add 3 ices

rust-lang/rust#99866
rust-lang/rust#99914
rust-lang/rust#99945

ices/99866.rs

@@ -0,0 +1,25 @@
+#![crate_type = "lib"]
+
+pub trait Backend {
+    type DescriptorSetLayout;
+}
+
+pub struct Back;
+
+impl Backend for Back {
+    type DescriptorSetLayout = u32;
+}
+
+pub struct HalSetLayouts {
+    vertex_layout: <Back as Backend>::DescriptorSetLayout,
+}
+
+impl HalSetLayouts {
+    pub fn iter<DSL>(self) -> DSL
+    where
+        Back: Backend<DescriptorSetLayout = DSL>,
+    {
+        self.vertex_layout
+    }
+}
+

ices/99914.rs

@@ -0,0 +1,10 @@
+struct Error;
+
+fn foo() {
+    let initial_exchange: Result<usize, Error> = todo!();
+    initial_exchange.and_then(|_|
+        serve_udp_tunnel()
+    ).await;
+}
+
+async fn serve_udp_tunnel() {}

ices/99945.rs

@@ -0,0 +1,31 @@
+#![feature(type_alias_impl_trait)]
+
+trait Widget<E> {
+    type State;
+
+    fn make_state(&self) -> Self::State;
+}
+
+impl<E> Widget<E> for () {
+    type State = ();
+
+    fn make_state(&self) -> Self::State {}
+}
+
+struct StatefulWidget<F>(F);
+
+type StateWidget<'a> = impl Widget<&'a ()>;
+
+impl<F: for<'a> Fn(&'a ()) -> StateWidget<'a>> Widget<()> for StatefulWidget<F> {
+    type State = ();
+
+    fn make_state(&self) -> Self::State {}
+}
+
+fn new_stateful_widget<F: for<'a> Fn(&'a ()) -> StateWidget<'a>>(build: F) -> impl Widget<()> {
+    StatefulWidget(build)
+}
+
+fn main() {
+    new_stateful_widget(|_| ()).make_state();
+}