diff --git a/vlib/v/checker/tests/assign_expr_undefined_err_e.out b/vlib/v/checker/tests/assign_expr_undefined_err_e.out
new file mode 100644
index 0000000000..185abb3be8
--- /dev/null
+++ b/vlib/v/checker/tests/assign_expr_undefined_err_e.out
@@ -0,0 +1,6 @@
+vlib/v/checker/tests/assign_expr_undefined_err_e.v:2:11: error: undefined variable: `a`
+    1 | fn main() {
+    2 |     a, b := -a, -b
+      |              ^
+    3 |     println(s)
+    4 | }
diff --git a/vlib/v/checker/tests/assign_expr_undefined_err_e.vv b/vlib/v/checker/tests/assign_expr_undefined_err_e.vv
new file mode 100644
index 0000000000..47e4ed5f6a
--- /dev/null
+++ b/vlib/v/checker/tests/assign_expr_undefined_err_e.vv
@@ -0,0 +1,4 @@
+fn main() {
+	a, b := -a, -b
+	println(s)
+}
diff --git a/vlib/v/checker/tests/assign_expr_undefined_err_f.out b/vlib/v/checker/tests/assign_expr_undefined_err_f.out
new file mode 100644
index 0000000000..62f7ed3c89
--- /dev/null
+++ b/vlib/v/checker/tests/assign_expr_undefined_err_f.out
@@ -0,0 +1,6 @@
+vlib/v/checker/tests/assign_expr_undefined_err_f.v:2:12: error: undefined variable: `a`
+    1 | fn main() {
+    2 |     a, b := (-a + 1), 1
+      |               ^
+    3 |     println('$a, $b')
+    4 | }
diff --git a/vlib/v/checker/tests/assign_expr_undefined_err_f.vv b/vlib/v/checker/tests/assign_expr_undefined_err_f.vv
new file mode 100644
index 0000000000..79ec34862c
--- /dev/null
+++ b/vlib/v/checker/tests/assign_expr_undefined_err_f.vv
@@ -0,0 +1,4 @@
+fn main() {
+	a, b := (-a + 1), 1
+	println('$a, $b')
+}
diff --git a/vlib/v/parser/assign.v b/vlib/v/parser/assign.v
index 733af7cf9c..6917b819a3 100644
--- a/vlib/v/parser/assign.v
+++ b/vlib/v/parser/assign.v
@@ -22,6 +22,15 @@ fn (mut p Parser) check_undefined_variables(idents []ast.Ident, expr ast.Expr) {
 			p.check_undefined_variables(idents, it.left)
 			p.check_undefined_variables(idents, it.right)
 		}
+		ast.ParExpr {
+			p.check_undefined_variables(idents, it.expr)
+		}
+		ast.PostfixExpr {
+			p.check_undefined_variables(idents, it.expr)
+		}
+		ast.PrefixExpr {
+			p.check_undefined_variables(idents, it.right)
+		}
 		ast.StringInterLiteral {
 			for expr_ in it.exprs {
 				p.check_undefined_variables(idents, expr_)