acquire additional semantics as variable is examined; map them to marks

[dhh1128]

Notice in this screenshot that coverity has detected that a variable might be null, based on a test that the code did. Once that information was known, semantics in the next line were demonstrably wrong. Intent needs to ship with a set of marks that work this way, such that we can refine semantics as we examine the value of a variable. For example, if we have a line that says "if len(mystring) < 25", then inside that block, we need to add a +range(1,25) mark to mystring. This should then be passed to all called functions, instead of simply passing the range that the string started with.

[dhh1128]

Note the false positive from the attached coverity screenshot. Coverity didn't pick up that right before we call MUArrayListGet(), we resize the array so that we're guaranteed to have a valid index. A mark indicating that the size of the array was known to be x because we had just resized would have allowed us to understand that we are guaranteed to have a valid value on line 348.