Commit Graph

1082 Commits

Author SHA1 Message Date
Joe Pamer
784fe6d601 Normalize some diagnostics by walking into tuple expressions. Doing so can
result in slightly more descriptive diagnostics in some cases. (Specifically,
for diagnostics involving binary operators.)

(rdar://problem/21080030)

Swift SVN r29020
2015-05-26 03:46:15 +00:00
Chris Lattner
3f0ca3e2c8 - Change the general assignment failure diagnostic to include the type of the
result and make it more specific.
- Move the 'assignment failure' diagnostic logic to CSDiags.cpp where it belongs.



Swift SVN r28937
2015-05-22 22:07:26 +00:00
Chris Willmore
1efc1430b1 Followup to r28883: pack SavedTypeVariableBinding::Options with TypeVar
and do less work in setMustBeMaterializableRecursive().

Swift SVN r28890
2015-05-21 22:40:10 +00:00
Chris Willmore
df9136e0e0 When unifying two type variables, make sure the new representative type
variable has the must-be-materializable bit set if the old one does.
When assigning a fixed type to a type variable that must be
materializable, transfer the bit to any type variables within the fixed
type, as appropriate.

Add Options field to SavedTypeVariableBinding to save/restore type
variable options during solution.

<rdar://problem/21026806> Propagate MustBeMaterializable bit among type variables appropriately

Swift SVN r28883
2015-05-21 19:53:48 +00:00
Chris Lattner
ec097fac23 add an accessor, NFC.
Swift SVN r28866
2015-05-21 05:48:45 +00:00
Chris Willmore
5905d07a08 Don't bind generic type parameters to non-materializable types.
Add a new option, TVO_MustBeMaterializable, to
TypeVariableType::Implementation, and set it for type variables
resulting from opening a generic type. This solution isn't complete (we
don't yet copy the non-materializable bit on unification of type
variables, and it's possible to bind a must-be-materializable type
variable to a type with type variables that later get bound to
non-materializable types) but it addresses all reported crashes for this
issue.

<rdar://problem/20807269> Crash in non-materializable type

Swift SVN r28792
2015-05-19 21:50:26 +00:00
David Farler
dbd78643ce Build fix: Adventure triggers nullptr dereference
Fix a nullptr dereference when looking for a base expression
in a member access. Remove use of Optional<T*>, it wasn't providing
any value versus nullptr checking.

Swift SVN r28648
2015-05-15 23:36:33 +00:00
David Farler
80571cf916 Check base expr when determining mutability of a member
When in an initializer, we allow setting into immutable properties
provided that the type of base in `base.member` matches that of that
initializer's containing type. This was an approximation for allowing
full access into `self` during initialization but this doesn't work when
passing in a different struct of the same type because that struct
should be still be immutable.

Check whether the base of the member access is the implicit self
parameter of the initializer before allowing mutation.

rdar://problem/19814302

Swift SVN r28634
2015-05-15 18:48:54 +00:00
John McCall
5d4fa0b7b6 A better fix: stop storing the address of a type in the constraint
system in the first place, because it's totally immutable on all
access paths.

Swift SVN r28595
2015-05-15 01:05:56 +00:00
Doug Gregor
83d336e714 Stop using TupleTypeElts in the type checking for arg/param matching.
Instead, use a dedicated struct. NFC

Swift SVN r28207
2015-05-06 17:05:27 +00:00
Chris Lattner
976620b513 random tidying up, rename the raw_ostream form of
ConstraintSystem::dump to ConstraintSystem::print for
consistency with other parts of the compiler.  Enhance
CS::print to print the ID # of a Type Variable, so you
don't have to count them to realize that you're looking
at typevar #13


Swift SVN r27874
2015-04-28 17:50:24 +00:00
Chris Lattner
d18740d603 Fix <rdar://problem/19773562> Closures executed immediately { like this }() are not automatically @noescape
In addition to being better for performance in these cases, this disables the "self." 
requirement in these blocks.  {}() constructs are often used to work around statements
that are not exprs in Swift, so they are reasonably important.

Fixing this takes a couple of pieces working together:
 - Add a new 'extraFunctionAttrs' map to the ConstraintSystem for solution
   invariant function attributes that are inferred (like @noescape).
 - Teach constraint simplification of function applications to propagate 
   @noescape between unified function types.
 - Teach CSGen of ApplyExprs to mark the callee functiontype as noescape
   when it is obviously a ClosureExpr.

