libsyntax: Implement the impl Trait for Type syntax

src/test/run-pass/new-impl-syntax.rs

@@ -0,0 +1,26 @@
+struct Thingy {
+    x: int,
+    y: int
+}
+
+impl ToStr for Thingy {
+    pure fn to_str() -> ~str {
+        fmt!("{ x: %d, y: %d }", self.x, self.y)
+    }
+}
+
+struct PolymorphicThingy<T> {
+    x: T
+}
+
+impl<T:ToStr> ToStr for PolymorphicThingy<T> {
+    pure fn to_str() -> ~str {
+        self.x.to_str()
+    }
+}
+
+fn main() {
+    io::println(Thingy { x: 1, y: 2 }.to_str());
+    io::println(PolymorphicThingy { x: Thingy { x: 1, y: 2 } }.to_str());
+}
+