4 files changed, 6 insertions, 4 deletions

diff --git a/crates/ra_hir_ty/src/infer/expr.rs b/crates/ra_hir_ty/src/infer/expr.rs
index 31259a01d..97cb20cea 100644
--- a/crates/ra_hir_ty/src/infer/expr.rs
+++ b/crates/ra_hir_ty/src/infer/expr.rs
@@ -10,7 +10,7 @@ use hir_def::{
     resolver::resolver_for_expr,
     AdtId, AssocContainerId, Lookup, StructFieldId,
 };
-use hir_expand::name::{name, Name};
+use hir_expand::name::Name;
 use ra_syntax::ast::RangeOp;
 
 use crate::{
@@ -654,7 +654,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         // Parent arguments are unknown, except for the receiver type
         if let Some(parent_generics) = def_generics.as_ref().map(|p| p.iter_parent()) {
             for (_id, param) in parent_generics {
-                if param.name == name![Self] {
+                if param.provenance == hir_def::generics::TypeParamProvenance::TraitSelf {
                     substs.push(receiver_ty.clone());
                 } else {
                     substs.push(Ty::Unknown);
diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index c64b81f98..cb7a60352 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -368,7 +368,7 @@ impl Substs {
     /// Return Substs that replace each parameter by itself (i.e. `Ty::Param`).
     pub(crate) fn identity(generic_params: &Generics) -> Substs {
         Substs(
-            generic_params.iter().map(|(idx, p)| Ty::Param { idx, name: p.name.clone() }).collect(),
+            generic_params.iter().map(|(idx, p)| Ty::Param { idx, name: p.name.clone().unwrap_or_else(Name::missing) }).collect(),
         )
     }
 
diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs
index 39406d8ce..6f7681475 100644
--- a/crates/ra_hir_ty/src/lower.rs
+++ b/crates/ra_hir_ty/src/lower.rs
@@ -341,6 +341,7 @@ pub(super) fn substs_from_path_segment(
         // Self type as an implicit first type parameter, but it can't be
         // actually provided in the type arguments
         // (well, actually sometimes it can, in the form of type-relative paths: `<Foo as Default>::default()`)
+        // TODO handle this using type param provenance
         substs.push(Ty::Unknown);
     }
     if let Some(generic_args) = &segment.args_and_bindings {
diff --git a/crates/ra_hir_ty/src/utils.rs b/crates/ra_hir_ty/src/utils.rs
index 0b1806a84..314a3241f 100644
--- a/crates/ra_hir_ty/src/utils.rs
+++ b/crates/ra_hir_ty/src/utils.rs
@@ -127,7 +127,8 @@ impl Generics {
         self.find_param(param).0
     }
     pub(crate) fn param_name(&self, param: TypeParamId) -> Name {
-        self.find_param(param).1.name.clone()
+        // FIXME make this return Option
+        self.find_param(param).1.name.clone().unwrap_or_else(Name::missing)
     }
     fn find_param(&self, param: TypeParamId) -> (u32, &TypeParamData) {
         if param.parent == self.def {