From 3af720921c6dbc9732d7096169b6e19cf19bf4ed Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Wed, 30 Oct 2024 11:56:21 -0300
Subject: [PATCH] checker: fix selector with prefixed `&` structinit (#22689)

---
 vlib/v/checker/checker.v                              | 3 +++
 vlib/v/checker/tests/selector_struct_init_amp_err.out | 7 +++++++
 vlib/v/checker/tests/selector_struct_init_amp_err.vv  | 8 ++++++++
 3 files changed, 18 insertions(+)
 create mode 100644 vlib/v/checker/tests/selector_struct_init_amp_err.out
 create mode 100644 vlib/v/checker/tests/selector_struct_init_amp_err.vv

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index d16fd0b87..f77d6a53f 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -4498,6 +4498,9 @@ fn (mut c Checker) prefix_expr(mut node ast.PrefixExpr) ast.Type {
 		} else if mut node.right is ast.SelectorExpr {
 			if node.right.expr.is_literal() {
 				c.error('cannot take the address of a literal value', node.pos.extend(node.right.pos))
+			} else if node.right.expr is ast.StructInit {
+				c.error('should not create object instance on the heap to simply access a member',
+					node.pos.extend(node.right.pos))
 			}
 			right_sym := c.table.sym(right_type)
 			expr_sym := c.table.sym(node.right.expr_type)
diff --git a/vlib/v/checker/tests/selector_struct_init_amp_err.out b/vlib/v/checker/tests/selector_struct_init_amp_err.out
new file mode 100644
index 000000000..797e60029
--- /dev/null
+++ b/vlib/v/checker/tests/selector_struct_init_amp_err.out
@@ -0,0 +1,7 @@
+vlib/v/checker/tests/selector_struct_init_amp_err.vv:6:11: error: should not create object instance on the heap to simply access a member
+    4 | 
+    5 | fn test_main() {
+    6 |     field := &Object{}.a
+      |              ~~~~~~~~~~~
+    7 |     assert field == 123
+    8 | }
diff --git a/vlib/v/checker/tests/selector_struct_init_amp_err.vv b/vlib/v/checker/tests/selector_struct_init_amp_err.vv
new file mode 100644
index 000000000..7386c39ff
--- /dev/null
+++ b/vlib/v/checker/tests/selector_struct_init_amp_err.vv
@@ -0,0 +1,8 @@
+struct Object {
+	a int = 123
+}
+
+fn test_main() {
+	field := &Object{}.a
+	assert field == 123
+}
-- 
2.39.5