all: change optional to result of io (#16075)

vlib/x/json2/decoder_test.v

@@ -1,43 +1,43 @@
 module json2
 
 fn test_raw_decode_string() {
-	str := raw_decode('"Hello!"')?
+	str := raw_decode('"Hello!"')!
 	assert str.str() == 'Hello!'
 }
 
 fn test_raw_decode_string_escape() {
-	jstr := raw_decode('"\u001b"')?
+	jstr := raw_decode('"\u001b"')!
 	str := jstr.str()
 	assert str.len == 1
 	assert str[0] == 27
 }
 
 fn test_raw_decode_number() {
-	num := raw_decode('123')?
+	num := raw_decode('123')!
 	assert num.int() == 123
 }
 
 fn test_raw_decode_array() {
-	raw_arr := raw_decode('["Foo", 1]')?
+	raw_arr := raw_decode('["Foo", 1]')!
 	arr := raw_arr.arr()
 	assert arr[0] or { 0 }.str() == 'Foo'
 	assert arr[1] or { 0 }.int() == 1
 }
 
 fn test_raw_decode_bool() {
-	bol := raw_decode('false')?
+	bol := raw_decode('false')!
 	assert bol.bool() == false
 }
 
 fn test_raw_decode_map() {
-	raw_mp := raw_decode('{"name":"Bob","age":20}')?
+	raw_mp := raw_decode('{"name":"Bob","age":20}')!
 	mp := raw_mp.as_map()
 	assert mp['name'] or { 0 }.str() == 'Bob'
 	assert mp['age'] or { 0 }.int() == 20
 }
 
 fn test_raw_decode_null() {
-	nul := raw_decode('null')?
+	nul := raw_decode('null')!
 	assert nul is Null
 }
 
@@ -50,12 +50,12 @@ fn test_raw_decode_invalid() {
 }
 
 fn test_raw_decode_string_with_dollarsign() {
-	str := raw_decode(r'"Hello $world"')?
+	str := raw_decode(r'"Hello $world"')!
 	assert str.str() == r'Hello $world'
 }
 
 fn test_raw_decode_map_with_whitespaces() {
-	raw_mp := raw_decode(' \n\t{"name":"Bob","age":20}\n\t')?
+	raw_mp := raw_decode(' \n\t{"name":"Bob","age":20}\n\t')!
 	mp := raw_mp.as_map()
 	assert mp['name'] or { 0 }.str() == 'Bob'
 	assert mp['age'] or { 0 }.int() == 20
@@ -63,7 +63,7 @@ fn test_raw_decode_map_with_whitespaces() {
 
 fn test_nested_array_object() {
 	mut parser := new_parser(r'[[[[[],[],[]]]],{"Test":{}},[[]]]', false)
-	decoded := parser.decode()?
+	decoded := parser.decode()!
 	assert parser.n_level == 0
 }