rustc: fix ICE when trait alias has bare Self

4 files changed, 29 insertions, 2 deletions

diff --git a/src/librustc/hir/map/mod.rs b/src/librustc/hir/map/mod.rs
index 86b6805cc9b..0e83ce009c9 100644
--- a/src/librustc/hir/map/mod.rs
+++ b/src/librustc/hir/map/mod.rs
@@ -541,7 +541,8 @@ impl<'hir> Map<'hir> {
 
     pub fn ty_param_owner(&self, id: HirId) -> HirId {
         match self.get_by_hir_id(id) {
-            Node::Item(&Item { node: ItemKind::Trait(..), .. }) => id,
+            Node::Item(&Item { node: ItemKind::Trait(..), .. }) |
+            Node::Item(&Item { node: ItemKind::TraitAlias(..), .. }) => id,
             Node::GenericParam(_) => self.get_parent_node_by_hir_id(id),
             _ => bug!("ty_param_owner: {} not a type parameter", self.hir_to_string(id))
         }
@@ -549,7 +550,8 @@ impl<'hir> Map<'hir> {
 
     pub fn ty_param_name(&self, id: HirId) -> Name {
         match self.get_by_hir_id(id) {
-            Node::Item(&Item { node: ItemKind::Trait(..), .. }) => keywords::SelfUpper.name(),
+            Node::Item(&Item { node: ItemKind::Trait(..), .. }) |
+            Node::Item(&Item { node: ItemKind::TraitAlias(..), .. }) => keywords::SelfUpper.name(),
             Node::GenericParam(param) => param.name.ident().name,
             _ => bug!("ty_param_name: {} not a type parameter", self.hir_to_string(id)),
         }
diff --git a/src/test/ui/issues/issue-59029-1.rs b/src/test/ui/issues/issue-59029-1.rs
new file mode 100644
index 00000000000..e98a4d0e491
--- /dev/null
+++ b/src/test/ui/issues/issue-59029-1.rs
@@ -0,0 +1,8 @@
+#![feature(trait_alias)]
+
+trait Svc<Req> { type Res; }
+
+trait MkSvc<Target, Req> = Svc<Target> where Self::Res: Svc<Req>;
+//~^ ERROR associated type `Res` not found for `Self`
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-59029-1.stderr b/src/test/ui/issues/issue-59029-1.stderr
new file mode 100644
index 00000000000..ed1d98c40d1
--- /dev/null
+++ b/src/test/ui/issues/issue-59029-1.stderr
@@ -0,0 +1,9 @@
+error[E0220]: associated type `Res` not found for `Self`
+  --> $DIR/issue-59029-1.rs:5:46
+   |
+LL | trait MkSvc<Target, Req> = Svc<Target> where Self::Res: Svc<Req>;
+   |                                              ^^^^^^^^^ associated type `Res` not found
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0220`.
diff --git a/src/test/ui/issues/issue-59029-2.rs b/src/test/ui/issues/issue-59029-2.rs
new file mode 100644
index 00000000000..2bdb128d8c4
--- /dev/null
+++ b/src/test/ui/issues/issue-59029-2.rs
@@ -0,0 +1,8 @@
+// run-pass
+#![feature(trait_alias)]
+
+trait Svc<Req> { type Res; }
+
+trait MkSvc<Target, Req> = Svc<Target> where <Self as Svc<Target>>::Res: Svc<Req>;
+
+fn main() {}