diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index b146ec38d0..42979abdce 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -227,7 +227,7 @@ jobs:
         run: |
             # Package lpynn has lpython_emulation as dependency
             # Hence, it should by default install lpython_emulation
-            python -m pip install lpython_emulation==0.0.1.8 lpynn==0.0.1.3 numpy==1.24.3
+            python -m pip install lpython_emulation==0.0.1.9 lpynn==0.0.1.4 numpy==1.24.3
 
       - name: PIP show installed packages
         shell: bash -l {0}
diff --git a/integration_tests/lnn/perceptron/perceptron_main.py b/integration_tests/lnn/perceptron/perceptron_main.py
index 924c2d4f14..a60fe8a4e8 100644
--- a/integration_tests/lnn/perceptron/perceptron_main.py
+++ b/integration_tests/lnn/perceptron/perceptron_main.py
@@ -1,4 +1,4 @@
-from lpython import dataclass, i32, f64
+from lpython import dataclass, i32, f64, InOut
 from sys import exit
 
 @dataclass
@@ -27,7 +27,7 @@ def init_weights(size: i32) -> list[f64]:
     weights.append(0.0) # append bias
     return weights
 
-def init_perceptron(p: Perceptron, n: i32, rate: f64, iterations_limit: i32, des_accuracy: f64):
+def init_perceptron(p: InOut[Perceptron], n: i32, rate: f64, iterations_limit: i32, des_accuracy: f64):
     if (n < 1 or n > 1000):
         print("no_of_inputs must be between [1, 1000]")
         exit(1)
@@ -39,7 +39,7 @@ def init_perceptron(p: Perceptron, n: i32, rate: f64, iterations_limit: i32, des
     p.cur_accuracy = 0.0
     p.epochs_cnt = 0
 
-def train_perceptron(p: Perceptron, input_vector: list[f64], actual_output: i32):
+def train_perceptron(p: InOut[Perceptron], input_vector: list[f64], actual_output: i32):
     predicted_output: i32 = predict_perceptron(p, input_vector)
     error: i32 = actual_output - predicted_output
     i: i32
@@ -65,7 +65,7 @@ def train_epoch(p: Perceptron, input_vectors: list[list[f64]], outputs: list[i32
         if predict_perceptron(p, input_vector) != outputs[i]:
             train_perceptron(p, input_vector, outputs[i])
 
-def train_dataset(p: Perceptron, input_vectors: list[list[f64]], outputs: list[i32]):
+def train_dataset(p: InOut[Perceptron], input_vectors: list[list[f64]], outputs: list[i32]):
     p.cur_accuracy = 0.0
     p.epochs_cnt = 0
     while p.cur_accuracy < p.des_accuracy and p.epochs_cnt < p.iterations_limit:
diff --git a/integration_tests/lnn/regression/regression_main.py b/integration_tests/lnn/regression/regression_main.py
index 9caa4983db..f5ad9979f7 100644
--- a/integration_tests/lnn/regression/regression_main.py
+++ b/integration_tests/lnn/regression/regression_main.py
@@ -1,4 +1,4 @@
-from lpython import dataclass, i32, f64
+from lpython import dataclass, i32, f64, InOut
 from sys import exit
 
 @dataclass
@@ -27,7 +27,7 @@ def init_weights(size: i32) -> list[f64]:
     weights.append(0.0) # append bias
     return weights
 
-def init_perceptron(p: Perceptron, n: i32, rate: f64, iterations_limit: i32, err_limit: f64):
+def init_perceptron(p: InOut[Perceptron], n: i32, rate: f64, iterations_limit: i32, err_limit: f64):
     p.no_of_inputs = n
     p.weights = init_weights(n)
     p.learn_rate = rate
@@ -36,7 +36,7 @@ def init_perceptron(p: Perceptron, n: i32, rate: f64, iterations_limit: i32, err
     p.err = 1.0
     p.epochs_cnt = 0
 
