[SR-15165] Roundabout error message is viewed when Int is passed to where NSNumber is expected.

[YOCKOW]

Previous ID	SR-15165
Radar	rdar://problem/82828226
Original Reporter	@YOCKOW
Type	Improvement
Status	Closed
Resolution	Done

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Improvement, DiagnosticsQoI, StarterBug
Assignee	@YOCKOW
Priority	Medium

md5: ee5ef301fae73e1dec12f385ba78f3ac

Issue Description:

Given the following code:

import Foundation

func f(_ n: NSNumber) {}

let int: Int = 0

f(int)
/*
⛔️ error: cannot convert value of type 'Int' to expected argument type 'NSNumber'
f(int)
 ^
 NSNumber( )
 */

// Fix it as advised...
f(NSNumber(int))
/*
⛔️ error: no exact matches in call to initializer
f(NSNumber(int))
 ^
Foundation.NSNumber:41:12: note: incorrect labels for candidate (have: '(_:)', expected: '(value:)')
   public init(value: Int)
          ^
Foundation.NSNumber:2:42: note: incorrect labels for candidate (have: '(_:)', expected: '(integerLiteral:)')
   @nonobjc required public convenience init(integerLiteral value: Int)
                                        ^
 */

f(NSNumber(value: int)) // ✅ OK

I believe NSNumber(value: ) should be suggested first.

[typesanitizer]

@swift-ci create

[swift-ci]

Comment by jiaren wang (JIRA)

Could I get some hints?

[typesanitizer]

cc @xedin for implementation suggestions 🙂

[xedin]

I think all we need to do here is to detect that `toType` is `NSNumber` and add a label to the fix-it here - https://github.com/apple/swift/blob/main/lib/Sema/CSDiagnostics.cpp#L2876

[xedin]

Fixed by #39261 Please use next available toolchain to verify and close.

[YOCKOW]

Thank you for having worked on it.