Better errors for implied static bound

[rust.git] / compiler / rustc_middle / src / traits / mod.rs

diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs
index a95e6a61854cf62757c58445809ac672aaee7aa2..68a7af0b8c8d75669028135952d7f8e921431d45 100644 (file)
--- a/compiler/rustc_middle/src/traits/mod.rs
+++ b/compiler/rustc_middle/src/traits/mod.rs
@@ -10,6 +10,7 @@
 pub mod util;
 
 use crate::infer::canonical::Canonical;
+use crate::mir::ConstraintCategory;
 use crate::ty::abstract_const::NotConstEvaluatable;
 use crate::ty::subst::SubstsRef;
 use crate::ty::{self, AdtKind, Ty, TyCtxt};
@@ -183,6 +184,16 @@ pub fn derived_cause(
             variant(DerivedObligationCause { parent_trait_pred, parent_code: self.code }).into();
         self
     }
+
+    pub fn to_constraint_category(&self) -> ConstraintCategory<'tcx> {
+        match self.code() {
+            MatchImpl(cause, _) => cause.to_constraint_category(),
+            AscribeUserTypeProvePredicate(predicate_span) => {
+                ConstraintCategory::Predicate(*predicate_span)
+            }
+            _ => ConstraintCategory::BoringNoLocation,
+        }
+    }
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Lift)]
@@ -418,6 +429,8 @@ pub enum ObligationCauseCode<'tcx> {
         is_lit: bool,
         output_ty: Option<Ty<'tcx>>,
     },
+
+    AscribeUserTypeProvePredicate(Span),
 }
 
 /// The 'location' at which we try to perform HIR-based wf checking.