Special DeclNames represent names that do not have an identifier in the
surface language. This implies serializing the information about whether
a name is special together with its identifier (if it is not special)
in both the module file and the swift lookup table.
By default, end expression type checking after the elapsed process time
is more than 60 seconds for the current expression. This threshold can
be overridden by using -solver-expression-time-threshold=<seconds>.
Resolves rdar://problem/32859654
Track outcomes of `conformsToProtocol` calls in `simplifyConformanceConstraints`
to be able to validate conformances when solution is formed to avoid returning
solutions with nominal types with invalid conformances to protocols.
- Unqualified lookup was incorrectly checking generic arguments even
when resolving interface types, resulting in a bogus 'Self does
not conform to P' error when referencing a generic typealias from
inside a protocol.
- The generic argument check was also done incorrectly if the
underlying type did not contain any type parameters, resulting
in bogus ErrorTypes. Just remove the no-type-parameter
"optimization" instead, since it was working around another
crash.
- When opening up a generic typealias in the constraint solver, we
did the wrong thing if the generic typealias was defined in a
protocol, producing concrete substitutions for the parent type
instead of a 'Self := ParentType' substitution.
Fixes <rdar://problem/32633645>.
There is a short-circuiting hack in the constraint solver that speeds up
solving, but isn't generally sound. If we allow unavailable decls to be
considered "favored", this can fire and result in our choosing a
solution that involves the unavailable decl where other solutions exist.
Fixes rdar://problem/32570734.
The old TVO_MustBeMaterializable is now equivalent to
!TVO_CanBindToLValue && !TVO_CanBindToInOut.
I tried to update all usages of createTypeVariable() to
pass TVO_CanBindToInOut unless they explicitly passed
TVO_MustBeMaterializable before.
However, in reality TVO_CanBindToInOut is the rare case;
we can remove this flag gradually over time to fix
crashes and diagnostics.
Enum elements have to be treated the same way as regular functions
when passed as values, which means labels have to be stripped from
their argument types.
Resolves: rdar://problem/32300339.
We don't actually want to open the type; instead, calculate the
substituted member type using substMemberTypeWithBase(), which
will return an unbound generic type if the member is a generic
nominal or type alias, and then it open it with openUnboundGenericType().
This is NFC for now, but I need generic typealiases to come in as
UnboundGenericTypes here in a subsequent patch.
The openType() function did two things:
- Replace unbound generic types like 'G' with fresh type variables
applied to bound generic types, like 'G<$T0>'.
- Replace generic parameters with type variables from the replacement
map.
The two behaviors were mutually exclusive and never used from the
same call site, so split them up into two independent functions.
Also, eliminate ConstraintSystem::openBindingType() since it was only
used in one place and could be expressed in terms of existing functions.
If we had an unbound generic type whose parent was a bound
generic type, and the outer type's generic signature
placed generic constraints on outer parameters, we would
create type variables that weren't ever bound to anything.
Previously, this would never come up, but it will once
preCheckExpression() is folding more MemberRefExprs down
to TypeExprs.
Now that SILGen can correctly lower lvalue accesses of
class existential payloads, remove a hack in Sema that
was simply doing the wrong thing.
Fixes <rdar://problem/31858378>.
There were various problems with layout constraints either
being ignored or handled incorrectly. Now that I've exercised
this support with an upcoming patch, there are some fixes
here.
Also, introduce a new ExistentialLayout::getLayoutConstriant()
which returns a value for existentials which are class-constrained
but don't have a superclass or any class-constrained protocols;
an example would be AnyObject, or AnyObject & P for some
non-class protocol P.
NFC for now, since these layout-constrained existentials cannot
be constructed yet.
If the member came from a class, we're not going to substitute
the 'Self' type. Instead, we open the existential, upcast the
archetype up to the class type and access the member as if it
were a class member in the usual way.
Don't pass in the opened type; instead have the caller call
simplifyType() if needed. Also, make computeSubstitutions()
bail out if there's no generic signature, which allowed
unifying several generic vs non-generic code paths.
Hopefully there is enough short circuiting in there now that
we're not doing any extra work in the non-generic case.
First, add some new utility methods to create SubstitutionMaps:
- GenericSignature::getSubstitutionMap() -- provides a new
way to directly build a SubstitutionMap. It takes a
TypeSubstitutionFn and LookupConformanceFn. This is
equivalent to first calling getSubstitutions() with the two
functions to create an ArrayRef<Substitution>, followed by
the old form of getSubstitutionMap() on the result.
- TypeBase::getContextSubstitutionMap() -- replacement for
getContextSubstitutions(), returning a SubstitutionMap.
- TypeBase::getMemberSubstitutionMap() -- replacement for
getMemberSubstitutions(), returning a SubstitutionMap.
With these in place, almost all existing uses of subst() taking
a ModuleDecl can now use the new form taking a SubstitutionMap
instead. The few remaining cases are explicitly written to use a
TypeSubstitutionFn and LookupConformanceFn.
We can end up with IUOs bound as a result of overload resolution. When
this happens and the resulting type is used as a generic, we can end up
with dependent member types that fail to simplify properly as a result
of failing to substitute due to the IUO getting in the way. In these
cases it should be completely safe to strip the IUO off and retry
substitution with the base type.
This isn't really an ideal fix by any means, and we need to revisit how
we handle bindings to make it more uniform, but for now I think this is
a reasonable path to move forward.
Fixes a source compatibility regression.
rdar://problem/29960575
Without this, CSGen/CSSimplify and CSApply may have differing
opinions about whether e.g. a let property is settable, which
can lead to invalid ASTs.
Arguably, a better fix would be to remove the dependency on the
exact nested DC. For example, we could treat lets as settable
in all contexts and then just complain later about invalid
attempts to set them. Or we could change CSApply to directly
use the information it already has about how an l-value is used,
rather than trying to figure out whether it *might* be getting set.
But somehow, tracking a new piece of information through the
entire constraint system seems to be the more minimal change.
Fixes rdar://29810997.
ConstraintSystem::simplifyType() replaced types with their fixed types
from the global map.
Solution::simplifyType() replaced types with their fixed types from the
current bindings.
There were some minor differences between the two, and some dead code.
