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      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 func RatherStupidConditions() {
     12 	var f, g func() int
     13 	if f() == 0 || f() == 0 { // OK f might have side effects
     14 	}
     15 	if v, w := f(), g(); v == w || v == w { // ERROR "redundant or: v == w || v == w"
     16 	}
     17 	_ = f == nil || f == nil // ERROR "redundant or: f == nil || f == nil"
     18 
     19 	_ = i == byte(1) || i == byte(1) // TODO conversions are treated as if they may have side effects
     20 
     21 	var c chan int
     22 	_ = 0 == <-c || 0 == <-c                                  // OK subsequent receives may yield different values
     23 	for i, j := <-c, <-c; i == j || i == j; i, j = <-c, <-c { // ERROR "redundant or: i == j || i == j"
     24 	}
     25 
     26 	var i, j, k int
     27 	_ = i+1 == 1 || i+1 == 1         // ERROR "redundant or: i\+1 == 1 || i\+1 == 1"
     28 	_ = i == 1 || j+1 == i || i == 1 // ERROR "redundant or: i == 1 || i == 1"
     29 
     30 	_ = i == 1 || i == 1 || f() == 1 // ERROR "redundant or: i == 1 || i == 1"
     31 	_ = i == 1 || f() == 1 || i == 1 // OK f may alter i as a side effect
     32 	_ = f() == 1 || i == 1 || i == 1 // ERROR "redundant or: i == 1 || i == 1"
     33 
     34 	// Test partition edge cases
     35 	_ = f() == 1 || i == 1 || i == 1 || j == 1 // ERROR "redundant or: i == 1 || i == 1"
     36 	_ = f() == 1 || j == 1 || i == 1 || i == 1 // ERROR "redundant or: i == 1 || i == 1"
     37 	_ = i == 1 || f() == 1 || i == 1 || i == 1 // ERROR "redundant or: i == 1 || i == 1"
     38 	_ = i == 1 || i == 1 || f() == 1 || i == 1 // ERROR "redundant or: i == 1 || i == 1"
     39 	_ = i == 1 || i == 1 || j == 1 || f() == 1 // ERROR "redundant or: i == 1 || i == 1"
     40 	_ = j == 1 || i == 1 || i == 1 || f() == 1 // ERROR "redundant or: i == 1 || i == 1"
     41 	_ = i == 1 || f() == 1 || f() == 1 || i == 1
     42 
     43 	_ = i == 1 || (i == 1 || i == 2)             // ERROR "redundant or: i == 1 || i == 1"
     44 	_ = i == 1 || (f() == 1 || i == 1)           // OK f may alter i as a side effect
     45 	_ = i == 1 || (i == 1 || f() == 1)           // ERROR "redundant or: i == 1 || i == 1"
     46 	_ = i == 1 || (i == 2 || (i == 1 || i == 3)) // ERROR "redundant or: i == 1 || i == 1"
     47 
     48 	var a, b bool
     49 	_ = i == 1 || (a || (i == 1 || b)) // ERROR "redundant or: i == 1 || i == 1"
     50 
     51 	// Check that all redundant ors are flagged
     52 	_ = j == 0 ||
     53 		i == 1 ||
     54 		f() == 1 ||
     55 		j == 0 || // ERROR "redundant or: j == 0 || j == 0"
     56 		i == 1 || // ERROR "redundant or: i == 1 || i == 1"
     57 		i == 1 || // ERROR "redundant or: i == 1 || i == 1"
     58 		i == 1 ||
     59 		j == 0 ||
     60 		k == 0
     61 
     62 	_ = i == 1*2*3 || i == 1*2*3 // ERROR "redundant or: i == 1\*2\*3 || i == 1\*2\*3"
     63 
     64 	// These test that redundant, suspect expressions do not trigger multiple errors.
     65 	_ = i != 0 || i != 0 // ERROR "redundant or: i != 0 || i != 0"
     66 	_ = i == 0 && i == 0 // ERROR "redundant and: i == 0 && i == 0"
     67 
     68 	// and is dual to or; check the basics and
     69 	// let the or tests pull the rest of the weight.
     70 	_ = 0 != <-c && 0 != <-c         // OK subsequent receives may yield different values
     71 	_ = f() != 0 && f() != 0         // OK f might have side effects
     72 	_ = f != nil && f != nil         // ERROR "redundant and: f != nil && f != nil"
     73 	_ = i != 1 && i != 1 && f() != 1 // ERROR "redundant and: i != 1 && i != 1"
     74 	_ = i != 1 && f() != 1 && i != 1 // OK f may alter i as a side effect
     75 	_ = f() != 1 && i != 1 && i != 1 // ERROR "redundant and: i != 1 && i != 1"
     76 }
     77 
     78 func RoyallySuspectConditions() {
     79 	var i, j int
     80 
     81 	_ = i == 0 || i == 1 // OK
     82 	_ = i != 0 || i != 1 // ERROR "suspect or: i != 0 || i != 1"
     83 	_ = i != 0 || 1 != i // ERROR "suspect or: i != 0 || 1 != i"
     84 	_ = 0 != i || 1 != i // ERROR "suspect or: 0 != i || 1 != i"
     85 	_ = 0 != i || i != 1 // ERROR "suspect or: 0 != i || i != 1"
     86 
     87 	_ = (0 != i) || i != 1 // ERROR "suspect or: 0 != i || i != 1"
     88 
     89 	_ = i+3 != 7 || j+5 == 0 || i+3 != 9 // ERROR "suspect or: i\+3 != 7 || i\+3 != 9"
     90 
     91 	_ = i != 0 || j == 0 || i != 1 // ERROR "suspect or: i != 0 || i != 1"
     92 
     93 	_ = i != 0 || i != 1<<4 // ERROR "suspect or: i != 0 || i != 1<<4"
     94 
     95 	_ = i != 0 || j != 0
     96 	_ = 0 != i || 0 != j
     97 
     98 	var s string
     99 	_ = s != "one" || s != "the other" // ERROR "suspect or: s != .one. || s != .the other."
    100 
    101 	_ = "et" != "alii" || "et" != "cetera"         // ERROR "suspect or: .et. != .alii. || .et. != .cetera."
    102 	_ = "me gustas" != "tu" || "le gustas" != "tu" // OK we could catch this case, but it's not worth the code
    103 
    104 	var err error
    105 	_ = err != nil || err != io.EOF // TODO catch this case?
    106 
    107 	// Sanity check and.
    108 	_ = i != 0 && i != 1 // OK
    109 	_ = i == 0 && i == 1 // ERROR "suspect and: i == 0 && i == 1"
    110 	_ = i == 0 && 1 == i // ERROR "suspect and: i == 0 && 1 == i"
    111 	_ = 0 == i && 1 == i // ERROR "suspect and: 0 == i && 1 == i"
    112 	_ = 0 == i && i == 1 // ERROR "suspect and: 0 == i && i == 1"
    113 }
    114