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

vlib/flag/flag_test.v

@@ -153,9 +153,9 @@ fn test_finalize_returns_error_for_unknown_flags_short() {
 	assert finalized.len < 0 // expect error to be returned
 }
 
-fn test_allow_to_build_usage_message() ? {
+fn test_allow_to_build_usage_message() {
 	mut fp := flag.new_flag_parser([])
-	fp.limit_free_args(1, 4)?
+	fp.limit_free_args(1, 4)!
 	fp.application('flag_tool')
 	fp.version('v0.0.0')
 	fp.description('some short information about this tool')
@@ -194,9 +194,9 @@ fn test_if_no_options_given_usage_message_does_not_contain_options() {
 	assert !fp.usage().contains('Options:')
 }
 
-fn test_free_args_could_be_limited() ? {
+fn test_free_args_could_be_limited() {
 	mut fp1 := flag.new_flag_parser(['a', 'b', 'c'])
-	fp1.limit_free_args(1, 4)?
+	fp1.limit_free_args(1, 4)!
 	args := fp1.finalize() or {
 		assert false
 		return
@@ -206,9 +206,9 @@ fn test_free_args_could_be_limited() ? {
 	assert args[2] == 'c'
 }
 
-fn test_error_for_to_few_free_args() ? {
+fn test_error_for_to_few_free_args() {
 	mut fp1 := flag.new_flag_parser(['a', 'b', 'c'])
-	fp1.limit_free_args(5, 6)?
+	fp1.limit_free_args(5, 6)!
 	args := fp1.finalize() or {
 		assert err.msg().starts_with('Expected at least 5 arguments')
 		return
@@ -216,9 +216,9 @@ fn test_error_for_to_few_free_args() ? {
 	assert args.len < 0 // expect an error and need to use args
 }
 
-fn test_error_for_to_much_free_args() ? {
+fn test_error_for_to_much_free_args() {
 	mut fp1 := flag.new_flag_parser(['a', 'b', 'c'])
-	fp1.limit_free_args(1, 2)?
+	fp1.limit_free_args(1, 2)!
 	args := fp1.finalize() or {
 		assert err.msg().starts_with('Expected at most 2 arguments')
 		return
@@ -226,9 +226,9 @@ fn test_error_for_to_much_free_args() ? {
 	assert args.len < 0 // expect an error and need to use args
 }
 
-fn test_could_expect_no_free_args() ? {
+fn test_could_expect_no_free_args() {
 	mut fp1 := flag.new_flag_parser(['a'])
-	fp1.limit_free_args(0, 0)?
+	fp1.limit_free_args(0, 0)!
 	args := fp1.finalize() or {
 		assert err.msg().starts_with('Expected no arguments')
 		return
@@ -383,7 +383,7 @@ fn test_optional_flags() {
 	assert b == 'some_default_value'
 }
 
-fn test_dashdash_acts_as_parser_full_stop() ? {
+fn test_dashdash_acts_as_parser_full_stop() {
 	mut fp := flag.new_flag_parser(['-b', '5', '--', '-d', '-x', '-b', '4', '-a', '-c', 'hello',
 		'some', 'other', 'parameters'])
 	a := fp.bool_opt('a-bool-flag', `a`, '') or { false }
@@ -392,17 +392,17 @@ fn test_dashdash_acts_as_parser_full_stop() ? {
 	assert a == false
 	assert b == 5
 	assert c == 'default'
-	args := fp.finalize()?
+	args := fp.finalize()!
 	assert args.len > 0
 	assert args[0] != '--'
 	assert args == ['-d', '-x', '-b', '4', '-a', '-c', 'hello', 'some', 'other', 'parameters']
 }
 
-fn test_dashdash_acts_as_parser_full_stop_dashdash_at_end() ? {
+fn test_dashdash_acts_as_parser_full_stop_dashdash_at_end() {
 	mut fp := flag.new_flag_parser(['-b', '5', '-b', '4', 'other', 'params', '--'])
 	b := fp.int_multi('an-int-flag', `b`, '')
 	assert b == [5, 4]
-	args := fp.finalize()?
+	args := fp.finalize()!
 	assert args.len > 0
 }