x/tools/gopls/internal/analysis/modernize: slicedelete: triggers on non idempotent slice identifiers

[ashurbekovz]

gopls version

x/tools/gopls v0.18.1

go env

irrelevant

What did you do?

This program prints [1 4]

package main

import (
	"fmt"
)

func main() {
	counter := 0
	getSlice := func() []int {
		counter++
		return []int{counter, counter + 1, counter + 2}
	}
	fmt.Println(append(getSlice()[:1], getSlice()[2:]...))
}

What did you see happen?

Gopls wants to modernize append(getSlice()[:1], getSlice()[2:]...) -> slices.Delete(getSlice(), 1, 2).
Since the two calls to getSlice() are replaced by one, the final output is replaced by [1 3].

What did you expect to see?

Behavior unchanged.

Editor and settings

No response

Logs

No response

[gopherbot]

Change https://go.dev/cl/659295 mentions this issue: gopls/internal/analysis/modernize: fix slicedelete triggers on non idempotent slice identifiers