This is a very limited fix in some ways: you could argue that ApplyExpr should
*always* mark its callee as noescape.  However, doing so would just introduce a
ton of function conversions to remove it again, so we don't do that.




Swift SVN r27723
2015-04-25 23:34:18 +00:00
Slava Pestov
2e083fd8ed ConstraintSystem.h: Fix grammar in doc comment
Swift SVN r27583
2015-04-22 17:18:43 +00:00
Chris Willmore
d4db635e3d Add object literal syntax and _{Color,Image}LiteralConvertible protocols
Add syntax "[#Color(...)#]" for object literals, to be used by
Playgrounds for inline color wells etc. The arguments are forwarded to
the relevant constructor (although we will probably change this soon,
since (colorLiteralRed:... blue:... green:... alpha) is kind of
verbose). Add _ColorLiteralConvertible and _ImageLiteralConvertible
protocols, and link them to the new expressions in the type checker.
CSApply replaces the object literal expressions with a call to the
appropriate protocol witness.

Swift SVN r27479
2015-04-20 12:55:56 +00:00
Doug Gregor
9256250273 Fix type checking for a non-throwing function as a subtype of a throwing function.
A non-throwing function can be a trivial subtype of a throwing
function. Encode this rule more directly, introduce some additional
tests to ensure that we get the behavior right where we need exact
matches, and add a failure kind with custom diagnostic for cases where
function types mismatch due to 'throws'.

Swift SVN r27255
2015-04-13 18:39:39 +00:00
Doug Gregor
7d6f2accd9 Improve use of properties/subscripts of protocol extensions via existentials.
Improves the placement of open-existential expressions when accessing
a property or subscript declared in a protocol extension. We need to
delay until the load occurs when the property/subscript has a usable
setter.

Swift SVN r27064
2015-04-07 06:01:14 +00:00
Doug Gregor
f4d98da668 Support the use of members of protocol extensions on existential types.
To use members of protocol extensions on existential types, we
introduce an OpenExistentialExpr expression to open up the existential
type (into a local archetype) and perform the operations on that local
archetype.

Unlike with uses of initializers or dynamic-Self-producing
methods of protocols, which produce similar ASTs, we have the type
checker perform the "open" operation and then track it through
constraint application. This scheme is better (because it's more
direct), but it's still using a simplistic approach to deciding where
the actual OpenExistentialExpr goes that needs improvement.

Swift SVN r26964
2015-04-04 00:00:14 +00:00
Chris Lattner
8a07a85a91 Progress towards let/else:
- Implement SILGen for conditional multi-pattern PBD's.
 - Have the type checker check where clauses on PBDs.
 - Change the AST to represent complex if/let PBD's with
   composed PBDs instead of breaking them down. For example, 
   represent:
     if let x? = foo(), y? = bar() where x == y {
   as a single PBD in a StmtCondition instead of representing
   it as three entries in the condition.

The later change is good for AST/source fidelity as well as providing
a cheap way to exercise all the logic I'm building.



Swift SVN r26959
2015-04-03 22:46:34 +00:00
Chris Lattner
f7fe8a5f4a Fix <rdar://problem/20392122> Destructuring tuple with labels doesn't work
This pushes tuple pattern labels forward:
  - Actually record them in TuplePatternElt.
  - Remove the tuple shuffle ban that prevents some cases
    (e.g. the one in the radar) of a tuple with labels being shuffled
    onto a tuple without labels.
  - Remove dead code enabled by removing the restriction.



Swift SVN r26852
2015-04-02 04:23:54 +00:00
Chris Willmore
fc561cd7ea Fix errant fixit "as!" -> "as?!"
"let x: Int? = 5 as Any as! Int" now suggests changing "as!" to "as?"
instead of "as?!".

rdar://problem/19883819

Swift SVN r25490
2015-02-23 22:59:46 +00:00
Doug Gregor
3805e18090 Explicitly track the mapping from dependent types to their opened type variables.
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
2015-02-18 19:41:40 +00:00
Doug Gregor
0e74268ea5 Strongly prefer available declarations to unavailable ones in type checking.
Fixes rdar://problem/18847642, rdar://problem/16554496, and the
current 1_stdlib/Array.swift.

