libgo/go/cmd/vet/testdata/bool.go

   1 // Copyright 2014 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 // This file contains tests for the bool checker.
   6
   7 package testdata
   8
   9 import "io"
  10
  11 type T int
  12
  13 func (t T) Foo() int { return int(t) }
  14
  15 type FT func() int
  16
  17 var S []int
  18
  19 func RatherStupidConditions() {
  20         var f, g func() int
  21         if f() == 0 || f() == 0 { // OK f might have side effects
  22         }
  23         var t T
  24         _ = t.Foo() == 2 || t.Foo() == 2        // OK Foo might have side effects
  25         if v, w := f(), g(); v == w || v == w { // ERROR "redundant or: v == w || v == w"
  26         }
  27         _ = f == nil || f == nil // ERROR "redundant or: f == nil || f == nil"
  28
  29         _ = i == byte(1) || i == byte(1) // ERROR "redundant or: i == byte(1) || i == byte(1)"
  30         _ = i == T(2) || i == T(2)       // ERROR "redundant or: i == T(2) || i == T(2)"
  31         _ = FT(f) == nil || FT(f) == nil // ERROR "redundant or: FT(f) == nil || FT(f) == nil"
  32
  33         _ = (func() int)(f) == nil || (func() int)(f) == nil // ERROR "redundant or: (func() int)(f) == nil || (func() int)(f) == nil"
  34         _ = append(S, 3) == nil || append(S, 3) == nil       // OK append has side effects
  35
  36         var namedFuncVar FT
  37         _ = namedFuncVar() == namedFuncVar() // OK still func calls
  38
  39         var c chan int
  40         _ = 0 == <-c || 0 == <-c                                  // OK subsequent receives may yield different values
  41         for i, j := <-c, <-c; i == j || i == j; i, j = <-c, <-c { // ERROR "redundant or: i == j || i == j"
  42         }
  43
  44         var i, j, k int
  45         _ = i+1 == 1 || i+1 == 1         // ERROR "redundant or: i\+1 == 1 || i\+1 == 1"
  46         _ = i == 1 || j+1 == i || i == 1 // ERROR "redundant or: i == 1 || i == 1"
  47
  48         _ = i == 1 || i == 1 || f() == 1 // ERROR "redundant or: i == 1 || i == 1"
  49         _ = i == 1 || f() == 1 || i == 1 // OK f may alter i as a side effect
  50         _ = f() == 1 || i == 1 || i == 1 // ERROR "redundant or: i == 1 || i == 1"
  51
  52         // Test partition edge cases
  53         _ = f() == 1 || i == 1 || i == 1 || j == 1 // ERROR "redundant or: i == 1 || i == 1"
  54         _ = f() == 1 || j == 1 || i == 1 || i == 1 // ERROR "redundant or: i == 1 || i == 1"
  55         _ = i == 1 || f() == 1 || i == 1 || i == 1 // ERROR "redundant or: i == 1 || i == 1"
  56         _ = i == 1 || i == 1 || f() == 1 || i == 1 // ERROR "redundant or: i == 1 || i == 1"
  57         _ = i == 1 || i == 1 || j == 1 || f() == 1 // ERROR "redundant or: i == 1 || i == 1"
  58         _ = j == 1 || i == 1 || i == 1 || f() == 1 // ERROR "redundant or: i == 1 || i == 1"
  59         _ = i == 1 || f() == 1 || f() == 1 || i == 1
  60
  61         _ = i == 1 || (i == 1 || i == 2)             // ERROR "redundant or: i == 1 || i == 1"
  62         _ = i == 1 || (f() == 1 || i == 1)           // OK f may alter i as a side effect
  63         _ = i == 1 || (i == 1 || f() == 1)           // ERROR "redundant or: i == 1 || i == 1"
  64         _ = i == 1 || (i == 2 || (i == 1 || i == 3)) // ERROR "redundant or: i == 1 || i == 1"
  65
  66         var a, b bool
  67         _ = i == 1 || (a || (i == 1 || b)) // ERROR "redundant or: i == 1 || i == 1"
  68
  69         // Check that all redundant ors are flagged
  70         _ = j == 0 ||
  71                 i == 1 ||
  72                 f() == 1 ||
  73                 j == 0 || // ERROR "redundant or: j == 0 || j == 0"
  74                 i == 1 || // ERROR "redundant or: i == 1 || i == 1"
  75                 i == 1 || // ERROR "redundant or: i == 1 || i == 1"
  76                 i == 1 ||
  77                 j == 0 ||
  78                 k == 0
  79
  80         _ = i == 1*2*3 || i == 1*2*3 // ERROR "redundant or: i == 1\*2\*3 || i == 1\*2\*3"
  81
  82         // These test that redundant, suspect expressions do not trigger multiple errors.
