Closed Unassigned: Specialized predicates should include mutually recursive predicates [170]

Dafny performs some rewrites in an `inductive lemma` and in a `colemma`. This bug report pertains to the rewrite that is being done with the "focus predicates" (aka "specialized predicates") of the `inductive lemma` or `colemma`. A focus predicate for an `inductive lemma` is an `inductive predicate` that occurs in the lemma's precondition; a focus predicate for a `colemma` is a `copredicate` that occurs in the lemma's postcondition. If an inductive/co-lemma is specialized for an inductive/co-predicate `P`, then in the body of the lemma, Dafny will rewrite calls to `P` into calls to `P#[_k-1]`.

The bug is that if `P` is found to be a focus predicate, then all other inductive/co-predicates in `P`'s strongly connected component (that is, all inductive/co-predicates that are mutually recursive with `P`) should also be included as focus predicates.

I imagine that the code currently does something like:

* Find the set S of focus predicates in the lemma's pre- or postcondition.
* NEW STEP TO FIX THE BUG: For every inductive/co-predicate `P` in S, add to S all inductive/co-predicates in the same strongly connected component (in the call graph) as `P`
* Add a hover text to the lemma, saying "specialized for ...members of S..."
* Do the rewrite in the body of the lemma

I imagine that three of these steps are already done (probably in the order I described), but the "NEW STEP" needs to be implemented. Once that step is implemented, I think the hover text and the rewriting should not need any further change.

In the test examples I'm including below, there are currently four places where verification errors occur. I expect that fixing the bug in the way I just described will cause everything to verify in this test file. (I don't know if the bug fix perhaps causes other things to break in the test suite; if so, let's talk if there's any confusion.) Optionally, the .expect file for this new test file could turn on `/printTooltips`, so that the test also shows the "specialized for ..." text.

Thanks,
Rustan

```
module InductiveThings {
predicate P(x: int)
predicate Q(x: int)

inductive predicate A(x: int)
{
P(x) || B(x+1)
}

inductive predicate B(x: int)
{
Q(x) || A(x+1)
}

inductive lemma AA(x: int) // should be specialized not just for A, but also for B, which is in the same strongly connected component as A in the call graph
requires A(x)
{
if B(x+1) { // this one should be replaced by B#[_k-1](x+1)
BB(x+1);
}
}

inductive lemma BB(x: int) // should be specialized not just for B, but also for A, which is in the same strongly connected component as B in the call graph
requires B(x)
{
if A(x+1) { // this one should be replaced by A#[_k-1](x+1)
AA(x+1);
}
}
}

module CoThings {
copredicate A(x: int)
{
B(x+1)
}

copredicate B(x: int)
{
A(x+1)
}

colemma AA(x: int) // should be specialized not just for A, but also for B, which is in the same strongly connected component as A in the call graph
ensures A(x)
{
BB(x+1);
assert B(x+1); // this one should be replaced by B#[_k-1] (which will happen, provided that AA is listed as also being specialized for B)
}

colemma BB(x: int) // should be specialized not just for B, but also for A, which is in the same strongly connected component as B in the call graph
ensures B(x)
{
AA(x+1);
assert A(x+1); // this one should be replaced by A#[_k-1] (which will happen, provided that BB is listed as also being specialized for A)
}
}
```