cgen: fix sorting of shared array fields (fix #15244)

vlib/v/gen/c/array.v

@@ -519,8 +519,15 @@ fn (mut g Gen) gen_array_sort(node ast.CallExpr) {
 }
 
 fn (mut g Gen) gen_array_sort_call(node ast.CallExpr, compare_fn string) {
-	deref_field := if node.left_type.is_ptr() || node.left_type.is_pointer() { '->' } else { '.' }
+	mut deref_field := if node.left_type.is_ptr() || node.left_type.is_pointer() {
-	// eprintln('> qsort: pointer $node.left_type | deref: `$deref`')
+		'->'
+	} else {
+		'.'
+	}
+	if node.left_type.has_flag(.shared_f) {
+		deref_field += 'val.'
+	}
+	// eprintln('> qsort: pointer $node.left_type | deref_field: `$deref_field`')
 	g.empty_line = true
 	g.write('qsort(')
 	g.expr(node.left)

vlib/v/tests/shared_array_sort_test.v

@@ -0,0 +1,34 @@
+module main
+
+import time
+
+struct Alarms {
+mut:
+	times shared []time.Time
+}
+
+fn (alarms Alarms) add(alarm time.Time) {
+	lock alarms.times {
+		alarms.times << alarm
+		alarms.times.sort(a < b)
+	}
+}
+
+fn test_sorting_shared_arrays() ? {
+	alarms := Alarms{}
+	utc := time.utc()
+	alarms.add(utc)
+	alarms.add(time.parse_iso8601('2022-03-01')?)
+	alarms.add(time.parse_iso8601('3001-03-01')?)
+	alarms.add(time.parse_iso8601('2002-03-01')?)
+	alarms.add(time.parse_iso8601('3002-03-01')?)
+	alarms.add(time.parse_iso8601('2021-03-01')?)
+	println(alarms)
+	lock alarms.times {
+		assert alarms.times.len == 6
+		assert alarms.times[0].year == 2002
+		assert alarms.times.pop().year == 3002
+		assert alarms.times.pop().year == 3001
+		assert alarms.times.len == 4
+	}
+}