-def train_perceptron(p: Perceptron, input_vector: list[f64], actual_output: f64):
+def train_perceptron(p: InOut[Perceptron], input_vector: list[f64], actual_output: f64):
     predicted_output: f64 = predict_perceptron(p, input_vector)
     error: f64 = actual_output - predicted_output
     i: i32
@@ -60,7 +60,7 @@ def train_epoch(p: Perceptron, input_vectors: list[list[f64]], outputs: list[f64
         if predict_perceptron(p, input_vector) != outputs[i]:
             train_perceptron(p, input_vector, outputs[i])
 
-def train_dataset(p: Perceptron, input_vectors: list[list[f64]], outputs: list[f64]):
+def train_dataset(p: InOut[Perceptron], input_vectors: list[list[f64]], outputs: list[f64]):
     prev_err: f64 = 0.0
     p.err = 1.0
     p.epochs_cnt = 0
diff --git a/integration_tests/lnn/utils/utils_main.py b/integration_tests/lnn/utils/utils_main.py
index fd0b67c232..4ee4f32f66 100644
--- a/integration_tests/lnn/utils/utils_main.py
+++ b/integration_tests/lnn/utils/utils_main.py
@@ -1,4 +1,4 @@
-from lpython import i32, f64
+from lpython import i32, f64, InOut
 
 def normalize(value: f64, leftMin: f64, leftMax: f64, rightMin: f64, rightMax: f64) -> f64:
     # Figure out how 'wide' each range is
@@ -11,7 +11,7 @@ def normalize(value: f64, leftMin: f64, leftMax: f64, rightMin: f64, rightMax: f
     # Convert the 0-1 range into a value in the right range.
     return rightMin + (valueScaled * rightSpan)
 
-def normalize_input_vectors(input_vectors: list[list[f64]]):
+def normalize_input_vectors(input_vectors: InOut[list[list[f64]]]):
     rows: i32 = len(input_vectors)
     cols: i32 = len(input_vectors[0])
 
@@ -29,7 +29,7 @@ def normalize_input_vectors(input_vectors: list[list[f64]]):
         for i in range(rows):
             input_vectors[i][j] = normalize(input_vectors[i][j], colMinVal, colMaxVal, -1.0, 1.0)
 
-def normalize_output_vector(output_vector: list[f64]):
+def normalize_output_vector(output_vector: InOut[list[f64]]):
     rows: i32 = len(output_vector)
     colMinVal: f64 = output_vector[0]
     colMaxVal: f64 = output_vector[0]
diff --git a/integration_tests/print_list_tuple_01.py b/integration_tests/print_list_tuple_01.py
index 841c8baea5..2c599d9c0a 100644
--- a/integration_tests/print_list_tuple_01.py
+++ b/integration_tests/print_list_tuple_01.py
@@ -1,4 +1,4 @@
-from lpython import f64, i32, c64
+from lpython import f64, i32, c64, InOut
 
 
 def test_print_list():
@@ -20,7 +20,7 @@ def test_print_list():
     print(x, y, z, t)
 
 
-def f(y: list[i32]) -> list[i32]:
+def f(y: InOut[list[i32]]) -> list[i32]:
     y.append(4)
     return y
 
diff --git a/integration_tests/print_list_tuple_02.py b/integration_tests/print_list_tuple_02.py
index 3db9c45a1f..57666c50e5 100644
--- a/integration_tests/print_list_tuple_02.py
+++ b/integration_tests/print_list_tuple_02.py
@@ -1,6 +1,6 @@
-from lpython import i32, f64
+from lpython import i32, f64, InOut
 
-def insert_tuples_into_list(l: list[tuple[i32, f64, str]], size: i32) -> list[tuple[i32, f64, str]]:
+def insert_tuples_into_list(l: InOut[list[tuple[i32, f64, str]]], size: i32) -> list[tuple[i32, f64, str]]:
     i: i32
     string: str
     t: tuple[i32, f64, str]
diff --git a/integration_tests/structs_01.py b/integration_tests/structs_01.py
index e588116414..7ad860f5f2 100644
--- a/integration_tests/structs_01.py
+++ b/integration_tests/structs_01.py
@@ -1,4 +1,4 @@
-from lpython import i32, f32, f64, dataclass
+from lpython import i32, f32, f64, dataclass, InOut
 