  83         _ = i != 0 || i != 0 // ERROR "redundant or: i != 0 || i != 0"
  84         _ = i == 0 && i == 0 // ERROR "redundant and: i == 0 && i == 0"
  85
  86         // and is dual to or; check the basics and
  87         // let the or tests pull the rest of the weight.
  88         _ = 0 != <-c && 0 != <-c         // OK subsequent receives may yield different values
  89         _ = f() != 0 && f() != 0         // OK f might have side effects
  90         _ = f != nil && f != nil         // ERROR "redundant and: f != nil && f != nil"
  91         _ = i != 1 && i != 1 && f() != 1 // ERROR "redundant and: i != 1 && i != 1"
  92         _ = i != 1 && f() != 1 && i != 1 // OK f may alter i as a side effect
  93         _ = f() != 1 && i != 1 && i != 1 // ERROR "redundant and: i != 1 && i != 1"
  94 }
  95
  96 func RoyallySuspectConditions() {
  97         var i, j int
  98
  99         _ = i == 0 || i == 1 // OK
 100         _ = i != 0 || i != 1 // ERROR "suspect or: i != 0 || i != 1"
 101         _ = i != 0 || 1 != i // ERROR "suspect or: i != 0 || 1 != i"
 102         _ = 0 != i || 1 != i // ERROR "suspect or: 0 != i || 1 != i"
 103         _ = 0 != i || i != 1 // ERROR "suspect or: 0 != i || i != 1"
 104
 105         _ = (0 != i) || i != 1 // ERROR "suspect or: 0 != i || i != 1"
 106
 107         _ = i+3 != 7 || j+5 == 0 || i+3 != 9 // ERROR "suspect or: i\+3 != 7 || i\+3 != 9"
 108
 109         _ = i != 0 || j == 0 || i != 1 // ERROR "suspect or: i != 0 || i != 1"
 110
 111         _ = i != 0 || i != 1<<4 // ERROR "suspect or: i != 0 || i != 1<<4"
 112
 113         _ = i != 0 || j != 0
 114         _ = 0 != i || 0 != j
 115
 116         var s string
 117         _ = s != "one" || s != "the other" // ERROR "suspect or: s != .one. || s != .the other."
 118
 119         _ = "et" != "alii" || "et" != "cetera"         // ERROR "suspect or: .et. != .alii. || .et. != .cetera."
 120         _ = "me gustas" != "tu" || "le gustas" != "tu" // OK we could catch this case, but it's not worth the code
 121
 122         var err error
 123         _ = err != nil || err != io.EOF // TODO catch this case?
 124
 125         // Sanity check and.
 126         _ = i != 0 && i != 1 // OK
 127         _ = i == 0 && i == 1 // ERROR "suspect and: i == 0 && i == 1"
 128         _ = i == 0 && 1 == i // ERROR "suspect and: i == 0 && 1 == i"
 129         _ = 0 == i && 1 == i // ERROR "suspect and: 0 == i && 1 == i"
 130         _ = 0 == i && i == 1 // ERROR "suspect and: 0 == i && i == 1"
 131 }