why-cant-i-get-the-address-of-a-type-conversion-in-go
Expressions
An expression specifies the computation of a value by applying operators and functions to operands.
Conversions
Conversions are expressions of the form T(x) where T is a type and x is an expression that can be converted to type T.
Address operators
For an operand x of type T, the address operation &x generates a pointer of type *T to x. The operand must be addressable, that is, either a variable, pointer indirection, or slice indexing operation; or a field selector of an addressable struct operand; or an array indexing operation of an addressable array. As an exception to the addressability requirement, x may also be a (possibly parenthesized) composite literal. If the evaluation of x would cause a run-time panic, then the evaluation of &x does too.
Expressions are temporary, transient values. The expression value has no address. It may be stored in a register. A comversion is an expression. For example,
package main
import (
"fmt"
)
func main() {
type str string
s := "hello, world"
fmt.Println(&s, s)
// error: cannot take the address of str(s)
sp := &str(s)
fmt.Println(sp, *sp)
}
