Read "A Theory of Type Qualifiers" and "Practical Pluggable Types for Java", and then
answer the following reading questions:

1. Choose two rules from Figure 4b of "A Theory of Type Qualifiers". The set of rules you
choose must not be {"Var", "Int"}. Give the name of each chosen rule and then explain the
rule in English. Your explanation should make clear the difference between this rule and
a rule for a similar language lacking type qualifiers.

2. Consider rule "Unsound" on page 196 of "A Theory of Type Qualifiers". The authors claim
that this rule is both "obvious" and "unsound". In a sentence each, explain why they claim
these adjectives describe this rule.

3. What is the primary research contribution of the paper "Practical Pluggable Types for Java"?

4. It took multiple submissions for "Practical Pluggable Types for Java" to be published; it
also won the "Test of Time" award at ISSTA 2018, ten years after publication. Why do you think
the paper was both difficult to publish and was extremely influential over the following ten
years? You might use your answer to question 3 as part of your answer.

5. What was the most confusing part of the reading? Is there anything you still don't understand?

6. How much time did you spend on this assignment (both the reading and answering the questions, combined)?