skiptools / skiptools/skip-lib

ClosedRange .lowerBound and .upperBound transpiled incorrectly

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Dominant language
Swift
Stars
13
Forks
4
Avg merge
1h 49m
Merged PRs (30d)
2

Description

Issue

I have a function with the following Swift code:

if value > bounds.lowerBound {
     self.value -= 1
}

if value < bounds.upperBound {
     self.value += 1
}

This gets transpiled to the following Kotlin code:

if (value > bounds.lowerBound) {
     this.value -= 1
}

if (value < bounds.upperBound) {
     this.value += 1
}

I'm getting an error from the compiler that refers to the following line:
if (value > bounds.lowerBound) {
and
if (value < bounds.upperBound) {

Unresolved reference. None of the following candidates is applicable because of a receiver type mismatch:

Proposed solution:

I think this:

if (value > bounds.lowerBound) {
}

needs to change to this:

if (value > bounds.start) {
}

and this:

if (value < bounds.upperBound) {
}

needs to change to this:

if (value < bounds.endInclusive) {
}
Workaround:
if isHigher(value: value, than: bounds) {
     self.value -= 1
}

if isLower(value: value, than: bounds) {
     self.value += 1
}


// SKIP REPLACE:
// private fun isHigher(value: Int, than: ClosedRange<Int>): Boolean {
//     val bounds = than
//     return value > bounds.start
// }
fileprivate func isHigher(value: Int, than bounds: ClosedRange<Int>) -> Bool {
    return value > bounds.lowerBound
}

// SKIP REPLACE:
// private fun isLower(value: Int, than: ClosedRange<Int>): Boolean {
//     val bounds = than
//     return value < bounds.endInclusive
// }
fileprivate func isLower(value: Int, than bounds: ClosedRange<Int>) -> Bool {
    return value < bounds.upperBound
}

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Research direction

No source file or test is named. Start by reproducing the transpilation from the Swift ClosedRange snippet and inspect the generated Kotlin references to lowerBound and upperBound. Done means the generated comparisons use the Kotlin ClosedRange properties shown in the proposed solution and compile successfully.

Written by the indexing model from the issue text.

Assessment

Tech stack
kotlin, swift
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
38/100

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