Rollup merge of #47892 - Badel2:const_type_id_of, r=oli-obk

Turn `type_id` into a constant intrinsic

https://github.com/rust-lang/rust/issues/27745

The method `get_type_id` in `Any` is intended to support reflection. It's currently unstable in favor of using an associated constant instead. This PR makes the `type_id` intrinsic a constant intrinsic, the same as `size_of` and `align_of`, allowing `TypeId::of` to be a `const fn`, which will allow using an associated constant in `Any`.

1 files changed, 18 insertions, 0 deletions

diff --git a/src/test/compile-fail/const-typeid-of.rs b/src/test/compile-fail/const-typeid-of.rs
new file mode 100644
index 00000000000..401125cef09
--- /dev/null
+++ b/src/test/compile-fail/const-typeid-of.rs
@@ -0,0 +1,18 @@
+// Copyright 2018 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.
+
+use std::any::TypeId;
+
+struct A;
+
+fn main() {
+    const A_ID: TypeId = TypeId::of::<A>();
+    //~^ ERROR `std::any::TypeId::of` is not yet stable as a const fn
+}