default:
}
+ // switch on interface.
+ switch i := interface{}("hello"); i {
+ case 42:
+ assert(false, `i should be "hello"`)
+ case "hello":
+ assert(true, "hello")
+ default:
+ assert(false, `i should be "hello"`)
+ }
+
+ // switch on implicit bool converted to interface
+ // was broken: see issue 3980
+ switch i := interface{}(true); {
+ case i:
+ assert(true, "true")
+ case false:
+ assert(false, "i should be true")
+ default:
+ assert(false, "i should be true")
+ }
+
+ // switch on interface with constant cases differing by type.
+ // was rejected by compiler: see issue 4781
+ type T int
+ type B bool
+ type F float64
+ type S string
+ switch i := interface{}(float64(1.0)); i {
+ case nil:
+ assert(false, "i should be float64(1.0)")
+ case (*int)(nil):
+ assert(false, "i should be float64(1.0)")
+ case 1:
+ assert(false, "i should be float64(1.0)")
+ case T(1):
+ assert(false, "i should be float64(1.0)")
+ case F(1.0):
+ assert(false, "i should be float64(1.0)")
+ case 1.0:
+ assert(true, "true")
+ case "hello":
+ assert(false, "i should be float64(1.0)")
+ case S("hello"):
+ assert(false, "i should be float64(1.0)")
+ case true, B(false):
+ assert(false, "i should be float64(1.0)")
+ case false, B(true):
+ assert(false, "i should be float64(1.0)")
+ }
+
+ // switch on array.
+ switch ar := [3]int{1, 2, 3}; ar {
+ case [3]int{1, 2, 3}:
+ assert(true, "[1 2 3]")
+ case [3]int{4, 5, 6}:
+ assert(false, "ar should be [1 2 3]")
+ default:
+ assert(false, "ar should be [1 2 3]")
+ }
+
+ // switch on channel
+ switch c1, c2 := make(chan int), make(chan int); c1 {
+ case nil:
+ assert(false, "c1 did not match itself")
+ case c2:
+ assert(false, "c1 did not match itself")
+ case c1:
+ assert(true, "chan")
+ default:
+ assert(false, "c1 did not match itself")
+ }
+
+ // empty switch
+ switch {
+ }
+
+ // empty switch with default case.
+ fired = false
+ switch {
+ default:
+ fired = true
+ }
+ assert(fired, "fail")
+
+ // Default and fallthrough.
+ count = 0
+ switch {
+ default:
+ count++
+ fallthrough
+ case false:
+ count++
+ }
+ assert(count == 2, "fail")
+
+ // fallthrough to default, which is not at end.
+ count = 0
+ switch i5 {
+ case 5:
+ count++
+ fallthrough
+ default:
+ count++
+ case 6:
+ count++
+ }
+ assert(count == 2, "fail")
+
i := 0
switch x := 5; {
- case i < x:
- os.Exit(0)
- case i == x:
- case i > x:
- os.Exit(1)
+ case i < x:
+ os.Exit(0)
+ case i == x:
+ case i > x:
+ os.Exit(1)
+ }
+
+ // Unified IR converts the tag and all case values to empty
+ // interface, when any of the case values aren't assignable to the
+ // tag value's type. Make sure that `case nil:` compares against the
+ // tag type's nil value (i.e., `(*int)(nil)`), not nil interface
+ // (i.e., `any(nil)`).
+ switch (*int)(nil) {
+ case nil:
+ // ok
+ case any(nil):
+ assert(false, "case any(nil) matched")
+ default:
+ assert(false, "default matched")
}
}