A variadic parameter of function type must be @escaping -- we cannot
reason about an array of non-escaping closures, so this was a safety
hole.
Also, attempting to define an @autoclosure variadic did not produce a
diagnostic, but would fail later on if you actually tried to do
anything with it. Let's ban this completely.
Both changes are source breaking, but impact is limited to code that
was already only marginally valid.
When replace something with a punctuator, we often prefer adding spaces around it.
For instance,
func foo(): bar {}
// fix it
func foo() -> bar {}
In this case we want to add a space before '->', but not after that.
With this change, we can simply `fixItReplace(ColonLoc, " -> ")`.
`fixItReplace()` automatically adjust the spaces around it.
- If a parameter type is a sugared function type, mark the type
as non-escaping by default. Previously, we were only doing this
if the parameter type was written as a function type, with no
additional sugar.
This means in the following cases, the function parameter type
is now non-escaping:
func foo(f: ((Int) -> Void))
typealias Fn = (Int) -> Void
func foo(f: Fn)
- Also, allow @escaping to be used in the above cases:
func foo(f: @escaping ((Int) -> Void))
typealias Fn = (Int) -> Void
func foo(f: @escaping Fn)
- Diagnose usages of @escaping in inappropriate locations, instead
of just ignoring them.
It is unfortunate that sometimes we end up desugaring the typealias,
but currently there are other cases where this occurs too, such as
qualified lookpu of protocol typealiases with a concrete base
type, and generic type aliases. A more general representation for
sugared types (such as an AttributedType sugared type) would allow
us to solve this in a more satisfactory manner in the future.
However at the very least this patch factors out the common code
paths and adds comments, so it shouldn't be too bad going forward.
Note that this is a source-breaking change, both because @escaping
might need to be added to parameters with a sugared function type,
and @escaping might be removed if it appears somewhere where we
do not mark function types as non-escaping by default.
Member operators should be placed within a nominal type (or extension
thereof) that they operate on. Aside from being good style, enforcing
this in the type checker can help with dependency tracking. Addresses
rdar://problem/27536066.
If an inout parameter has an invalid type, we were unable to
distinguish it from a 'var' parameter, resulting in an invalid
diagnostic.
Fix this by adding a VarDecl::isInOut() flag, instead of
introspecting the type.
This flips the switch to have @noescape be the default semantics for
function types in argument positions, for everything except property
setters. Property setters are naturally escaping, so they keep their
escaping-by-default behavior.
Adds contentual printing, and updates the test cases.
There is some further (non-source-breaking) work to be done for
SE-0103:
- We need the withoutActuallyEscaping function
- Improve diagnostics and QoI to at least @noescape's standards
- Deprecate / drop @noescape, right now we allow it
- Update internal code completion printing to be contextual
- Add more tests to explore tricky corner cases
- Small regressions in fixits in attr/attr_availability.swift
What I've implemented here deviates from the current proposal text
in the following ways:
- I had to introduce a FunctionArrowPrecedence to capture the parsing
of -> in expression contexts.
- I found it convenient to continue to model the assignment property
explicitly.
- The comparison and casting operators have historically been
non-associative; I have chosen to preserve that, since I don't
think this proposal intended to change it.
- This uses the precedence group names and higherThan/lowerThan
as agreed in discussion.
Allow 'static' (or, in classes, final 'class') operators to be
declared within types and extensions thereof. Within protocols,
require operators to be marked 'static'. Use a warning with a Fix-It
to stage this in, so we don't break the world's code.
Protocol conformance checking already seems to work, so add some tests
for that. Update a pile of tests and the standard library to include
the required 'static' keywords.
There is an amusing name-mangling change here. Global operators were
getting marked as 'static' (for silly reasons), so their mangled names
had the 'Z' modifier for static methods, even though this doesn't make
sense. Now, operators within types and extensions need to be 'static'
as written.
The previous check excluded nested functions that took and returned
static Self. e.g.
protocol P {}
extension P {
func foo() -> Self {
func bar() -> Self {
return self
}
return bar()
}
}
Instead, search up the decl context chain until we find a protocol
extension context.
trying to set the superclass on classes in such situations by setting the superclass of an invalid decl to the error type.
This fixes a bunch of compiler crashes, and also changes some errors in other tests where the main error is the invalid declaration and now the
downstream errors can be a bit different because the decl has been invalidated.
* [Fixit] Add a fixit for converting non-trailing closures to trailing closures.
