allow using tuple variant names as function handles in presence of NonZero optimizations

src/terminator/mod.rs

@@ -258,7 +258,12 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
                                     discr_size,
                                 )?;
                             },
-                            // FIXME: raw nullable pointer constructors
+                            Layout::StructWrappedNullablePointer { .. } |
+                            Layout::RawNullablePointer { .. } => {
+                                assert_eq!(args.len(), 1);
+                                let (val, ty) = args.pop().unwrap();
+                                self.write_value(val, lvalue, ty)?;
+                            },
                             _ => bug!("bad layout for tuple struct constructor: {:?}", dest_layout),
                         }
                         self.goto_block(target);

tests/run-pass/tuple_like_enum_variant_constructor_pointer_opt.rs

@@ -0,0 +1,4 @@
+fn main() {
+    let x = 5;
+    assert_eq!(Some(&x).map(Some), Some(Some(&x)));
+}

tests/run-pass/tuple_like_enum_variant_constructor_struct_pointer_opt.rs

@@ -0,0 +1,11 @@
+#[derive(Copy, Clone, PartialEq, Debug)]
+struct A<'a> {
+    x: i32,
+    y: &'a i32,
+}
+
+fn main() {
+    let x = 5;
+    let a = A { x: 99, y: &x };
+    assert_eq!(Some(a).map(Some), Some(Some(a)));
+}