1 files changed, 21 insertions, 0 deletions
diff --git a/tests/stdlib/concurrency/tatomics_size.nim b/tests/stdlib/concurrency/tatomics_size.nim
new file mode 100644
index 000000000..f64adb308
--- /dev/null
+++ b/tests/stdlib/concurrency/tatomics_size.nim
@@ -0,0 +1,21 @@
+discard """
+  # test C with -d:nimUseCppAtomics as well to check nothing breaks
+  matrix: "--mm:refc; --mm:orc; --mm:refc -d:nimUseCppAtomics; --mm:orc -d:nimUseCppAtomics"
+  targets: "c cpp"
+"""
+import std/atomics
+import std/assertions
+
+block testSize: # issue 12726
+  type
+    Node = ptr object
+      # works
+      next: Atomic[pointer]
+      f:AtomicFlag
+    MyChannel = object
+      # type not defined completely
+      back: Atomic[ptr int]
+      f: AtomicFlag
+  static:
+    doAssert sizeof(Node) == sizeof(pointer)
+    doAssert sizeof(MyChannel) == sizeof(pointer) * 2