diff --git a/libcxx/test/std/experimental/memory/memory.resource.global/new_delete_resource.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.global/new_delete_resource.pass.cpp
--- a/libcxx/test/std/experimental/memory/memory.resource.global/new_delete_resource.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.global/new_delete_resource.pass.cpp
@@ -26,13 +26,13 @@
 {
 protected:
     virtual void * do_allocate(size_t, size_t)
-    { assert(false); }
+    { assert(false); return nullptr; }
 
     virtual void do_deallocate(void *, size_t, size_t)
     { assert(false); }
 
     virtual bool do_is_equal(ex::memory_resource const &) const noexcept
-    { assert(false); }
+    { assert(false); return false; }
 };
 
 void test_return()
diff --git a/libcxx/test/std/experimental/memory/memory.resource.global/null_memory_resource.pass.cpp b/libcxx/test/std/experimental/memory/memory.resource.global/null_memory_resource.pass.cpp
--- a/libcxx/test/std/experimental/memory/memory.resource.global/null_memory_resource.pass.cpp
+++ b/libcxx/test/std/experimental/memory/memory.resource.global/null_memory_resource.pass.cpp
@@ -26,13 +26,13 @@
 {
 protected:
     virtual void * do_allocate(size_t, size_t)
-    { assert(false); }
+    { assert(false); return nullptr; }
 
     virtual void do_deallocate(void *, size_t, size_t)
     { assert(false); }
 
     virtual bool do_is_equal(ex::memory_resource const &) const noexcept
-    { assert(false); }
+    { assert(false); return false; }
 };
 
 void test_return()