This lets us eliminate the _getObjectiveCType() value witness, which
was working around the lack of proper type witness metadata in witness
tables. Boilerplate -= 1.
mode (take 2)
Allow untyped placeholder to take arbitrary type, but default to Void.
Add _undefined<T>() function, which is like fatalError() but has
arbitrary return type. In playground mode, merely warn about outstanding
placeholders instead of erroring out, and transform placeholders into
calls to _undefined(). This way, code with outstanding placeholders will
only crash when it attempts to evaluate such placeholders.
When generating constraints for an iterated sequence of type T, emit
T convertible to $T1
$T1 conforms to SequenceType
instead of
T convertible to SequenceType
This ensures that an untyped placeholder in for-each sequence position
doesn't get inferred to have type SequenceType. (The conversion is still
necessary because the sequence may have IUO type.) The new constraint
system precipitates changes in CSSimplify and CSDiag, and ends up fixing
18741539 along the way.
(NOTE: There is a small regression in diagnosis of issues like the
following:
class C {}
class D: C {}
func f(a: [C]!) { for _: D in a {} }
It complains that [C]! doesn't conform to SequenceType when it should be
complaining that C is not convertible to D.)
<rdar://problem/21167372>
(Originally Swift SVN r31481)
of providing contextual diagnostics (e.g. producing the warning in
Constraints/dynamic_lookup.swift). This drops a specific diagnostic about
force casting the result of as! which was added in the Swift 1.2 timeframe
to explain the change in cast semantics. Now that as! has been around for
a long time, it is more confusing than helpful.
Swift SVN r31887
where we type check the destination first, then apply its type to the source.
This allows us to get diagnostics for assignments that are as good as PBD
initializers and other cases.
Swift SVN r31404
Now we can propagate contextual types through collection literals even when they are generic, producing
specific diagnostics for elements within them.
Swift SVN r31327
we process contextual constraints when producing diagnostic. Formerly,
we would aggressively drop contextual type information on the floor under
the idea that it would reduce constraints on the system and make it more
likely to be solvable. However, this also has the downside of introducing
ambiguity into the system, and some expr nodes (notably closures) cannot
usually be solved without that contextual information.
In the new model, expr diagnostics are expected to handle the fact that
contextual information may be present, and bail out without diagnosing an
error if that is the case. This gets us more information into closures,
allowing more specific return type information, e.g. in the case in
test/expr/closure/closures.swift.
This approach also produces more correct diagnostics in a bunch of other
cases as well, e.g.:
- var c = [:] // expected-error {{type '[_ : _]' does not conform to protocol 'DictionaryLiteralConvertible'}}
+ var c = [:] // expected-error {{expression type '[_ : _]' is ambiguous without more context}}
and the examples in test/stmt/foreach.swift, test/expr/cast/as_coerce.swift,
test/expr/cast/array_iteration.swift, etc.
That said, this another two steps forward, one back thing. Because we
don't handle propagating sametype constraints from results of calls to their
arguments, we regress a couple of (admittedly weird) cases. This is now
tracked by:
<rdar://problem/22333090> QoI: Propagate contextual information in a call to operands
There is also the one-off narrow case tracked by:
<rdar://problem/22333281> QoI: improve diagnostic when contextual type of closure disagrees with arguments
Swift SVN r31319
diagnoseGeneralConversionFailure() to handle them (instead of it handling as? but
special code handling as!).
As part of this, enhance things so we get error messages about both the problem,
and the overall type involved (when they're different) e.g.:
if let s = setD as? Set<BridgedToObjC> { }
error: 'ObjC' is not a subtype of 'DerivesObjC'
note: in cast from type 'Set<DerivesObjC>' to 'Set<BridgedToObjC>'
This also finally fixes the case in test/Generics/existential_restrictions.swift
Swift SVN r31299
specific when it fails, by printing a potentially partially resolved type for the
ambiguous expression in question, which it carries information. This can at least
tell what the ambiguous parts of the resultant type *are* in some cases (e.g. in
the Constraints/array_literal.swift case). That said, this diagnostic is still
admittedly not great.
