Async drop fix for async_drop_in_place<T> layout calculated for unspecified T

Author: azhogin

compiler/rustc_mir_transform/src/dataflow_const_prop.rs

@@ -811,6 +811,9 @@ impl<'a, 'tcx> Collector<'a, 'tcx> {
         map: &Map<'tcx>,
     ) -> Option<Const<'tcx>> {
         let ty = place.ty(self.local_decls, self.patch.tcx).ty;
+        if ty.is_async_drop_in_place_coroutine(self.patch.tcx) {
+            return None;
+        }
         let layout = ecx.layout_of(ty).ok()?;
 
         if layout.is_zst() {

tests/ui/async-await/async-drop/open-drop-error.rs

@@ -0,0 +1,21 @@
+//@ compile-flags: -Zmir-enable-passes=+DataflowConstProp
+//@ edition: 2021
+//@ build-pass
+#![feature(async_drop)]
+#![allow(incomplete_features)]
+
+use std::mem::ManuallyDrop;
+use std::{
+    future::async_drop_in_place,
+    pin::{pin, Pin},
+};
+fn main() {
+    a(b)
+}
+fn b() {}
+fn a<C>(d: C) {
+    let e = pin!(ManuallyDrop::new(d));
+    let f = unsafe { Pin::map_unchecked_mut(e, |g| &mut **g) };
+    let h = unsafe { async_drop_in_place(f.get_unchecked_mut()) };
+    h;
+}