 @dataclass
 class A:
@@ -9,7 +9,7 @@ def f(a: A):
     print(a.x)
     print(a.y)
 
-def change_struct(a: A):
+def change_struct(a: InOut[A]):
     a.x = a.x + 1
     a.y = a.y + f32(1)
 
diff --git a/integration_tests/structs_05.py b/integration_tests/structs_05.py
index b730a5387b..7d66f41a58 100644
--- a/integration_tests/structs_05.py
+++ b/integration_tests/structs_05.py
@@ -1,4 +1,4 @@
-from lpython import i32, f64, i64, i16, i8, f32, dataclass
+from lpython import i32, f64, i64, i16, i8, f32, dataclass, InOut
 from numpy import empty
 
 @dataclass
@@ -33,7 +33,7 @@ def verify(s: A[:], x1: i32, y1: f64, x2: i32, y2: f64):
     assert s1.c == i8(x2)
     assert s1.d
 
-def update_1(s: A):
+def update_1(s: InOut[A]):
     s.x = 2
     s.y = 1.2
     s.z = i64(2)
diff --git a/integration_tests/test_list_03.py b/integration_tests/test_list_03.py
index dc69e445b7..1cb6953e7d 100644
--- a/integration_tests/test_list_03.py
+++ b/integration_tests/test_list_03.py
@@ -1,4 +1,4 @@
-from lpython import i32
+from lpython import i32, InOut
 
 def test_list_01(n: i32) -> i32:
     a: list[i32] = []
@@ -10,7 +10,7 @@ def test_list_01(n: i32) -> i32:
         sum += a[i]
     return sum
 
-def test_list_insert_02(x: list[i32], n: i32) -> list[i32]:
+def test_list_insert_02(x: InOut[list[i32]], n: i32) -> list[i32]:
     i: i32
     imod: i32
     for i in range(n):
diff --git a/integration_tests/test_list_05.py b/integration_tests/test_list_05.py
index 325e047b6c..7708b95dec 100644
--- a/integration_tests/test_list_05.py
+++ b/integration_tests/test_list_05.py
@@ -1,4 +1,4 @@
-from lpython import i32, f64
+from lpython import i32, f64, InOut
 
 def check_list_of_tuples(l: list[tuple[i32, f64, str]], sign: i32):
     size: i32 = len(l)
@@ -29,7 +29,7 @@ def fill_list_of_tuples(size: i32) -> list[tuple[i32, f64, str]]:
 
     return l1
 
-def insert_tuples_into_list(l: list[tuple[i32, f64, str]], size: i32) -> list[tuple[i32, f64, str]]:
+def insert_tuples_into_list(l: InOut[list[tuple[i32, f64, str]]], size: i32) -> list[tuple[i32, f64, str]]:
     i: i32
     string: str
     t: tuple[i32, f64, str]
diff --git a/integration_tests/test_list_08.py b/integration_tests/test_list_08.py
index 9b120f15ae..f5a2cd33f3 100644
--- a/integration_tests/test_list_08.py
+++ b/integration_tests/test_list_08.py
@@ -1,7 +1,7 @@
-from lpython import i32, f64
+from lpython import i32, f64, InOut
 from copy import deepcopy
 
-def sort(l: list[i32]) -> list[i32]:
+def sort(l: InOut[list[i32]]) -> list[i32]:
     i: i32; j: i32
 
     for i in range(len(l)):
diff --git a/src/lpython/semantics/python_ast_to_asr.cpp b/src/lpython/semantics/python_ast_to_asr.cpp
index 8c4dbbc497..e0c2ccc220 100644
--- a/src/lpython/semantics/python_ast_to_asr.cpp
+++ b/src/lpython/semantics/python_ast_to_asr.cpp
@@ -4662,6 +4662,38 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
                 targets.size());
     }
 
