diff --git a/src/ndto_generator.erl b/src/ndto_generator.erl
index be5a528..df85ef1 100644
--- a/src/ndto_generator.erl
+++ b/src/ndto_generator.erl
@@ -463,7 +463,7 @@ is_valid(Prefix, #{one_of := Subschemas} = Schema) when is_list(Subschemas) ->
             none,
             [
                 erl_syntax:case_expr(
-                    hd(chain_conditions(FunName, ValidationConditions, 'xor')),
+                    erlang:hd(chain_conditions(FunName, ValidationConditions, 'xor')),
                     [
                         erl_syntax:clause(
                             [erl_syntax:atom('true')],
@@ -583,7 +583,7 @@ is_valid(Prefix, #{any_of := Subschemas} = Schema) when is_list(Subschemas) ->
             none,
             [
                 erl_syntax:case_expr(
-                    hd(chain_conditions(FunName, ValidationConditions, 'orelse', true)),
+                    erlang:hd(chain_conditions(FunName, ValidationConditions, 'orelse', true)),
                     [
                         erl_syntax:clause(
                             [erl_syntax:atom('true')],
@@ -661,7 +661,7 @@ is_valid(Prefix, #{all_of := Subschemas} = Schema) when is_list(Subschemas) ->
             none,
             [
                 erl_syntax:case_expr(
-                    hd(chain_conditions(FunName, ValidationConditions, 'andalso', true)),
+                    erlang:hd(chain_conditions(FunName, ValidationConditions, 'andalso', true)),
                     [
                         erl_syntax:clause(
                             [erl_syntax:atom('true')],
@@ -2615,7 +2615,7 @@ chain_conditions(FunName, ValidationConditions, Operator) ->
 chain_conditions(FunName, ValidationConditions, 'andalso', false) ->
     [
         erl_syntax:case_expr(
-            hd(chain_conditions(FunName, ValidationConditions, 'andalso', true)),
+            erlang:hd(chain_conditions(FunName, ValidationConditions, 'andalso', true)),
             [
                 erl_syntax:clause(
                     [erl_syntax:atom('true')],
diff --git a/test/ndto_SUITE.erl b/test/ndto_SUITE.erl
index 3149415..be0b675 100644
--- a/test/ndto_SUITE.erl
+++ b/test/ndto_SUITE.erl
@@ -168,7 +168,7 @@ nullable(_Conf) ->
             DTO2 = ndto:generate(test_nullable2, Schema2),
             ok = ndto:load(DTO2),
 
-            <<Char:1/binary, _Rest/binary>> = TypeBin = atom_to_binary(Type),
+            <<Char:1/binary, _Rest/binary>> = TypeBin = erlang:atom_to_binary(Type),
             Article =
                 case Char of
                     Vocal when Vocal =:= <<"a">>; Vocal =:= <<"o">>; Vocal =:= <<"i">> ->