Add trait obligations for where clauses when calling functions/methods

E.g. if we call `foo<T: Into<u32>>(x)`, that adds an obligation that `x:
Into<u32>`, etc.

1 files changed, 10 insertions, 1 deletions

diff --git a/crates/ra_hir/src/ty/traits.rs b/crates/ra_hir/src/ty/traits.rs
index cff4de316..23a26a971 100644
--- a/crates/ra_hir/src/ty/traits.rs
+++ b/crates/ra_hir/src/ty/traits.rs
@@ -7,7 +7,7 @@ use parking_lot::Mutex;
 use ra_prof::profile;
 use rustc_hash::FxHashSet;
 
-use super::{Canonical, ProjectionTy, TraitRef, Ty};
+use super::{Canonical, GenericPredicate, ProjectionTy, TraitRef, Ty};
 use crate::{db::HirDatabase, Crate, ImplBlock, Trait};
 
 use self::chalk::{from_chalk, ToChalk};
@@ -78,6 +78,15 @@ pub enum Obligation {
     // Projection(ProjectionPredicate),
 }
 
+impl Obligation {
+    pub fn from_predicate(predicate: GenericPredicate) -> Option<Obligation> {
+        match predicate {
+            GenericPredicate::Implemented(trait_ref) => Some(Obligation::Trait(trait_ref)),
+            GenericPredicate::Error => None,
+        }
+    }
+}
+
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct ProjectionPredicate {
     pub projection_ty: ProjectionTy,