markers.rs:27:1
+  --> $DIR/multiple-markers.rs:43:1
    |
-LL | trait C: M0 + T + M1 + M2 {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | impl C for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as D>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
            Method(<S as T>::method),
        ]
-  --> $DIR/multiple-markers.rs:30:1
+  --> $DIR/multiple-markers.rs:47:1
    |
-LL | trait D: T + M0 + M1 + M2 {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | impl D for S {}
+   | ^^^^^^^^^^^^
 
 error: aborting due to 4 previous errors
 

tests/ui/traits/vtable/vtable-diamond.rs

@@ -1,44 +1,37 @@
-//@ build-fail
 #![feature(rustc_attrs)]
 
-#[rustc_dump_vtable]
 trait A {
     fn foo_a(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait B: A {
     fn foo_b(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait C: A {
-    //~^ error vtable
     fn foo_c(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait D: B + C {
-    //~^ error vtable
     fn foo_d(&self) {}
 }
 
 struct S;
 
+#[rustc_dump_vtable]
 impl A for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl B for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl C for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl D for S {}
+//~^ ERROR vtable entries
 
-fn foo(d: &dyn D) {
-    d.foo_d();
-}
-
-fn bar(d: &dyn C) {
-    d.foo_c();
-}
-
-fn main() {
-    foo(&S);
-    bar(&S);
-}
+fn main() {}

tests/ui/traits/vtable/vtable-diamond.stderr

@@ -1,4 +1,39 @@
-error: vtable entries for `<S as D>`: [
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a),
+       ]
+  --> $DIR/vtable-diamond.rs:22:1
+   |
+LL | impl A for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a),
+           Method(<S as B>::foo_b),
+       ]
+  --> $DIR/vtable-diamond.rs:26:1
+   |
+LL | impl B for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a),
+           Method(<S as C>::foo_c),
+       ]
+  --> $DIR/vtable-diamond.rs:30:1
+   |
+LL | impl C for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
@@ -8,22 +43,10 @@ error: vtable entries for `<S as D>`: [
            TraitVPtr(<S as C>),
            Method(<S as D>::foo_d),
        ]
-  --> $DIR/vtable-diamond.rs:21:1
+  --> $DIR/vtable-diamond.rs:34:1
    |
-LL | trait D: B + C {
-   | ^^^^^^^^^^^^^^
+LL | impl D for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as C>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as A>::foo_a),
-           Method(<S as C>::foo_c),
-       ]
-  --> $DIR/vtable-diamond.rs:15:1
-   |
-LL | trait C: A {
-   | ^^^^^^^^^^
-
-error: aborting due to 2 previous errors
+error: aborting due to 4 previous errors
 

tests/ui/traits/vtable/vtable-dyn-incompatible.rs

@@ -1,15 +1,16 @@
-//@ build-fail
 #![feature(rustc_attrs)]
 
 // Ensure that dyn-incompatible methods in Iterator does not generate
 // vtable entries.
 
-#[rustc_dump_vtable]
 trait A: Iterator {}
-//~^ error vtable
 
 impl<T> A for T where T: Iterator {}
 
+#[rustc_dump_vtable]
+type Test = dyn A<Item=u8>;
+//~^ error vtable
+
 fn foo(_a: &mut dyn A<Item=u8>) {
 }
 

tests/ui/traits/vtable/vtable-dyn-incompatible.stderr

@@ -1,16 +1,16 @@
-error: vtable entries for `<std::vec::IntoIter<u8> as A>`: [
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
-           Method(<std::vec::IntoIter<u8> as Iterator>::next),
-           Method(<std::vec::IntoIter<u8> as Iterator>::size_hint),
-           Method(<std::vec::IntoIter<u8> as Iterator>::advance_by),
-           Method(<std::vec::IntoIter<u8> as Iterator>::nth),
+           Method(<dyn A<Item = u8> as Iterator>::next - shim(reify)),
+           Method(<dyn A<Item = u8> as Iterator>::size_hint - shim(reify)),
+           Method(<dyn A<Item = u8> as Iterator>::advance_by - shim(reify)),
+           Method(<dyn A<Item = u8> as Iterator>::nth - shim(reify)),
        ]
-  --> $DIR/vtable-dyn-incompatible.rs:8:1
+  --> $DIR/vtable-dyn-incompatible.rs:11:1
    |
-LL | trait A: Iterator {}
-   | ^^^^^^^^^^^^^^^^^
+LL | type Test = dyn A<Item=u8>;
+   | ^^^^^^^^^
 
 error: aborting due to 1 previous error
 

tests/ui/traits/vtable/vtable-multi-level.rs

@@ -1,4 +1,3 @@
-//@ build-fail
 #![feature(rustc_attrs)]
 
