Haskell-src-extsにおけるマイナスの扱い

マイナスはどうなってんのかなということで解析．
結果として別々である．

x = -3
y = 5 - 6

Module (SrcLoc {srcFilename = "<unknown>.hs", srcLine = 1, srcColumn = 1})
       (ModuleName "Main")
       []
       Nothing
       (Just [EVar (UnQual (Ident "main"))]) 
       [] 
       [PatBind (SrcLoc {srcFilename = "<unknown>.hs", srcLine = 1, srcColumn = 1}) 
                (PVar (Ident "x")) 
                Nothing 
                (UnGuardedRhs (NegApp (Lit (Int 3)))) 
                (BDecls []),
        PatBind (SrcLoc {srcFilename = "<unknown>.hs", srcLine = 2, srcColumn = 1}) 
                (PVar (Ident "y")) 
                Nothing 
                (UnGuardedRhs (InfixApp (Lit (Int 5)) 
                                        (QVarOp (UnQual (Symbol "-"))) 
                                        (Lit (Int 6)))) 
                (BDecls [])]