github.com/sbinet/go@v0.0.0-20160827155028-54d7de7dd62b/test/sliceopt.go (about)

     1  // +build !amd64,!arm,!amd64p32,!386,!arm64,!ppc64le,!mips64,!mips64le
     2  // errorcheck -0 -d=append,slice
     3  
     4  // Copyright 2015 The Go Authors. All rights reserved.
     5  // Use of this source code is governed by a BSD-style
     6  // license that can be found in the LICENSE file.
     7  
     8  // Check optimization results for append and slicing.
     9  
    10  package main
    11  
    12  func a1(x []int, y int) []int {
    13  	x = append(x, y) // ERROR "append: len-only update"
    14  	return x
    15  }
    16  
    17  func a2(x []int, y int) []int {
    18  	return append(x, y) // ERROR "append: full update"
    19  }
    20  
    21  func a3(x *[]int, y int) {
    22  	*x = append(*x, y) // ERROR "append: len-only update"
    23  }
    24  
    25  func s1(x **[]int, xs **string, i, j int) {
    26  	var z []int
    27  	z = (**x)[2:]         // ERROR "slice: omit check for 2nd index"
    28  	z = (**x)[2:len(**x)] // not yet: "slice: reuse len" "slice: omit check for 2nd index"
    29  	z = (**x)[2:cap(**x)] // not yet: "slice: reuse cap" "slice: omit check for 2nd index"
    30  	z = (**x)[i:i]        // ERROR "slice: reuse 1st index" "slice: omit check for 1st index" "slice: result len == 0"
    31  	z = (**x)[1:i:i]      // ERROR "slice: reuse 2nd index" "slice: omit check for 2nd index" "slice: result cap == result len"
    32  	z = (**x)[i:j:0]      // ERROR "slice: omit check for 3rd index"
    33  	z = (**x)[i:0:j]      // ERROR "slice: omit check for 2nd index"
    34  	z = (**x)[0:i:j]      // ERROR "slice: omit check for 1st index" "slice: skip base adjustment for 1st index 0"
    35  	z = (**x)[0:]         // ERROR "slice: omit slice operation"
    36  	z = (**x)[2:8]        // ERROR "slice: omit check for 1st index" "slice: result len == 6"
    37  	z = (**x)[2:2]        // ERROR "slice: omit check for 1st index" "slice: result len == 0"
    38  	z = (**x)[0:i]        // ERROR "slice: omit check for 1st index" "slice: skip base adjustment for 1st index 0"
    39  	z = (**x)[2:i:8]      // ERROR "slice: result cap == 6"
    40  	z = (**x)[i:2:i]      // ERROR "slice: reuse 1st index" "slice: result cap == 0" "slice: skip base adjustment for cap == 0"
    41  
    42  	z = z[0:i]       // ERROR "slice: omit check for 1st index" "slice: result cap not computed" "slice: skip base adjustment for 1st index 0" "slice: len-only update"
    43  	z = z[0:i : i+1] // ERROR "slice: omit check for 1st index" "slice: skip base adjustment for 1st index 0" "slice: len/cap-only update"
    44  	z = z[i : i+1]
    45  
    46  	println(z)
    47  
    48  	var zs string
    49  	zs = (**xs)[2:]          // ERROR "slice: omit check for 2nd index"
    50  	zs = (**xs)[2:len(**xs)] // not yet: "slice: reuse len" "slice: omit check for 2nd index"
    51  	zs = (**xs)[i:i]         // ERROR "slice: reuse 1st index" "slice: omit check for 1st index" "slice: result len == 0" "slice: skip base adjustment for string len == 0"
    52  	zs = (**xs)[0:]          // ERROR "slice: omit slice operation"
    53  	zs = (**xs)[2:8]         // ERROR "slice: omit check for 1st index" "slice: result len == 6"
    54  	zs = (**xs)[2:2]         // ERROR "slice: omit check for 1st index" "slice: result len == 0" "slice: skip base adjustment for string len == 0"
    55  	zs = (**xs)[0:i]         // ERROR "slice: omit check for 1st index" "slice: skip base adjustment for 1st index 0"
    56  
    57  	zs = zs[0:i] // ERROR "slice: omit check for 1st index" "slice: skip base adjustment for 1st index 0" "slice: len-only update"
    58  	zs = zs[i : i+1]
    59  	println(zs)
    60  }