From 19eaee2c329a428ba052ef30a5d51464b098e591 Mon Sep 17 00:00:00 2001
From: Gary Guo <gary@garyguo.net>
Date: Thu, 16 Sep 2021 22:49:34 +0100
Subject: [PATCH] Report heap allocation instead of non-const fn for
 exchange_malloc call

---
 .../rustc_const_eval/src/transform/check_consts/check.rs     | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/compiler/rustc_const_eval/src/transform/check_consts/check.rs b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
index 8b28c8fa219d..57d92005a564 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/check.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
@@ -913,6 +913,11 @@ impl Visitor<'tcx> for Checker<'mir, 'tcx> {
                     return;
                 }
 
+                if Some(callee) == tcx.lang_items().exchange_malloc_fn() {
+                    self.check_op(ops::HeapAllocation);
+                    return;
+                }
+
                 // `async` blocks get lowered to `std::future::from_generator(/* a closure */)`.
                 let is_async_block = Some(callee) == tcx.lang_items().from_generator_fn();
                 if is_async_block {