[SR-5112] Not correct function types in Swift4 (typeof) #47688

swift-ci · 2017-06-06T19:00:02Z


Previous ID	SR-5112
Radar	rdar://problem/32601617
Original Reporter	VladimirS (JIRA User)
Type	Bug

Environment

swift-4.0-DEVELOPMENT-SNAPSHOT-2017-06-01-a-osx

Additional Detail from JIRA


Votes	1
Component/s
Labels	Bug
Assignee	@xedin
Priority	Medium

md5: e265814eeaa6d3f294a7315eed219f29

is blocked by:

SR-5127 Single-tuple and multiple-argument function types should not be considered equal

is duplicated by:

SR-5129 Don't treat func signatures as being the same when they are in fact different

Issue Description:

Mark Lacey <mark.lacey@apple.com> asked to create this issue.

I believe fooParam should have type of (Int,Int) -> () and fooTuple of type ((Int,Int)) -> (), but it seems like they have the same type:

func fooParam(_ x: Int, _ y: Int){}
func fooTuple(_ x: (Int, Int)) {}

print("type of fooParam is", type(of:fooParam))
// result: type of fooParam is (Int, Int) -> ()

print("type of fooTuple is", type(of:fooTuple))
// result: type of fooTuple is (Int, Int) -> ()

print("type of fooTuple as (_:(Int,Int))->Void is", type(of: fooTuple as (_:(Int,Int))->()))
// result: type of fooTuple as (_:(Int,Int))->() is (Int, Int) -> ()

print("type of fooParam == type of fooTuple ?", type(of: fooParam) == type(of: fooTuple))
// result: true

//--- closure ---

var closureParam = { (x: Int, y: Int) in  }
var closureTuple = { (x: (Int, Int)) in  }

print("type of closureParam is", type(of:closureParam))
// result: type of closureParam is (Int, Int) -> ()

print("type of closureTuple is", type(of:closureTuple))
// result: type of closureTuple is (Int, Int) -> ()

rudkx · 2017-06-07T00:40:29Z

@swift-ci create

rudkx · 2017-06-07T02:00:33Z

For

  func fooTuple(_ x: (Int, Int)) {}
  let t = type(of: fooTuple)

we maintain the fact that it’s a function taking a tuple through the AST passes, but it looks like the SIL metatype instruction treats it like a function taking two arguments.

I suspect this is simply a result of canonicalizing the type when generating SIL.

belkadan · 2017-06-07T18:10:25Z

We've also historically had problems printing function types. @slavapestov, @jckarter?

jepers · 2017-06-07T20:12:02Z

Also, note that:

typealias A = (Int, Int) -> ()
typealias B = ((Int, Int)) -> ()

print(A.self == B.self) // true

func representsSameType<T>(_: T.Type, _: T.Type) -> Bool { return true }
func representsSameType<T, U>(_: T.Type, _: U.Type) -> Bool { return false }
print(representsSameType(A.self, B.self)) // true

func takesOnlyA(_: A.Type) { print("A!") }
takesOnlyA(A.self) // A!
takesOnlyA(B.self) // A!

Result is the same with (Swift 4) 2017-06-06 snapshots and Xcode 8.3.3 default toolchain.

slavapestov · 2017-06-08T00:29:41Z

Yeah, the current implementation of SE-0110 does not fully address this. Runtime types are still canonicalized. We need to represent FunctionType as having an argument list and a result, instead of a single input and a result, so that single-argument function types canonicalize properly.

swift-ci transferred this issue from apple/swift-issues Apr 25, 2022

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[SR-5112] Not correct function types in Swift4 (typeof) #47688

[SR-5112] Not correct function types in Swift4 (typeof) #47688

swift-ci commented Jun 6, 2017

rudkx commented Jun 7, 2017

rudkx commented Jun 7, 2017

belkadan commented Jun 7, 2017

jepers commented Jun 7, 2017

slavapestov commented Jun 8, 2017

[SR-5112] Not correct function types in Swift4 (typeof) #47688

[SR-5112] Not correct function types in Swift4 (typeof) #47688

Comments

swift-ci commented Jun 6, 2017

rudkx commented Jun 7, 2017

rudkx commented Jun 7, 2017

belkadan commented Jun 7, 2017

jepers commented Jun 7, 2017

slavapestov commented Jun 8, 2017