Remove code that was removed in master, and the corresponding diagnostic

compiler/rustc_passes/src/check_const.rs

@@ -17,7 +17,7 @@ use rustc_middle::ty::TyCtxt;
 use rustc_session::parse::feature_err;
 use rustc_span::{sym, Span, Symbol};
 
-use crate::errors::{ConstImplConstTrait, ExprNotAllowedInContext};
+use crate::errors::ExprNotAllowedInContext;
 
 /// An expression that is not *always* legal in a const context.
 #[derive(Clone, Copy)]
@@ -196,26 +196,6 @@ impl<'tcx> Visitor<'tcx> for CheckConstVisitor<'tcx> {
         self.tcx.hir()
     }
 
-    fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
-        let tcx = self.tcx;
-        if let hir::ItemKind::Impl(hir::Impl {
-            constness: hir::Constness::Const,
-            of_trait: Some(trait_ref),
-            ..
-        }) = item.kind
-            && let Some(def_id) = trait_ref.trait_def_id()
-        {
-            let source_map = tcx.sess.source_map();
-            if !tcx.has_attr(def_id, sym::const_trait) {
-                tcx.sess.emit_err(ConstImplConstTrait {
-                    span: source_map.guess_head_span(item.span),
-                    def_span: source_map.guess_head_span(tcx.def_span(def_id)),
-                });
-            }
-        }
-        intravisit::walk_item(self, item);
-    }
-
     fn visit_anon_const(&mut self, anon: &'tcx hir::AnonConst) {
         let kind = Some(hir::ConstContext::Const);
         self.recurse_into(kind, None, |this| intravisit::walk_anon_const(this, anon));

compiler/rustc_passes/src/errors.rs

@@ -859,15 +859,6 @@ pub struct ExprNotAllowedInContext<'a> {
     pub context: &'a str,
 }
 
-#[derive(Diagnostic)]
-#[diag(passes::const_impl_const_trait)]
-pub struct ConstImplConstTrait {
-    #[primary_span]
-    pub span: Span,
-    #[note]
-    pub def_span: Span,
-}
-
 pub struct BreakNonLoop<'a> {
     pub span: Span,
     pub head: Option<Span>,