# nim c button.nim
import gintro/[gtk, glib, gobject]
import gintro/gio except Application, newApplication

proc buttonClicked (button: Button) =
  button.label = utf8Strreverse(button.label, -1)

proc activate (app: Application) =
  let window = newApplicationWindow(app)
  window.title = "GNOME Button"
  window.defaultSize = (250, 50)
  let button = newButton("Click Me")
  window.add(button)
  button.connect("clicked",  buttonClicked)
  window.showAll

proc main =
  let app = newApplication("org.gtk.example")
  connect(app, "activate", activate) # with connect(app, "activate", MODULENAME.activate) it compiles fine
  discard app.run

main()

$ nim c button.nim

button.nim(19, 10) Error: type mismatch: got (Application, string, proc (app: Application){.gcsafe, locks: <unknown>.} | proc (self: CellAccessibleParent, cell: CellAccessible){.noSideEffect, gcsafe, locks: 0.} | proc (self: AccelGroup, accelQuark: int, acceleratable: Object, accelKey: int, accelMods: ModifierType): bool{.noSideEffect, gcsafe, locks: 0.} | proc (self: MenuItem){.noSideEffect, gcsafe, locks: 0.} | proc (self: CellArea, context: CellAreaContext, widget: Widget, cellArea: Rectangle, flags: CellRendererState, editOnly: bool): bool{.noSideEffect, gcsafe, locks: 0.} | proc (self: Action){.noSideEffect, gcsafe, locks: 0.} | proc (self: Widget): bool{.noSideEffect, gcsafe, locks: 0.} | proc (self: CellRenderer, event: Event, widget: Widget, path: string, backgroundArea: Rectangle, cellArea: Rectangle, flags: CellRendererState): bool{.noSideEffect, gcsafe, locks: 0.} | proc (self: GApplication){.noSideEffect, gcsafe, locks: 0.} | proc (self: Action, parameter: Variant){.noSideEffect, gcsafe, locks: 0.})
but expected one of: 
template connect(widget: gobject.Object; signal: string; p: typed): untyped
template connect(widget: gobject.Object; signal: string; p: typed; arg: typed): untyped
proc connect(self: AccelGroup; accelKey: int; accelMods: gdk.ModifierType;
            accelFlags: AccelFlags; closure: gobject.Closure)
proc connect(self: SocketClient; connectable: SocketConnectable | InetSocketAddress |
    NetworkAddress | NetworkService | ProxyAddress | UnixSocketAddress | SocketAddress;
            cancellable: Cancellable = nil): SocketConnection
proc connect(self: SocketConnection; address: SocketAddress;
            cancellable: Cancellable = nil): bool
proc connect(self: Socket; address: SocketAddress; cancellable: Cancellable = nil): bool
proc connect(self: Cancellable; callback: Callback; data: pointer;
            dataDestroyFunc: DestroyNotify): uint64
proc connect(self: Proxy; connection: IOStream; proxyAddress: ProxyAddress;
            cancellable: Cancellable = nil): IOStream