 //   O --> G --> C --> A
@@ -10,134 +9,126 @@
 //           |-> M --> K
 //                 \-> L
 
-#[rustc_dump_vtable]
 trait A {
-    //~^ error vtable
     fn foo_a(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait B {
-    //~^ error vtable
     fn foo_b(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait C: A + B {
-    //~^ error vtable
     fn foo_c(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait D {
-    //~^ error vtable
     fn foo_d(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait E {
-    //~^ error vtable
     fn foo_e(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait F: D + E {
-    //~^ error vtable
     fn foo_f(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait G: C + F {
     fn foo_g(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait H {
-    //~^ error vtable
     fn foo_h(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait I {
-    //~^ error vtable
     fn foo_i(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait J: H + I {
-    //~^ error vtable
     fn foo_j(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait K {
-    //~^ error vtable
     fn foo_k(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait L {
-    //~^ error vtable
     fn foo_l(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait M: K + L {
-    //~^ error vtable
     fn foo_m(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait N: J + M {
-    //~^ error vtable
     fn foo_n(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait O: G + N {
-    //~^ error vtable
     fn foo_o(&self) {}
 }
 
 struct S;
 
+#[rustc_dump_vtable]
 impl A for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl B for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl C for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl D for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl E for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl F for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl G for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl H for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl I for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl J for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl K for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl L for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl M for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl N for S {}
+//~^ ERROR vtable entries
+
+#[rustc_dump_vtable]
 impl O for S {}
+//~^ ERROR vtable entries
 
-macro_rules! monomorphize_vtable {
-    ($trait:ident) => {{
-        fn foo(_ : &dyn $trait) {}
-        foo(&S);
-    }}
-}
-
-fn main() {
-    monomorphize_vtable!(O);
-
-    monomorphize_vtable!(A);
-    monomorphize_vtable!(B);
-    monomorphize_vtable!(C);
-    monomorphize_vtable!(D);
-    monomorphize_vtable!(E);
-    monomorphize_vtable!(F);
-    monomorphize_vtable!(H);
-    monomorphize_vtable!(I);
-    monomorphize_vtable!(J);
-    monomorphize_vtable!(K);
-    monomorphize_vtable!(L);
-    monomorphize_vtable!(M);
-    monomorphize_vtable!(N);
-}
+fn main() {}

