From the Swift documentation:
"If you define an optional variable without providing a default value,
the variable is automatically set to nil for you."
This fixes several issues:
- By default parent types of alias types are not printed which results in
- Erroneous fixits, for example when casting to 'Notification.Name' from a string, which ends up adding erroneous cast
as "Name(rawValue: ...)"
- Hard to understand types in code-completion results and diagnostics
- When printing with 'fully-qualified' option typealias types are printed erroneously like this "<PARENT>.Type.<TYPEALIAS>"
The change make typealias printing same as nominal types and addresses the above.
Avoid calling lookupMemberType() with an existential base
altogether.
With the previous resolveTypeInContext() patch, a compiler_crasher
regressed and hit this, because the behavior of lookupMemberType()
changed to return nullptr in fewer cases.
as a failure to convert the individual operand, since the operator
is likely conceptually generic in some way and the choice of any
specific overload is probably arbitrary.
Since we now fall back to a better-informed diagnostics point, take
advantage of this to generate a specialized diagnostic when trying to
compare values of function type with ===.
Fixes rdar://25666129.
This reverts commit 073f427942,
i.e. it reapplies 35ba809fd0 with a
test fix to expect an extra note in one place.
as a failure to convert the individual operand, since the operator
is likely conceptually generic in some way and the choice of any
specific overload is probably arbitrary.
Since we now fall back to a better-informed diagnostics point, take
advantage of this to generate a specialized diagnostic when trying to
compare values of function type with ===.
Fixes rdar://25666129.
call expression onto a callee when it was a binary expression. Doing this
requires improving the diagnostics for when the contextual result type is
incompatible with all candidates, but that is general goodness all around.
This fixes:
<rdar://problem/22333090> QoI: Propagate contextual information in a call to operands
and improves a number of diagnostics where the problem is that an operator
is used in a context that expects a type that it cannot produce.
Swift SVN r31891
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
Take expression depth and preorder traversal index into account when
deciding which unresolved overload to complain about, rather than giving
up if there are two exprs with the same number of overloads. Don't
consider solutions with fixes when emitting ambiguous-system
diagnostics.
Swift SVN r30931
down to call argument lists that have more than one operand (heavily leveraging
"computeTupleShuffle"). This resolves a great number of QoI radars, including
things like:
<rdar://problem/19981782> QoI: poor diagnostic for call to memcmp with UInt length parameter
where we used to produce:
error: cannot invoke 'memcmp' with an argument list of type '([UInt8], [UInt8], UInt)'
return memcmp(left, right, UInt(left.count)) == 0
^
note: expected an argument list of type '(UnsafePointer<Void>, UnsafePointer<Void>, Int)'
but now we produce:
error: cannot convert value of type 'UInt' to expected argument type 'Int'
return memcmp(left, right, UInt(left.count)) == 0
^~~~~~~~~~~~~~~~
which is more "to the point"
Swift SVN r30930
machinery, instead of in multiple places in CSSolver and CSDiags. This leads
to more predictable behavior (e.g. by removing the UnboundGenericParameter
failure kind) and eliminates a class of "'_' is not convertible to 'FooType'"
diagnostics.
Swift SVN r30923
other constraints intentionally ripped off, tell the recursive solution that
we can tolerate an ambiguous result. The point of this walk is not to
produce a concrete type for the subexpression, it is to expose any structural
errors within that subsystem that don't depend on the contextual constraints.
Swift SVN r30917
- Produce more specific diagnostics relating to different kinds of invalid
- add a testcase, nfc
- Reimplement FailureDiagnosis::diagnoseGeneralMemberFailure in terms of
Not including r30787 means that we still generate bogus diagnostics like:
[1, 2, 3].doesntExist(0) // expected-error {{type 'Int2048' does not conform to protocol 'IntegerLiteralConvertible'}}
But it is an existing and separable problem from the issues addressed here.
Swift SVN r30819
r30787 causes our tests to time out; the other commits depend on r30787.
Revert "revert part of my previous patch."
Revert "Produce more specific diagnostics relating to different kinds of invalid"
Revert "add a testcase, nfc"
Revert "- Reimplement FailureDiagnosis::diagnoseGeneralMemberFailure in terms of"
Revert "Fix places in the constraint solver where it would give up once a single "
Swift SVN r30805
performMemberLookup, eliminating a ton of duplicated logic, but keeping the
same general behavior.
