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[ConstraintSystem] Small refactor of determining optional conversions. #17849

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Merged
merged 1 commit into from
Jul 12, 2018
Merged

[ConstraintSystem] Small refactor of determining optional conversions. #17849

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30 changes: 13 additions & 17 deletions lib/Sema/CSSimplify.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
Expand Down Expand Up @@ -1437,10 +1437,16 @@ static bool isStringCompatiblePointerBaseType(TypeChecker &TC,
/// Determine whether the first type with the given number of optionals
/// is potentially more optional than the second type with its number of
/// optionals.
static bool isPotentiallyMoreOptionalThan(Type objType1,
unsigned numOptionals1,
Type objType2,
unsigned numOptionals2) {
static bool isPotentiallyMoreOptionalThan(Type type1, Type type2) {

SmallVector<Type, 2> optionals1;
Type objType1 = type1->lookThroughAllOptionalTypes(optionals1);
auto numOptionals1 = optionals1.size();

SmallVector<Type, 2> optionals2;
type2->lookThroughAllOptionalTypes(optionals2);
auto numOptionals2 = optionals2.size();

if (numOptionals1 <= numOptionals2 && !objType1->isTypeVariableOrMember())
return false;

Expand All @@ -1452,22 +1458,12 @@ static void enumerateOptionalConversionRestrictions(
Type type1, Type type2,
ConstraintKind kind, ConstraintLocatorBuilder locator,
llvm::function_ref<void(ConversionRestrictionKind)> fn) {
SmallVector<Type, 2> optionals1;
Type objType1 = type1->lookThroughAllOptionalTypes(optionals1);

SmallVector<Type, 2> optionals2;
Type objType2 = type2->lookThroughAllOptionalTypes(optionals2);

if (optionals1.empty() && optionals2.empty())
return;

// Optional-to-optional.
if (!optionals1.empty() && !optionals2.empty())
if (type1->getOptionalObjectType() && type2->getOptionalObjectType())
fn(ConversionRestrictionKind::OptionalToOptional);

// Inject a value into an optional.
if (isPotentiallyMoreOptionalThan(objType2, optionals2.size(),
objType1, optionals1.size())) {
if (isPotentiallyMoreOptionalThan(type2, type1)) {
fn(ConversionRestrictionKind::ValueToOptional);
}
}
Expand Down