Error building using gcc go 1.13.1

c29cfd277c87e6115f89ba29f0f7b0544b2bfd68 go version go1.18 gccgo (GCC) 13.1.1 20230429 linux/amd64
go build
# github.com/rivo/uniseg
./properties.go:137:20: error: expected ‘(’
  137 | func propertySearch[E interface{ [3]int | [4]int }](dictionary []E, r rune) (result E) {
      |                    ^
./properties.go:137:23: error: expected ‘]’
  137 | func propertySearch[E interface{ [3]int | [4]int }](dictionary []E, r rune) (result E) {
      |                       ^
./properties.go:137:23: error: expected ‘;’ or newline after top level declaration
./properties.go:140:9: error: expected declaration
  140 |         to := len(dictionary)
      |         ^
./properties.go:141:9: error: expected declaration
  141 |         for to > from {
      |         ^
./properties.go:143:17: error: expected declaration
  143 |                 cpRange := dictionary[middle]
      |                 ^
./properties.go:144:17: error: expected declaration
  144 |                 if int(r) < cpRange[0] {
      |                 ^
./properties.go:146:25: error: expected declaration
  146 |                         continue
      |                         ^
./properties.go:147:17: error: expected declaration
  147 |                 }
      |                 ^
./properties.go:148:17: error: expected declaration
  148 |                 if int(r) > cpRange[1] {
      |                 ^
./properties.go:150:25: error: expected declaration
  150 |                         continue
      |                         ^
./properties.go:151:17: error: expected declaration
  151 |                 }
      |                 ^
./properties.go:152:17: error: expected declaration
  152 |                 return cpRange
      |                 ^
./properties.go:153:9: error: expected declaration
  153 |         }
      |         ^
./properties.go:154:9: error: expected declaration
  154 |         return
      |         ^
./properties.go:155:1: error: expected declaration
  155 | }
      | ^
rivo / uniseg

Error building using gcc go 1.13.1 #33