+    bool check_is_assign_to_input_param(AST::expr_t* x) {
+        if (AST::is_a<AST::Name_t>(*x)) {
+            AST::Name_t* n = AST::down_cast<AST::Name_t>(x);
+            ASR::symbol_t* s = current_scope->resolve_symbol(n->m_id);
+            if (!s) {
+                throw SemanticError("Variable: '" + std::string(n->m_id) + "' is not declared",
+                        x->base.loc);
+            }
+            ASR::Variable_t* v =  ASR::down_cast<ASR::Variable_t>(s);
+            if (v->m_intent == ASR::intentType::In) {
+                throw SemanticError("Assignment to an input function parameter `"
+                    + std::string(v->m_name) + "` is not allowed", x->base.loc);
+            }
+            return true;
+        } else if (AST::is_a<AST::Subscript_t>(*x)) {
+            AST::Subscript_t* s = AST::down_cast<AST::Subscript_t>(x);
+            return check_is_assign_to_input_param(s->m_value);
+        } else if (AST::is_a<AST::Attribute_t>(*x)) {
+            AST::Attribute_t* s = AST::down_cast<AST::Attribute_t>(x);
+            return check_is_assign_to_input_param(s->m_value);
+        } else if (AST::is_a<AST::Tuple_t>(*x)) {
+            AST::Tuple_t* t = AST::down_cast<AST::Tuple_t>(x);
+            bool is_assign_to_input = false;
+            for (size_t i = 0; i < t->n_elts && !is_assign_to_input; i++) {
+                is_assign_to_input = is_assign_to_input || check_is_assign_to_input_param(t->m_elts[i]);
+            }
+            return is_assign_to_input;
+        }else {
+            throw SemanticError("Unsupported type in check_is_assign_to_input_param()", x->base.loc);
+        }
+    }
+
     void visit_Assign(const AST::Assign_t &x) {
         ASR::expr_t *target, *assign_value = nullptr, *tmp_value;
         bool is_c_p_pointer_call_copy = is_c_p_pointer_call;
@@ -4689,6 +4721,7 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
         }
         for (size_t i=0; i<x.n_targets; i++) {
             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])) {
                 AST::Subscript_t *sb = AST::down_cast<AST::Subscript_t>(x.m_targets[i]);
                 if (AST::is_a<AST::Name_t>(*sb->m_value)) {
@@ -4831,13 +4864,6 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
                     std::string var_name = std::string(v->m_name);
                     throw SemanticError("Assignment to loop variable `" + std::string(to_lower(var_name)) +"` is not allowed", target->base.loc);
                 }
-                if (sym->type == ASR::symbolType::Variable) {
-                    ASR::Variable_t *v = ASR::down_cast<ASR::Variable_t>(sym);
-                    if (v->m_intent == ASR::intentType::In) {
-                        throw SemanticError("Assignment to an input function parameter `"
-                            + std::string(v->m_name) + "` is not allowed", target->base.loc);
-                    }
-                }
             }
             tmp_vec.push_back(ASR::make_Assignment_t(al, x.base.base.loc, target, tmp_value,
                                     overloaded));
diff --git a/src/lpython/semantics/python_attribute_eval.h b/src/lpython/semantics/python_attribute_eval.h
index eb658913f5..3d07d598e2 100644
--- a/src/lpython/semantics/python_attribute_eval.h
+++ b/src/lpython/semantics/python_attribute_eval.h
@@ -16,6 +16,7 @@ struct AttributeHandler {
                                 const Location &, Vec<ASR::expr_t*> &, diag::Diagnostics &);
 
     std::map<std::string, attribute_eval_callback> attribute_map;
+    std::set<std::string> modify_attr_set;
 
     AttributeHandler() {
         attribute_map = {
@@ -35,6 +36,10 @@ struct AttributeHandler {
             {"dict@get", &eval_dict_get},
             {"dict@pop", &eval_dict_pop}
         };
+
+        modify_attr_set = {"list@append", "list@remove",
+            "list@reverse", "list@clear", "list@insert", "list@pop",
+            "set@pop", "set@add", "set@remove", "dict@pop"};
     }
 
