1 files changed, 34 insertions, 42 deletions

diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs
index 5d536e982..40c0c806e 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs
@@ -1,15 +1,17 @@
 //! Error Reporting for `impl` items that do not match the obligations from their `trait`.
 
+use crate::errors::{ConsiderBorrowingParamHelp, RelationshipHelp, TraitImplDiff};
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
 use crate::infer::lexical_region_resolve::RegionResolutionError;
-use crate::infer::Subtype;
+use crate::infer::{Subtype, ValuePairs};
 use crate::traits::ObligationCauseCode::CompareImplItemObligation;
-use rustc_errors::{ErrorGuaranteed, MultiSpan};
+use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::Visitor;
 use rustc_middle::hir::nested_filter;
+use rustc_middle::ty::error::ExpectedFound;
 use rustc_middle::ty::print::RegionHighlightMode;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor};
 use rustc_span::Span;
@@ -22,22 +24,27 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         let error = self.error.as_ref()?;
         debug!("try_report_impl_not_conforming_to_trait {:?}", error);
         if let RegionResolutionError::SubSupConflict(
-                _,
-                var_origin,
-                sub_origin,
-                _sub,
-                sup_origin,
-                _sup,
-                _,
-            ) = error.clone()
+            _,
+            var_origin,
+            sub_origin,
+            _sub,
+            sup_origin,
+            _sup,
+            _,
+        ) = error.clone()
             && let (Subtype(sup_trace), Subtype(sub_trace)) = (&sup_origin, &sub_origin)
-            && let sub_expected_found @ Some((sub_expected, sub_found)) = sub_trace.values.ty()
-            && let sup_expected_found @ Some(_) = sup_trace.values.ty()
             && let CompareImplItemObligation { trait_item_def_id, .. } = sub_trace.cause.code()
-            && sup_expected_found == sub_expected_found
+            && sub_trace.values == sup_trace.values
+            && let ValuePairs::Sigs(ExpectedFound { expected, found }) = sub_trace.values
         {
-            let guar =
-                self.emit_err(var_origin.span(), sub_expected, sub_found, *trait_item_def_id);
+            // FIXME(compiler-errors): Don't like that this needs `Ty`s, but
+            // all of the region highlighting machinery only deals with those.
+            let guar = self.emit_err(
+                var_origin.span(),
+                self.cx.tcx.mk_fn_ptr(ty::Binder::dummy(expected)),
+                self.cx.tcx.mk_fn_ptr(ty::Binder::dummy(found)),
+                *trait_item_def_id,
+            );
             return Some(guar);
         }
         None
@@ -51,10 +58,6 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         trait_def_id: DefId,
     ) -> ErrorGuaranteed {
         let trait_sp = self.tcx().def_span(trait_def_id);
-        let mut err = self
-            .tcx()
-            .sess
-            .struct_span_err(sp, "`impl` item signature doesn't match `trait` item signature");
 
         // Mark all unnamed regions in the type with a number.
         // This diagnostic is called in response to lifetime errors, so be informative.
@@ -91,9 +94,6 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         let found =
             self.cx.extract_inference_diagnostics_data(found.into(), Some(found_highlight)).name;
 
-        err.span_label(sp, &format!("found `{}`", found));
-        err.span_label(trait_sp, &format!("expected `{}`", expected));
-
         // Get the span of all the used type parameters in the method.
         let assoc_item = self.tcx().associated_item(trait_def_id);
         let mut visitor = TypeParamSpanVisitor { tcx: self.tcx(), types: vec![] };
@@ -110,26 +110,18 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
             }
             _ => {}
         }
-        let mut type_param_span: MultiSpan = visitor.types.to_vec().into();
-        for &span in &visitor.types {
-            type_param_span
-                .push_span_label(span, "consider borrowing this type parameter in the trait");
-        }
 
-        err.note(&format!("expected `{}`\n   found `{}`", expected, found));
-
-        err.span_help(
-            type_param_span,
-            "the lifetime requirements from the `impl` do not correspond to the requirements in \
-             the `trait`",
-        );
-        if visitor.types.is_empty() {
-            err.help(
-                "verify the lifetime relationships in the `trait` and `impl` between the `self` \
-                 argument, the other inputs and its output",
-            );
-        }
-        err.emit()
+        let diag = TraitImplDiff {
+            sp,
+            trait_sp,
+            note: (),
+            param_help: ConsiderBorrowingParamHelp { spans: visitor.types.to_vec() },
+            rel_help: visitor.types.is_empty().then_some(RelationshipHelp),
+            expected,
+            found,
+        };
+
+        self.tcx().sess.emit_err(diag)
     }
 }
 
@@ -147,7 +139,7 @@ impl<'tcx> Visitor<'tcx> for TypeParamSpanVisitor<'tcx> {
 
     fn visit_ty(&mut self, arg: &'tcx hir::Ty<'tcx>) {
         match arg.kind {
-            hir::TyKind::Rptr(_, ref mut_ty) => {
+            hir::TyKind::Ref(_, ref mut_ty) => {
                 // We don't want to suggest looking into borrowing `&T` or `&Self`.
                 hir::intravisit::walk_ty(self, mut_ty.ty);
                 return;