cgen: fix shared optional (#15462)

vlib/v/gen/c/cgen.v

@@ -2948,7 +2948,7 @@ fn (mut g Gen) expr(node_ ast.Expr) {
 				node.return_type.clear_flag(.optional)
 			}
 			mut shared_styp := ''
-			if g.is_shared && !ret_type.has_flag(.shared_f) {
+			if g.is_shared && !ret_type.has_flag(.shared_f) && !g.inside_or_block {
 				ret_sym := g.table.sym(ret_type)
 				shared_typ := ret_type.set_flag(.shared_f)
 				shared_styp = g.typ(shared_typ)
@@ -2977,7 +2977,7 @@ fn (mut g Gen) expr(node_ ast.Expr) {
 				g.strs_to_free0 = []
 				// println('pos=$node.pos.pos')
 			}
-			if g.is_shared && !ret_type.has_flag(.shared_f) {
+			if g.is_shared && !ret_type.has_flag(.shared_f) && !g.inside_or_block {
 				g.writeln('}, sizeof($shared_styp))')
 			}
 			// if g.autofree && node.autofree_pregen != '' { // g.strs_to_free0.len != 0 {

vlib/v/tests/shared_optional_test.v

@@ -0,0 +1,25 @@
+module main
+
+struct ABC {
+mut:
+	s string
+}
+
+fn test_shared_optional() {
+	shared abc := foo() or { panic('scared') }
+	rlock abc {
+		println(abc)
+		assert abc.s == 'hello'
+	}
+}
+
+fn foo() ?ABC {
+	mut a := ABC{}
+	a.bar()?
+	return a
+}
+
+fn (mut a ABC) bar() ? {
+	a.s = 'hello'
+	println(a.s)
+}