enhance: implement hasOverriddenWasMoved check and integrate semMove for handling =wasMoved calls

compiler/semmagic.nim

@@ -591,6 +591,22 @@ proc checkDefault(c: PContext, n: PNode): PNode =
   if constructed.requiresInit:
     message(c.config, n.info, warnUnsafeDefault, typeToString(constructed))
 
+proc hasOverriddenWasMoved(c: PContext; n: PNode): bool =
+  if n.len != 2 or n[1].typ == nil: return false
+  let typ = n[1].typ.skipTypes({tyAlias, tyVar, tySink})
+  let op = getAttachedOp(c.graph, typ, attachedWasMoved)
+  result = op != nil and sfOverridden in op.flags
+
+proc semMove(c: PContext; n: PNode): PNode =
+  result = n
+  if hasOverriddenWasMoved(c, n):
+    # Use the instantiated body of system.move[T] for overridden hooks so
+    # normal semantic lowering/codegen handles the =wasMoved call.
+    let callee = result[0].sym
+    ensureMutable callee
+    callee.magic = mNone
+    setOwner(callee, c.module)
+
 proc magicsAfterOverloadResolution(c: PContext, n: PNode,
                                    flags: TExprFlags; expectedType: PType = nil): PNode =
   ## This is the preferred code point to implement magics.
@@ -657,6 +673,8 @@ proc magicsAfterOverloadResolution(c: PContext, n: PNode,
       result = addDefaultFieldForNew(c, n)
   of mNewFinalize:
     result = semNewFinalize(c, n)
+  of mMove:
+    result = semMove(c, n)
   of mDestroy:
     result = replaceHookMagic(c, n, attachedDestructor)
   of mTrace: