Rollup merge of #50257 - estebank:fix-49560, r=nikomatsakis

[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 3eb45439001cd16298fd037056b8b5819fb5d536..047d4bb893096103d38a4f6c3a6af6132ea3133d 100644 (file)
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.rs
@@ -24,6 +24,7 @@
     SelectionContext,
     SelectionError,
     ObjectSafetyViolation,
+    Overflow,
 };
 
 use errors::DiagnosticBuilder;
@@ -659,8 +660,7 @@ pub fn report_selection_error(&self,
                                 predicate: ty::Predicate::Trait(predicate),
                                 .. obligation.clone()
                             };
-                            let mut selcx = SelectionContext::new(self);
-                            if selcx.evaluate_obligation(&unit_obligation) {
+                            if self.predicate_may_hold(&unit_obligation) {
                                 err.note("the trait is implemented for `()`. \
                                          Possibly this error has been caused by changes to \
                                          Rust's type-inference algorithm \
@@ -830,6 +830,10 @@ pub fn report_selection_error(&self,
                 }
                 err.struct_error(self.tcx, span, "constant expression")
             }
+
+            Overflow => {
+                bug!("overflow should be handled before the `report_selection_error` path");
+            }
         };
         self.note_obligation_cause(&mut err, obligation);
         err.emit();
@@ -872,7 +876,6 @@ fn suggest_remove_reference(&self,
                 .count();
 
             let mut trait_type = trait_ref.self_ty();
-            let mut selcx = SelectionContext::new(self);
 
             for refs_remaining in 0..refs_number {
                 if let ty::TypeVariants::TyRef(_, ty::TypeAndMut{ ty: t_type, mutbl: _ }) =
@@ -886,7 +889,7 @@ fn suggest_remove_reference(&self,
                                                          obligation.param_env,
                                                          new_trait_ref.to_predicate());
 
-                    if selcx.evaluate_obligation(&new_obligation) {
+                    if self.predicate_may_hold(&new_obligation) {
                         let sp = self.tcx.sess.codemap()
                             .span_take_while(span, |c| c.is_whitespace() || *c == '&');
 
@@ -1328,7 +1331,7 @@ fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
                 cleaned_pred.to_predicate()
             );
 
-            selcx.evaluate_obligation(&obligation)
+            self.predicate_may_hold(&obligation)
         })
     }