add test

vlib/v/checker/checker.v

@@ -4204,7 +4204,8 @@ fn (mut c Checker) smartcast(mut expr ast.Expr, cur_type ast.Type, to_type_ ast.
 				smartcasts << field.smartcasts
 			}
 			// smartcast either if the value is immutable or if the mut argument is explicitly given
-			if !is_mut || expr.is_mut {
+			if !is_mut || expr.is_mut
+				|| (cur_type.has_flag(.option) && cur_type.clear_flag(.option) == to_type_) {
 				smartcasts << to_type
 				scope.register_struct_field(expr.expr.str(), ast.ScopeStructField{
 					struct_type: expr.expr_type

vlib/v/gen/c/cgen.v

@@ -4043,7 +4043,7 @@ fn (mut g Gen) selector_expr(node ast.SelectorExpr) {
 					}
 					for i, typ in field.smartcasts {
 						if i == 0 && is_option_unwrap {
-							g.write('*(${g.styp(typ)}*)')
+							g.write('(*(${g.styp(typ)}*)')
 						}
 						g.write('(')
 						if field_sym.kind == .sum_type && !is_option {
@@ -4203,7 +4203,7 @@ fn (mut g Gen) selector_expr(node ast.SelectorExpr) {
 	}
 	g.write(field_name)
 	if is_option_unwrap {
-		g.write('.data)')
+		g.write('.data))')
 	}
 	if sum_type_deref_field != '' {
 		g.write('${sum_type_dot}${sum_type_deref_field})')

vlib/v/tests/options/option_selector_unwrap_test.v

@@ -0,0 +1,31 @@
+import datatypes { DoublyLinkedList }
+
+pub type LayoutBoxId = usize
+
+pub struct LayoutBox {
+}
+
+pub struct LayoutTree {
+mut:
+	root  ?LayoutBoxId
+	boxes []LayoutBox
+}
+
+pub fn LayoutTree.new() LayoutTree {
+	return LayoutTree{
+		root:  ?LayoutBoxId(none)
+		boxes: []LayoutBox{}
+	}
+}
+
+fn test_main() {
+	mut tree := LayoutTree.new()
+	tree.root = 1
+	if tree.root != none {
+		mut parents := DoublyLinkedList[LayoutBoxId]{}
+		parents.push_back(tree.root)
+		assert parents.len == 1
+	} else {
+		assert false
+	}
+}

vlib/v/tests/options/option_selector_unwrap_types_test.v

@@ -0,0 +1,47 @@
+type SumType = int | string
+
+struct Struct {
+	a int
+}
+
+struct Foo {
+	a ?int
+	b ?string
+	c ?SumType
+	d ?Struct
+}
+
+fn test_main() {
+	w := Foo{
+		a: 123
+		b: 'foo'
+		c: SumType(123)
+		d: Struct{
+			a: 123
+		}
+	}
+	if w.a != none {
+		dump(w.a)
+		assert w.a == 123
+	} else {
+		assert false
+	}
+	if w.b != none {
+		dump(w.b)
+		assert w.b == 'foo'
+	} else {
+		assert false
+	}
+	if w.c != none {
+		dump(w.c)
+		assert w.c is int
+	} else {
+		assert false
+	}
+	if w.d != none {
+		dump(w.d)
+		assert w.d.a == 123
+	} else {
+		assert false
+	}
+}