2 tcfail016.hs:9: Couldn't match the type
3 `PrelTup.(,) taRi' against `Expr'
5 Inferred: `AnnExpr taRi'
6 In the first argument of `g', namely `e1'
7 In the first argument of `PrelBase.++', namely `(g e1)'
8 In an equation for function `g':
9 `g (App e1 e2) = (g e1) PrelBase.++ (g e2)'
12 Compilation had errors