...
Run Format

Source file test/convlit.go

Documentation: test

  // errorcheck
  
  // Copyright 2009 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  // Verify that illegal assignments with both explicit and implicit conversions of literals are detected.
  // Does not compile.
  
  package main
  
  import "unsafe"
  
  // explicit conversion of constants
  var x1 = string(1)
  var x2 string = string(1)
  var x3 = int(1.5)     // ERROR "convert|truncate"
  var x4 int = int(1.5) // ERROR "convert|truncate"
  var x5 = "a" + string(1)
  var x6 = int(1e100)      // ERROR "overflow"
  var x7 = float32(1e1000) // ERROR "overflow"
  
  // unsafe.Pointer can only convert to/from uintptr
  var _ = string(unsafe.Pointer(uintptr(65)))  // ERROR "convert"
  var _ = float64(unsafe.Pointer(uintptr(65))) // ERROR "convert"
  var _ = int(unsafe.Pointer(uintptr(65)))     // ERROR "convert"
  
  // implicit conversions merit scrutiny
  var s string
  var bad1 string = 1  // ERROR "conver|incompatible|invalid|cannot"
  var bad2 = s + 1     // ERROR "conver|incompatible|invalid"
  var bad3 = s + 'a'   // ERROR "conver|incompatible|invalid"
  var bad4 = "a" + 1   // ERROR "literals|incompatible|convert|invalid"
  var bad5 = "a" + 'a' // ERROR "literals|incompatible|convert|invalid"
  
  var bad6 int = 1.5       // ERROR "convert|truncate"
  var bad7 int = 1e100     // ERROR "overflow"
  var bad8 float32 = 1e200 // ERROR "overflow"
  
  // but these implicit conversions are okay
  var good1 string = "a"
  var good2 int = 1.0
  var good3 int = 1e9
  var good4 float64 = 1e20
  
  // explicit conversion of string is okay
  var _ = []rune("abc")
  var _ = []byte("abc")
  
  // implicit is not
  var _ []int = "abc"  // ERROR "cannot use|incompatible|invalid"
  var _ []byte = "abc" // ERROR "cannot use|incompatible|invalid"
  
  // named string is okay
  type Tstring string
  
  var ss Tstring = "abc"
  var _ = []rune(ss)
  var _ = []byte(ss)
  
  // implicit is still not
  var _ []rune = ss // ERROR "cannot use|incompatible|invalid"
  var _ []byte = ss // ERROR "cannot use|incompatible|invalid"
  
  // named slice is now ok
  type Trune []rune
  type Tbyte []byte
  
  var _ = Trune("abc") // ok
  var _ = Tbyte("abc") // ok
  
  // implicit is still not
  var _ Trune = "abc" // ERROR "cannot use|incompatible|invalid"
  var _ Tbyte = "abc" // ERROR "cannot use|incompatible|invalid"
  

View as plain text