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Sema: Explicitly allow Optional-to-IUO when converting functions. #7153

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Merged
merged 1 commit into from
Jan 31, 2017
Merged

Sema: Explicitly allow Optional-to-IUO when converting functions. #7153

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10 changes: 6 additions & 4 deletions lib/Sema/CSSimplify.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1232,7 +1232,7 @@ static bool isPotentiallyMoreOptionalThan(Type objType1,
/// Enumerate all of the applicable optional conversion restrictions
static void enumerateOptionalConversionRestrictions(
Type type1, Type type2,
ConstraintKind kind,
ConstraintKind kind, ConstraintLocatorBuilder locator,
llvm::function_ref<void(ConversionRestrictionKind)> fn) {
SmallVector<Type, 2> optionals1;
Type objType1 = type1->lookThroughAllAnyOptionalTypes(optionals1);
Expand All @@ -1251,6 +1251,7 @@ static void enumerateOptionalConversionRestrictions(
// Break cyclic conversions between T? and U! by only allowing it for
// conversion constraints.
if (kind >= ConstraintKind::Conversion ||
locator.isFunctionConversion() ||
!(optionalKind1 == OTK_Optional &&
optionalKind2 == OTK_ImplicitlyUnwrappedOptional))
fn(ConversionRestrictionKind::OptionalToOptional);
Expand Down Expand Up @@ -2055,9 +2056,10 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
// A value of type T, T?, or T! can be converted to type U? or U! if
// T is convertible to U.
if (concrete && kind >= ConstraintKind::Subtype) {
enumerateOptionalConversionRestrictions(type1, type2, kind,
[&](ConversionRestrictionKind restriction) {
conversionsOrFixes.push_back(restriction);
enumerateOptionalConversionRestrictions(
type1, type2, kind, locator,
[&](ConversionRestrictionKind restriction) {
conversionsOrFixes.push_back(restriction);
});
}

Expand Down
5 changes: 5 additions & 0 deletions test/Constraints/closures.swift
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Expand Up @@ -437,3 +437,8 @@ func sr3497_unfold<A, B>(_ a0: A, next: (inout A) -> B) {}
func sr3497() {
let _ = sr3497_unfold((0, 0)) { s in 0 } // ok
}

// SR-3758: Swift 3.1 fails to compile 3.0 code involving closures and IUOs
let _: ((Any?) -> Void) = { (arg: Any!) in }
// This example was rejected in 3.0 as well, but accepting it is correct.
let _: ((Int?) -> Void) = { (arg: Int!) in }
11 changes: 11 additions & 0 deletions test/SILGen/implicitly_unwrapped_optional.swift
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Expand Up @@ -59,3 +59,14 @@ func return_any() -> AnyObject! { return nil }
func bind_any() {
let object : AnyObject? = return_any()
}

// CHECK-LABEL: sil hidden @_T029implicitly_unwrapped_optional6sr3758yyF
func sr3758() {
// Verify that there are no additional reabstractions introduced.
// CHECK: [[CLOSURE:%.+]] = function_ref @_T029implicitly_unwrapped_optional6sr3758yyFySQyypGcfU_ : $@convention(thin) (@in Optional<Any>) -> ()
// CHECK: [[F:%.+]] = thin_to_thick_function [[CLOSURE]] : $@convention(thin) (@in Optional<Any>) -> () to $@callee_owned (@in Optional<Any>) -> ()
// CHECK: [[CALLEE:%.+]] = copy_value [[F]] : $@callee_owned (@in Optional<Any>) -> ()
// CHECK: = apply [[CALLEE]]({{%.+}}) : $@callee_owned (@in Optional<Any>) -> ()
let f: ((Any?) -> Void) = { (arg: Any!) in }
f(nil)
} // CHECK: end sil function '_T029implicitly_unwrapped_optional6sr3758yyF'