* [test] Update test to reflect the added note about converting to trailing closures.
Consider this code:
struct A<T> {
struct B {}
struct C<U> {}
}
Previously:
- getDeclaredType() of 'A.B' would give 'A<T>.B'
- getDeclaredTypeInContext() of 'A.B' would give 'A<T>.B'
- getDeclaredType() of 'A.C' would give 'A<T>.C'
- getDeclaredTypeInContext() of 'A.C' would give 'A<T>.C<U>'
This was causing problems for nested generics. Now, with this change,
- getDeclaredType() of 'A.B' gives 'A.B' (*)
- getDeclaredTypeInContext() of 'A.B' gives 'A<T>.B'
- getDeclaredType() of 'A.C' gives 'A.C' (*)
- getDeclaredTypeInContext() of 'A.C' gives 'A<T>.C<U>'
(Differences marked with (*)).
Also, this change makes these accessors fully lazy. Previously,
only getDeclaredTypeInContext() and getDeclaredIterfaceType()
were lazy, whereas getDeclaredType() was built from validateDecl().
Fix a few spots where the return value wasn't being checked
properly.
These functions return ErrorType if a circularity was detected via
the generic parameter list, or if the extension did not resolve.
They return Type() if the extension cannot be resolved *yet*.
This is pretty subtle, and I'll need to do another pass over
callers of these functions at some point. Many of them should be
moved over to use getSelfInContext(), getSelfOfContext() and
getSelfInterfaceType() instead.
Finally, this patch consolidates logic for diagnosting invalid
nesting of types.
The parser had some code for protocols in bad places and bad things
inside protocols, and Sema had several different bail-outs for
bad things in protocols, nested generic types, and stuff nested
inside protocol extensions.
Combine all of these into a single set of checks in Sema. Note
that we no longer give up early if we find invalid nesting.
Leaving decls unvalidated and un-type-checked only leads to
further problems. Now that all the preliminary crap has been
fixed, we can go ahead and start validating these funny nested
decls, actually fixing some crashers in the process.
When resolving a particular locator for a ".foo" expression that
references a static/class function, make sure we pass through the
proper locator. Otherwise, when that ".foo" is somehow generic, we
won't be able to find the opened type and, therefore, will crash when
trying to form the substitution.
While I'm here, simplify the "default arguments owner" computation
logic to simply retrieve the callee declaration, which is useful for
more than just default arguments.
along with recent policy changes:
- For expression types that are not specifically handled, make sure to
produce a general "unused value" warning, catching a bunch of unused
values in the testsuite.
- For unused operator results, diagnose them as uses of the operator
instead of "calls".
- For calls, mutter the type of the result for greater specificity.
- For initializers, mutter the type of the initialized value.
- Look through OpenExistentialExpr's so we can handle protocol member
references propertly.
- Look through several other expressions so we handle @discardableResult
better.
Try to match the original spelling of static/class in diagnostics and
when printing the AST. Also fixes cases with
PrintOptions.PrintImplicitAttrs = false, where we would just print
'class', which was not valid code.
A catch block can only be entered if the do block threw an error. In a
rethrows function, if the do block throws an error only under rethrows
conditions, then the catch block can only be entered under rethrows
conditions, which means the catch block can unconditionally throw and
it's still safe.
This enables code that looks like
```swift
func foo(f: () throws -> Void) rethrows {
do {
try f()
} catch is SomeError {
throw OtherError()
}
}
```
The issue here is that the constraint solver was deciding on
FixKind::RelabelCallTuple as the fix for the problem and emitting the
diagnostic, even though there were two different fixes possible.
CSDiags has the infrastructure to support doing doing the right thing
here, but is only being used for ApplyExprs, not SubscriptExprs.
The solution is to fix both problems: remove FixKind::RelabelCallTuple,
to let CSDiags handle the problem, and enhance CSDiags to treat
SubscriptExpr more commonly with ApplyExpr. This improves several cases
where the solver was picking one solution randomly and suggesting that
as a fix, instead of listing that there are multiple different solutions.
This is a case where we used to produce:
<unknown>:0: warning: no calls to throwing functions occur within 'try' expression
Which is bogus, due to the try expr implicitly generated as part of the
implicit super.init call for an init that doesn't otherwise contain a super.init.
Silence this warning by ignoring implicitly generated trys, since this try gets
produced before name binding has resolved exactly which try is being invoked.