This also exposes a couple of cases where we produce bogus diagnostics in general
(expr/cast/as_coerce.swift). The issue here is that these shouldn't be ambiguous
at all, they are being misreported due to 22320758), which I'll fix separately.
Swift SVN r31292
allowing these failures to hook into other diagnostic goodies (e.g. the
"did you mean to use '!' or '?'?" cases showing in the testsuite). That said,
by itself this doesn't have a huge impact, but avoids regressions with other
pending changes.
Swift SVN r31289
<rdar://problem/18397777> QoI: special case comparisons with nil
<rdar://problem/18042123> QoI: Fixit for "if !optional" should suggest "if optional == nil"
Swift SVN r31204
It's not /really/ an infix operator, but it behaves like a very low
precedence prefix operator. On the other hand, 'try' and 'try!' can
freely move in and out of all the operations we add in fix-its, so
don't bother.
rdar://problem/22259867
Swift SVN r31200
and diagnoseGeneralConversionFailure(). The previous approach of trying
to dig into anchors would often lead to complaining about types at
different levels in the same diagnostic, and the complexity of the former
code isn't needed now that other changes have landed.
Swift SVN r31036
- Improve handling of if_expr in a couple of ways: teach constraint simplification
about IfThen/IfElse and teach CSDiags about the case when the cond expr doesn't match
BooleanType. This is rarely necessary, but CSDiags is all about cornercases, and this
does fix a problem in a testcase.
- Be a bit more specific about the constraint failure kind (e.g. say subtype) and when
we have a protocol conformance failure, emit a specific diagnostic about it, instead of
just saying that the types aren't convertible.
Swift SVN r30650
conversion failures, making a bunch of diagnostics more specific and useful.
UnavoidableFailures can be very helpful, but they can also be the first constraint
failure that the system happened to come across... which is not always the most
meaningful one. CSDiag's expr processing machinery has a generally better way of
narrowing down which ones make the most sense.
Swift SVN r30647
- Don't "aka" a Builtin.Int2123 type, it just makes a bad diagnostic worse.
- Split out the predicate that CSDiag uses to determine what a conversion
constraint is to a helper fn, and add subtype constraints to the mix.
- Move eraseTypeData into CSDiag (its own client) as a static function.
- Make eraseTypeData be a bit more careful about literals, in an attempt to
improve diagnostics when literals get re-type-checked. It turns out that
this still isn't enough as shown by the regression on the
decl/func/default-values.swift testcase, and the
Constraints/dictionary_literal.swift testcase where one bad diagnostic turns
into another different one, but I'll keep working on it.
- Beef up diagnoseContextualConversionError and the caller to it to be more
self contained and principled about the conversion constraints it digs out
of the system. This improves the diagnostics on a couple of cases.
Swift SVN r30642
directly into the diagnostics subsystem. This ensures a more consistent
treatment of type printing (e.g. catches a case where a diagnostic didn't
single quote the type) and gives these diagnostics access to "aka".
Swift SVN r30609
- Have DiagnosticEngine produce "aka" annotations for sugared types.
- Fix the "optional type '@lvalue C?' cannot be used as a boolean; test for '!= nil' instead"
diagnostic to stop printing @lvalue noise.
This addresses:
<rdar://problem/19036351> QoI: Print minimally-desugared 'aka' types like Clang does
Swift SVN r30587
facilities used by operators etc. This required a bunch of changes to make
the diagnostics changes strictly an improvement:
- Teach the new path about calls to TypeExprs.
- Teach evaluateCloseness some simple things about varargs.
- Make the generic diagnosis logic produce a better error when there is
exactly one match.
Overall, the resultant diagnostics are a step forward: we now produce candidate
set notes more uniformly, and the messages about some existing ones are
more specific. This is just another stepping stone towards progress though.
