cgen: allow generic alias enum comptime (fix #25249) (#25251)

vlib/v/gen/c/comptime.v

@@ -781,7 +781,7 @@ fn (mut g Gen) comptime_for(node ast.ComptimeFor) {
 					if g.pref.translated && node.typ.is_number() {
 						g.writeln('_const_main__${val};')
 					} else {
-						node_sym := g.table.sym(node.typ)
+						node_sym := g.table.sym(g.unwrap_generic(node.typ))
 						if node_sym.info is ast.Alias {
 							g.writeln('${g.styp(node_sym.info.parent_type)}__${val};')
 						} else {

vlib/v/tests/comptime/comptime_enum_values_test.v

@@ -24,6 +24,14 @@ fn CharacterGroup.values() []CharacterGroup {
 	return res
 }
 
+fn do_generic[T](t T) []EnumData {
+	mut vals := []EnumData{}
+	$for value in T.values {
+		vals << value
+	}
+	return vals
+}
+
 fn test_main() {
 	values := CharacterGroup.values()
 	println('Char group values: ${values}')
@@ -53,3 +61,19 @@ fn test_alias_enum() {
 	assert values[3].value == int(CharacterGroup.special)
 	assert values[3].name == CharacterGroup.special.str()
 }
+
+fn test_generic_alias_enum() {
+	values := do_generic(AnotherCharGroup.chars)
+
+	assert values[0].value == int(CharacterGroup.chars)
+	assert values[0].name == CharacterGroup.chars.str()
+
+	assert values[1].value == int(CharacterGroup.alphanumerics)
+	assert values[1].name == CharacterGroup.alphanumerics.str()
+
+	assert values[2].value == int(CharacterGroup.numeric)
+	assert values[2].name == CharacterGroup.numeric.str()
+
+	assert values[3].value == int(CharacterGroup.special)
+	assert values[3].name == CharacterGroup.special.str()
+}