Redundant Buffer Allocation & Copy

[jfcg]

Hi,
Please see the discussion here. This piece of code:

package main

import (
	"fmt"
	"unsafe"
)

// ToLower converts ascii string s to lower-case
func ToLower(s string) string {
	if s == "" {
		return ""
	}
	buf := make([]byte, len(s))
	fmt.Println(unsafe.Pointer(&buf[0])) // just to identify buffer

	for i := 0; i < len(s); i++ {
		c := s[i]
		if 'A' <= c && c <= 'Z' {
			c |= 32
		}
		buf[i] = c
	}
	return string(buf)
}

func main() {
	s := ToLower("ASfgQW")

	fmt.Println(*(*unsafe.Pointer)(unsafe.Pointer(&s)))
}

shows that both Go and TinyGo compilers fail to detect that buf does not escape, can just be converted to a string and returned. Instead both compilers redundantly allocate a new buffer and copy bytes in return string(buf).

How can this be solved in TinyGo?