modernc.org/gc@v1.0.1-0.20240304020402-f0dba7c97c2b/testdata/errchk/test/const1.go (about)

     1  // errorcheck
     2  
     3  // Copyright 2009 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  // Verify overflow is detected when using numeric constants.
     8  // Does not compile.
     9  
    10  package main
    11  
    12  import "unsafe"
    13  
    14  type I interface{}
    15  
    16  const (
    17  	// assume all types behave similarly to int8/uint8
    18  	Int8   int8  = 101
    19  	Minus1 int8  = -1
    20  	Uint8  uint8 = 102
    21  	Const        = 103
    22  
    23  	Float32    float32 = 104.5
    24  	Float64    float64 = 105.5
    25  	ConstFloat         = 106.5
    26  	Big        float64 = 1e300
    27  
    28  	String = "abc"
    29  	Bool   = true
    30  )
    31  
    32  var (
    33  	a1 = Int8 * 100              // ERROR "overflow"
    34  	a2 = Int8 * -1               // OK
    35  	a3 = Int8 * 1000             // ERROR "overflow"
    36  	a4 = Int8 * int8(1000)       // ERROR "overflow"
    37  	a5 = int8(Int8 * 1000)       // ERROR "overflow"
    38  	a6 = int8(Int8 * int8(1000)) // ERROR "overflow"
    39  	a7 = Int8 - 2*Int8 - 2*Int8  // ERROR "overflow"
    40  	a8 = Int8 * Const / 100      // ERROR "overflow"
    41  	a9 = Int8 * (Const / 100)    // OK
    42  
    43  	b1        = Uint8 * Uint8         // ERROR "overflow"
    44  	b2        = Uint8 * -1            // ERROR "overflow"
    45  	b3        = Uint8 - Uint8         // OK
    46  	b4        = Uint8 - Uint8 - Uint8 // ERROR "overflow"
    47  	b5        = uint8(^0)             // ERROR "overflow"
    48  	b5a       = int64(^0)             // OK
    49  	b6        = ^uint8(0)             // OK
    50  	b6a       = ^int64(0)             // OK
    51  	b7        = uint8(Minus1)         // ERROR "overflow"
    52  	b8        = uint8(int8(-1))       // ERROR "overflow"
    53  	b8a       = uint8(-1)             // ERROR "overflow"
    54  	b9   byte = (1 << 10) >> 8        // OK
    55  	b10  byte = (1 << 10)             // ERROR "overflow"
    56  	b11  byte = (byte(1) << 10) >> 8  // ERROR "overflow"
    57  	b12  byte = 1000                  // ERROR "overflow"
    58  	b13  byte = byte(1000)            // ERROR "overflow"
    59  	b14  byte = byte(100) * byte(100) // ERROR "overflow"
    60  	b15  byte = byte(100) * 100       // ERROR "overflow"
    61  	b16  byte = byte(0) * 1000        // ERROR "overflow"
    62  	b16a byte = 0 * 1000              // OK
    63  	b17  byte = byte(0) * byte(1000)  // ERROR "overflow"
    64  	b18  byte = Uint8 / 0             // ERROR "division by zero"
    65  
    66  	c1 float64 = Big
    67  	c2 float64 = Big * Big          // ERROR "overflow"
    68  	c3 float64 = float64(Big) * Big // ERROR "overflow"
    69  	c4         = Big * Big          // ERROR "overflow"
    70  	c5         = Big / 0            // ERROR "division by zero"
    71  	c6         = 1000 % 1e3         // ERROR "floating-point % operation|expected integer type"
    72  )
    73  
    74  func f(int)
    75  
    76  func main() {
    77  	f(Int8)             // ERROR "convert|wrong type|cannot"
    78  	f(Minus1)           // ERROR "convert|wrong type|cannot"
    79  	f(Uint8)            // ERROR "convert|wrong type|cannot"
    80  	f(Const)            // OK
    81  	f(Float32)          // ERROR "convert|wrong type|cannot"
    82  	f(Float64)          // ERROR "convert|wrong type|cannot"
    83  	f(ConstFloat)       // ERROR "truncate"
    84  	f(ConstFloat - 0.5) // OK
    85  	f(Big)              // ERROR "convert|wrong type|cannot"
    86  	f(String)           // ERROR "convert|wrong type|cannot|incompatible"
    87  	f(Bool)             // ERROR "convert|wrong type|cannot|incompatible"
    88  }
    89  
    90  const ptr = nil // ERROR "const.*nil"
    91  const _ = string([]byte(nil)) // ERROR "is not a? ?constant"
    92  const _ = uintptr(unsafe.Pointer((*int)(nil))) // ERROR "is not a? ?constant"
    93  const _ = unsafe.Pointer((*int)(nil)) // ERROR "cannot be nil|invalid constant type"
    94  const _ = (*int)(nil) // ERROR "cannot be nil|invalid constant type"