1// +build go1.13 2 3package errors 4 5import ( 6 stderrors "errors" 7) 8 9// Is reports whether any error in err's chain matches target. 10// 11// The chain consists of err itself followed by the sequence of errors obtained by 12// repeatedly calling Unwrap. 13// 14// An error is considered to match a target if it is equal to that target or if 15// it implements a method Is(error) bool such that Is(target) returns true. 16func Is(err, target error) bool { return stderrors.Is(err, target) } 17 18// As finds the first error in err's chain that matches target, and if so, sets 19// target to that error value and returns true. 20// 21// The chain consists of err itself followed by the sequence of errors obtained by 22// repeatedly calling Unwrap. 23// 24// An error matches target if the error's concrete value is assignable to the value 25// pointed to by target, or if the error has a method As(interface{}) bool such that 26// As(target) returns true. In the latter case, the As method is responsible for 27// setting target. 28// 29// As will panic if target is not a non-nil pointer to either a type that implements 30// error, or to any interface type. As returns false if err is nil. 31func As(err error, target interface{}) bool { return stderrors.As(err, target) } 32 33// Unwrap returns the result of calling the Unwrap method on err, if err's 34// type contains an Unwrap method returning error. 35// Otherwise, Unwrap returns nil. 36func Unwrap(err error) error { 37 return stderrors.Unwrap(err) 38} 39