Skip to content
Snippets Groups Projects

TemplateHaskell - variables in top level splices and loading modules.

    • Open Issue created by mkloczko @trac-mkloczko

    The following code fails when loading Main module:

    {-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE ScopedTypeVariables #-}

module TH where

import Language.Haskell.TH
import Language.Haskell.TH.Syntax
import Data.Typeable


usingType :: a -> Q [Dec]
usingType _ = do
    let name = "The name!"
    -- theF = "The name!"
    return [FunD (mkName "theF") [Clause [] (NormalB $ LitE $ StringL name )  []]]
    {-# LANGUAGE TemplateHaskell #-}

module Main where
import TH 

data A = A Int

-- Runs with `usingType (undefined :: A)` instead
$(usingType (A 3) )


main = putStrLn $ theF

    The error:

    $ ghc --make Main.hs
[1 of 2] Compiling TH               ( TH.hs, TH.o )
[2 of 2] Compiling Main             ( Main.hs, Main.o )
attempting to use module ‘Main’ (Main.hs) which is not loaded
    Trac metadata
    Trac field Value
    Version 8.0.1
    Type Bug
    TypeOfFailure OtherFailure
    Priority normal
    Resolution Unresolved
    Component Compiler
    Test case
    Differential revisions
    BlockedBy
    Related
    Blocking
    CC
    Operating system
    Architecture
    To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information

    Child items 0

    • No child items are currently assigned. Use child items to break down this issue into smaller parts.

    Activity

    Please register or sign in to reply