Also make minor updates to the skeletal design in
docs/design/name_lookup.md following #2113, as there are no longer any prelude names that are made available to unqualified name lookup by default.
Add `type` to the keyword list in
docs/design/lexical_conventions/words.md, following #2360.
Features:
* Add basic support for `impl` virtual methods (override virtual method)
* Error on invalid declaration for `impl` and `virtual`, covering simple use cases
* Add `abstract` fn parser-only support
Changes:
* Modify parser to handle new function specifiers, resolve conflicts
* Group `virtual_override` and `FN`, and group `impl_kind` and `IMPL` to avoid ambiguities with around `impl` token parsing
* Add new `VirtualOverride` enum for function declarations, and matching `virt_override() -> VirtualOverride` getter
* Update function declaration logic
Depends on #2462
Features:
* Add `virtual` virtual override keyword for functions
* Support `virtual` class methods using dynamic dispatch
Changes:
* Add `vtable` in `NominalClassType`,
* Add `NominalClassValue**` in class values pointing to descendant-most class
* Resolve virtual methods during member lookup
Limitations:
* Does not include yet `impl`, `abstract` virtual override keywords, or the complete logic for virtual function declaration
Depends on #2460
Relates to #1881
Relates to #2493
Adds a simple script to merge stdout/stderr and put on labels. This is hidden to the RUN line using lit.cfg.py.
This is my solution to addressing how errors printed by the toolchain break sorting of stdout output; just put stdout first. We could also have toggles for interleaving output or such, which might help test whether we do it properly.
This also moves some previous-distributed replacement logic into lit_autoupdate_base.py: I think having that adjacent to lit.cfg.py is probably the better choice, and it reduces duplication in toolchain scripts. It happens here because I need to change the resulting commands to include the merge.
On #2224 @zygoloid pointed out we needed --implicit-check-not to ensure we were correctly matching output. This is the standard way we're writing explorer tests, so I was looking at unifying our lit approaches.
This is one take on it, making more use of substitutions to bring various testing into alignment, as well as symlinks to avoid config skew (maybe I'll eventually figure out a better solution than symlinks).
Makes a couple small fixes in explorer to remove end-of-line whitespace on output.
The syntax permitted in an `interface` is similar to, but different from, that permitted elsewhere. For example, associated constant declarations (`let T:! Type;`) with no initializers are valid in interfaces but nowhere else, and are a different kind of declaration from what a normal `let` declaration would produce both syntactically and semantically.
Because interfaces and impls permit only a very small subset of the complete set of kinds of declaration, it's simpler to list only the kinds that are permitted rather than to allow an arbitrary declaration and semantically disallow the invalid cases, and it's also likely to lead to better error messages as we won't try to parse unintended or meaningless things.
Richard Smith
Adrien Leravat
Jon Ross-Perkins