Swift SVN r25212
2015-02-12 01:01:11 +00:00
Jordan Rose
07041fc7d3 Revert all the function type ABI restriction changes.
John pointed out that messing with the type checker's notion of "subtype"
is a bad idea. Instead, we should just have a separate check for ABI
compatibility...and eventually (rdar://problem/19517003) just insert the
appropriate thunks rather than forcing the user to perform the conversion.

I'm leaving all the tests as they are because I'm adding a post-type-checking
diagnostic in the next commit, and that should pass all the same tests.

Part of rdar://problem/19600325

Swift SVN r25116
2015-02-10 03:46:46 +00:00
Chris Willmore
e2ac9f65ac Add FixKind for 'as' -> 'as!' conversion
Penalize solutions that involve 'as' -> 'as!' changes by recording a Fix
when simplifying the corresponding checked-cast constraint.

<rdar://problem/19724719> Type checker thinks "(optionalNSString ?? nonoptionalNSString) as String" is a forced cast

Swift SVN r25061
2015-02-07 00:33:37 +00:00
Jordan Rose
3e1e2c4852 Lock down on function conversions that change the ABI of the function.
These haven't ever been safe in Swift's development because they require
generating thunks, and we currently don't do that. However, we were letting
existential conversions slip through the cracks because we consider them
subtypes, so that /metatype/ conversions work correctly. To be concrete:

  "let _: Any.Type = Int.self" is okay.
  "let _: (Int) -> Void = { (_: Any) -> Void in return }" is not.

We should implement this some day; that's rdar://problem/19517003.

This produces some lousy error messages, which I intend to fix soon.

Part of rdar://problem/19600325

Swift SVN r24915
2015-02-03 03:44:05 +00:00
Joe Pamer
0562411bb2 Improve support for diagnosing errors that result from contextual or conversion type mismatches. Doing so allows us to improve our diagnostics for a few important cases:
- Situations where the type of a return statement's result expression doesn't line up with the function's type annotation.
- Situations where the type of an initializer expression doesn't line up with its declaration's type pattern.
- Situations where we assume a conversion to a built-in protocol must take place, such as in if-statement conditionals.

(Addresses rdar://problem/19224776, rdar://problem/19422107, rdar://problem/19422156, rdar://problem/19547806 and lots of other dupes.)

Swift SVN r24853
2015-01-30 19:32:20 +00:00
Joe Pamer
a18bedf079 Factor the constraint-favoring machinery out of the constraint generation process, and re-work it into a series of passes over an expression sub-tree.
Aside from tidying things up, doing this results in some significant benefits:
- Allows for global constraint ordering optimizations over a given expression, not just on a peephole basis.
- Eliminates a set of order-dependent bugs in the solver that have been dogging us for a while. (rdar://problem/19459079)
- Brings another set of tyvar-to-tyvar solving problems out of the realm of the exponential. (rdar://problem/19005271)
- Opens up the possibility of optimizing constraints during later solving phases - not just while generating them.

Swift SVN r24693
2015-01-23 23:10:50 +00:00
Chris Willmore
3dea623b71 <rdar://problem/19495142> Various incorrect diagnostics for explicit type conversions
Fix diagnostics for 'as' and 'as!' expressions by ensuring that the
conversion constraint used to generate them actually corresponds to the
expression in question. Add tests from 19495142.

Swift SVN r24547
2015-01-20 04:16:37 +00:00
Joe Pamer
35184ff7b5 Utilize argument type information to favor overload binding constraints on initializers. Doing so addresses a number of cases where the type checker was going exponential on seemingly simple user code.
Also, these changes fix the performance regressions that were introduced as a result of September's convertible/init requirement modifications, and allow us to roll back the associated workarounds that were added to the Adventure sample (rdar://problem/18942100).

Swift SVN r24520
2015-01-19 20:59:14 +00:00
Joe Pamer
f56949846f Propagate constraint favoring information across nodes of chained operations. This allows us to properly favor constraints for expressions the form "(float0 + float1) * float2".
Swift SVN r24519
2015-01-19 20:59:14 +00:00
Chris Willmore
68dd563fbf <rdar://problem/18311362> TLF: Eliminate implicit bridging conversions
Require 'as' when converting from Objective-C type to native type (but
continue to allow implicit conversion from native to Objective-C). This
conversion constraint is called ExplicitConversion; all implicit
conversions are covered by the existing Conversion constraint. Update
standard library and tests to match.