     std::string get_type_name(ASR::ttype_t *t) {
@@ -60,6 +65,13 @@ struct AttributeHandler {
             throw SemanticError("Type name is not implemented yet.", loc);
         }
         std::string key = class_name + "@" + attr_name;
+        if (modify_attr_set.find(key) != modify_attr_set.end()) {
+            ASR::Variable_t* v = ASRUtils::EXPR2VAR(e);
+            if (v->m_intent == ASRUtils::intent_in) {
+                throw SemanticError("Modifying input function parameter `"
+                            + std::string(v->m_name) + "` is not allowed", loc);
+            }
+        }
         auto search = attribute_map.find(key);
         if (search != attribute_map.end()) {
             attribute_eval_callback cb = search->second;
diff --git a/tests/dictionary1.py b/tests/dictionary1.py
index 77d4aae151..b50e326d5a 100644
--- a/tests/dictionary1.py
+++ b/tests/dictionary1.py
@@ -33,7 +33,7 @@ def test_dict_pop():
     x = y.pop("a")
 
 
-def f(x: dict[i32, i32]):
+def f(x: InOut[dict[i32, i32]]):
     x[2] = 4
 
 def test_issue_204():
diff --git a/tests/reference/asr-dictionary1-a105a36.json b/tests/reference/asr-dictionary1-a105a36.json
index 365841f186..52503c6bf0 100644
--- a/tests/reference/asr-dictionary1-a105a36.json
+++ b/tests/reference/asr-dictionary1-a105a36.json
@@ -2,11 +2,11 @@
     "basename": "asr-dictionary1-a105a36",
     "cmd": "lpython --show-asr --no-color {infile} -o {outfile}",
     "infile": "tests/dictionary1.py",
-    "infile_hash": "2d9f15b746aa8185afb3f2dc6415c20a7edccc8e711df1b323178d94",
+    "infile_hash": "f164e8dbe52a04e4fd541d6ff6edae2994d683074087d8785a1759e4",
     "outfile": null,
     "outfile_hash": null,
     "stdout": "asr-dictionary1-a105a36.stdout",
-    "stdout_hash": "0bd85eafba7412639903c3cf431f99a5cec2e2e48e265f0f8014a641",
+    "stdout_hash": "54e029691491889b71111718910b430fa193a93b95b6258fc0c8fbff",
     "stderr": null,
     "stderr_hash": null,
     "returncode": 0
diff --git a/tests/reference/asr-dictionary1-a105a36.stdout b/tests/reference/asr-dictionary1-a105a36.stdout
index b344ac9f2a..9d4fba0917 100644
--- a/tests/reference/asr-dictionary1-a105a36.stdout
+++ b/tests/reference/asr-dictionary1-a105a36.stdout
@@ -17,7 +17,7 @@
                                                     6
                                                     x
                                                     []
-                                                    In
+                                                    InOut
                                                     ()
                                                     ()
                                                     Default
diff --git a/tests/reference/asr-structs_01-be14d49.json b/tests/reference/asr-structs_01-be14d49.json
index 4040befa65..a462e8fa55 100644
--- a/tests/reference/asr-structs_01-be14d49.json
+++ b/tests/reference/asr-structs_01-be14d49.json
@@ -2,11 +2,11 @@
     "basename": "asr-structs_01-be14d49",
     "cmd": "lpython --show-asr --no-color {infile} -o {outfile}",
     "infile": "tests/../integration_tests/structs_01.py",
-    "infile_hash": "c8012b0c841b0d8e304c18ca7c6d4365f1d5e41235dc6f4e2dc21664",
+    "infile_hash": "9f36a4abcc3a50ccc10df1f6b04998b7a20041853142c85a2e86b724",
     "outfile": null,
     "outfile_hash": null,
     "stdout": "asr-structs_01-be14d49.stdout",
-    "stdout_hash": "d23a95b31aa0235947d1720b9f812b84e9c67cafa0e32a3b27802025",
+    "stdout_hash": "cca5515fad19fdf65edf97e51effc67b37295513eaaab45f174854a9",
     "stderr": null,
     "stderr_hash": null,
     "returncode": 0
diff --git a/tests/reference/asr-structs_01-be14d49.stdout b/tests/reference/asr-structs_01-be14d49.stdout
index 0c3f3ea279..b373dcadba 100644
--- a/tests/reference/asr-structs_01-be14d49.stdout
+++ b/tests/reference/asr-structs_01-be14d49.stdout
@@ -103,7 +103,7 @@
                                                     4
