Currently single parameter tuple splat fix/diagnostic supports only
cases where parameter is a concrete tuple type, let's enhance that to
support generic parameters as well e.g.:
```swift
func foo<T>(_: T) {}
foo(0, 1, 2) // `T` expects arguments to form a tuple e.g. `foo((0, 1, 2))`
```
Extend the recently-refactored logic for determining whether the
getter/setter for a wrapped property is "mutating" to also consider
the projection variables (e.g., $foo). Fixes SR-11393 /
rdar://problem/54839570.
Make `TypeBase::getTypeOfMember` more resilient to base type
being either an l-value (which we can look through), or an
error type - in such can it would return immediately.
Resolves: rdar://problem/54184846
Instead, check them and their error handling right away.
In addition to fixing the crash in the radar, this also causes
us to emit unused variable warnings in functions containing
local functions.
Eventually, TC.definedFunctions should go away altogether.
Fixes <rdar://problem/53956342>.
Accessors logically belong to their storage and can be synthesized
on the fly, so removing them from the members list eliminates one
source of mutability (but doesn't eliminate it; there are also
witnesses for derived conformances, and implicit constructors).
Since a few ASTWalker implementations break in non-trivial ways when
the traversal is changed to visit accessors as children of the storage
rather than peers, I hacked up the ASTWalker to optionally preserve
the old traversal order for now. This is ugly and needs to be cleaned up,
but I want to avoid breaking _too_ much with this commit.
Fixes rdar://problem/53407949 | SR-11138. Previously, we'd only look at the outermost property wrapper to decide whether the wrapped property's getter and setter were `mutating` (or exist at all). In reality, this requires considering the semantics of the composed accesses of each wrapper layer's
`wrappedValue` property. Fixing this systematically addresses a number of issues:
- As SR-11138 reported, composing a nonmutating-get-set wrapper ought to produce a composed wrapper
that's nonmutating.
- We would previously allow a property wrapper with a mutating getter to be nested inside one with
only a getter, even though the resulting implementation was unsound (because there's no mutable
context for the inner wrapper to execute its get on.)
- Similarly, we would construct unsound setters in cases where the setter can't exist, such as when
the nested wrapper isn't settable but the outer wrapper is.
This merges Sema's special logic for updating the ImplInfo of lazy properties
and property wrappers with the StorageImplInfoRequest.
I had to move some code from the parser into the StorageImplInfoRequest, to
avoid request cycles caused by hasStorage() calls; this is the right thing to
do anyway.
Since hasStorage() now answers false for lazy properties and property wrappers,
we have to move some diagnostic checks from checkDeclAttributesEarly() to
the StorageImplInfoRequest implementation itself.
Over time, I expect all of the checks currently in checkDeclAttributesEarly()
and checkDeclAttributes() to either migrate to requests, or typeCheckDecl().
While trying to figure out whether there is a missing or extraneous
property wrapper reference, let's not try to fix any generic argument
mismatches associated with wrapper or wrapped types, otherwise the
fix is going to be incorrect.
Extend handling of enclosing-self subscripts by differentiating
between the original wrapped property (which now goes through
`subscript(_enclosingInstance:wrapped:storage:)`) and the projected
property (which goes through
`subscript(_enclosingInstance:projected:storage:)`). The new middle
argument provides a key path to the property that was accessed,
allowing one to distinguish the property being updated.
Allow property wrapper types to support a second access pattern for
instance properties of classes. When supported, the property wrapper's
static subscript(_enclosingInstance:storage:) is provided with the
enclosing "self" and a reference-writable key path referring to the
backing storage property.
Implements rdar://problem/52222560.
