When a particular nominal type or extension thereof declares conformance
to a protocol, check whether that type or extension contains any members
that *nearly* match a defaulted requirement (i.e., a requirement that
is satisfied by something in a protocol extension), but didn’t match
for some reason and weren’t used to satisfy any other requirement of
that protocol. It’s intended to catch subtle mistakes where a default
gets picked instead of the intended member.
This is a generalization of the code we’ve had for @objc optional
requirements for a long time.
Fixes rdar://problem/24714887.
Now that the GenericSignatureBuilder is no longer sensitive to the input
module, stop uniquing the canonical GSBs based on that module. The main
win here is when deserializing a generic environment: we would end up
creating a canonical GSB in the module we deserialized and another
canonical GSB in the module in which it is used.
Implement a module-agnostic conformance lookup operation within the GSB
itself, so it does not need to be supplied by the code constructing the
generic signature builder. This makes the generic signature builder
(closer to) being module-agnostic.
When an associated type declaration “overrides” (restates) an associated
type from a protocol it inherits, note that it overrides that declaration.
SourceKit now reports overrides of associated types.
The number of generic signature builders “registered” indicates how many
times a generic signature builder (GSB) was moved in to become the canonical
GSB, rather than recreating the GSB. When a GSB is “already registered”, it
means that we’ve constructed a new GSB only to find that there already was
a canonical GSB for that particular generic signature. These latter cases
could potentially benefit from more caching.
Once we compute a generic signature from a generic signature builder,
all queries involving that generic signature will go through a separate
(canonicalized) builder, and the original builder can no longer be used.
The canonicalization process then creates a new, effectively identical
generic signature builder. How silly.
Once we’ve computed the signature of a generic signature builder, “register”
it with the ASTContext, allowing us to move the existing generic signature
builder into place as the canonical generic signature builder. The builder
requires minimal patching but is otherwise fully usable.
Thanks to Slava Pestov for the idea!
Funnel all places where we create a generic signature builder to compute
the generic signature through a single entry point in the GSB
(`computeGenericSignature()`), and make `finalize` and `getGenericSignature`
private so no new uses crop up.
Tighten up the signature of `computeGenericSignature()` so it only works on
GSB rvalues, and ensure that all clients consider the GSB dead after that
point by clearing out the internal representation of the GSB.
Funnel all places where we create a generic signature builder to compute
the generic signature through a single entry point in the GSB
(`computeGenericSignature()`), and make `finalize` and `getGenericSignature`
private so no new uses crop up.
Tighten up the signature of `computeGenericSignature()` so it only works on
GSB rvalues, and ensure that all clients consider the GSB dead after that
point by clearing out the internal representation of the GSB.
For enums, we now only call _mixInt on the computed hash value if
it has associated values; for enums without associated values, we
use the ordinal alone, as before.
The number of generic signature builders “registered” indicates how many
times a generic signature builder (GSB) was moved in to become the canonical
GSB, rather than recreating the GSB. When a GSB is “already registered”, it
means that we’ve constructed a new GSB only to find that there already was
a canonical GSB for that particular generic signature. These latter cases
could potentially benefit from more caching.
Once we compute a generic signature from a generic signature builder,
all queries involving that generic signature will go through a separate
(canonicalized) builder, and the original builder can no longer be used.
The canonicalization process then creates a new, effectively identical
generic signature builder. How silly.
Once we’ve computed the signature of a generic signature builder, “register”
it with the ASTContext, allowing us to move the existing generic signature
builder into place as the canonical generic signature builder. The builder
requires minimal patching but is otherwise fully usable.
Thanks to Slava Pestov for the idea!
Funnel all places where we create a generic signature builder to compute
the generic signature through a single entry point in the GSB
(`computeGenericSignature()`), and make `finalize` and `getGenericSignature`
private so no new uses crop up.
Tighten up the signature of `computeGenericSignature()` so it only works on
GSB rvalues, and ensure that all clients consider the GSB dead after that
point by clearing out the internal representation of the GSB.
Given an existential type E, this creates a new canonical
generic signature <T : E>.
If E is a protocol composition containing members of protocol,
class or AnyObject type, the resulting generic signature will
split up the T : E requirement into a canonical and minimal
set of conformance, superclass and layout requirements.
If/when we implement generalized existentials, existential
types will be defined in terms of an arbitrary set of
generic requirements applied to a single generic parameter;
at that point, this method will be replaced with a generic
signature stored inside the type itself.
For now, this will be used to simplify some logic in the
SILOptimizer.
This implementation required a compromise between parser
performance and AST structuring. On the one hand, Parse
must be fast in order to keep things in the IDE zippy, on
the other we must hit the disk to properly resolve 'canImport'
conditions and inject members of the active clause into the AST.
Additionally, a Parse-only pass may not provide platform-specific
information to the compiler invocation and so may mistakenly
activate or de-activate branches in the if-configuration decl.
The compromise is to perform condition evaluation only when
continuing on to semantic analysis. This keeps the parser quick
and avoids the unpacking that parse does for active conditions
while still retaining the ability to see through to an active
condition when we know we're moving on to semantic analysis anyways.
A protocol extension initializer creates a new instance of the
static type of Self at the call site.
However a convenience initializer in a class is expected to
initialize an instance of the dynamic type of the 'self' value,
because convenience initializers can be inherited by subclasses.
This means that when a convenience initializer delegates to a
protocol extension initializer, we have to substitute the
'Self' type in the protocol extension generic signature with
the DynamicSelfType, and not the static type.
Since the substitution is formed from the type of the 'self'
parameter in the class convenience initializer, the solution is
to change the type of 'self' in a class convenience initializer
to DynamicSelfType, just like we do for methods that return
'Self'.
This fixes cases where we allowed code to type check that
should not type check (if the protocol extension initializer
has 'Self' in contravariant position, and we pass in an
instance of the static type).
It also fixes a miscompile with valid code -- if the protocol
extension initializer was implemented by calling 'Self()',
it would again use the static type and not the dynamic type.
Note that the SILGen change is necessary because Sema now creates
CovariantReturnExprs that convert a static class type to
DynamicSelfType, but the latter lowers to the former at the
SIL level, so we have to peephole away unnecessary unchecked_ref_cast
instructions in this case.
Because this change breaks source compatibility, it is guarded
by a '-swift-version 5' check.
I don't have reduced test cases. The original test cases
were a series of frontend invocations in -parse-stdlib
mode.
While the original bugs seem to have been fixed, while
verifying I found a few places where we weren't checking
for null decls property in the ASTContext.
Probably not too useful to check this in, but I don't see it
causing any harm, either.
To remove some callers of 'is<InOutType>' after Sema, start using what will soon be a structural invariant - the only expressions that can possibly have 'inout' type are semantically InOut expressions.
As a step toward eliminating the single input type
representation of function parameters, add more constraints on that
input type. It can be one of:
* A tuple type, for multiple parameters,
* A parenthesized type, for a single parameter, or
* A type variable type, for specific cases in the type checker
Enforce these constraints for *canonical* types as well, so the
canonical form of:
typealias MyInt = Int
typealias MyFuncType = (MyInt) -> Int
is now:
(Int) -> Int
rather than:
Int -> Int
This affects canonicalization of FunctionType and
GenericFunctionType. Enchance both, as well as their Can*Type
counterparts, with "get" operators that take an array of
AnyFunctionType::Param, and start switching a few clients over to this
new, preferred API.
AnyFunctionType::Param carries around information about decomposed
parameters now. Information about default arguments must be computed
separately with swift::computeDefaultMap.
