JuniorTheoryOccasional

What does the program print?

package main

import "fmt"

func main() {
    var p *int
    var v any = p
    switch x := v.(type) {
    case nil, *int:
        fmt.Println(x == nil)
    }
}

false

Expecting true: when a case lists more than one type, x keeps the type any, and an interface that holds the type *int is not equal to nil.
Expecting a nil pointer to match no branch: v holds the dynamic type *int, so it matches *int in the list, not nil.

What would the program print if the branch were case *int: alone?
Which branch would var v any with no assignment match, and what would x == nil print there?

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Back to questions

JuniorTheoryOccasional

What does the program print?

package main

import "fmt"

func main() {
    var p *int
    var v any = p
    switch x := v.(type) {
    case nil, *int:
        fmt.Println(x == nil)
    }
}

false

Expecting true: when a case lists more than one type, x keeps the type any, and an interface that holds the type *int is not equal to nil.
Expecting a nil pointer to match no branch: v holds the dynamic type *int, so it matches *int in the list, not nil.

What would the program print if the branch were case *int: alone?
Which branch would var v any with no assignment match, and what would x == nil print there?

Back to questions Open topic in roadmap →Answer it yourself — Quiz