What version are you running?
3.0.5
What's the URL of the page containing the problem?
https://reviewboard/r/12256/#comment19826
What steps will reproduce the problem?

Create a review request with this patch
Let a review bot create an issue for that line
Show diff fragments

I cannot see the line number of the issue. Maybe the review bot added a line number that cannot be displayed in diff fragment???
What is the expected output? What do you see instead?
There was an error displaying this diff. 
Traceback (most recent call last):

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/reviewboard/reviews/views.py", line 381, in build_diff_comment_fragments

    first_line = max(1, comment.first_line - lines_of_context[0])

TypeError: unsupported operand type(s) for -: 'NoneType' and 'int'
What operating system are you using? What browser?
Linux, Firefox
Please provide any additional information below.
diff --git a/app/src/test/java/com/companyname/instantbankshowcase/ExampleUnitTest.java b/app/src/test/java/com/companyname/demobank/ExampleUnitTest.java

rename from app/src/test/java/com/companyname/instantbankshowcase/ExampleUnitTest.java

rename to app/src/test/java/com/companyname/demobank/ExampleUnitTest.java

--- a/app/src/test/java/com/companyname/instantbankshowcase/ExampleUnitTest.java

+++ b/app/src/test/java/com/companyname/demobank/ExampleUnitTest.java

@@ -1,4 +1,4 @@

-package com.companyname.instantbankshowcase;

+package com.companyname.demobank;
import org.junit.Test;