- Now that r30787 landed, we can have diagnoseGeneralMemberFailure inform
clients when a member lookup fails due to referencing a candidate decl of
ErrorType (i.e, it is already invalid somehow). When this happens, there is
no reason to diagnose a problem, because the original issue has been diagnosed
and anything we produce now is just garbage.
The second point cleans up a bunch of bogus diagnostics in the testsuite, which are
*actually* due to upstream error that are already diagnosed.
Swift SVN r30789
"unavoidable failure" path, along with Failure::DoesNotHaveNonMutatingMember and
just doing some basic disambiguation in CSDiags.
This provides some benefits:
- Allows us to plug in much more specific diagnostics for the existing "only has
mutating members" diagnostic, including producing notes for why the base expr
isn't mutable (see e.g. test/Sema/immutability.swift diffs).
- Corrects issues where we'd drop full decl name info for selector references.
- Wordsmiths diagnostics to not complain about "values of type Foo.Type" instead
complaining about "type Foo"
- Where before we would diagnose all failures with "has no member named", we now
distinguish between when there is no member, and when you can't use it. When you
can't use it, you get a vauge "cannot use it" diagnostic, but...
- This provides an infrastructure for diagnosing other kinds of problems (e.g.
trying to use a private member or a static member from an instance).
- Improves a number of cases where failed type member constraints would produce uglier
diagnostics than a different constraint failure would.
- Resolves a number of rdars, e.g. (and probably others):
<rdar://problem/20294245> QoI: Error message mentions value rather than key for subscript
Swift SVN r30715
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
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
- 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
value member constraints do.
This fixes:
<rdar://problem/21662365> QoI: diagnostic for for-each over an optional sequence isn't great
before we'd produce:
t.swift:3:10: error: '[Int]?' does not have a member named 'Generator'
for x in array {
^
now we produce:
t.swift:3:10: error: value of optional type '[Int]?' not unwrapped; did you mean to use '!' or '?'?
for x in array {
^
Swift SVN r29902
Inference of type witnesses for associated types was previously
implemented as part of value witness matching in the constraint
solver. This led to a number of serious problems, including:
- Recursion problems with the solver hunting for a type witness,
which triggers more attemts to match value witnesses...
- Arbitrarily crummy attempts to break the recursion causing
type-check failures in fun places.
- Ordering dependencies abound: different results depending on which
value witnesses were satisfied first, failures because of the order
in which we attempted to infer type witnesses, etc.
This new implementation of type witness inference uses a separate pass
that occurs whenever we're looking for any type witness, and solves
all of the type witnesses within a given conformance
simultaneously. We still look at potential value witnesses to infer
type witnesses, but we match them structurally, without invoking the
constraint solver.
There are a few caveats to this implementation:
* We're not currently able to infer type witnesses from value
witnesses that are global operators, so some tricks involving global
operators (*cough* ~> *cough*) might require some manually-specified
type witnesses. Note that the standard library doesn't include any
such cases.
* Yes, it's another kind of solver. At simple one, fortunately.
On the other hand, this implementation should be a big step forward:
* It's far more predictable, order-invariant, and non-recursive.
* The diagnostics for failures to infer type witnesses have
improved.
Fixes rdar://problem/20598513.
Swift SVN r27616
This was because the ambiguity between c-style and foreach loops wasn't being
properly handled. Use the canParsePattern() logic to handle this in full
generality.
Since that logic was unused, dust it off and clean it up a bit. Similarly,
remove some old vestigates of default argument parsing in tuples and
old-syntax array handling.
Swift SVN r26164
* Lift NormalProtocolConformance::hasTypeWitness() to
ProtocolConformance. This method can be used to determine whether a
potentially invalid conformance has a particular type witness.
* ProtocolConformance::getWitness() may return nullptr if the witness
does not exist.
* In TypeChecker::getWitnessType(), don't complain that a builtin
protocol is broken if it's the conformance that's broken.
* ConformanceChecker should only emit diagnostics from within calls to
checkConformance().
* TypeChecker::conformsToProtocol() now returns true if the type
has a declared conformance to the protocol, regardless of whether the
conformance is valid. Clients must check the validity of the
ProtocolConformance themselves if necessary.
