Rollup of 11 pull requests

compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs

@@ -21,19 +21,9 @@ impl<'tcx> super::QueryTypeOp<'tcx> for ProvePredicate<'tcx> {
 
  if let ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(term)) =
  key.value.predicate.kind().skip_binder()
+ && term.is_trivially_wf(tcx)
  {
- match term.as_type()?.kind() {
- ty::Param(_)
- | ty::Bool
- | ty::Char
- | ty::Int(_)
- | ty::Float(_)
- | ty::Str
- | ty::Uint(_) => {
- return Some(());
- }
- _ => {}
- }
+ return Some(());
  }
 
  None

compiler/rustc_trait_selection/src/traits/util.rs

@@ -368,16 +368,17 @@ pub fn sizedness_fast_path<'tcx>(tcx: TyCtxt<'tcx>, predicate: ty::Predicate<'tc
  // Proving `Sized`/`MetaSized`, very often on "obviously sized" types like
  // `&T`, accounts for about 60% percentage of the predicates we have to prove. No need to
  // canonicalize and all that for such cases.
- if let ty::PredicateKind::Clause(ty::ClauseKind::Trait(trait_ref)) =
+ if let ty::PredicateKind::Clause(ty::ClauseKind::Trait(trait_pred)) =
  predicate.kind().skip_binder()
+ && trait_pred.polarity == ty::PredicatePolarity::Positive
  {
- let sizedness = match tcx.as_lang_item(trait_ref.def_id()) {
+ let sizedness = match tcx.as_lang_item(trait_pred.def_id()) {
  Some(LangItem::Sized) => SizedTraitKind::Sized,
  Some(LangItem::MetaSized) => SizedTraitKind::MetaSized,
  _ => return false,
  };
 
- if trait_ref.self_ty().has_trivial_sizedness(tcx, sizedness) {
+ if trait_pred.self_ty().has_trivial_sizedness(tcx, sizedness) {
  debug!("fast path -- trivial sizedness");
  return true;
  }

compiler/rustc_traits/src/codegen.rs

@@ -6,11 +6,11 @@
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::bug;
 use rustc_middle::traits::CodegenObligationError;
-use rustc_middle::ty::{self, PseudoCanonicalInput, TyCtxt, TypeVisitableExt, Upcast};
+use rustc_middle::ty::{self, PseudoCanonicalInput, TyCtxt, TypeVisitableExt};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::traits::{
  ImplSource, Obligation, ObligationCause, ObligationCtxt, ScrubbedTraitError, SelectionContext,
- SelectionError, sizedness_fast_path,
+ SelectionError,
 };
 use tracing::debug;
 
@@ -34,13 +34,6 @@ pub(crate) fn codegen_select_candidate<'tcx>(
  let (infcx, param_env) = tcx.infer_ctxt().ignoring_regions().build_with_typing_env(typing_env);
  let mut selcx = SelectionContext::new(&infcx);
 
- if sizedness_fast_path(tcx, trait_ref.upcast(tcx)) {
- return Ok(&*tcx.arena.alloc(ImplSource::Builtin(
- ty::solve::BuiltinImplSource::Trivial,
- Default::default(),
- )));
- }
-
  let obligation_cause = ObligationCause::dummy();
  let obligation = Obligation::new(tcx, obligation_cause, param_env, trait_ref);
 

tests/ui/traits/negative-bounds/negative-sized.rs

@@ -0,0 +1,8 @@
+#![feature(negative_bounds)]
+
+fn foo<T: !Sized>() {}
+
+fn main() {
+ foo::<()>();
+ //~^ ERROR the trait bound `(): !Sized` is not satisfied
+}

tests/ui/traits/negative-bounds/negative-sized.stderr

@@ -0,0 +1,15 @@
+error[E0277]: the trait bound `(): !Sized` is not satisfied
+ --> $DIR/negative-sized.rs:6:11
+ |
+LL | foo::<()>();
+ | ^^ the trait bound `(): !Sized` is not satisfied
+ |
+note: required by a bound in `foo`
+ --> $DIR/negative-sized.rs:3:11
+ |
+LL | fn foo<T: !Sized>() {}
+ | ^^^^^^ required by this bound in `foo`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.