Typecheck constructor initializers properly

test/codegen/expect/math/math.js

Index: test/codegen/expect/math/math.js
diff --git a/test/codegen/expect/math/math.js b/test/codegen/expect/math/math.js
index d6794459317203678471b2c905adac5024ec613d..af9ca3a18bb9bf90c687c3555dde4f1799207da0 100644
--- a/test/codegen/expect/math/math.js
+++ b/test/codegen/expect/math/math.js
@@ -357,8 +357,8 @@ var math;
       Rectangle(left, top, width, height) {
         this.left = left;
         this.top = top;
-        this.width = width['<'](0) ? dart.notNull(dart.throw_("Unimplemented PrefixExpression: -width")) * 0 : width;
-        this.height = height['<'](0) ? dart.notNull(dart.throw_("Unimplemented PrefixExpression: -height")) * 0 : height;
+        this.width = dart.as(width['<'](0) ? dart.notNull(dart.throw_("Unimplemented PrefixExpression: -width")) * 0 : width, T);
+        this.height = dart.as(height['<'](0) ? dart.notNull(dart.throw_("Unimplemented PrefixExpression: -height")) * 0 : height, T);
         super._RectangleBase();
       }
       Rectangle$fromPoints(a, b) {
@@ -378,8 +378,8 @@ var math;
       MutableRectangle(left, top, width, height) {
         this.left = left;
         this.top = top;
-        this._width = width['<'](0) ? _clampToZero(width) : width;
-        this._height = height['<'](0) ? _clampToZero(height) : height;
+        this._width = dart.as(width['<'](0) ? _clampToZero(width) : width, T);
+        this._height = dart.as(height['<'](0) ? _clampToZero(height) : height, T);
         super._RectangleBase();
       }
       MutableRectangle$fromPoints(a, b) {