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[ConstraintSystem] Make sure that keypath dynamic member lookup could be used recursively

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For example if there a structure which requires multiple implicit
dynamic member calls to get the members:

```swift
struct Point { var x, y: Int }

@dynamicMemberLookup
struct Lens<T> {
   var obj: T

   subscript<U>(dynamicMember member: KeyPath<T, U>) -> U {
     get { return obj[keyPath: member] }
   }
}

func foo(_ lens: Lens<Lens<Point>>) {
  _ = lens.x
  _ = lens.obj.x
  _ = lens.obj.obj.x
}

_ = \Lens<Lens<Point>>.x
```
This commit is contained in:
Pavel Yaskevich
2019-04-03 19:19:59 -07:00
parent 2e8d163655
commit b388d83426
3 changed files with 92 additions and 25 deletions
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24
test/Constraints/keypath_dynamic_member_lookup.swift
View File

@@ -226,3 +226,27 @@ func test_keypath_dynamic_lookup_inside_keypath() {
// CHECK-NEXT: keypath $KeyPath<Lens<Array<Array<Int>>>, Lens<Int>>, (root $Lens<Array<Array<Int>>>; settable_property $Lens<Array<Int>>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs15WritableKeyPathCyxqd__G_tcluig : {{.*}})
_ = \Lens<[[Int]]>.[0].count
}
func test_recursive_dynamic_lookup(_ lens: Lens<Lens<Point>>) {
// CHECK: keypath $KeyPath<Point, Int>, (root $Point; stored_property #Point.x : $Int)
// CHECK-NEXT: keypath $KeyPath<Lens<Point>, Lens<Int>>, (root $Lens<Point>; gettable_property $Lens<Int>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig : {{.*}})
// CHECK: function_ref @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig
_ = lens.x
// CHECK: keypath $KeyPath<Point, Int>, (root $Point; stored_property #Point.x : $Int)
// CHECK: function_ref @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig
_ = lens.obj.x
// CHECK: [[FIRST_OBJ:%.*]] = struct_extract {{.*}} : $Lens<Lens<Point>>, #Lens.obj
// CHECK-NEXT: [[SECOND_OBJ:%.*]] = struct_extract [[FIRST_OBJ]] : $Lens<Point>, #Lens.obj
// CHECK-NEXT: struct_extract [[SECOND_OBJ]] : $Point, #Point.y
_ = lens.obj.obj.y
// CHECK: keypath $KeyPath<Point, Int>, (root $Point; stored_property #Point.x : $Int)
// CHECK-NEXT: keypath $KeyPath<Lens<Point>, Lens<Int>>, (root $Lens<Point>; gettable_property $Lens<Int>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig : {{.*}})
// CHECK-NEXT: keypath $KeyPath<Lens<Lens<Point>>, Lens<Lens<Int>>>, (root $Lens<Lens<Point>>; gettable_property $Lens<Lens<Int>>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig : {{.*}})
_ = \Lens<Lens<Point>>.x
// CHECK: keypath $WritableKeyPath<Rectangle, Point>, (root $Rectangle; stored_property #Rectangle.topLeft : $Point)
// CHECK-NEXT: keypath $WritableKeyPath<Lens<Rectangle>, Lens<Point>>, (root $Lens<Rectangle>; settable_property $Lens<Point>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs15WritableKeyPathCyxqd__G_tcluig : {{.*}})
// CHECK-NEXT: keypath $KeyPath<Point, Int>, (root $Point; stored_property #Point.x : $Int)
// CHECK-NEXT: keypath $KeyPath<Lens<Point>, Lens<Int>>, (root $Lens<Point>; gettable_property $Lens<Int>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs7KeyPathCyxqd__G_tcluig : {{.*}})
// CHECK-NEXT: keypath $KeyPath<Lens<Lens<Rectangle>>, Lens<Lens<Int>>>, (root $Lens<Lens<Rectangle>>; settable_property $Lens<Lens<Point>>, id @$s29keypath_dynamic_member_lookup4LensV0B6MemberACyqd__Gs15WritableKeyPathCyxqd__G_tcluig : {{.*}})
_ = \Lens<Lens<Rectangle>>.topLeft.x
}