Rollup merge of #145235 - compiler-errors:comment, r=BoxyUwU

Minor `[const]` tweaks
Self explanatory

Author: Zalathar

compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs

@@ -390,45 +390,13 @@ fn check_predicates<'tcx>(
 
 letmut res = Ok(());
 for(clause, span)in impl1_predicates {
-if !impl2_predicates.iter().any(|pred2| trait_predicates_eq(clause.as_predicate(),*pred2))
-{
+if !impl2_predicates.iter().any(|&pred2| clause.as_predicate() == pred2){
  res = res.and(check_specialization_on(tcx, clause, span))
 }
 }
  res
 }
 
-/// Checks if some predicate on the specializing impl (`predicate1`) is the same
-/// as some predicate on the base impl (`predicate2`).
-///
-/// This basically just checks syntactic equivalence, but is a little more
-/// forgiving since we want to equate `T: Tr` with `T: [const] Tr` so this can work:
-///
-/// ```ignore (illustrative)
-/// #[rustc_specialization_trait]
-/// trait Specialize { }
-///
-/// impl<T: Bound> Tr for T { }
-/// impl<T: [const] Bound + Specialize> const Tr for T { }
-/// ```
-///
-/// However, we *don't* want to allow the reverse, i.e., when the bound on the
-/// specializing impl is not as const as the bound on the base impl:
-///
-/// ```ignore (illustrative)
-/// impl<T: [const] Bound> const Tr for T { }
-/// impl<T: Bound + Specialize> const Tr for T { } // should be T: [const] Bound
-/// ```
-///
-/// So we make that check in this function and try to raise a helpful error message.
-fntrait_predicates_eq<'tcx>(
-predicate1: ty::Predicate<'tcx>,
-predicate2: ty::Predicate<'tcx>,
-) -> bool{
-// FIXME(const_trait_impl)
- predicate1 == predicate2
-}
-
 #[instrument(level = "debug", skip(tcx))]
 fncheck_specialization_on<'tcx>(
 tcx:TyCtxt<'tcx>,

compiler/rustc_hir_typeck/src/callee.rs

@@ -910,7 +910,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 // const stability checking here too, I guess.
 ifself.tcx.is_conditionally_const(callee_did){
 let q = self.tcx.const_conditions(callee_did);
-// FIXME(const_trait_impl): Use this span with a better cause code.
 for(idx,(cond, pred_span))in
  q.instantiate(self.tcx, callee_args).into_iter().enumerate()
 {

compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs

@@ -37,7 +37,6 @@ use super::on_unimplemented::{AppendConstMessage, OnUnimplementedNote};
 usesuper::suggestions::get_explanation_based_on_obligation;
 usesuper::{
 ArgKind,CandidateSimilarity,FindExprBySpan,GetSafeTransmuteErrorAndReason,ImplCandidate,
-UnsatisfiedConst,
 };
 usecrate::error_reporting::TypeErrCtxt;
 usecrate::error_reporting::infer::TyCategory;
@@ -374,13 +373,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 }
 }
 
-letUnsatisfiedConst(unsatisfied_const) = self
-.maybe_add_note_for_unsatisfied_const(
- leaf_trait_predicate,
-&mut err,
- span,
-);
-
 ifletSome((msg, span)) = type_def {
  err.span_label(span, msg);
 }
@@ -506,7 +498,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
  span,
  is_fn_trait,
  suggested,
- unsatisfied_const,
 );
 
 // Changing mutability doesn't make a difference to whether we have
@@ -2716,7 +2707,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 span:Span,
 is_fn_trait:bool,
 suggested:bool,
-unsatisfied_const:bool,
 ){
 let body_def_id = obligation.cause.body_id;
 let span = ifletObligationCauseCode::BinOp{rhs_span:Some(rhs_span), .. } =
@@ -2763,10 +2753,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 self.tcx.def_span(trait_def_id),
 crate::fluent_generated::trait_selection_trait_has_no_impls,
 );
-}elseif !suggested
- && !unsatisfied_const
- && trait_predicate.polarity() == ty::PredicatePolarity::Positive
-{
+}elseif !suggested && trait_predicate.polarity() == ty::PredicatePolarity::Positive{
 // Can't show anything else useful, try to find similar impls.
 let impl_candidates = self.find_similar_impl_candidates(trait_predicate);
 if !self.report_similar_impl_candidates(
@@ -2878,17 +2865,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 }
 }
 
-fnmaybe_add_note_for_unsatisfied_const(
-&self,
-_trait_predicate: ty::PolyTraitPredicate<'tcx>,
-_err:&mutDiag<'_>,
-_span:Span,
-) -> UnsatisfiedConst{
-let unsatisfied_const = UnsatisfiedConst(false);
-// FIXME(const_trait_impl)
- unsatisfied_const
-}
-
 fnreport_closure_error(
 &self,
 obligation:&PredicateObligation<'tcx>,

compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs

@@ -51,8 +51,6 @@ enum GetSafeTransmuteErrorAndReason {
 Error{err_msg:String,safe_transmute_explanation:Option<String>},
 }
 
-structUnsatisfiedConst(pubbool);
-
 /// Crude way of getting back an `Expr` from a `Span`.
 pubstructFindExprBySpan<'hir>{
 pubspan:Span,