delegation: Implement list delegation

```rust
reuse prefix::{a, b, c}
```

1 files changed, 26 insertions, 0 deletions

diff --git a/tests/ui/delegation/macro-inside-list.rs b/tests/ui/delegation/macro-inside-list.rs
new file mode 100644
index 00000000000..16c74d396ef
--- /dev/null
+++ b/tests/ui/delegation/macro-inside-list.rs
@@ -0,0 +1,26 @@
+//@ check-pass
+
+#![feature(fn_delegation)]
+#![allow(incomplete_features)]
+
+trait Trait {
+    fn foo(&self) -> u8 { 0 }
+    fn bar(&self) -> u8 { 1 }
+}
+
+impl Trait for u8 {}
+
+struct S(u8);
+
+// Macro expansion works inside delegation items.
+macro_rules! u8 { () => { u8 } }
+macro_rules! self_0 { () => { &self.0 } }
+impl Trait for S {
+    reuse <u8!() as Trait>::{foo, bar} { self_0!() }
+}
+
+fn main() {
+    let s = S(2);
+    s.foo();
+    s.bar();
+}