<rdar://problem/19495341> Can't upcast to parent types of type constraints without forcing
Swift SVN r25326
Most tests were using %swift or similar substitutions, which did not
include the target triple and SDK. The driver was defaulting to the
host OS. Thus, we could not run the tests when the standard library was
not built for OS X.
Swift SVN r24504
These changes make the following improvements to how we generate diagnostics for expression typecheck failure:
- Customizing a diagnostic for a specific expression kind is as easy as adding a new method to the FailureDiagnosis class,
and does not require intimate knowledge of the constraint solver’s inner workings.
- As part of this patch, I’ve introduced specialized diagnostics for call, binop, unop, subscript, assignment and inout
expressions, but we can go pretty far with this.
- This also opens up the possibility to customize diagnostics not just for the expression kind, but for the specific types
involved as well.
- For the purpose of presenting accurate type info, partially-specialized subexpressions are individually re-typechecked
free of any contextual types. This allows us to:
- Properly surface subexpression errors.
- Almost completely avoid any type variables in our diagnostics. In cases where they could not be eliminated, we now
substitute in "_".
- More accurately indicate the sources of errors.
- We do a much better job of diagnosing disjunction failures. (So no more nonsensical ‘UInt8’ error messages.)
- We now present reasonable error messages for overload resolution failures, informing the user of partially-matching
parameter lists when possible.
At the very least, these changes address the following bugs:
<rdar://problem/15863738> More information needed in type-checking error messages
<rdar://problem/16306600> QoI: passing a 'let' value as an inout results in an unfriendly diagnostic
<rdar://problem/16449805> Wrong error for struct-to-protocol downcast
<rdar://problem/16699932> improve type checker diagnostic when passing Double to function taking a Float
<rdar://problem/16707914> fatal error: Can't unwrap Optional.None…Optional.swift, line 75 running Master-Detail Swift app built from template
<rdar://problem/16785829> Inout parameter fixit
<rdar://problem/16900438> We shouldn't leak the internal type placeholder
<rdar://problem/16909379> confusing type check diagnostics
<rdar://problem/16951521> Extra arguments to functions result in an unhelpful error
<rdar://problem/16971025> Two Terrible Diagnostics
<rdar://problem/17007804> $T2 in compiler error string
<rdar://problem/17027483> Terrible diagnostic
<rdar://problem/17083239> Mysterious error using find() with Foundation types
<rdar://problem/17149771> Diagnostic for closure with no inferred return value leaks type variables
<rdar://problem/17212371> Swift poorly-worded error message when overload resolution fails on return type
<rdar://problem/17236976> QoI: Swift error for incorrectly typed parameter is confusing/misleading
<rdar://problem/17304200> Wrong error for non-self-conforming protocols
<rdar://problem/17321369> better error message for inout protocols
<rdar://problem/17539380> Swift error seems wrong
<rdar://problem/17559593> Bogus locationless "treating a forced downcast to 'NSData' as optional will never produce 'nil'" warning
<rdar://problem/17567973> 32-bit error message is really far from the mark: error: missing argument for parameter 'withFont' in call
<rdar://problem/17671058> Wrong error message: "Missing argument for parameter 'completion' in call"
<rdar://problem/17704609> Float is not convertible to UInt8
<rdar://problem/17705424> Poor error reporting for passing Doubles to NSColor: extra argument 'red' in call
<rdar://problem/17743603> Swift compiler gives misleading error message in "NSLayoutConstraint.constraintsWithVisualFormat("x", options: 123, metrics: nil, views: views)"
<rdar://problem/17784167> application of operator to generic type results in odd diagnostic
<rdar://problem/17801696> Awful diagnostic trying to construct an Int when .Int is around
<rdar://problem/17863882> cannot convert the expression's type '()' to type 'Seq'
<rdar://problem/17865869> "has different argument names" diagnostic when parameter defaulted-ness differs
<rdar://problem/17937593> Unclear error message for empty array literal without type context
<rdar://problem/17943023> QoI: compiler displays wrong error when a float is provided to a Int16 parameter in init method
<rdar://problem/17951148> Improve error messages for expressions inside if statements by pre-evaluating outside the 'if'
<rdar://problem/18057815> Unhelpful Swift error message
<rdar://problem/18077468> Incorrect argument label for insertSubview(...)
