diff --git a/kclvm/parser/src/parser/stmt.rs b/kclvm/parser/src/parser/stmt.rs
index dc31323c6..071e4a800 100644
--- a/kclvm/parser/src/parser/stmt.rs
+++ b/kclvm/parser/src/parser/stmt.rs
@@ -306,6 +306,7 @@ impl<'a> Parser<'a> {
                         None
                     }
                 })
+                // Drop error assign target nodes.
                 .flatten()
                 .collect();
 
@@ -369,6 +370,7 @@ impl<'a> Parser<'a> {
                                 None
                             }
                         })
+                        // Drop error assign target nodes.
                         .flatten()
                         .collect();
                     Some(Box::new(Node::node_with_pos(
diff --git a/test/grammar/assign/assign_fail_2/main.k b/test/grammar/assign/assign_fail_2/main.k
new file mode 100644
index 000000000..1ef8a0c15
--- /dev/null
+++ b/test/grammar/assign/assign_fail_2/main.k
@@ -0,0 +1,2 @@
+_a = [1, 2, 3]
+_a[1:2] = [2, 3]
\ No newline at end of file
diff --git a/test/grammar/assign/assign_fail_2/stderr.golden b/test/grammar/assign/assign_fail_2/stderr.golden
new file mode 100644
index 000000000..e282bf990
--- /dev/null
+++ b/test/grammar/assign/assign_fail_2/stderr.golden
@@ -0,0 +1 @@
+'SubscriptExpression' is an illegal expression for assignment, because the left-hand side of an assignment expression may not be a slice access
\ No newline at end of file
diff --git a/test/grammar/assign/assign_fail_3/main.k b/test/grammar/assign/assign_fail_3/main.k
new file mode 100644
index 000000000..af839bf50
--- /dev/null
+++ b/test/grammar/assign/assign_fail_3/main.k
@@ -0,0 +1,2 @@
+_a = {}
+_a?.b = "value"
\ No newline at end of file
diff --git a/test/grammar/assign/assign_fail_3/stderr.golden b/test/grammar/assign/assign_fail_3/stderr.golden
new file mode 100644
index 000000000..f485aa623
--- /dev/null
+++ b/test/grammar/assign/assign_fail_3/stderr.golden
@@ -0,0 +1 @@
+'SelectorExpression' is an illegal expression for assignment, because the left-hand side of an assignment expression may not be an optional attribute access.
diff --git a/test/grammar/assign/assign_fail_4/main.k b/test/grammar/assign/assign_fail_4/main.k
new file mode 100644
index 000000000..f1097573a
--- /dev/null
+++ b/test/grammar/assign/assign_fail_4/main.k
@@ -0,0 +1 @@
+_a + 1 = 2
\ No newline at end of file
diff --git a/test/grammar/assign/assign_fail_4/stderr.golden b/test/grammar/assign/assign_fail_4/stderr.golden
new file mode 100644
index 000000000..af7a9f804
--- /dev/null
+++ b/test/grammar/assign/assign_fail_4/stderr.golden
@@ -0,0 +1 @@
+'BinaryExpression' is an illegal expression for assignment
\ No newline at end of file
diff --git a/test/grammar/assign/assign_fail_5/main.k b/test/grammar/assign/assign_fail_5/main.k
new file mode 100644
index 000000000..ad7d54061
--- /dev/null
+++ b/test/grammar/assign/assign_fail_5/main.k
@@ -0,0 +1 @@
+[1] = 2
\ No newline at end of file
diff --git a/test/grammar/assign/assign_fail_5/stderr.golden b/test/grammar/assign/assign_fail_5/stderr.golden
new file mode 100644
index 000000000..9b88d5258
--- /dev/null
+++ b/test/grammar/assign/assign_fail_5/stderr.golden
@@ -0,0 +1 @@
+'ListExpression' is an illegal expression for assignment
\ No newline at end of file
diff --git a/test/grammar/assign/assign_fail_6/main.k b/test/grammar/assign/assign_fail_6/main.k
new file mode 100644
index 000000000..41c9a8a35
--- /dev/null
+++ b/test/grammar/assign/assign_fail_6/main.k
@@ -0,0 +1 @@
+_f() = 2
\ No newline at end of file
diff --git a/test/grammar/assign/assign_fail_6/stderr.golden b/test/grammar/assign/assign_fail_6/stderr.golden
new file mode 100644
index 000000000..fc14ede0d
--- /dev/null
+++ b/test/grammar/assign/assign_fail_6/stderr.golden
@@ -0,0 +1 @@
+'CallExpression' is an illegal expression for assignment
\ No newline at end of file