dhall-toml: Fix loading of relative paths

Fixes #2606

dhall-toml/dhall-toml.cabal

@@ -36,6 +36,7 @@ Library
     Build-Depends:
         base                 >= 4.12     && < 5    ,
         dhall                >= 1.39.0   && < 1.43 ,
+        filepath                            < 1.6  ,
         tomland              >= 1.3.2.0  && < 1.4  ,
         text                 >= 0.11.1.0 && < 2.2  ,
         containers           >= 0.5.9    && < 0.8  ,

dhall-toml/src/Dhall/Toml/Utils.hs

@@ -10,13 +10,15 @@ module Dhall.Toml.Utils
 
 import Data.Text    (Text)
 import Data.Void    (Void)
+import Dhall.Import (SemanticCacheMode(..))
 import Dhall.Parser (Src)
 
 import qualified Data.Text.IO    as Text.IO
 import qualified Dhall.Core      as Core
 import qualified Dhall.Import
 import qualified Dhall.Parser
 import qualified Dhall.TypeCheck
+import qualified System.FilePath as FilePath
 
 -- | Read the file fileName and return the normalized Dhall AST
 fileToDhall :: String -> IO (Core.Expr Src Void)
@@ -35,9 +37,15 @@ inputToDhall = do
 --   by the parser for generating error messages.
 textToDhall :: String -> Text -> IO (Core.Expr Src Void)
 textToDhall fileName text = do
-    parsedExpression <-
+    parsedExpression <- do
         Core.throws (Dhall.Parser.exprFromText fileName text)
-    resolvedExpression <- Dhall.Import.load parsedExpression
+
+    let directory = FilePath.takeDirectory fileName
+
+    resolvedExpression <- do
+        Dhall.Import.loadRelativeTo directory UseSemanticCache parsedExpression
+
     _ <- Core.throws (Dhall.TypeCheck.typeOf resolvedExpression)
+
     return resolvedExpression