From 88fd4943a65fe7b18c0468255c54f9dee591dd1b Mon Sep 17 00:00:00 2001
From: Dylan MacKenzie <ecstaticmorse@gmail.com>
Date: Wed, 29 Jul 2020 14:58:06 -0700
Subject: [PATCH] Test `{align,size}_of_val` in a const context

---
 ...st-size_of_val-align_of_val-extern-type.rs | 14 ++++++
 ...ize_of_val-align_of_val-extern-type.stderr | 20 +++++++++
 .../consts/const-size_of_val-align_of_val.rs  | 45 +++++++++++++++++++
 3 files changed, 79 insertions(+)
 create mode 100644 src/test/ui/consts/const-size_of_val-align_of_val-extern-type.rs
 create mode 100644 src/test/ui/consts/const-size_of_val-align_of_val-extern-type.stderr
 create mode 100644 src/test/ui/consts/const-size_of_val-align_of_val.rs

diff --git a/src/test/ui/consts/const-size_of_val-align_of_val-extern-type.rs b/src/test/ui/consts/const-size_of_val-align_of_val-extern-type.rs
new file mode 100644
index 0000000000000..96a8a8452edb0
--- /dev/null
+++ b/src/test/ui/consts/const-size_of_val-align_of_val-extern-type.rs
@@ -0,0 +1,14 @@
+#![feature(extern_types)]
+#![feature(core_intrinsics)]
+#![feature(const_size_of_val, const_align_of_val)]
+
+use std::intrinsics::{size_of_val, min_align_of_val};
+
+extern {
+    type Opaque;
+}
+
+const _SIZE: usize = unsafe { size_of_val(&4 as *const i32 as *const Opaque) }; //~ ERROR
+const _ALIGN: usize = unsafe { min_align_of_val(&4 as *const i32 as *const Opaque) }; //~ ERROR
+
+fn main() {}
diff --git a/src/test/ui/consts/const-size_of_val-align_of_val-extern-type.stderr b/src/test/ui/consts/const-size_of_val-align_of_val-extern-type.stderr
new file mode 100644
index 0000000000000..d3f1b04d25154
--- /dev/null
+++ b/src/test/ui/consts/const-size_of_val-align_of_val-extern-type.stderr
@@ -0,0 +1,20 @@
+error: any use of this value will cause an error
+  --> $DIR/const-size_of_val-align_of_val-extern-type.rs:11:31
+   |
+LL | const _SIZE: usize = unsafe { size_of_val(&4 as *const i32 as *const Opaque) };
+   | ------------------------------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^---
+   |                               |
+   |                               `extern type` does not have known layout
+   |
+   = note: `#[deny(const_err)]` on by default
+
+error: any use of this value will cause an error
+  --> $DIR/const-size_of_val-align_of_val-extern-type.rs:12:32
+   |
+LL | const _ALIGN: usize = unsafe { min_align_of_val(&4 as *const i32 as *const Opaque) };
+   | -------------------------------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^---
+   |                                |
+   |                                `extern type` does not have known layout
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/consts/const-size_of_val-align_of_val.rs b/src/test/ui/consts/const-size_of_val-align_of_val.rs
new file mode 100644
index 0000000000000..e8e6f1d390099
--- /dev/null
+++ b/src/test/ui/consts/const-size_of_val-align_of_val.rs
@@ -0,0 +1,45 @@
+// run-pass
+
+#![feature(const_size_of_val, const_align_of_val)]
+
+use std::mem;
+
+struct Foo(u32);
+
+#[derive(Clone, Copy)]
+struct Bar {
+    _x: u8,
+    _y: u16,
+    _z: u8,
+}
+
+union Ugh {
+    _a: [u8; 3],
+    _b: Bar,
+}
+
+const FOO: Foo = Foo(4);
+const BAR: Bar = Bar { _x: 4, _y: 1, _z: 2 };
+const UGH: Ugh = Ugh { _a: [0; 3] };
+
+const SIZE_OF_FOO: usize = mem::size_of_val(&FOO);
+const SIZE_OF_BAR: usize = mem::size_of_val(&BAR);
+const SIZE_OF_UGH: usize = mem::size_of_val(&UGH);
+
+const ALIGN_OF_FOO: usize = mem::align_of_val(&FOO);
+const ALIGN_OF_BAR: usize = mem::align_of_val(&BAR);
+const ALIGN_OF_UGH: usize = mem::align_of_val(&UGH);
+
+const SIZE_OF_SLICE: usize = mem::size_of_val("foobar".as_bytes());
+
+fn main() {
+    assert_eq!(SIZE_OF_FOO, mem::size_of::<Foo>());
+    assert_eq!(SIZE_OF_BAR, mem::size_of::<Bar>());
+    assert_eq!(SIZE_OF_UGH, mem::size_of::<Ugh>());
+
+    assert_eq!(ALIGN_OF_FOO, mem::align_of::<Foo>());
+    assert_eq!(ALIGN_OF_BAR, mem::align_of::<Bar>());
+    assert_eq!(ALIGN_OF_UGH, mem::align_of::<Ugh>());
+
+    assert_eq!(SIZE_OF_SLICE, "foobar".len());
+}