In Go, a "constant overflows rune" error typically occurs when you try to assign an integer constant to a `rune` type, and the constant's value is outside the valid rune range. Runes are Unicode code points and are represented by 32 bits in Go.
Here's an example that demonstrates the error:
```go
package main
import "fmt"
func main() {
var r rune
r = 0x110000 // This value is outside the valid rune range (0 to 0x10FFFF)
fmt.Printf("%c\n", r)
}
```
In this example, `0x110000` is outside the valid range for runes, and you'll encounter the "constant overflows rune" error when you try to assign it to a `rune` variable.
To resolve this issue, make sure that the value you're assigning to a `rune` falls within the valid range, which is from 0 to 0x10FFFF (0 to 1114111 in decimal). For example:
```go
package main
import "fmt"
func main() {
var r rune
r = 0x1F600 // A valid rune value (a Unicode emoji)
fmt.Printf("%c\n", r)
}
```
In this corrected example, `0x1F600` is a valid Unicode code point, and it doesn't cause an overflow error.