In `BuildUnaryOperator`, `GetOperatorOpFunction` is treated as
desugaring, but `PerformCompoundMemberAccess` and `PerformCall` are not.
This treats all of destruction as desugaring.
This leads to some instructions being elided, because of `GetOrAddInst`
behaviors:
> // If the instruction has a desugared location and a constant value,
returns
> // the constant value's instruction ID. Otherwise, same as AddInst.
This changes instructions that previously had a non-desugared location
to instead have a desugared location, so if they also have a constant
value then the constant value can be used directly.
This changes `Destroy` to use an interface for its implementation.
Note that this change includes a lot of test updates. Even when
`Destroy` is a no-op, it still causes code generation as part of
determining that.
Originally I was trying to use ranges to cut down the scope of this, and
to a degree I think they have. But a flipside here is that cases where
no destructors should be generated -- particularly globals -- would be
needed to completely remove destructor calls. Even for ranges, the range
can often include the destructor placement. So I've shifted
frame-of-thought a little: accept a bunch of destructor churn, because
destructors are needed and will be prevalent. The verbosity is a feature
of the design to make desugaring apparent in IR, not a bug.
Now that included files can specify `EXTRA-ARGS`, this uses that to
handle min_prelude files. Also moves `As`/`ImplicitAs` out to a shared
file, partly because we duplicate it a few times over, partly just to
show that it works.
Also removes the `min_prelude/` subdirectories because many of these
files were touched by autoupdate regardless. I noticed one conflict for
`impl_thunk.carbon`, so renaming that one to
`impl_thunk_min_prelude.carbon`.
`GetArgReplacements` I simply noticed was unused, so removing it.
Jon Ross-Perkins