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Lazy accessors have the same essential problem as described in
recent commit messages, so this still doesn't work:
def f() = { case class Bob(); Bob } ; lazy val g = f
On the whole I'm trying to solve this at the wrong level. The derived
accessor methods and fields of a declaration should not ever wander far
enough apart that there is any challenge in reconciling them. (The same
is true for case classes/objects.) They're dependent synthetics who know
about one another from the beginning, all we have to do is not forget.
In the meantime, test case.
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There is a window of danger when multiple related elements are
being typed where something which is conceptually one thing can
slip into two things, and those two things can be incompatible
with one another. Less mysteriously, c478eb770d fixed this:
def f = { object Bob ; Bob } ; val g = f
But, it did not fix this:
def f = { case class Bob() ; Bob } ; val g = f
See test case pos/existentials-harmful.scala for an "in the wild"
code example fixed by this commit.
The root of the problem was that the getter and the field would each
independently derive the same existential type to describe Bob, but
those existentials were not the same as one another.
This has been the most elusive bug I have ever fixed. I want to cry when
I think of how much time I've put into it over the past half decade or
so. Unfortunately the way the repl works it is particularly good at
eliciting those grotesque found/required error messages and so I was
never able to let the thing go.
There is still a cosmetic issue (from the last commit really) where
compound types wind up with repeated parents.
Closes SI-1195, SI-1201.
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