Convert verification errors into diagnostics, closes #14768

Author: josevalim

lib/elixir/lib/module/parallel_checker.ex

@@ -283,7 +283,21 @@ defmodule Module.ParallelChecker do
       |> emit_warnings(file, log?)
 
     Enum.each(after_verify, fn {verify_mod, verify_fun} ->
-      apply(verify_mod, verify_fun, [module])
+      try do
+        apply(verify_mod, verify_fun, [module])
+      catch
+        # We need to catch exceptions because files have already been written to disk,
+        # so we need to convert verification errors into diagnostics by using IO.warn.
+        kind, reason ->
+          IO.warn(
+            "exception happened while verifying module #{inspect(module)}\n\n" <>
+              Exception.format(kind, reason, __STACKTRACE__),
+            file: file,
+            line: line,
+            module: verify_mod,
+            function: {verify_fun, 1}
+          )
+      end
     end)
 
     diagnostics

lib/elixir/test/elixir/module/types/integration_test.exs

@@ -1296,6 +1296,27 @@ defmodule Module.Types.IntegrationTest do
 
       assert_warnings(files, warning)
     end
+
+    test "converts errors into diagnostics" do
+      files = %{
+        "a.ex" => """
+        defmodule A do
+          @after_verify __MODULE__
+
+          def __after_verify__(__MODULE__) do
+            raise "oops"
+          end
+        end
+        """
+      }
+
+      warning = [
+        "warning: exception happened while verifying module A",
+        "** (RuntimeError) oops"
+      ]
+
+      assert_warnings(files, warning)
+    end
   end
 
   describe "deprecated" do