Auto merge of #31307 - nagisa:mir-drop-terminator, r=nikomatsakis

The scope of these refactorings is a little bit bigger than the title implies. See each commit for details.

I’m submitting this for nitpicking now (the first 4 commits), because I feel the basic idea/implementation is sound and should work. I will eventually expand this PR to cover the translator changes necessary for all this to work (+ tests), ~~and perhaps implement a dynamic dropping scheme while I’m at it as well.~~

r? @nikomatsakis

1 files changed, 6 insertions, 0 deletions

diff --git a/src/doc/book/lang-items.md b/src/doc/book/lang-items.md
index e492bd3e782..b948567ac5b 100644
--- a/src/doc/book/lang-items.md
+++ b/src/doc/book/lang-items.md
@@ -39,11 +39,17 @@ unsafe fn allocate(size: usize, _align: usize) -> *mut u8 {
 
     p
 }
+
 #[lang = "exchange_free"]
 unsafe fn deallocate(ptr: *mut u8, _size: usize, _align: usize) {
     libc::free(ptr as *mut libc::c_void)
 }
 
+#[lang = "box_free"]
+unsafe fn box_free<T>(ptr: *mut T) {
+    deallocate(ptr as *mut u8, ::core::mem::size_of::<T>(), ::core::mem::align_of::<T>());
+}
+
 #[start]
 fn main(argc: isize, argv: *const *const u8) -> isize {
     let x = box 1;