Unless -enable-resilient-objc-class-stubs is passed in, these cases
are not supported, so now we diagnose them instead of asserting or
failing to link.
Note the behavior change here; classes with resilient ancestry were
previously isObjC(). However this is wrong since isObjC() means
"statically visible to Objective-C via the generated header".
After this patch, isObjC() only returns true for a class with resilient
ancestry if -enable-resilient-objc-class-stubs is passed in.
Cases with arguments form `(Self.Type) -> (Arg...) -> Self`
function types, so `areConservativelyCompatibleArgumentLabels`
should remove curried self before trying to match argument/parameter
labels.
Resolves: rdar://problem/49159472
This is a step in the direction of fixing the fallthrough bug. Specifically, in
this commit I give case stmts a set of var decls for the bodies of the case
statement. I have not wired them up to anything except the var decl
list/typechecking.
rdar://47467128
Before extending TupleShuffleExpr to represent all tuple
conversions allowed by the constraint solver, remove the
parts of TupleShuffleExpr that are no longer needed; this is
support for default arguments, varargs, and scalar-to-tuple and
tuple-to-scalar conversions.
Right now we use TupleShuffleExpr for two completely different things:
- Tuple conversions, where elements can be re-ordered and labels can be
introduced/eliminated
- Complex argument lists, involving default arguments or varargs
The first case does not allow default arguments or varargs, and the
second case does not allow re-ordering or introduction/elimination
of labels. Furthermore, the first case has a representation limitation
that prevents us from expressing tuple conversions that change the
type of tuple elements.
For all these reasons, it is better if we use two separate Expr kinds
for these purposes. For now, just make an identical copy of
TupleShuffleExpr and call it ArgumentShuffleExpr. In CSApply, use
ArgumentShuffleExpr when forming the arguments to a call, and keep
using TupleShuffleExpr for tuple conversions. Each usage of
TupleShuffleExpr has been audited to see if it should instead look at
ArgumentShuffleExpr.
In sequent commits I plan on redesigning TupleShuffleExpr to correctly
represent all tuple conversions without any unnecessary baggage.
Longer term, we actually want to change the representation of CallExpr
to directly store an argument list; then instead of a single child
expression that must be a ParenExpr, TupleExpr or ArgumentShuffleExpr,
all CallExprs will have a uniform representation and ArgumentShuffleExpr
will go away altogether. This should reduce memory usage and radically
simplify parts of SILGen.
We weren't renaming all occurrences of 'x' in the cases like the below:
case .first(let x), .second(let x):
print("foo \(x)")
fallthrough
case .third(let x):
print("bar \(x)")
We would previously only rename occurrences within the case statement the query
was made in (ignoring fallthroughs) and for cases with multiple patterns (as in
the first case above) we would only rename the occurrence in the first pattern.
This is in preparation for fixing issues around SILGenPattern fallthrough
emission and bad rename/edit all in scope of case stmt var decls. Specifically,
I am going to ensure that we can get from any VarDecl in the following to any
other VarDecl:
switch x {
case .a(let v1, let v2), .b(let v1, let v2):
...
fallthrough
case .c(let v1, let v2), .d(let v1, let v2):
...
}
This will be done by:
1. Pointing the var decls in .d at the corresponding var decls in .c.
2. Pointing the var decls in .c at the corresponding var decls in .b.
3. Pointing the var decls in .b at the corresponding var decls in .a.
4. Pointing the var decls in .a at the case stmt. Recognizing that we are asking
for the next VarDecl, but have a case stmt, we check if we have a fallthrough
case stmt. If so, follow down the fallthrough case stmts until you find a
fallthrough case stmt that doesn't fallthrough itself and then return the
corresponding var decl in the last case label item in that var decl (in the
above .d).
In a subsequent commit I am going to add case body var decls. The only change as
a result of that is that I will insert them into the VarDecl double linked list
after the last case var decl of each case stmt.
