[core.atomic] atomicStore for alias this

src/core/atomic.d

@@ -110,13 +110,23 @@ TailShared!T atomicLoad(MemoryOrder ms = MemoryOrder.seq, T)(ref shared const T
  *  newval = The value to store.
  */
 void atomicStore(MemoryOrder ms = MemoryOrder.seq, T, V)(ref T val, V newval) pure nothrow @nogc @trusted
-    if (!is(T == shared) && !is(V == shared))
+    if (!is(T == shared) && !is(V == shared) && is(T : V))
 {
     import core.internal.traits : hasElaborateCopyConstructor;
     static assert (!hasElaborateCopyConstructor!T, "`T` may not have an elaborate copy: atomic operations override regular copying semantics.");
 
     // resolve implicit conversions
-    T arg = newval;
+    import core.internal.traits : Unqual;
+    static if (is(Unqual!T == Unqual!V))
+    {
+        alias arg = newval;
+    }
+    else
+    {
+        // don't construct directly from `newval`, assign instead (`alias this` etc.)
+        T arg;
+        arg = newval;
+    }
 
     static if (__traits(isFloating, T))
     {
@@ -1194,4 +1204,16 @@ version (CoreUnittest)
         shared NoIndirections n;
         static assert(is(typeof(atomicLoad(n)) == NoIndirections));
     }
+
+    unittest
+    {
+        static struct S
+        {
+            int a;
+            alias a this;
+        }
+
+        S s;
+        atomicStore(s, 123);
+    }
 }