closes #23394; adds a test case (#25416)

closes #23394

tests/arc/tgenerics.nim

@@ -0,0 +1,19 @@
+discard """
+  matrix: "--mm:refc"
+"""
+type
+  State = enum
+    Uninit
+    Init
+  Uart[T: static State] = object
+    baudRate: int
+    port: int
+
+proc `=destroy`(uart: var Uart[Init]) = raiseAssert "Destroyed"
+
+# proc `=copy`(a: var Uart[Init], b: Uart[Init]) {.error.} # Error: signature for '=copy' must be proc[T: object](x: var T; y: T)
+
+proc main() =
+  var a = Uart[Uninit]()
+
+main()