tests/ui/traits/vtable/vtable-multi-level.stderr

@@ -1,4 +1,190 @@
-error: vtable entries for `<S as O>`: [
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a),
+       ]
+  --> $DIR/vtable-multi-level.rs:75:1
+   |
+LL | impl A for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as B>::foo_b),
+       ]
+  --> $DIR/vtable-multi-level.rs:79:1
+   |
+LL | impl B for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a),
+           Method(<S as B>::foo_b),
+           TraitVPtr(<S as B>),
+           Method(<S as C>::foo_c),
+       ]
+  --> $DIR/vtable-multi-level.rs:83:1
+   |
+LL | impl C for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as D>::foo_d),
+       ]
+  --> $DIR/vtable-multi-level.rs:87:1
+   |
+LL | impl D for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as E>::foo_e),
+       ]
+  --> $DIR/vtable-multi-level.rs:91:1
+   |
+LL | impl E for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as D>::foo_d),
+           Method(<S as E>::foo_e),
+           TraitVPtr(<S as E>),
+           Method(<S as F>::foo_f),
+       ]
+  --> $DIR/vtable-multi-level.rs:95:1
+   |
+LL | impl F for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a),
+           Method(<S as B>::foo_b),
+           TraitVPtr(<S as B>),
+           Method(<S as C>::foo_c),
+           Method(<S as D>::foo_d),
+           TraitVPtr(<S as D>),
+           Method(<S as E>::foo_e),
+           TraitVPtr(<S as E>),
+           Method(<S as F>::foo_f),
+           TraitVPtr(<S as F>),
+           Method(<S as G>::foo_g),
+       ]
+  --> $DIR/vtable-multi-level.rs:99:1
+   |
+LL | impl G for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as H>::foo_h),
+       ]
+  --> $DIR/vtable-multi-level.rs:103:1
+   |
+LL | impl H for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as I>::foo_i),
+       ]
+  --> $DIR/vtable-multi-level.rs:107:1
+   |
+LL | impl I for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as H>::foo_h),
+           Method(<S as I>::foo_i),
+           TraitVPtr(<S as I>),
+           Method(<S as J>::foo_j),
+       ]
+  --> $DIR/vtable-multi-level.rs:111:1
+   |
+LL | impl J for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as K>::foo_k),
+       ]
+  --> $DIR/vtable-multi-level.rs:115:1
+   |
+LL | impl K for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as L>::foo_l),
+       ]
+  --> $DIR/vtable-multi-level.rs:119:1
+   |
+LL | impl L for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as K>::foo_k),
+           Method(<S as L>::foo_l),
+           TraitVPtr(<S as L>),
+           Method(<S as M>::foo_m),
+       ]
+  --> $DIR/vtable-multi-level.rs:123:1
+   |
+LL | impl M for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as H>::foo_h),
+           Method(<S as I>::foo_i),
+           TraitVPtr(<S as I>),
+           Method(<S as J>::foo_j),
+           Method(<S as K>::foo_k),
+           TraitVPtr(<S as K>),
+           Method(<S as L>::foo_l),
+           TraitVPtr(<S as L>),
+           Method(<S as M>::foo_m),
+           TraitVPtr(<S as M>),
+           Method(<S as N>::foo_n),
+       ]
+  --> $DIR/vtable-multi-level.rs:127:1
+   |
+LL | impl N for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
@@ -29,175 +215,10 @@ error: vtable entries for `<S as O>`: [
            TraitVPtr(<S as N>),
            Method(<S as O>::foo_o),
        ]
-  --> $DIR/vtable-multi-level.rs:97:1
+  --> $DIR/vtable-multi-level.rs:131:1
    |
-LL | trait O: G + N {
-   | ^^^^^^^^^^^^^^
+LL | impl O for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as A>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as A>::foo_a),
-       ]
-  --> $DIR/vtable-multi-level.rs:14:1
-   |
-LL | trait A {
-   | ^^^^^^^
-
-error: vtable entries for `<S as B>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as B>::foo_b),
-       ]
-  --> $DIR/vtable-multi-level.rs:20:1
-   |
-LL | trait B {
-   | ^^^^^^^
-
-error: vtable entries for `<S as C>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as A>::foo_a),
-           Method(<S as B>::foo_b),
-           TraitVPtr(<S as B>),
-           Method(<S as C>::foo_c),
-       ]
-  --> $DIR/vtable-multi-level.rs:26:1
-   |
-LL | trait C: A + B {
-   | ^^^^^^^^^^^^^^
-
-error: vtable entries for `<S as D>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as D>::foo_d),
-       ]
-  --> $DIR/vtable-multi-level.rs:32:1
-   |
-LL | trait D {
-   | ^^^^^^^
-
-error: vtable entries for `<S as E>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as E>::foo_e),
-       ]
-  --> $DIR/vtable-multi-level.rs:38:1
-   |
-LL | trait E {
-   | ^^^^^^^
-
-error: vtable entries for `<S as F>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as D>::foo_d),
-           Method(<S as E>::foo_e),
-           TraitVPtr(<S as E>),
-           Method(<S as F>::foo_f),
-       ]
-  --> $DIR/vtable-multi-level.rs:44:1
-   |
-LL | trait F: D + E {
-   | ^^^^^^^^^^^^^^
-
-error: vtable entries for `<S as H>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as H>::foo_h),
-       ]
-  --> $DIR/vtable-multi-level.rs:55:1
-   |
-LL | trait H {
-   | ^^^^^^^
-
-error: vtable entries for `<S as I>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as I>::foo_i),
-       ]
-  --> $DIR/vtable-multi-level.rs:61:1
-   |
-LL | trait I {
-   | ^^^^^^^
-
-error: vtable entries for `<S as J>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as H>::foo_h),
-           Method(<S as I>::foo_i),
-           TraitVPtr(<S as I>),
-           Method(<S as J>::foo_j),
-       ]
-  --> $DIR/vtable-multi-level.rs:67:1
-   |
-LL | trait J: H + I {
-   | ^^^^^^^^^^^^^^
-
-error: vtable entries for `<S as K>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as K>::foo_k),
-       ]
-  --> $DIR/vtable-multi-level.rs:73:1
-   |
-LL | trait K {
-   | ^^^^^^^
-
-error: vtable entries for `<S as L>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as L>::foo_l),
-       ]
-  --> $DIR/vtable-multi-level.rs:79:1
-   |
-LL | trait L {
-   | ^^^^^^^
-
-error: vtable entries for `<S as M>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as K>::foo_k),
-           Method(<S as L>::foo_l),
-           TraitVPtr(<S as L>),
-           Method(<S as M>::foo_m),
-       ]
-  --> $DIR/vtable-multi-level.rs:85:1
-   |
-LL | trait M: K + L {
-   | ^^^^^^^^^^^^^^
-
-error: vtable entries for `<S as N>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as H>::foo_h),
-           Method(<S as I>::foo_i),
-           TraitVPtr(<S as I>),
-           Method(<S as J>::foo_j),
-           Method(<S as K>::foo_k),
-           TraitVPtr(<S as K>),
-           Method(<S as L>::foo_l),
-           TraitVPtr(<S as L>),
-           Method(<S as M>::foo_m),
-           TraitVPtr(<S as M>),
-           Method(<S as N>::foo_n),
-       ]
-  --> $DIR/vtable-multi-level.rs:91:1
-   |
-LL | trait N: J + M {
-   | ^^^^^^^^^^^^^^
-
-error: aborting due to 14 previous errors
+error: aborting due to 15 previous errors
 

tests/ui/traits/vtable/vtable-multiple.rs

@@ -1,33 +1,29 @@
-//@ build-fail
 #![feature(rustc_attrs)]
 
-#[rustc_dump_vtable]
 trait A {
     fn foo_a(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait B {
-    //~^ error vtable
     fn foo_b(&self) {}
 }
 
-#[rustc_dump_vtable]
 trait C: A + B {
-    //~^ error vtable
     fn foo_c(&self) {}
 }
 
 struct S;
 
+#[rustc_dump_vtable]
 impl A for S {}
+//~^ error vtable
+
+#[rustc_dump_vtable]
 impl B for S {}
+//~^ error vtable
+
+#[rustc_dump_vtable]
 impl C for S {}
+//~^ error vtable
 
-fn foo(c: &dyn C) {}
-fn bar(c: &dyn B) {}
-
-fn main() {
-    foo(&S);
-    bar(&S);
-}
+fn main() {}

tests/ui/traits/vtable/vtable-multiple.stderr

@@ -1,4 +1,26 @@
-error: vtable entries for `<S as C>`: [
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a),
+       ]
+  --> $DIR/vtable-multiple.rs:18:1
+   |
+LL | impl A for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as B>::foo_b),
+       ]
+  --> $DIR/vtable-multiple.rs:22:1
+   |
+LL | impl B for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
@@ -7,21 +29,10 @@ error: vtable entries for `<S as C>`: [
            TraitVPtr(<S as B>),
            Method(<S as C>::foo_c),
        ]
-  --> $DIR/vtable-multiple.rs:16:1
+  --> $DIR/vtable-multiple.rs:26:1
    |
-LL | trait C: A + B {
-   | ^^^^^^^^^^^^^^
+LL | impl C for S {}
+   | ^^^^^^^^^^^^
 
-error: vtable entries for `<S as B>`: [
-           MetadataDropInPlace,
-           MetadataSize,
-           MetadataAlign,
-           Method(<S as B>::foo_b),
-       ]
-  --> $DIR/vtable-multiple.rs:10:1
-   |
-LL | trait B {
-   | ^^^^^^^
-
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 

tests/ui/traits/vtable/vtable-vacant.rs

@@ -1,18 +1,14 @@
-//@ build-fail
 #![feature(rustc_attrs)]
 #![feature(negative_impls)]
 
 // B --> A
 
-#[rustc_dump_vtable]
 trait A {
     fn foo_a1(&self) {}
     fn foo_a2(&self) where Self: Send {}
 }
 
-#[rustc_dump_vtable]
 trait B: A {
-    //~^ error vtable
     fn foo_b1(&self) {}
     fn foo_b2(&self) where Self: Send {}
 }
@@ -20,11 +16,12 @@ trait B: A {
 struct S;
 impl !Send for S {}
 
+#[rustc_dump_vtable]
 impl A for S {}
+//~^ error vtable
+
+#[rustc_dump_vtable]
 impl B for S {}
+//~^ error vtable
 
-fn foo(_: &dyn B) {}
-
-fn main() {
-    foo(&S);
-}
+fn main() {}

tests/ui/traits/vtable/vtable-vacant.stderr

@@ -1,4 +1,16 @@
-error: vtable entries for `<S as B>`: [
+error: vtable entries: [
+           MetadataDropInPlace,
+           MetadataSize,
+           MetadataAlign,
+           Method(<S as A>::foo_a1),
+           Vacant,
+       ]
+  --> $DIR/vtable-vacant.rs:20:1
+   |
+LL | impl A for S {}
+   | ^^^^^^^^^^^^
+
+error: vtable entries: [
            MetadataDropInPlace,
            MetadataSize,
            MetadataAlign,
@@ -7,10 +19,10 @@ error: vtable entries for `<S as B>`: [
            Method(<S as B>::foo_b1),
            Vacant,
        ]
-  --> $DIR/vtable-vacant.rs:14:1
+  --> $DIR/vtable-vacant.rs:24:1
    |
-LL | trait B: A {
-   | ^^^^^^^^^^
+LL | impl B for S {}
+   | ^^^^^^^^^^^^
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors