issue60601.go

     1  // run
     2  
     3  // Copyright 2023 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  package main
     8  
     9  import (
    10  	"strings"
    11  	"unsafe"
    12  )
    13  
    14  func shift[T any]() int64 {
    15  	return 1 << unsafe.Sizeof(*new(T))
    16  }
    17  
    18  func div[T any]() uintptr {
    19  	return 1 / unsafe.Sizeof(*new(T))
    20  }
    21  
    22  func add[T any]() int64 {
    23  	return 1<<63 - 1 + int64(unsafe.Sizeof(*new(T)))
    24  }
    25  
    26  func main() {
    27  	shift[[62]byte]()
    28  	shift[[63]byte]()
    29  	shift[[64]byte]()
    30  	shift[[100]byte]()
    31  	shift[[1e6]byte]()
    32  
    33  	add[[1]byte]()
    34  	shouldPanic("divide by zero", func() { div[[0]byte]() })
    35  }
    36  
    37  func shouldPanic(str string, f func()) {
    38  	defer func() {
    39  		err := recover()
    40  		if err == nil {
    41  			panic("did not panic")
    42  		}
    43  		s := err.(error).Error()
    44  		if !strings.Contains(s, str) {
    45  			panic("got panic " + s + ", want " + str)
    46  		}
    47  	}()
    48  
    49  	f()
    50  }
    51
View as plain text