modernc.org/gc@v1.0.1-0.20240304020402-f0dba7c97c2b/testdata/errchk/test/nilcheck.go (about) 1 // errorcheck -0 -N -d=nil 2 3 // Copyright 2013 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 // Test that nil checks are inserted. 8 // Optimization is disabled, so redundant checks are not removed. 9 10 package p 11 12 type Struct struct { 13 X int 14 Y float64 15 } 16 17 type BigStruct struct { 18 X int 19 Y float64 20 A [1 << 20]int 21 Z string 22 } 23 24 type Empty struct { 25 } 26 27 type Empty1 struct { 28 Empty 29 } 30 31 var ( 32 intp *int 33 arrayp *[10]int 34 array0p *[0]int 35 bigarrayp *[1 << 26]int 36 structp *Struct 37 bigstructp *BigStruct 38 emptyp *Empty 39 empty1p *Empty1 40 ) 41 42 func f1() { 43 _ = *intp // ERROR "nil check" 44 _ = *arrayp // ERROR "nil check" 45 _ = *array0p // ERROR "nil check" 46 _ = *array0p // ERROR "nil check" 47 _ = *intp // ERROR "nil check" 48 _ = *arrayp // ERROR "nil check" 49 _ = *structp // ERROR "nil check" 50 _ = *emptyp // ERROR "nil check" 51 _ = *arrayp // ERROR "nil check" 52 } 53 54 func f2() { 55 var ( 56 intp *int 57 arrayp *[10]int 58 array0p *[0]int 59 bigarrayp *[1 << 20]int 60 structp *Struct 61 bigstructp *BigStruct 62 emptyp *Empty 63 empty1p *Empty1 64 ) 65 66 _ = *intp // ERROR "nil check" 67 _ = *arrayp // ERROR "nil check" 68 _ = *array0p // ERROR "nil check" 69 _ = *array0p // ERROR "nil check" 70 _ = *intp // ERROR "nil check" 71 _ = *arrayp // ERROR "nil check" 72 _ = *structp // ERROR "nil check" 73 _ = *emptyp // ERROR "nil check" 74 _ = *arrayp // ERROR "nil check" 75 _ = *bigarrayp // ERROR "nil check" 76 _ = *bigstructp // ERROR "nil check" 77 _ = *empty1p // ERROR "nil check" 78 } 79 80 func fx10k() *[10000]int 81 82 var b bool 83 84 func f3(x *[10000]int) { 85 // Using a huge type and huge offsets so the compiler 86 // does not expect the memory hardware to fault. 87 _ = x[9999] // ERROR "nil check" 88 89 for { 90 if x[9999] != 0 { // ERROR "nil check" 91 break 92 } 93 } 94 95 x = fx10k() 96 _ = x[9999] // ERROR "nil check" 97 if b { 98 _ = x[9999] // ERROR "nil check" 99 } else { 100 _ = x[9999] // ERROR "nil check" 101 } 102 _ = x[9999] // ERROR "nil check" 103 104 x = fx10k() 105 if b { 106 _ = x[9999] // ERROR "nil check" 107 } else { 108 _ = x[9999] // ERROR "nil check" 109 } 110 _ = x[9999] // ERROR "nil check" 111 112 fx10k() 113 // This one is a bit redundant, if we figured out that 114 // x wasn't going to change across the function call. 115 // But it's a little complex to do and in practice doesn't 116 // matter enough. 117 _ = x[9999] // ERROR "nil check" 118 } 119 120 func f3a() { 121 x := fx10k() 122 y := fx10k() 123 z := fx10k() 124 _ = &x[9] // ERROR "nil check" 125 y = z 126 _ = &x[9] // ERROR "nil check" 127 x = y 128 _ = &x[9] // ERROR "nil check" 129 } 130 131 func f3b() { 132 x := fx10k() 133 y := fx10k() 134 _ = &x[9] // ERROR "nil check" 135 y = x 136 _ = &x[9] // ERROR "nil check" 137 x = y 138 _ = &x[9] // ERROR "nil check" 139 } 140 141 func fx10() *[10]int 142 143 func f4(x *[10]int) { 144 // Most of these have no checks because a real memory reference follows, 145 // and the offset is small enough that if x is nil, the address will still be 146 // in the first unmapped page of memory. 147 148 _ = x[9] // ERROR "nil check" 149 150 for { 151 if x[9] != 0 { // ERROR "nil check" 152 break 153 } 154 } 155 156 x = fx10() 157 _ = x[9] // ERROR "nil check" 158 if b { 159 _ = x[9] // ERROR "nil check" 160 } else { 161 _ = x[9] // ERROR "nil check" 162 } 163 _ = x[9] // ERROR "nil check" 164 165 x = fx10() 166 if b { 167 _ = x[9] // ERROR "nil check" 168 } else { 169 _ = &x[9] // ERROR "nil check" 170 } 171 _ = x[9] // ERROR "nil check" 172 173 fx10() 174 _ = x[9] // ERROR "nil check" 175 176 x = fx10() 177 y := fx10() 178 _ = &x[9] // ERROR "nil check" 179 y = x 180 _ = &x[9] // ERROR "nil check" 181 x = y 182 _ = &x[9] // ERROR "nil check" 183 } 184 185 func f5(m map[string]struct{}) bool { 186 // Existence-only map lookups should not generate a nil check 187 _, ok := m[""] 188 return ok 189 }