don't crash language server if suggest_contracts fails

Author: lukaszsamson

apps/language_server/lib/language_server/dialyzer.ex

@@ -82,7 +82,16 @@ defmodule ElixirLS.LanguageServer.Dialyzer do
   def suggest_contracts(_server, []), do: []
 
   def suggest_contracts(server, files) do
-    GenServer.call(server, {:suggest_contracts, files}, :infinity)
+    try do
+      GenServer.call(server, {:suggest_contracts, files}, :infinity)
+    catch
+      kind, payload ->
+        {payload, stacktrace} = Exception.blame(kind, payload, __STACKTRACE__)
+        error_msg = Exception.format(kind, payload, stacktrace)
+
+        Logger.error("Unable to suggest contracts: #{error_msg}")
+        []
+    end
   end
 
   # Server callbacks

apps/language_server/lib/language_server/dialyzer/manifest.ex

@@ -32,7 +32,7 @@ defmodule ElixirLS.LanguageServer.Dialyzer.Manifest do
 
           JsonRpc.show_message(
             :error,
-            "Unable to build dialyzer PLT. Most likely there are problems with your OTP and elixir installation."
+            "Unable to build dialyzer PLT. Please make sure that #{elixir_plt_path()} is writable and your OTP install is complete. Visit https://github.com/elixir-lsp/elixir-ls/issues/540 for help"
           )
 
           Logger.error("Dialyzer PLT build process exited with reason: #{error_msg}")