If you look at the type of labelNew GlibString string => Maybe string -> IO Label If you look at the instances for GlibString, they could be Text or [Char]. You have to decide which. The fact that you are using Nothing does not tell you the entire final type. It could be Maybe [Char], or Maybe Text. Even though the choice seems arbitrary in this instance, you have to decide which it is. So try this. lprog <- G.labelNew (Nothing :: Maybe [Char]) On Fri, Jun 23, 2017 at 3:22 AM, Agustin Larreinegabe wrote:

Hello, I'm trying to install an application Termite - Debug but I get this error in line 929:14

when it try to do this

lprog <- G.labelNew Nothing

The error says:

Could not deduce (glib-0.13.4.1:System.Glib.UTFString.GlibString string0) arising from a use of ‘G.labelNew’ from the context (D.Rel c v a s) bound by the type signature for sourceWindowCreate :: D.Rel c v a s => RSourceView c a u -> IO G.Widget at Debug/SourceView.hs:913:23-73 instance glib-0.13.4.1:System.Glib.UTFString.GlibString [Char] -- Defined in ‘glib-0.13.4.1:System.Glib.UTFString’ In a stmt of a 'do' block: lprog <- G.labelNew Nothing In the expression: do { vbox <- G.vBoxNew False 0; G.widgetShow vbox; spec <- getIORef svInputSpec ref; code <- codeWinNew spec; .... } In an equation for ‘sourceWindowCreate’: sourceWindowCreate ref = do { vbox <- G.vBoxNew False 0; G.widgetShow vbox; spec <- getIORef svInputSpec ref; cabal: Error: some packages failed to install:

I really don't know how to proceed, I'm new with Haskell

Thanks in advance.

----------------- Agustin Larreinegabe

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