Swift SVN r30057
expressions. Broadening from callexpr to apply expr (picking up operators) improves
several diagnostics in the testsuite, and is important to avoid regressions from an
upcoming patch.
Swift SVN r29821
The case where this comes up is when people name their app and framework
targets the same thing, or when they've renamed their test target module
in an attempt to avoid issues with NSClassFromString and differing
runtime names. We currently do various wrong things when this happens,
so just emit an error instead.
I left a hole for our overlays, which use '@exported import <the-current-module>'
to get at their Clang modules. The previous commit means this can be
replaced by -import-underlying-module, but that doesn't help our tests,
which use -enable-source-import for their overlays. Which we should stop doing.
rdar://problem/21254367
Swift SVN r29440
checking checked cast via bridging. It prevented bridging upcasts using
'as!' from typechecking; we should emit an 'as!'->'as' warning instead.
Also, use ExplicitConversion constraint instead of Conversion when
determining whether a checked cast can be carried out unconditionally.
This matches the constraint used after applying the 'as!'->'as' fixit.
(Also, fix the error that was responsible for breaking
the expr/cast/bridged.swift test.)
<rdar://problem/19813772>
Swift SVN r28034
checking checked cast via bridging. It prevented bridging upcasts using
'as!' from typechecking; we should emit an 'as!'->'as' warning instead.
Also, use ExplicitConversion constraint instead of Conversion when
determining whether a checked cast can be carried out unconditionally.
This matches the constraint used after applying the 'as!'->'as' fixit.
<rdar://problem/19813772>
Swift SVN r28028
includes a number of QoI things to help people write the correct code. I will commit
the testcase for it as the next patch.
The bulk of this patch is moving the stdlib, testsuite and validation testsuite to
the new syntax. I moved a few uses of "as" patterns back to as? expressions in the
stdlib as well.
Swift SVN r27959
The type checker (and various other parts of the front end) jump
through many hoops to try to cope with the lack of a proper
declaration for an inferred type witness, causing various annoying
bugs. Additionally, we were creating implicit declarations for
derived/synthesized witnesses, leading to inconsistent AST
representations. This ch
Note that we'll now end up printing the inferred type aliases for type
witnesses, which represents a reversal of the decision that closed
rdar://problem/15168378. This result is more consistent.
Now with a simpler accessibility computation.
Swift SVN r27512
The type checker (and various other parts of the front end) jump
through many hoops to try to cope with the lack of a proper
declaration for an inferred type witness, causing various annoying
bugs. Additionally, we were creating implicit declarations for
derived/synthesized witnesses, leading to inconsistent AST
representations. This ch
Note that we'll now end up printing the inferred type aliases for type
witnesses, which represents a reversal of the decision that closed
rdar://problem/15168378. This result is more consistent.
Swift SVN r27487
This changes 'if let' conditions to take general refutable patterns, instead of
taking a irrefutable pattern and implicitly matching against an optional.
Where before you might have written:
if let x = foo() {
you now need to write:
if let x? = foo() {
The upshot of this is that you can write anything in an 'if let' that you can
write in a 'case let' in a switch statement, which is pretty general.
To aid with migration, this special cases certain really common patterns like
the above (and any other irrefutable cases, like "if let (a,b) = foo()", and
tells you where to insert the ?. It also special cases type annotations like
"if let x : AnyObject = " since they are no longer allowed.
For transitional purposes, I have intentionally downgraded the most common
diagnostic into a warning instead of an error. This means that you'll get:
t.swift:26:10: warning: condition requires a refutable pattern match; did you mean to match an optional?
if let a = f() {
^
?
I think this is important to stage in, because this is a pretty significant
source breaking change and not everyone internally may want to deal with it
at the same time. I filed 20166013 to remember to upgrade this to an error.
In addition to being a nice user feature, this is a nice cleanup of the guts
of the compiler, since it eliminates the "isConditional()" bit from
PatternBindingDecl, along with the special case logic in the compiler to handle
it (which variously added and removed Optional around these things).
Swift SVN r26150
