From a3b62cba31c428bd7566dd81fc2b86088fb45e3e Mon Sep 17 00:00:00 2001
From: Amrita kumari mishra <amritamishraxa06@gmail.com>
Date: Fri, 28 Nov 2025 21:40:40 +0000
Subject: [PATCH 1/5] Add semantic error test for assignment to literal

---
 tests/errors/reproduce_bug_01.py | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 tests/errors/reproduce_bug_01.py

diff --git a/tests/errors/reproduce_bug_01.py b/tests/errors/reproduce_bug_01.py
new file mode 100644
index 0000000000..de24edaa2a
--- /dev/null
+++ b/tests/errors/reproduce_bug_01.py
@@ -0,0 +1,2 @@
+# TEST EXPECTS SEMANTIC ERROR
+'a' = 1

From 8f557cbcfa9bf3dcaede02799b8011ff70304abb Mon Sep 17 00:00:00 2001
From: Amrita kumari mishra <amritamishraxa06@gmail.com>
Date: Fri, 28 Nov 2025 22:05:33 +0000
Subject: [PATCH 2/5] Fix: prevent assignment to literal (semantic error)

---
 src/lpython/semantics/python_ast_to_asr.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/lpython/semantics/python_ast_to_asr.cpp b/src/lpython/semantics/python_ast_to_asr.cpp
index 4d116cfce7..45dd778691 100644
--- a/src/lpython/semantics/python_ast_to_asr.cpp
+++ b/src/lpython/semantics/python_ast_to_asr.cpp
@@ -5654,6 +5654,11 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
             assign_value = ASRUtils::EXPR(tmp);
         }
         for (size_t i=0; i<x.n_targets; i++) {
+            if (AST::is_a<AST::Constant_t>(*x.m_targets[i]) ||
+                AST::is_a<AST::Set_t>(*x.m_targets[i]) ||
+                AST::is_a<AST::Dict_t>(*x.m_targets[i])) {
+                throw SemanticError("SyntaxError: cannot assign to literal", x.m_targets[i]->base.loc);
+            }
             tmp_value = assign_value;
             check_is_assign_to_input_param(x.m_targets[i]);
             if (AST::is_a<AST::Subscript_t>(*x.m_targets[i])) {

From 7afdb32591dfecee78c03e5b91408a428f73074c Mon Sep 17 00:00:00 2001
From: Amrita kumari mishra <amritamishraxa06@gmail.com>
Date: Fri, 28 Nov 2025 22:47:30 +0000
Subject: [PATCH 3/5] Remove forbidden iostream header

---
 src/lpython/semantics/python_ast_to_asr.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/lpython/semantics/python_ast_to_asr.cpp b/src/lpython/semantics/python_ast_to_asr.cpp
index 45dd778691..ade5aec269 100644
--- a/src/lpython/semantics/python_ast_to_asr.cpp
+++ b/src/lpython/semantics/python_ast_to_asr.cpp
@@ -1,5 +1,4 @@
 #include <fstream>
-#include <iostream>
 #include <map>
 #include <set>
 #include <memory>

From 94fabb0765e46b6c213fb9974ef13c3bd8d34414 Mon Sep 17 00:00:00 2001
From: Amrita kumari mishra <amritamishraxa06@gmail.com>
Date: Fri, 28 Nov 2025 23:09:38 +0000
Subject: [PATCH 4/5] Fix: Use correct AST types for literal assignment check

---
 src/lpython/semantics/python_ast_to_asr.cpp | 9 ++++++++-
 tests/errors/reproduce_bug_01.out           | 9 +++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 tests/errors/reproduce_bug_01.out

diff --git a/src/lpython/semantics/python_ast_to_asr.cpp b/src/lpython/semantics/python_ast_to_asr.cpp
index ade5aec269..d713de7c73 100644
--- a/src/lpython/semantics/python_ast_to_asr.cpp
+++ b/src/lpython/semantics/python_ast_to_asr.cpp
@@ -5653,7 +5653,14 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
             assign_value = ASRUtils::EXPR(tmp);
         }
         for (size_t i=0; i<x.n_targets; i++) {
-            if (AST::is_a<AST::Constant_t>(*x.m_targets[i]) ||
+            if (AST::is_a<AST::ConstantStr_t>(*x.m_targets[i]) ||
+                AST::is_a<AST::ConstantInt_t>(*x.m_targets[i]) ||
+                AST::is_a<AST::ConstantBool_t>(*x.m_targets[i]) ||
+                AST::is_a<AST::ConstantFloat_t>(*x.m_targets[i]) ||
+                AST::is_a<AST::ConstantComplex_t>(*x.m_targets[i]) ||
+                AST::is_a<AST::ConstantEllipsis_t>(*x.m_targets[i]) ||
+                AST::is_a<AST::ConstantNone_t>(*x.m_targets[i]) ||
+                AST::is_a<AST::ConstantBytes_t>(*x.m_targets[i]) ||
                 AST::is_a<AST::Set_t>(*x.m_targets[i]) ||
                 AST::is_a<AST::Dict_t>(*x.m_targets[i])) {
                 throw SemanticError("SyntaxError: cannot assign to literal", x.m_targets[i]->base.loc);
diff --git a/tests/errors/reproduce_bug_01.out b/tests/errors/reproduce_bug_01.out
new file mode 100644
index 0000000000..1cb4c03f92
--- /dev/null
+++ b/tests/errors/reproduce_bug_01.out
@@ -0,0 +1,9 @@
+semantic error: SyntaxError: cannot assign to literal
+ --> tests/errors/reproduce_bug_01.py:2:1
+  |
+2 | 'a' = 1
+  | ^^^ 
+
+
+Note: Please report unclear, confusing or incorrect messages as bugs at
+https://github.com/lfortran/lfortran/issues.

From 85d32c6fa38cde30e35229903e2058c92faf7ad8 Mon Sep 17 00:00:00 2001
From: Amrita kumari mishra <amritamishraxa06@gmail.com>
Date: Sat, 29 Nov 2025 08:38:04 +0000
Subject: [PATCH 5/5] CI: re-run tests