librustc: Check structure constructors against their types.

This breaks code like:

    struct Point<T> {
        x: T,
        y: T,
    }

    let pt = Point::<bool> {
        x: 1,
        y: 2,
    };

Change this code to not contain a type error. For example:

    let pt = Point::<int> {
        x: 1,
        y: 2,
    };

Closes #9620.
Closes #15875.

[breaking-change]

src/test/compile-fail/structure-constructor-type-mismatch.rs

@@ -0,0 +1,56 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct Point<T> {
+    x: T,
+    y: T,
+}
+
+type PointF = Point<f32>;
+
+struct Pair<T,U> {
+    x: T,
+    y: U,
+}
+
+type PairF<U> = Pair<f32,U>;
+
+fn main() {
+    let pt = PointF {
+        //~^ ERROR expected f32 but found int
+        x: 1i,
+        y: 2i,
+    };
+
+    let pt2 = Point::<f32> {
+        //~^ ERROR expected f32 but found int
+        x: 3i,
+        y: 4i,
+    };
+
+    let pair = PairF {
+        //~^ ERROR expected f32 but found int
+        x: 5i,
+        y: 6i,
+    };
+
+    let pair2 = PairF::<int> {
+        //~^ ERROR expected f32 but found int
+        x: 7i,
+        y: 8i,
+    };
+
+    let pt3 = PointF::<int> {
+        //~^ ERROR wrong number of type arguments
+        x: 9i,
+        y: 10i,
+    };
+}
+