<rdar://problem/18079213> 'T1' is not identical to 'T2' lacks directionality
<rdar://problem/18086470> Confusing Swift error message: error: 'T' is not convertible to 'MirrorDisposition'
<rdar://problem/18098995> QoI: Unhelpful compiler error when leaving off an & on an inout parameter
<rdar://problem/18104379> Terrible error message
<rdar://problem/18121897> unexpected low-level error on assignment to immutable value through array writeback
<rdar://problem/18123596> unexpected error on self. capture inside class method
<rdar://problem/18152074> QoI: Improve diagnostic for type mismatch in dictionary subscripting
<rdar://problem/18242160> There could be a better error message when using [] instead of [:]
<rdar://problem/18242812> 6A1021a : Type variable leaked
<rdar://problem/18331819> Unclear error message when trying to set an element of an array constant (Swift)
<rdar://problem/18414834> Bad diagnostics example
<rdar://problem/18422468> Calculation of constant value yields unexplainable error
<rdar://problem/18427217> Misleading error message makes debugging difficult
<rdar://problem/18439742> Misleading error: "cannot invoke" mentions completely unrelated types as arguments
<rdar://problem/18535804> Wrong compiler error from swift compiler
<rdar://problem/18567914> Xcode 6.1. GM, Swift, assignment from Int64 to NSNumber. Warning shown as problem with UInt8
<rdar://problem/18784027> Negating Int? Yields Float
<rdar://problem/17691565> attempt to modify a 'let' variable with ++ results in typecheck error about @lvalue Float
<rdar://problem/17164001> "++" on let value could give a better error message
Swift SVN r23782
Start capitalizing on some of the new diagnostic machinery in a few different ways:
- When mining constraints for type information, utilize constraints "favored" by the overload resolution process.
- When printing type variables, if the variable was created by opening a literal expression, utilize the literal
default type or conformance if possible.
- Utilize syntactic information when crafting diagnostics:
- If the constraint miner can produce a better diagnostic than the recorded failure, diagnose via constraints.
- Factor in the expression kind when choosing which types to include in a diagnostic message.
- Start customizing diagnostics based on the amount of type data available.
What does all this mean?
- Fewer type variables leaking into diagnostic messages.
- Far better diagnostics for overload resolution failures. Specifically, we now print proper argument type data
for failed function calls.
- No more "'Foo' is not convertible to 'Foo'" error messages
- A greater emphasis on type data means less dependence on the ordering of failed constraints. This means fewer
inscrutable diagnostics complaining about 'UInt8' when all the constituent expressions are of type Float.
So we still have a ways to go, but these changes should greatly improve the number of head-scratchers served up
by the type checker.
These changes address the following radars:
rdar://problem/17618403
rdar://problem/17559042
rdar://problem/17007456
rdar://problem/17559042
rdar://problem/17590992
rdar://problem/17646988
rdar://problem/16979859
rdar://problem/16922560
rdar://problem/17144902
rdar://problem/16616948
rdar://problem/16756363
rdar://problem/16338509
Swift SVN r20927
This addresses or improves several existing TC perf bugs (rdar://problem/15933674, rdar://problem/17110608, rdar://problem/17240816, rdar://problem/17244974), and seems to speed up our unit test runs by ~5%. (On my MacBook Pro, total average execution time is reduced from 557.28s to 531.89s.)
Swift SVN r19939
Mechanically add "Type" to the end of any protocol names that don't end
in "Type," "ible," or "able." Also, drop "Type" from the end of any
associated type names, except for those of the *LiteralConvertible
protocols.
There are obvious improvements to make in some of these names, which can
be handled with separate commits.
Fixes <rdar://problem/17165920> Protocols `Integer` etc should get
uglier names.
Swift SVN r19883
This change pulls the handling of the element pattern and sequence of
a for-each loop into a single constraint system, so that we get type
inference between the two. Among other things, this allows one to
infer generic arguments within the element pattern from the sequence's
element type as well as allowing type annotations or the form of the
element pattern to affect overload resolution and generic argument
deduction for the sequence itself.
Swift SVN r19721
