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>
We don't have overload resolution, so I've simply added PrintInt for now. But it's really tempting to turn __intrinsic_print into a total kludge function.
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.
Per the design of member access, evaluate the first operand of `.` if it's a type in order to find which type it is, and perform the lookup there.
This allows us to handle the case where the first operand is of type `Type` rather than a more specific type, but can still be evaluated to some specific type value while type-checking.
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
This renames `Witness` to `ImplWitness` and adds a new form, `SymbolicWitness`, that holds an expression by which a witness can be computed. A common base class `Witness` is provided.
We form the new kind of witness when evaluation of a witness expression fails because the witness is not in scope, as happens when evaluating a subexpression such as a type expression in isolation, and retry evaluation in the larger context when the interpreter performs type instantiation when running the code.
This allows us to properly handle compile-time evaluation of constructs involving witness table lookups when the witness can be statically determined. The intent is that we will eventually also form symbolic witness table references when impl selection finds a non-final witness, in order to support specialization.
Simplify `NominalClassValue`: it can now always store a witness map rather than either a witness map or a witness-or-witness-expression map.
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.
* added documentation for tracing output, changed the printing of scopes to be part of the stack, made other minor changes hoping to enhance readability
* reformat a list in the README
* minor edit
* fix the lists
* updates to the interpreter/README.md
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.
Prepend the generic class's list of parameters onto the `impl`'s list of
deduced parameters, and add the `impl` to the impl scope enclosing the
class rather than adding it to the impl scope for the class body.
When matching an impl, deduce against both the type and the interface.
This incidentally slightly improves support for nested classes in generic classes, because they have some of the same properties as `impl`s nested in generic classes, but that's still a fair way from working for various unrelated reasons.
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>
pmqttandm new
Thejaswi Kadur
Zenong Zhang
Josh Soref
pk19604014
Jeremy G. Siek
Darshal Shetty