cgen: fix option unwrapping on heap var (#23489)

Author: felipensp

vlib/v/gen/c/cgen.v

@@ -5115,8 +5115,13 @@ fn (mut g Gen) ident(node ast.Ident) {
 								}
 							}
 						}
-						if node.obj.ct_type_var != .smartcast && node.obj.is_unwrapped {
-							g.write('.data')
+						if i == 0 && node.obj.ct_type_var != .smartcast && node.obj.is_unwrapped {
+							dot := if !node.obj.orig_type.is_ptr() && obj_sym.is_heap() {
+								'->'
+							} else {
+								'.'
+							}
+							g.write('${dot}data')
 						}
 						g.write(')')
 					}

vlib/v/tests/options/option_heap_var_test.v

@@ -0,0 +1,21 @@
+@[heap]
+struct Foo {
+	a int
+}
+
+struct EdgeService {
+	foo Foo
+}
+
+fn t[S](s S) {
+}
+
+fn test_main() {
+	mut svc := ?EdgeService(EdgeService{})
+	if svc != none {
+		t(svc)
+		assert true
+	} else {
+		assert false
+	}
+}