This adds support for generic types in exhaustiveness checking.
There are two main obstacles:
1) Types that are not Dart subtypes might be related in the context
of exhaustiveness. For instance
sealed class A<X> {}
class B extends A<num> {}
method<T>(A<T> a) {
switch (a) {
case B(): ...
}
}
Here B is not a Dart subtype of A<T> but must still be a subtype
in the context of exhaustiveness since T could be num at runtime.
2) It is non-trivial to compute the subtypes of a generic sealed class
that is both sound and precise enough to be useful. For instance
sealed class A<X> {}
class B extends A<num> {}
class C<X> extends A<X> {}
class D<X extends num> extends A<X> {}
class E<X extends E<X>> extends A<X> {}
Computing the subtypes of A<F> for some type F, we would like to
exclude B (assuming F is not a supertype of num) because it
cannot be inhabit A<F>, and include C<F> so that we recognize
that C<F> exactly covers all C instances of A<F>. We would also
like to include D<F> but if we don't include the added `extends
num` bound, we might conclude that D<num> is _not_ sufficient to
cover D<F>. And what to do about E, can we even come up with a
type that represents the valid values?
The solution is threefold:
1) We add an 'overapproximate' function of types, which
replaces all type variables with their default types. This will compute
A<dynamic> for A<T>, A<int> for A<int>, A<List<dynamic>> for A<List<T>>,
and E<dynamic> for E<T extends E<T>>. This is similar to instantiate-
to-bounds, but is recursive.
We use this to test whether a type without type variables is a potential
subtype. For instance testing B <: overapproximate(A<F>) = A<F> shows
that B _cannot_ be a subtype of A<F>, and testing
B <: overapproximate(A<T>) = A<dynamic> shows that B _can_ be a subtype
of A<T>.
2) For finding subtypes of a sealed type, we recognize the case
when a type is a trivial subtype in which all type variables are passed
directly to the superclass, for instance like C<T> in the example. For
other cases we overapproximate the this type of the subclass.
3) To ensure that the [StaticType] can be subtype in the normal Dart
sense but also handle the overapproximation when computing sealed
subtypes, a new [WrappedStaticType] is added. This bridges the subtype
relation such that for instance B, when created as a sealed subtype
of A<T>, is both a subtype of A<num> (as it normally is) and of A<T>,
which it is by construction.
Change-Id: I9970c46009938ef15625e1193faf916b7544ce0b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/284681
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Paul Berry <paulberry@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>
This replaces the [Library] parameter from bounds checks and
type inference methods with a `isNonNullableByDefault` parameter,
enabling usage of these algorithms in library-agnostic code, like
features only available post-nnbd.
Change-Id: Id565d00e1c20d25e7e3388badbb2d7f11c015802
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/284642
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Mayank Patke <fishythefish@google.com>
The representation field of an inline class is not part of the
generated code - it does not have a corresponding synthesized top-level
methods like the other inline class members. Therefore, to support
access to the representation field, a new `representationName` field
is added to `InlineClass` that holds the name by which the
representation field can be accessed.
An access to the representation field is at runtime an access of the
receiver itself. To show that the static type of the expression changes
from the inline type of the receiver to the declared representation
type, an `AsExpression` is inserted. Since this check is not needed
at runtime, this node is marked with the new `isUnchecked` flag, that
backends can use to skip the check.
TEST=pkg/front_end/testcases/inline_class/field_access.dart
Change-Id: I635af414af2ddc541352078766ce57a9d8ded601
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/277983
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>
For now it's only done for unevaluated constants as that's where an
issue has been observed.
This CL further more limits the default nesting depth for both
expressions and statements (e.g. when .toString() printing an ast node)
to 50. Again this has been shown in one case to be a good place to
stop an (exponential time) issue from happening.
Change-Id: I6affb2846a6587542ffce3f8d6914a4209b08322
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/251103
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>
Adds a replacement visitor for Constant types using null as a
sentinel value for whether a subnode has changed or not (except
in the case of TreeNodes in order to match existing Visitor
semantics).
Change-Id: Iaaab1b1c608af07f36ece08071b3d703884cd91b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/248944
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Srujan Gaddam <srujzs@google.com>
This adds AbstractSuperMethodInvocation, AbstractSuperPropertyGet,
AbstractSuperPropertySet nodes which are to be used for super access
in mixin declaration.
These super accesses do not resolve to their statically bound target
but instead the interface target on the types in the 'on' clauses, and
need to be updated to the statically bound target upon mixin application.
This has lead backends to disregard the interface target provided by
the CFE and instead always compute targets for super accesses.
This change is a step towards creating a clear separation between the
two use cases, enabling a more precise handling of super accesses.
The new nodes are not created yet with this CL.
TEST=existing
Change-Id: I70ea9baf5b4b970b10cc72b7409633d270d57755
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/245168
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Nicholas Shahan <nshahan@google.com>
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>
This CL moves the bounds checking into the TypeBuilder instead of
performing it from the outside on the computed DartType node.
