False positive "result is never used" when caller is inside a nested closure and two other callers discard the result

[twz123]

In the program below, newInstance returns two values. The *recorder result is used, in the innermost closure, but unparam reports:

$ go run mvdan.cc/unparam@v0.0.0-20260823230713-2fa3d841b0c8 .
main.go:15:34: main$1 - result 1 (*example.com/unparamrepro.recorder) is never used
exit status 1

// Using module example.com/unparamrepro as module name
package main

import "fmt"

type widget struct{ n int }

type recorder struct{ entries []string }

func run(f func()) { f() }

func main() {
	// "result 1 (*example.com/unparamrepro.recorder) is never used"
	// Although the doubly-nested closure at the bottom uses it.
	newInstance := func() (*widget, *recorder) {
		return &widget{n: 1}, &recorder{}
	}

	// Deleting either one of the two discarding closures makes the warning disappear.
	run(func() {
		w, _ := newInstance()
		if w == nil {
			fmt.Println("nil widget")
		}
	})

	run(func() {
		w, _ := newInstance()
		if w == nil {
			fmt.Println("nil widget")
		}
	})

	// Removing one nesting level around the use makes the warning disappear as well.
	run(func() {
		run(func() {
			w, r := newInstance()
			if w == nil {
				fmt.Println("nil widget")
			}
			// This is the use that unparam fails to see.
			if len(r.entries) != 0 {
				fmt.Println("unexpected entries:", r.entries)
			}
		})
	})
}