Have these two files in a directory:

Main.hs:

{-# LANGUAGE TemplateHaskell #-}
module Main where
import Helper

main = return ()

test

Helper.hs:

{-# LANGUAGE TemplateHaskell #-}
module Helper where
import Language.Haskell.TH

test :: Q [Dec]
test = return []

If compiled with ghc Main.hs, the compilation freezes, when it reaches Main.

This compiles without problems on Linux (Ubuntu 18) using GHC 8.6.3, and there is no problem in GHC 8.4.3 on either Windows or Linux.

GCC version: 8.2.0 Rev3 (from MSYS2) / 7.2.0 Rev1 (from cmd.exe)

Adding -dcore-lint does not change the outcome.