Auto merge of #65456 - estebank:trait-bound-borrow, r=matthewjasper

[rust.git] / src / librustc / traits / error_reporting.rs

diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
index ffd4560d32d8e348ca41543952b3d7a33b12948c..ea29cc0d93f538a51c8f38375e24fde6a6bb4783 100644 (file)
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.rs
@@ -33,7 +33,7 @@
 use crate::ty::SubtypePredicate;
 use crate::util::nodemap::{FxHashMap, FxHashSet};
 
-use errors::{Applicability, DiagnosticBuilder, pluralise, Style};
+use errors::{Applicability, DiagnosticBuilder, pluralize, Style};
 use std::fmt;
 use syntax::ast;
 use syntax::symbol::{sym, kw};
@@ -776,6 +776,7 @@ pub fn report_selection_error(
                             &mut err,
                             &trait_ref,
                             points_at_arg,
+                            have_alt_message,
                         ) {
                             self.note_obligation_cause(&mut err, obligation);
                             err.emit();
@@ -1318,6 +1319,7 @@ fn suggest_add_reference_to_arg(
         err: &mut DiagnosticBuilder<'tcx>,
         trait_ref: &ty::Binder<ty::TraitRef<'tcx>>,
         points_at_arg: bool,
+        has_custom_message: bool,
     ) -> bool {
         if !points_at_arg {
             return false;
@@ -1339,21 +1341,23 @@ fn suggest_add_reference_to_arg(
                 param_env,
                 new_trait_ref.to_predicate(),
             );
-            if self.predicate_may_hold(&new_obligation) {
+            if self.predicate_must_hold_modulo_regions(&new_obligation) {
                 if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) {
                     // We have a very specific type of error, where just borrowing this argument
                     // might solve the problem. In cases like this, the important part is the
                     // original type obligation, not the last one that failed, which is arbitrary.
                     // Because of this, we modify the error to refer to the original obligation and
                     // return early in the caller.
-                    err.message = vec![(
-                        format!(
-                            "the trait bound `{}: {}` is not satisfied",
-                            found,
-                            obligation.parent_trait_ref.skip_binder(),
-                        ),
-                        Style::NoStyle,
-                    )];
+                    let msg = format!(
+                        "the trait bound `{}: {}` is not satisfied",
+                        found,
+                        obligation.parent_trait_ref.skip_binder(),
+                    );
+                    if has_custom_message {
+                        err.note(&msg);
+                    } else {
+                        err.message = vec![(msg, Style::NoStyle)];
+                    }
                     if snippet.starts_with('&') {
                         // This is already a literal borrow and the obligation is failing
                         // somewhere else in the obligation chain. Do not suggest non-sense.
@@ -1367,7 +1371,7 @@ fn suggest_add_reference_to_arg(
                         span,
                         "consider borrowing here",
                         format!("&{}", snippet),
-                        Applicability::MachineApplicable,
+                        Applicability::MaybeIncorrect,
                     );
                     return true;
                 }