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Re: [Patch] Java: Definite [Un]Assignment Issues

Ranjit Mathew wrote:

The first three - 16.2.{9,10,11}-definite-unassign-pass-3 - existed before
my patch and represent our decision to simplify the handling of loops w.r.t.
definite [un]assignment. See the comment for the "case LOOP_EXPR" in
check_init() in java/check-init.c for reference. Unless we want to change
that decision, I recommend that we simply mark these as expected "failures".

I have no objection to "changing that decision", I just didn't think getting this working was a priority. I obviously would prefer that we have it 100% correct. I also prefer an implementation that is both reasonably fast and reasonably simple.

I think implementing tests like the following need not be very
  Assuming V is definitely unassigned before e, V is definitely
  unassigned after S.
Basically, you run the check_init an extra time, but with the variables
unassigned.  This is the "Assuming V is definitely unassigned" part.
You then intersect that result with the existing tests.  Complications
are suppressing spurious errors during the auxiliary test, plus handling
continue statements.  (Of course I haven't looked at this stuff in a
while, so I may be off track.)

a. Surprisingly for me, we were not at all marking "blank final" local
   variables that represent the entities for which the whole "definite
   unassignment" brouhaha in JLS 2 Chapter 16 is about!

   I define DECL_LOCAL_FINAL_IUD in java-tree.h that is similar to - in fact
   the same as - DECL_FIELD_FINAL_IUD, that I use to mark final
   local variables that are initialised in their declaration. This is
   being done in declare_local_variables() in parse.y in my patch.

Why? My quick and dirty tests seem to show that: final int x = 10; and final int x; x = 10; are handled the same way and both give the errors I'd expect.

Which testcase is wrong before your patch and correct after?

I'll get back to you on the check_bool_init patch.
	--Per Bothner

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