                                                     a
                                                     []
-                                                    In
+                                                    InOut
                                                     ()
                                                     ()
                                                     Default
diff --git a/tests/reference/asr-structs_05-fa98307.json b/tests/reference/asr-structs_05-fa98307.json
index c0e703e984..ec64dc141d 100644
--- a/tests/reference/asr-structs_05-fa98307.json
+++ b/tests/reference/asr-structs_05-fa98307.json
@@ -2,11 +2,11 @@
     "basename": "asr-structs_05-fa98307",
     "cmd": "lpython --show-asr --no-color {infile} -o {outfile}",
     "infile": "tests/../integration_tests/structs_05.py",
-    "infile_hash": "94d06fb2844e1060d5df5291c3ccc4bd0e2bc8a8a59651814f0c4f0e",
+    "infile_hash": "5c587158fe09782d15aa8f5f9c24468c62795e9f537a9eb439d8e8a4",
     "outfile": null,
     "outfile_hash": null,
     "stdout": "asr-structs_05-fa98307.stdout",
-    "stdout_hash": "fb8c872aaca346b06d130d093b14f58f616b667e4613f765fb32a2e6",
+    "stdout_hash": "bde17720270048c509903eac1703b839f3e34c0a9cb1d8df1811bd55",
     "stderr": null,
     "stderr_hash": null,
     "returncode": 0
diff --git a/tests/reference/asr-structs_05-fa98307.stdout b/tests/reference/asr-structs_05-fa98307.stdout
index 68bd595cea..020049a803 100644
--- a/tests/reference/asr-structs_05-fa98307.stdout
+++ b/tests/reference/asr-structs_05-fa98307.stdout
@@ -419,7 +419,7 @@
                                                     195
                                                     s
                                                     []
-                                                    In
+                                                    InOut
                                                     ()
                                                     ()
                                                     Default
diff --git a/tests/reference/ast-dictionary1-1a7e00a.json b/tests/reference/ast-dictionary1-1a7e00a.json
index 41583be770..ba29488d33 100644
--- a/tests/reference/ast-dictionary1-1a7e00a.json
+++ b/tests/reference/ast-dictionary1-1a7e00a.json
@@ -2,11 +2,11 @@
     "basename": "ast-dictionary1-1a7e00a",
     "cmd": "lpython --show-ast --no-color {infile} -o {outfile}",
     "infile": "tests/dictionary1.py",
-    "infile_hash": "2d9f15b746aa8185afb3f2dc6415c20a7edccc8e711df1b323178d94",
+    "infile_hash": "f164e8dbe52a04e4fd541d6ff6edae2994d683074087d8785a1759e4",
     "outfile": null,
     "outfile_hash": null,
     "stdout": "ast-dictionary1-1a7e00a.stdout",
-    "stdout_hash": "cd85b7fa2f2f43a4be7a88c54d582616f529b9acee1de757eb361bd7",
+    "stdout_hash": "c347af8c0abbed4664f354dc24c1bd061218c0584aef27889fbf1745",
     "stderr": null,
     "stderr_hash": null,
     "returncode": 0
diff --git a/tests/reference/ast-dictionary1-1a7e00a.stdout b/tests/reference/ast-dictionary1-1a7e00a.stdout
index 41c449fc10..d300e7a74d 100644
--- a/tests/reference/ast-dictionary1-1a7e00a.stdout
+++ b/tests/reference/ast-dictionary1-1a7e00a.stdout
@@ -511,18 +511,25 @@
         [(x
         (Subscript
             (Name
-                dict
+                InOut
                 Load
             )
-            (Tuple
-                [(Name
-                    i32
+            (Subscript
+                (Name
+                    dict
                     Load
                 )
-                (Name
-                    i32
+                (Tuple
+                    [(Name
+                        i32
+                        Load
+                    )
+                    (Name
+                        i32
+                        Load
+                    )]
                     Load
-                )]
+                )
                 Load
             )
             Load