Document about some behaviors of `const_(de)allocate` and add some tests.

2 files changed, 33 insertions, 0 deletions

diff --git a/src/test/ui/consts/const-eval/heap/alloc_intrinsic_zero_sized.rs b/src/test/ui/consts/const-eval/heap/alloc_intrinsic_zero_sized.rs
new file mode 100644
index 00000000000..407e69d41a0
--- /dev/null
+++ b/src/test/ui/consts/const-eval/heap/alloc_intrinsic_zero_sized.rs
@@ -0,0 +1,16 @@
+// run-pass
+#![feature(core_intrinsics)]
+#![feature(const_heap)]
+#![feature(inline_const)]
+
+use std::intrinsics;
+
+struct ZST;
+
+fn main() {
+    const {
+        unsafe {
+            let _ = intrinsics::const_allocate(0, 0) as *mut ZST;
+        }
+    }
+}
diff --git a/src/test/ui/consts/const-eval/heap/dealloc_intrinsic_zero_sized.rs b/src/test/ui/consts/const-eval/heap/dealloc_intrinsic_zero_sized.rs
new file mode 100644
index 00000000000..84fb4d2ea87
--- /dev/null
+++ b/src/test/ui/consts/const-eval/heap/dealloc_intrinsic_zero_sized.rs
@@ -0,0 +1,17 @@
+// run-pass
+#![feature(core_intrinsics)]
+#![feature(const_heap)]
+#![feature(inline_const)]
+
+use std::intrinsics;
+
+fn main() {
+    const {
+        unsafe {
+            let ptr1 = intrinsics::const_allocate(0, 0);
+            let ptr2 = intrinsics::const_allocate(0, 0);
+            intrinsics::const_deallocate(ptr1, 0, 0);
+            intrinsics::const_deallocate(ptr2, 0, 0);
+        }
+    }
+}