Allow for API to throw exceptions

Moves the validation of tokens to be inside of LoginInternalAsync, and writes a Warning to the console when the supplied tokens are invalid

src/Discord.Net.Rest/BaseDiscordClient.cs

@@ -52,19 +52,14 @@ namespace Discord.Rest
         /// <inheritdoc />
         public async Task LoginAsync(TokenType tokenType, string token, bool validateToken = true)
         {
-            // If token validation is enabled, validate the token and let it throw any ArgumentExceptions
-            // that result from invalid parameters
-            if (validateToken)
-                TokenUtils.ValidateToken(tokenType, token);
-
             await _stateLock.WaitAsync().ConfigureAwait(false);
             try
             {
-                await LoginInternalAsync(tokenType, token).ConfigureAwait(false);
+                await LoginInternalAsync(tokenType, token, validateToken).ConfigureAwait(false);
             }
             finally { _stateLock.Release(); }
         }
-        private async Task LoginInternalAsync(TokenType tokenType, string token)
+        private async Task LoginInternalAsync(TokenType tokenType, string token, bool validateToken)
         {
             if (_isFirstLogin)
             {
@@ -78,6 +73,21 @@ namespace Discord.Rest
 
             try
             {
+                // If token validation is enabled, validate the token and let it throw any ArgumentExceptions
+                // that result from invalid parameters
+                if (validateToken)
+                {
+                    try
+                    {
+                        TokenUtils.ValidateToken(tokenType, token);
+                    }
+                    catch (ArgumentException ex)
+                    {
+                        // log these ArgumentExceptions and allow for the client to attempt to log in anyways
+                        await LogManager.WarningAsync("Discord", "A supplied token was invalid", ex).ConfigureAwait(false);
+                    }
+                }
+
                 await ApiClient.LoginAsync(tokenType, token).ConfigureAwait(false);
                 await OnLoginAsync(tokenType, token).ConfigureAwait(false);
                 LoginState = LoginState.LoggedIn;