Swift SVN r24496
2015-01-18 00:07:45 +00:00
Doug Gregor
fea55d98f2 Eliminate dependent types from within archetypes.
When dealing with multiple levels of generic parameters, the mapping
from potential archetypes down to actual archetypes did not have
access to the archetypes for outer generic parameters. When same-type
requirements equated a type from the inner generic parameter list with
one from the outer generic parameter list, the reference to the outer
generic parameter list's type would remain dependent. For example,
given:

  struct S<A: P> {
    init<Q: P where Q.T == A>(_ q: Q) {}
  }

we would end up with the dependent type for A (τ_0_0) in the same-type
constraint in the initializer requirement.

Now, notify the ArchetypeBuilder of outer generic signatures (and,
therefore, outer generic parameters), so that it has knowledge of the
mapping from those generic parameters to the corresponding
archetypes. Use that mapping when translating potential archetypes to
real archetypes. Additionally, when a potential archetype is mapped to
a concrete type (via a same-type constraint to a concrete type),
substitute archetypes for any dependent types within the concrete
type.

Remove a bunch of hacks in the compiler that identified dependent
types in "strange" places and tried to map them back to
archetypes. Those hacks handled some narrow cases we saw in the
standard library and some external code, but papered over the
underlying issue and left major gaps.

Sadly, introduce one hack into the type checker to help with the
matching of generic witnesses to generic requirements that follow the
pattern described above. See ConstraintSystem::SelfTypeVar; the proper
implementation for this matching involves substituting the adoptee
type in for Self within the requirement, and synthesizing new
archetypes from the result.

Fixes rdar://18435371, rdar://18803556, rdar://19082500,
rdar://19245317, rdar://19371678 and a half dozen compiler crashers
from the crash suite. There are a few other radars that I suspect this
fixes, but which require more steps to reproduce.

Swift SVN r24460
2015-01-16 00:27:18 +00:00
Doug Gregor
562b529d7a Start simplifying the "dependent type opener" contract.
The archetype opener only needs to perform basic substitutions; let it
do so, avoiding the creation of a pile of type variables that simply
get immediately bound.

Swift SVN r24399
2015-01-13 23:17:52 +00:00
Chris Willmore
03a6190a1f <rdar://problem/19031957> Change failable casts from "as" to "as!"
Previously the "as" keyword could either represent coercion or or forced
downcasting. This change separates the two notions. "as" now only means
type conversion, while the new "as!" operator is used to perform forced
downcasting. If a program uses "as" where "as!" is called for, we emit a
diagnostic and fixit.

Internally, this change removes the UnresolvedCheckedCastExpr class, in
favor of directly instantiating CoerceExpr when parsing the "as"
operator, and ForcedCheckedCastExpr when parsing the "as!" operator.

Swift SVN r24253
2015-01-08 00:33:59 +00:00
Chris Lattner
3578c7fde0 Teach the type checker about subtype relationships of noescape, and use this
to allow passing off a no-escape formal parameter to the argument of a 
noescape parameter call.



Swift SVN r24126
2014-12-23 22:18:09 +00:00
Joe Pamer
2912159776 Improve diagnostics for expression typecheck errors
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
2014-12-08 21:56:47 +00:00
Chris Willmore
36d0f187ec Sema, SILGen, ClangImporter: Add special support for Set<T>
Add the following functionality to the Swift compiler:

* covariant subtyping of Set
* upcasting, downcasting of Set
* automatic bridging between Set and NSSet, including
    * NSSet params/return values in ObjC are imported as Set<NSObject>
    * Set params/return values in Swift are visible to ObjC as NSSet

<rdar://problem/18853078> Implement Set<T> up and downcasting

Swift SVN r23751
2014-12-06 02:52:33 +00:00
Doug Gregor
c1c51b4e8b Move checking of non-failable-to-failable initializer calls into constraint application.
This makes sure we get the same checking for initializer delegation in
structs/enums as we do for classes, fixing rdar://problem/18458622.

