62 lines
965 B
Go
62 lines
965 B
Go
// RUN: llgo -o %t %s
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// RUN: %t 2>&1 | FileCheck %s
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// CHECK: x is nil
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// CHECK-NEXT: i2v: 123456
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// CHECK-NEXT: !
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// CHECK-NEXT: (*X).F1: 123456
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package main
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type X struct{ x int }
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func (x *X) F1() { println("(*X).F1:", x.x) }
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func (x *X) F2() { println("(*X).F2") }
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type I interface {
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F1()
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F2()
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}
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func main() {
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var x interface{}
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// x is nil. Let's make sure an assertion on it
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// won't cause a panic.
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if x, ok := x.(int32); ok {
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println("i2v:", x)
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}
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if x == nil {
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println("x is nil")
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}
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x = int32(123456)
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// Let's try an interface-to-value assertion.
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if x, ok := x.(int32); ok {
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println("i2v:", x)
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}
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if x, ok := x.(int64); ok {
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println("i2v:", x)
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}
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// This will fail the assertion.
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if i, ok := x.(I); ok {
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i.F1()
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_ = i
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} else {
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println("!")
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}
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// Assign an *X, which should pass the assertion.
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x_ := new(X)
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x_.x = 123456
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x = x_ //&X{x: 123456}
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if i, ok := x.(I); ok {
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i.F1()
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_ = i
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} else {
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println("!")
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}
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}
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