tl types: do not crash if given input file doesn't exist

spec/cli/types_spec.lua

@@ -4,6 +4,13 @@ local util = require("spec.util")
 
 describe("tl types works like check", function()
    describe("on .tl files", function()
+      it("reports missing files", function()
+         local pd = io.popen(util.tl_cmd("types", "nonexistent_file") .. "2>&1 1>" .. util.os_null, "r")
+         local output = pd:read("*a")
+         util.assert_popen_close(1, pd:close())
+         assert.match("could not open nonexistent_file", output, 1, true)
+      end)
+
       it("works on empty files", function()
          local name = util.write_tmp_file(finally, [[]])
          local pd = io.popen(util.tl_cmd("types", name) .. " 2>" .. util.os_null, "r")

tl

@@ -897,15 +897,23 @@ do
       env.report_types = true
 
       for i, input_file in ipairs(args["file"]) do
-         local pok, err = pcall(process_module, input_file, env)
+         local pok, perr, err = pcall(process_module, input_file, env)
          if not pok then
-            die("Internal Compiler Error: " .. err)
+            die("Internal Compiler Error: " .. perr)
          end
+         if err then
+            printerr(err)
+         end
+
          check_collect(i)
       end
 
       local ok, _, _, w = report_all_errors(tlconfig, env)
 
+      if not env.reporter then
+         os.exit(1)
+      end
+
       local tr = env.reporter:get_report()
       if tr then
          if w or not ok then