| // run |
| |
| // Copyright 2015 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Tests type assertion expressions and statements |
| |
| package main |
| |
| import ( |
| "fmt" |
| "runtime" |
| ) |
| |
| type ( |
| S struct{} |
| T struct{} |
| |
| I interface { |
| F() |
| } |
| ) |
| |
| var ( |
| s *S |
| t *T |
| ) |
| |
| func (s *S) F() {} |
| func (t *T) F() {} |
| |
| func e2t_ssa(e interface{}) *T { |
| return e.(*T) |
| } |
| |
| func i2t_ssa(i I) *T { |
| return i.(*T) |
| } |
| |
| func testAssertE2TOk() { |
| if got := e2t_ssa(t); got != t { |
| fmt.Printf("e2t_ssa(t)=%v want %v", got, t) |
| failed = true |
| } |
| } |
| |
| func testAssertE2TPanic() { |
| var got *T |
| defer func() { |
| if got != nil { |
| fmt.Printf("e2t_ssa(s)=%v want nil", got) |
| failed = true |
| } |
| e := recover() |
| err, ok := e.(*runtime.TypeAssertionError) |
| if !ok { |
| fmt.Printf("e2t_ssa(s) panic type %T", e) |
| failed = true |
| } |
| want := "interface conversion: interface {} is *main.S, not *main.T" |
| if err.Error() != want { |
| fmt.Printf("e2t_ssa(s) wrong error, want '%s', got '%s'\n", want, err.Error()) |
| failed = true |
| } |
| }() |
| got = e2t_ssa(s) |
| fmt.Printf("e2t_ssa(s) should panic") |
| failed = true |
| } |
| |
| func testAssertI2TOk() { |
| if got := i2t_ssa(t); got != t { |
| fmt.Printf("i2t_ssa(t)=%v want %v", got, t) |
| failed = true |
| } |
| } |
| |
| func testAssertI2TPanic() { |
| var got *T |
| defer func() { |
| if got != nil { |
| fmt.Printf("i2t_ssa(s)=%v want nil", got) |
| failed = true |
| } |
| e := recover() |
| err, ok := e.(*runtime.TypeAssertionError) |
| if !ok { |
| fmt.Printf("i2t_ssa(s) panic type %T", e) |
| failed = true |
| } |
| want := "interface conversion: main.I is *main.S, not *main.T" |
| if err.Error() != want { |
| fmt.Printf("i2t_ssa(s) wrong error, want '%s', got '%s'\n", want, err.Error()) |
| failed = true |
| } |
| }() |
| got = i2t_ssa(s) |
| fmt.Printf("i2t_ssa(s) should panic") |
| failed = true |
| } |
| |
| func e2t2_ssa(e interface{}) (*T, bool) { |
| t, ok := e.(*T) |
| return t, ok |
| } |
| |
| func i2t2_ssa(i I) (*T, bool) { |
| t, ok := i.(*T) |
| return t, ok |
| } |
| |
| func testAssertE2T2() { |
| if got, ok := e2t2_ssa(t); !ok || got != t { |
| fmt.Printf("e2t2_ssa(t)=(%v, %v) want (%v, %v)", got, ok, t, true) |
| failed = true |
| } |
| if got, ok := e2t2_ssa(s); ok || got != nil { |
| fmt.Printf("e2t2_ssa(s)=(%v, %v) want (%v, %v)", got, ok, nil, false) |
| failed = true |
| } |
| } |
| |
| func testAssertI2T2() { |
| if got, ok := i2t2_ssa(t); !ok || got != t { |
| fmt.Printf("i2t2_ssa(t)=(%v, %v) want (%v, %v)", got, ok, t, true) |
| failed = true |
| } |
| if got, ok := i2t2_ssa(s); ok || got != nil { |
| fmt.Printf("i2t2_ssa(s)=(%v, %v) want (%v, %v)", got, ok, nil, false) |
| failed = true |
| } |
| } |
| |
| var failed = false |
| |
| func main() { |
| testAssertE2TOk() |
| testAssertE2TPanic() |
| testAssertI2TOk() |
| testAssertI2TPanic() |
| testAssertE2T2() |
| testAssertI2T2() |
| if failed { |
| panic("failed") |
| } |
| } |