Add support for user-defined assignment, as well as compound assignment and increment, following the design direction in pending proposal #2511.
Some of this isn't fully testable yet: because explorer doesn't properly support `impl` specialization, the blanket `impl`s in the prelude prevent types from customizing assignment.
Add basic support for `match_first` declarations to explorer, as described in https://github.com/carbon-language/carbon-lang/blob/trunk/docs/design/generics/details.md#prioritization-rule. The concrete syntax here is not yet approved, so `match_first` is renamed to `__match_first` for now, but the semantics are necessary to implement other approved features in explorer so we're intentionally getting a little ahead of the design here.
Addresses comments from this discussion: https://github.com/carbon-language/carbon-lang/pull/2460#discussion_r1046444433
Features:
* Move subtyping logic from Interpreter to TypeChecker, exposing subtyping as a series of access to `.base`.
* Excludes function parameter conversion, which is still done in ::Convert due to parameters conversion being handled differently.
Changes:
* Add new `class BaseAccessExpression : public MemberAccessExpression`, allowing rewrites
* Handle `BaseAccessExpression` expression type in Interpreter
* Move subtyping logic to `TypeChecker::ImplicitlyConvert`
In particular, this means that a type can implement `ImplicitAs(Type)` and have values of that type behave like types.
This implies that `()` and `{}` are no longer types. They are now values whose type is the result of converting `()` or `{}` to type `Type`, as has been discussed recently and seems to be the supported direction. This fixes various cases where these types were previously mishandled.
Instead of forming a `SymbolicWitness` that contains an `Expression` when we can't directly resolve a witness to an `impl`, form different kinds of `Witness` values for the various situations:
- A `BindingWitness` witnesses that a type implements a constraint by reference to an `ImplBinding`.
- A `ConstraintWitness` witnesses that a type implements a constraint by reference to witnesses for each of the impl constraints within the constraint.
- A `ConstraintImplWitness` witnesses that a type implements a constraint by reference to a larger constraint which contains that constraint as an impl constraint.
Remove `SymbolicWitness` values and `InstantiateImpl` expressions, which are now unused. In order to remove the final usage of `SymbolicWitness`, I fixed a TODO to give `Self` the proper type within an interface declaration. I don't think this is an observable change.
No functional change intended.
* Replay changes from pre-force-push mixin branch
* Base MixinPseudoType off of the new InterfaceType
* Add more test cases.
Also removed an unnecessary check that would have already been
handled by the parser.
* WIP detect member clashes during mixing mixins
* Implement fuzzer changes
* Implement member name clash check when mixing mixins
* Modify parser and lexer for experimental mixin feature
* Add comments
* Update explorer/testdata/mixin/simple-mix-in-mixin.carbon
Co-authored-by: josh11b <josh11b@users.noreply.github.com>
* Update explorer/testdata/mixin/use-mixin-method-in-class-method.carbon
Co-authored-by: josh11b <josh11b@users.noreply.github.com>
* Make code review changes
Co-authored-by: josh11b <josh11b@users.noreply.github.com>
- Added detection of unformed usage with `return var`, control-flow statements and member access.
- Refactored the work flow: made flow facts a class and moved operations of flow facts into the class.
- Added, cleaned and renamed test cases. Some test cases for the dynamic unformed check were suppressed by the static check. They are now added back.
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
- An introprocedural forward analysis that checks the may-be-formed states on local variables.
- Returns compilation error on usage of must-be-unformed variables.
- Implemented as a pass of `ASTNode` traversal.
- Currently supports detection of: function parameter, return expression and rhs of assign.
Richard Smith
Adrien Leravat
Jon Ross-Perkins
pmqtt
Darshal Shettyandjosh11b
Zenong ZhangandJon Ross-Perkins