Swift SVN r23128
2014-11-06 06:29:35 +00:00
Chris Willmore
22f2452909 Only allow labeled parameters with function type to claim trailing closures, as opposed to any unlabeled argument.
For real this time. Added some additional tests.

rdar://problem/18778670

Swift SVN r23094
2014-11-04 03:40:08 +00:00
Chris Willmore
da2e3c4c73 Revert "Only allow labeled parameters with function type to claim trailing closures, as opposed to any unlabeled argument."
The commit broke the PerfTestSuite build:

/Users/buildslave/jenkins/sharedspace/swift-release-asserts/swift/src/tools/swift/benchmark/PerfTestSuite/SingleSource/DollarChain.swift:30:14:
error: missing argument label 'function:' in call
       $.tap(beatle, {$0.name = "Beatle"}).color = "Blue"

This reverts commit r23090.

Swift SVN r23093
2014-11-04 02:19:10 +00:00
Chris Willmore
f64bdb3021 Only allow labeled parameters with function type to claim trailing closures, as opposed to any unlabeled argument.
rdar://problem/18778670

Swift SVN r23090
2014-11-03 22:22:48 +00:00
Jordan Rose
3fcdfd40e9 Remove the "swift/Basic/Optional.h" header.
llvm::Optional lives in "llvm/ADT/Optional.h". Like Clang, we can get
Optional in the 'swift' namespace by including "swift/Basic/LLVM.h".

We're now fully switched over to llvm::Optional!

Swift SVN r22477
2014-10-02 18:51:45 +00:00
Jordan Rose
042569a3be Optional: Replace uses of Nothing with None.
llvm::Optional (like Swift.Optional!) uses None as its placeholder value,
not Nothing.

Swift SVN r22476
2014-10-02 18:51:42 +00:00
Devin Coughlin
3749a98763 Record the reason a declaration is potentially unavailable.
This commit adds tracking of the reason a declaration reference is potentially
unavailable to the UnavailableToOptionalExpr AST node and to OverloadChoice. We
will use this reason during SILGen to emit the appropriate run-time check and
during typechecking to provide more helpful diagnostics.

To keep OverloadChoice as small as possible, we encode the reason as an index
into a vector of reasons stored in a given instance of ConstraintSystem (this is
the same approach that Fix takes).

This commit adds Sema/OverloadChoice.cpp (for the parts of OverloadChoice that
now rely on ConstraintSystem) and AST/Availability.h (to bring in
availability-related structures without TypeRefinementContext).


Swift SVN r22377
2014-09-30 01:53:59 +00:00
Doug Gregor
e0afb13abb Remove the APINotes library; it lives in Clang, now.
Swift SVN r22286
2014-09-25 18:48:43 +00:00
Devin Coughlin
b727b6d932 Treat potentially unavailable global variable references as optional.
This patch adds the ability (-enable-experimental-unavailable-as-optional) to
treat potentially unavailable declarations as if they had optional types. For
the moment, this is only implemented for global variables.

The high-level approach is to (1) record the potential unavailability of a
declaration reference in the overload choice during constraint generation; (2)
treat the declaration as if it had an optional type during overload resolution
(this is similar to how optional protocol members are treated); and (3) add an
implicit conversion (UnavailableToOptionalExpr) during constraint application
to represent the run-time availability check and optional injection.

This patch does not implement SILGen for UnavailableToOptionalExpr.


Swift SVN r22245
2014-09-24 00:07:46 +00:00
Doug Gregor
55afb33c94 Associate argument labels with the callee in the solver.
When performing name lookup for a declaration that is being called,
use the argument labels at the call site to filter out those
declarations with incompatible argument labels.


Swift SVN r22176
2014-09-22 20:08:01 +00:00
Dmitri Hrybenko
fad578b304 stdlib: remove ArrayBonudType
Swift SVN r21991
2014-09-16 22:42:33 +00:00
Doug Gregor
8cf718f9f6 Don't allow a generic parameter with a non-@objc protocol requirement to bind to an existential.
We don't properly open up the existential to make this work, which
leads to an IRGen crash. Reject the uses of generics that would cause
such a crash rdar://problem/17491663.


Swift SVN r21946
2014-09-15 17:36:26 +00:00
Doug Gregor
e002261865 Diagnose free type variables that correspond to generic parameters.
t2.swift:3:1: error: argument for generic parameter 'U' could not be
inferred
f(i)
^
t2.swift:2:6: note: in call to function 'f'
func f<T, U>(t: T) -> U? { return nil }
     ^

Our lack of decent locator information means that we don't get notes
in all of the cases we want them. I'll look at that separately.

Swift SVN r21921
2014-09-12 20:27:21 +00:00