This solves several problems:
1) Errors are now reported on the type in the code instead of the
declaration which holds the type.
2) Checking of type aliases (both function and nonfunction type
aliases) is now handled correctly in all cases. This achieved by
computed the aliased type (containing TypedefType nodes)
internally and performing the checking on this type, and only
convert the type into the unaliased version (without TypedefType
nodes) after checks have been performed. Previously this handled
through the FunctionType.typedefType property for function type
aliases and through and incomplete work-around for nonfunction
type aliases.
3) With 2) FunctionType.typedefType is no longer needed and is
removed.
TEST=general/bounds_*
Change-Id: I7653bca5ccb0ebf4b3553828a298d1ad918ef235
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/243722
Reviewed-by: Mayank Patke <fishythefish@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Add `toText` to both Reference and CanonicalName.
Change how CanonicalNames are printed through `text_util.dart` to be
more aligned with how the corresponding node would be printed had
it existed (and the CanonicalName thus normally not been used for
printing).
Add a test for (some definition of) common cases where printing should
be the same wherther done though the node, the reference or the
canonical name.
Fix usage of toStringInternal in the constant evaluator (though only
in use through an experiment) and add a test that showed that the
previous output was bad and the new isn't (at least in this case).
Change-Id: I10cbc1a542c7d8b079e0510bbd5eb5173b2e7563
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/242102
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>
This changes tool/fasta.dart to run the subcommand in the same VM when
no VM arguments are specified. This speeds up the tool and as a
consequence speeds up the tool/update_all.dart and
tool/update_expectation.dart tools.
Change-Id: I80b61a692a3ac2e15a7d1d097e65e1efbf9e4aee
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/236560
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Use `hasScheme` in place of comparing against the empty string, and
`isScheme` to compare against all other schemes.
TEST=No behavior changes.
Change-Id: Ifc9fd13c6cf37933ebd4a754c4b500dedbcb291b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/231185
Reviewed-by: Kevin Moore <kevmoo@google.com>
Commit-Queue: Nate Bosch <nbosch@google.com>
This CL replaces most usages of `.from` (e.g.
`List<String>.from(variable)`) to use `.of` instead.
This is done because code like
`List<String> foo = new List<String>.from([null])`
is valid and gives no warnings or errors.
Using `.of` instead will give an error.
Also `.of` appears to be slightly faster.
Change-Id: I1b4327be228b77e6a3e9faa283f8ce64f0565608
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/228642
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>
Some subtype tests are crashing due to infinite recursion. It is a
known issue. An example of such test is FutureOr<T> against
FutureOr<S> where T and S are type variables declared as T extends
FutureOr<T> and S extends FutureOr<S>.
In some cases it's possible to fail early instead of crashing, for
exmaple, by checking Future-branch of the left-hand side first before
checking the type argumennt of FutureOr which would lead to the
infinite recursion. This CL does that, allowing some more type checks
to pass instead of crashing.
Change-Id: I075aa65522510db1a97ac2a8de7278a3ce3f400c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/227820
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Chloe Stefantsova <cstefantsova@google.com>
This CL splits the ClassHierarchyBuilder implementation into two parts:
1) ClassHierarchyBuilder (using ClassHierarchyNode and
ClassHierarchyNodeBuilder) which computes the superclass/
superinterface relations.
2) ClassMembersBuilder (using ClassMembersNode and
ClassMembersNodeBuilder) which computes the class members.
The CL prepares for supporting subtype queries from the macro generation
at point in time where members can still be added to the classes.
Change-Id: Ic28fc6eddd1b651916de46583aeed791ce81e844
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/222461
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
ReferenceName is used in equivalence testing to match reference
reguardless of whether the reference have associated nodes or
canonical names. The implementation didn't previously account for
fields, getters and setters with the same simple name, and would
wrongfully equate them.
Change-Id: Iacc8e0eb2c5c04a3cf11c3b5104a8f0441cf3ab6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/221621
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>
The added field holds the interface signature type for a Procedure when
this is different from the class signature type (implied by the function
parameters and return type). This is needed for forwarding semi stubs
when its declared type is different from the called super member.
Closes https://github.com/dart-lang/sdk/issues/47072
TEST=pkg/front_end/testcases/general/implement_semi_stub.dart and more
Change-Id: I4a7cdc9d564fb0a59e7b06e83646b5410d8d82f5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/216420
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Chloe Stefantsova <dmitryas@google.com>
This adds a third reference to Field declaration, so that we know have
three references, one for each use case:
1) fieldReference used for initialization; in FieldInitializer and as
the key in the InstanceConstant.fieldValues map.
2) getterReference used for reading; in InstanceGet, StaticGet and
SuperPropertyGet
3) setterReference used for writing; in InstanceSet, StaticSet and
SuperPropertySet
TEST=existing
Change-Id: I223f130e808e7f19a831c1fe5e3a4725d1bcdc3b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/203770
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Jens Johansen <jensj@google.com>
Johnni Winther