Implements basic support for rewrite constraints as proposed in #2173.
Support for associated constants and complex constraints in general is also made more robust: argument deduction now properly computes and substitutes witnesses, and interface declarations track a more correct description of the constraint that they introduce than the one we previously built.
Change explorer's handling of witnesses to track them wherever possible. Associated constant support needs witnesses to be available much more pervasively.
The main changes here are:
- `Substitute` now takes a set of bindings covering both `Value`s for `GenericBinding`s and `Witness`es for `ImplBinding`s, and substitutes both.
- Witnesses are now tracked within `ConstraintType`s. The `.Self` type has an `ImplBinding` that self-references from parts of the constraint to other parts of the constraint can use to access the witness for the constraint.
- The constraint type for an `impl` and for a `GenericBinding` are now stored in pre-substituted form, with references to the actual constrained type rather than symbolic references to `.Self`. This results in minor changes in diagnostic text.
Argument deduction still performs substitutions without remapping witnesses.
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.
Previously we used an expression in some places and a `Witness` values in others. The eventual goal is to make `Witness` values behave like other symbolic values such as `NominalClassType`, but the first step is to consistently treat them like values rather than expressions.
No functionality change intended.
* Multiplication and division have the same priority.
* A new builtin interface DivWith is added.
* In some tests expecting a compilation error (syntax error), the error
message now says it is expecting SLASH or binary *.
* 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>
The most significant change here is that explorer now uses the chosen spelling
rather than the old `Bool` spelling. Also update a few documentation examples
and some skeletal design docs to use the chosen spelling.
Provides a first implementation iteration towards class prefix and extension, along with user-friendly error regarding missing implementation for #1881
**Explorer behavior**
For class prefix `base` and `abstract`:
```
Class prefixes `base` and `abstract` are not supported yet
```
For extension with `extends`:
```
Class extension with `extends` is not supported yet
```
**Motivation**
* Provides user-friendly error for these unsupported features
* First implementation increment in supporting class prefix and extension.
Following #1191, add initial support for bitwise operators. Support for both
integer operations and for operator overloading via the interfaces specified in
#1191 is provided.
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Allows unformed state for local variables. Reports a run-time error when an unformed local variable is used.
- Added declaration without initialization for local variables in the parser.
- Made the init expression of VariableDefinition optional.
- Expanded (alive, dead) to (uninitialized, alive, dead) in the Heap.
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Basic support for declaring, specifying the values of, and using associated constants.
This is incomplete in various ways. For example, when checking whether a type satisfies a constraint, there is no check that its associated constants match those in the constraint, and name lookup into a value whose type is an associated constant is not supported yet.
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Instead of complaining that the name is not completely declared, say it's not
declared at all yet.
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
This PR implements the `returned var` for the explorer.
- Enabled `returned var` and `return var` syntax in lexer and parser.
- Split `Return` statement into `ReturnVar` and `ReturnExpression` to distinguish the two types of returns.
- Added logic in name resolution, type checking and interpretation to process `returned var` definition and `ReturnVar` statement.
Following #875, diagnose any use of a name prior to the point where it is introduced and its type is known.
This works by performing name resolution on a top-level class, interface, or impl twice: the first pass performs name-resolution for everything other than nested function bodies, and the second pass performs name resolution on function bodies. At the moment, the second pass does a superset of the work done by the first pass, and as a consequence, some identifier expressions now have their target set twice to the same thing.
We fundamentally have cyclic references between declarations,
statements, expressions, and patterns, and there's no meaningful
layering between them. Combine them into a single build target.
Components such as paren_contents, static_scope, and library_name that
are defined without reference to specific AST nodes are kept as separate
BUILD targets.
This avoids the need to make copies of potentially large maps when
the same bindings are used in multiple values, such as when forming
a bound method value.
Type checking now stores information on a member access identifying the member that was accessed, not only its name. This parallels what we do for other similar constructs whose meaning is resolved by name lookup or type-checking, and will allow us to avoid redoing lookups in some cases during interpretation.
This works by splitting the constraint up into interfaces and checking
that each of them is implemented in turn.
Also check that the parameters of the impl are deducible from each of
the resulting (type, interface) pairs.
`.Self` is modeled as a new kind of expression, `DotSelfExpression`. Name resolution associates each occurrence of a `DotSelfExpression` with a generic binding, much like for an `IdentifierExpression`.
Both `:!` bindings and `where` expressions bring `.Self` into scope. The tentative intent is that if there are multiple `.Self`s in scope and they refer to different bindings, the result of using a `.Self` expression is an ambiguity error, but that is not implemented in this patch. Instead, like for `IdentifierExpression`s, we find the innermost enclosing definition of `.Self`.
`.Foo` expressions are rewritten to `.Self.Foo`, but this isn't enough to make them do anything useful, because associated constants aren't supported in general yet.
This causes compile-time evaluation to give the same result as runtime
evaluation wherever possible. In particular, referencing a generic
parameter at compile time will resolve to the actual value if we're
evaluating a call to the enclosing function so a value for the
parameter is available in the call frame.
Clean up recently-added support for `SymbolicWitness`es using this.
* initial implementation of new and delete
* remove requirement for empty heap from trace.carbon
* more tests
* fixed substitution for generic function types
Build constraint types from `where` expressions. This is very bare-bones; there's no support for constraining `.Self` or associated types yet, but degenerate cases not involving self-reference work.
`==` constraints are syntactically supported but not semantically verified yet, and they aren't used for anything.
Add scaffolding for constraints in general, and support specifically constraints formed by applying a `&` operator.
No support for constraints formed with `where` nor for named constraints at this point.
* Implement addr keyword
* Add files that were deleted during merge
Some files got deleted during merging trunk because of the executable
semantics rename.
* Implement changes from code review.
Major changes:
- Rename AddrBindingPattern to AddrPattern
- Fix AddrPattern related changes in fuzzing
* Update documentation for GetField
* Fix AddPattern according to @zygoloid's suggestions
* Apply @zygoloid's changes to method comment
* Add a multi-component field example
* Incorporate AST changes to fuzzer corpus
* Refactor the deduced_param_list grammar rule
Suggested by @zygoloid
Support is added for all of the non-type expression contexts where we currently accept built-in conversions, such as reordering the fields in a struct.
This supports aliases for types (including interfaces), functions, parameterized types, instance member names, and interface member names.
Co-authored-by: Jon Meow <jperkins@google.com>
Richard Smith
Geoff Romer
pmqtt
Junhee Cho
Darshal Shettyandjosh11b
Adrien Leravat
Thejaswi Kadur
Tim Crown
Yen-Jen Wang
Josh Soref
Zenong ZhangandJon Ross-Perkins
Jeremy G. Siek
pk19604014