When opening generic types with type parameter requirements,
add information about requirement location to the locator of each
generated constraint to make it easier to extract such information
if needed.
Using this constraint locator element, we can check when a failed
constraint is due to an unsatisfied conditional requirement of a
protocol conformance. Unfortunately, it's hard to turn this into
an actionable diagnostic right now.
TODO:
- Select the KeyPath subclass corresponding to the write capability of the key path components
- Figure out an issue with unresolved solutions being chosen with contextually-typed keypaths
- Diagnostic QoI
Previously we would check TMF_UnwrappingOptional flag, which does not
stick with the constraint, so it would not always persist. Now, add a
new OptionalPayload locator element, which is more correct.
Fixes <rdar://problem/30429709>.
Simplify and improve the checking of @objc names when matching a
witness to a requirement in the @objc protocol. First, don't use
@objc-ness as part of the initial screening to determine whether a
witness potentially matches an @objc requirement: we will only reject
a potential witness when the potential witness has an explicit
"@nonobjc" attribute on it. Otherwise, the presence of @objc and the
corresponding Objective-C name is checked only after selecting a
candidate. This more closely mirrors what we do for override checking,
where we match based on the Swift names (first) and validate
@objc'ness afterward. It is also a stepping stone to inferring
@objc'ness and @objc names from protocol conformances.
Second, when emitting a diagnostic about a missing or incorrect @objc
annotation, make sure the Fix-It gets the @objc name right: this might
mean adding the Objective-C name along with @objc (e.g.,
"@objc(fooWithString:bar:)"), adding the name to an
unadorned-but-explicit "@objc" attribute, or fixing the name of an
@objc attribute (e.g., "@objc(foo:bar:)" becomes
@objc(fooWithString:bar:)"). Make this diagnostic an error, rather
than a note on a generic "does not conform" diagnostic, so it's much
easier to see the diagnostic and apply the Fix-It.
Third, when emitting the warning about a non-@objc near-match for an
optional @objc requirement, provide two Fix-Its: one that adds the
appropriate @objc annotation (per the paragraph above), and one that
adds @nonobjc to silence the warning.
Part of the QoI improvements for conformances to @objc protocols,
rdar://problem/25159872.
Simplify and improve the checking of @objc names when matching a
witness to a requirement in the @objc protocol. First, don't use
@objc-ness as part of the initial screening to determine whether a
witness potentially matches an @objc requirement: we will only reject
a potential witness when the potential witness has an explicit
"@nonobjc" attribute on it. Otherwise, the presence of @objc and the
corresponding Objective-C name is checked only after selecting a
candidate. This more closely mirrors what we do for override checking,
where we match based on the Swift names (first) and validate
@objc'ness afterward. It is also a stepping stone to inferring
@objc'ness and @objc names from protocol conformances.
Second, when emitting a diagnostic about a missing or incorrect @objc
annotation, make sure the Fix-It gets the @objc name right: this might
mean adding the Objective-C name along with @objc (e.g.,
"@objc(fooWithString:bar:)"), adding the name to an
unadorned-but-explicit "@objc" attribute, or fixing the name of an
@objc attribute (e.g., "@objc(foo:bar:)" becomes
@objc(fooWithString:bar:)"). Make this diagnostic an error, rather
than a note on a generic "does not conform" diagnostic, so it's much
easier to see the diagnostic and apply the Fix-It.
Third, when emitting the warning about a non-@objc near-match for an
optional @objc requirement, provide two Fix-Its: one that adds the
appropriate @objc annotation (per the paragraph above), and one that
adds @nonobjc to silence the warning.
Part of the QoI improvements for conformances to @objc protocols,
rdar://problem/25159872.
Introduce a new "OpenedGeneric" locator for when openGeneric opens a generic
decl into a plethora of constraints, and use this in CSDiags to distinguish
whether a constraint refers to an Expr as a whole or an "aspect" of the constraint.
Use that information in FailureDiagnosis::diagnoseGeneralConversionFailure
to know whether (as a fallback) we can correctly re-typecheck an entire expr
to obtain a missing type. If we are talking about an aspect of the expr, then
this clearly won't work.
The upshot of this is that where we previously compiled the testcase in 22519983
to:
y.swift:31:9: error: type '(inout _) -> Bool' does not conform to protocol 'RawRepresentable'
let a = safeAssign
^
we now produce the somewhat more useful:
y.swift:31:9: error: argument for generic parameter 'T' could not be inferred
let a = safeAssign
^
y.swift:27:6: note: in call to function 'safeAssign'
func safeAssign<T: RawRepresentable>(inout lhs: T) -> Bool {
^
Swift SVN r31620
get the same wording, fixing <rdar://problem/21964599> Different diagnostics for the same issue
While I'm in the area, remove some dead code.
Swift SVN r30713
If we end up trying to form a substitution where the replacement type
is an existential and there is a conformance to a non-@objc protocol
(i.e., a conformance where a witness table is required), complain in
Sema rather than crashing in IRGen. Fixes rdar://problem/21087341, but
the existential/generic interaction is still quite broken.
Swift SVN r29133
Previously, we were reconstructing this mapping from the "full" opened
type produced by declaration references. However, when dealing with
same-type constraints between associated types and type parameters, we
could end up with an incomplete mapping, which let archetypes slip
through. Most of the churn here is sorting out the locators we need to
use to find the opened-type information. Fixes rdar://problem/18208283
and at least 3 dupes of it that I've found so far.
Swift SVN r25375
checked cast expression.
We don't actually *use* that path for anything right now,
because we basically re-check the cast from scratch after
constraint application. This is nonetheless necessary to
avoid collisions with constraints which might be located
on the result, such as would arise in an initialization
context.
In particular, this patch fixes a crash arising when both
the operand and the result of a coercion require a
user-defined conversion. Test to follow.
Swift SVN r18386
Introduce a new locator kind for argument/parameter comparisons that
tracks both the argument and the parameter, which we will eventually
use in diagnostics more regularly. For now, this helps us smooth over
scalar-to-tuple/tuple-to-tuple/tuple-to-scalar nonsense when dealing
with calls.
Fix a pile of fallout from this change.
Swift SVN r17648
Add a third branch to the constraint system for '&x' expressions that allows conversion from an lvalue to a type via an additional writeback step:
- Add an LValueConversionExpr node that converts from @lvalue T to @lvalue U, given a pair of functions that convert T -> U and U -> T, to represent the writeback temporary.
- Allow conversion in an inout expression from @lvalue T to a type U that has the following members:
static func __writeback_conversion(Builtin.RawPointer, T.Type) -> U
static func __writeback_conversion_get(T) -> V
static func __writeback_conversion_set(V) -> T
which builds a solution that produces an LValueConversion from the get/set pair before passing the pointer to the writeback temporary off to the conversion function.
Swift SVN r15764
We'll need types to be convertible from multiple kinds of inouts, which currently can't be represented with protocol conformance since we only allow one protocol conformance per type per protocol. Instead just look for a magic "__inout_conversion" static method in the type; this is lame but easy, and inout conversions shouldn't be available outside of the stdlib anyway.
Swift SVN r15599
