checker: check struct aliased field unsign type assigning negative value

vlib/v/checker/struct.v

@@ -801,7 +801,7 @@ or use an explicit `unsafe{ a[..] }`, if you do not want a copy of the slice.',
 					c.fail_if_stack_struct_action_outside_unsafe(mut init_field.expr,
 						'assigned')
 				}
-				if field_info.typ in ast.unsigned_integer_type_idxs
+				if c.table.unaliased_type(exp_type) in ast.unsigned_integer_type_idxs
 					&& mut init_field.expr is ast.IntegerLiteral
 					&& (init_field.expr as ast.IntegerLiteral).val[0] == `-` {
 					c.error('cannot assign negative value to unsigned integer type', init_field.expr.pos)

vlib/v/checker/tests/struct_aliased_field_unsign_type_check_err.out

@@ -0,0 +1,7 @@
+vlib/v/checker/tests/struct_aliased_field_unsign_type_check_err.vv:9:9: error: cannot assign negative value to unsigned integer type
+    7 | fn main() {
+    8 |     app := App{
+    9 |         port: -1
+      |               ~~
+   10 |     }
+   11 |     println(app)

vlib/v/checker/tests/struct_aliased_field_unsign_type_check_err.vv

@@ -0,0 +1,12 @@
+type Port = u16
+
+struct App {
+	port Port
+}
+
+fn main() {
+	app := App{
+		port: -1
+	}
+	println(app)
+}