checker: check option fn returning error (fix #17423) (#17438)

vlib/semver/parse.v

@@ -53,7 +53,7 @@ fn (ver RawVersion) is_missing(typ int) bool {
 	return typ >= ver.raw_ints.len - 1
 }
 
-fn (raw_ver RawVersion) coerce() ?Version {
+fn (raw_ver RawVersion) coerce() !Version {
 	ver := raw_ver.complete()
 	if !is_valid_number(ver.raw_ints[semver.ver_major]) {
 		return error('Invalid major version: ${ver.raw_ints}[ver_major]')

vlib/semver/range.v

@@ -69,7 +69,7 @@ fn (c Comparator) satisfies(ver Version) bool {
 	return false
 }
 
-fn parse_range(input string) ?Range {
+fn parse_range(input string) !Range {
 	raw_comparator_sets := input.split(semver.comparator_set_sep)
 	mut comparator_sets := []ComparatorSet{}
 	for raw_comp_set in raw_comparator_sets {
@@ -84,7 +84,7 @@ fn parse_range(input string) ?Range {
 	return Range{comparator_sets}
 }
 
-fn parse_comparator_set(input string) ?ComparatorSet {
+fn parse_comparator_set(input string) !ComparatorSet {
 	raw_comparators := input.split(semver.comparator_sep)
 	if raw_comparators.len > 2 {
 		return &InvalidComparatorFormatError{

vlib/semver/semver.v

@@ -38,7 +38,7 @@ pub fn (err InvalidVersionFormatError) msg() string {
 
 // * Constructor.
 // from returns a `Version` structure parsed from `input` `string`.
-pub fn from(input string) ?Version {
+pub fn from(input string) !Version {
 	if input.len == 0 {
 		return &EmptyInputError{}
 	}
@@ -114,7 +114,7 @@ import semver
 v := semver.coerce('1.3-RC1-b2') or { semver.Version{} }
 assert v.satisfies('>1.0 <2.0') == true // 1.3.0
 */
-pub fn coerce(input string) ?Version {
+pub fn coerce(input string) !Version {
 	return coerce_version(input)
 }
 

vlib/semver/util.v

@@ -8,7 +8,7 @@ fn is_version_valid(input string) bool {
 }
 
 [inline]
-fn coerce_version(input string) ?Version {
+fn coerce_version(input string) !Version {
 	raw_ver := parse(input)
 	ver := raw_ver.coerce() or { return error('Invalid version for input "${input}"') }
 	return ver