llvm::function_ref (like std::unique_ptr, for instance) already has a
null/empty state, so use that to avoid confusion/duplication of empty
states between optional and the nested function_refs.
Add these interfaces to the core library. For now, they're two separate
interfaces because we don't yet support one interface extending another.
This collapses a lot of the layering in check: for example, the call
building logic depends on implicit conversions, conversions now depend
on the overloaded operator machinery, and that machinery depends on
building calls.
In passing, improve the diagnostics for failing to find a name required
from the prelude. Also convert all the transitively-called code from
`NodeId` to `LocId` given the latter is what the conversion machinery
has available.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Support is added for all overloaded operator interfaces in the current
design apart from `Assign`, which is going to require some more work to
properly handle, given that primitive assignment currently has a special
implementation for quite a few builtin types.
As we don't have support for generics yet -- in particular, generic
interfaces -- there is no support for `*With` interfaces, but homogenous
interfaces such as `Add` are supported instead.
Factor out building of call expressions so that overloaded operators can
generate calls.
Switch a few places from using specific kinds of NodeId to a general
NodeId. Because overloaded operators and other things like implicit
conversions can result in member access and function calls, those
operations can't require a specific kind of NodeId.
Add import support for associated entities, and fix import support for
interfaces and symbolic bindings. We now import interfaces in two steps,
first importing a forward declaration then a definition, just like we do
for classes. For symbolic bindings, we ensure that each BindSymbolicName
is imported only once, because its ID is used as its symbolic identity.
This is necessary because we (only) support operator interfaces that are
defined in an imported Carbon package for now.
The entire contents of `check/operator.cpp` should probably be
rethought. In particular, doing a lot of name lookups on each operator
is likely to be bad for performance. But this gets us to the point where
overloaded operators are basically working, which seems like a good
place to iterate from.
For now, the tests that the individual operators map to the right
interfaces are mostly generated by a script, but that's just because I'm
expecting a fair bit of churn in how we define the prelude and the
`impl`s -- in particular, when we add support for `AddWith`, we'll need
to update all the tests. The plan is to remove the script once things
settle down.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
David Blaikie
Richard SmithandJon Ross-Perkins
