Remove reloaded modules from the cache

Loading modules explicitly that were already loaded would cause the previous,
cached module to be kept, and the new checked one to be thrown away.

src/Cryptol/ModuleSystem.hs

@@ -53,6 +53,9 @@ findModule n env = runModuleM env (Base.findModule n)
 -- | Load the module contained in the given file.
 loadModuleByPath :: FilePath -> ModuleCmd T.Module
 loadModuleByPath path env = runModuleM (resetModuleEnv env) $ do
+  -- unload the module if it already exists
+  unloadModule path
+
   m <- Base.loadModuleByPath path
   setFocusedModule (T.mName m)
   return m
@@ -60,6 +63,9 @@ loadModuleByPath path env = runModuleM (resetModuleEnv env) $ do
 -- | Load the given parsed module.
 loadModule :: FilePath -> P.Module -> ModuleCmd T.Module
 loadModule path m env = runModuleM env $ do
+  -- unload the module if it already exists
+  unloadModule path
+
   let n = P.thing (P.mName m)
   m' <- loadingModule n (Base.loadModule path m)
   setFocusedModule (T.mName m')

src/Cryptol/ModuleSystem/Env.hs

@@ -163,6 +163,16 @@ addLoadedModule path tm lm
     , lmModule    = tm
     }
 
+removeLoadedModule :: FilePath -> LoadedModules -> LoadedModules
+removeLoadedModule path (LoadedModules ms) = LoadedModules (remove ms)
+  where
+
+  remove (lm:rest)
+    | lmFilePath lm == path = rest
+    | otherwise             = lm : remove rest
+
+  remove [] = []
+
 -- Dynamic Environments --------------------------------------------------------
 
 -- | Extra information we need to carry around to dynamically extend

src/Cryptol/ModuleSystem/Monad.hs

@@ -321,6 +321,12 @@ setNameSeeds seeds = ModuleT $ do
   env <- get
   set $! env { meNameSeeds = seeds }
 
+-- | Remove a module from the set of loaded module, by its path.
+unloadModule :: FilePath -> ModuleM ()
+unloadModule path = ModuleT $ do
+  env <- get
+  set $! env { meLoadedModules = removeLoadedModule path (meLoadedModules env) }
+
 loadedModule :: FilePath -> T.Module -> ModuleM ()
 loadedModule path m = ModuleT $ do
   env <- get