From fd47385ff2b36b9b72037ea5993e656780cdb4d9 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@vlang.io>
Date: Tue, 19 Jul 2022 13:31:10 +0300
Subject: [PATCH] checker: check untyped nil in assignment

---
 vlib/v/checker/assign.v      | 3 +++
 vlib/v/checker/tests/nil.out | 7 +++++++
 vlib/v/checker/tests/nil.vv  | 6 ++++++
 3 files changed, 16 insertions(+)
 create mode 100644 vlib/v/checker/tests/nil.out
 create mode 100644 vlib/v/checker/tests/nil.vv

diff --git a/vlib/v/checker/assign.v b/vlib/v/checker/assign.v
index d68ba66f75..ba5854e6a5 100644
--- a/vlib/v/checker/assign.v
+++ b/vlib/v/checker/assign.v
@@ -220,6 +220,9 @@ pub fn (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
 							c.error('invalid use of reserved type `$left.name` as a variable name',
 								left.pos)
 						}
+						if right is ast.Nil {
+							c.error('use of untyped nil in assignment', right.pos())
+						}
 					}
 					mut ident_var_info := left.info as ast.IdentVar
 					if ident_var_info.share == .shared_t {
diff --git a/vlib/v/checker/tests/nil.out b/vlib/v/checker/tests/nil.out
new file mode 100644
index 0000000000..6d4d981d28
--- /dev/null
+++ b/vlib/v/checker/tests/nil.out
@@ -0,0 +1,7 @@
+vlib/v/checker/tests/nil.vv:3:18: error: use of untyped nil in assignment
+    1 | fn main() {
+    2 |     unsafe {
+    3 |         value := nil
+      |                  ~~~
+    4 |         println(value)
+    5 |     }
diff --git a/vlib/v/checker/tests/nil.vv b/vlib/v/checker/tests/nil.vv
new file mode 100644
index 0000000000..09deb0011f
--- /dev/null
+++ b/vlib/v/checker/tests/nil.vv
@@ -0,0 +1,6 @@
+fn main() {
+    unsafe {
+        value := nil
+        println(value)
+    }
+}