This effectively reverts 6823744779
The blanket removal of isolation in default-value expressions had
unintented consequences for important workflows. It's still
a problem that needs to be addressed, but we need to be more precise
about the problematic situations.
Complete support is behind a flag, because it can result in a non-convergent
rewrite system if the opaque result type has a recursive conformance of its
own (eg, `some View` for SwiftUI's View protocol).
Without the flag, it's good enough for simple examples; you just can't have
a requirement that mentions a nested type of a type parameter equated to
the concrete type.
Fixes rdar://problem/88135291, https://bugs.swift.org/browse/SR-15983.
This hooks up call argument position completion to the typeCheckForCodeCompletion API to generate completions from all the solutions the constraint solver produces (even those requiring fixes), rather than relying on a single solution being applied to the AST (if any).
Co-authored-by: Nathan Hawes <nathan.john.hawes@gmail.com>
Fixes a crash during diagnostics by not assuming that optional chain
would always produce an optional type, which is not true because in
error scenarios it could get assigned an invalid type from context.
Resolves: rdar://85516390
If you have something like
protocol P {
typealias A = C
associatedtype T : A
}
class C {}
Then ::Structural resolution of 'A' in the inheritance clause will
produce a DependentMemberType 'Self.A'. Check for this case and
attempt ::Interface resolution to get the correct underlying type.
Fixes rdar://problem/90219229.
After https://github.com/apple/swift/pull/40793, alloc_boxes all have
their lifetimes protected by a lexical borrow scope. In that PR, DI had
been updated to see through begin_borrow instructions from a project_box
to a mark_uninitialized. It did not, however, correct the end_borrow
instructions when destroy_values of mark_uninitializeds were replaced
with destroy_addrs of project_boxes. That is done here.
In a bit more detail, in the following context
%box = alloc_box
%mark_uninit = mark_uninitialized %box
%lifetime = begin_borrow [lexical] %mark_uninit
%proj_box = project_box %lifetime
When it is not statically known whether a field is initialized, we are
replacing the instruction
// before
destroy_value %mark_uninit
// after
with the following diamond
// before
%initialized = load
cond_br %initialized, yes, no
yes:
destroy_addr %proj_box
br bottom
no:
br bottom
bottom:
dealloc_box %box
br keep_going
keep_going:
// after
Doing so is problematic, though, because by SILGen construction the
destroy_value is always preceded by an end_borrow:
end_borrow %lifetime
destroy_value %mark_uninit
Previously, that end_borrow remained above the
%initialized = load
instruction in the above. That was invalid because the the newly
introduced
destroy_addr %proj_box
was a use of the borrow scope (%proj_box is a projection of the
begin_borrow) and consequently must be within the borrow scope.
Note also that it would not be sufficient to simply emit the diamond
before the end_borrow. The end_borrow must come before the destruction
of the value whose lifetime it is protecting (%box), and the diamond
contains the instruction to destroy that value (dealloc_box) in its
bottom block.
To resolve this issue, just move the end_borrow instruction from where
it was to before the dealloc box. (This is actually done by moving it to
the top of the diamond's "continue" block prior to the emission of that
dealloc_box instruction.)
rdar://89984216
There are three kinds of invariant 'Self' uses here:
- 'Self' appears as the left hand side of a same-type requirement between type parameters
- 'Self' appears as a structural component of the right hand side of a concrete type requirement
- 'Self' appears as a structural component of the right hand side of a superclass requirement
My previous fix only handled the first case. Generalize it to handle all three.
Fixes rdar://problem/74944514.
The problem is that we currenly cannot represent the generic signature of
values of type `any P<some P>`. This is because we wind up producing
<Self where Self : P, Self.T == (some P)>
What we'd like to do in the future is erase the errant (some P) with
a fresh generic parameter and keep a substitution map on the side that
records the opaque type constraint. Something like
<Self, Opaque1 where Self : P, Opaque1 : P, Self.T == Opaque1> where Opaque1 == (some P)
The main point of this change is to make sure that a shared function always has a body: both, in the optimizer pipeline and in the swiftmodule file.
This is important because the compiler always needs to emit code for a shared function. Shared functions cannot be referenced from outside the module.
In several corner cases we missed to maintain this invariant which resulted in unresolved-symbol linker errors.
As side-effect of this change we can drop the shared_external SIL linkage and the IsSerializable flag, which simplifies the serialization and linkage concept.
`one-way` constraints disable some optimizations related to component
selection because they imply strict ordering. This is a problem for
multi-statement closures because variable declarations could involve
complex operator expressions that rely on aforementioned optimizations.
In order to fix that, let's move away from solving whole pattern binding
declaration into scheme that explodes such declarations into indvidual
elements and inlines them into a conjunction.
For example:
```
let x = 42, y = x + 1, z = (x, test())
```
Would result in a conjunction of three elements:
```
x = 42
y = x + 1
z = (x, test())
```
Each element is solved indepedently, which eliminates the need for
`one-way` constraints and re-enables component selection optimizations.
