From d46ac407584e4a19a9a24fe9a714bf86277073ad Mon Sep 17 00:00:00 2001
From: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Date: Sun, 6 Feb 2022 15:08:23 +0100
Subject: [PATCH] checker: add error for assigning `none` values (#13383)

---
 vlib/v/checker/assign.v              | 3 +++
 vlib/v/checker/tests/assing_none.out | 6 ++++++
 vlib/v/checker/tests/assing_none.vv  | 4 ++++
 3 files changed, 13 insertions(+)
 create mode 100644 vlib/v/checker/tests/assing_none.out
 create mode 100644 vlib/v/checker/tests/assing_none.vv

diff --git a/vlib/v/checker/assign.v b/vlib/v/checker/assign.v
index 887c49f757..ddc7cfaecb 100644
--- a/vlib/v/checker/assign.v
+++ b/vlib/v/checker/assign.v
@@ -47,6 +47,9 @@ pub fn (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
 				c.error('unexpected `mut` on right-hand side of assignment', right.mut_pos)
 			}
 		}
+		if right is ast.None {
+			c.error('you can not assign a `none` value to a variable', right.pos)
+		}
 	}
 	if node.left.len != right_len {
 		if right_first is ast.CallExpr {
diff --git a/vlib/v/checker/tests/assing_none.out b/vlib/v/checker/tests/assing_none.out
new file mode 100644
index 0000000000..d913002ccc
--- /dev/null
+++ b/vlib/v/checker/tests/assing_none.out
@@ -0,0 +1,6 @@
+vlib/v/checker/tests/assing_none.vv:2:9: error: you can not assign a `none` value to a variable
+    1 | fn main() {
+    2 |     val := none
+      |            ~~~~
+    3 |     println(val)
+    4 | }
diff --git a/vlib/v/checker/tests/assing_none.vv b/vlib/v/checker/tests/assing_none.vv
new file mode 100644
index 0000000000..c4617cc680
--- /dev/null
+++ b/vlib/v/checker/tests/assing_none.vv
@@ -0,0 +1,4 @@
+fn main() {
+	val := none
+	println(val)
+}