diff --git a/assets/parser.c.erb b/assets/parser.c.erb
index bcbd269..96c184b 100644
--- a/assets/parser.c.erb
+++ b/assets/parser.c.erb
@@ -695,11 +695,13 @@ typedef struct
 } state_value_t;
 
 /** Common AST node structure. */
-typedef struct
+typedef struct ASTNode_s
 {
     <%= @grammar.prefix %>position_t position;
     <%= @grammar.prefix %>position_t end_position;
-    void * fields[];
+    uint16_t n_fields;
+    uint8_t is_token;
+    struct ASTNode_s * fields[];
 } ASTNode;
 
 /** Parser shift table. */
@@ -992,6 +994,8 @@ size_t <%= @grammar.prefix %>parse(<%= @grammar.prefix %>context_t * context)
                 <%= @grammar.ast_prefix %>Token<%= @grammar.ast_suffix %> * token_ast_node = (<%= @grammar.ast_prefix %>Token<%= @grammar.ast_suffix %> *)malloc(sizeof(<%= @grammar.ast_prefix %>Token<%= @grammar.ast_suffix %>));
                 token_ast_node->position = token_info.position;
                 token_ast_node->end_position = token_info.end_position;
+                token_ast_node->n_fields = 0u;
+                token_ast_node->is_token = 1u;
                 token_ast_node->token = token;
                 token_ast_node->pvalue = token_info.pvalue;
                 state_values_stack_index(&statevalues, -1)->ast_node = token_ast_node;
@@ -1028,31 +1032,30 @@ size_t <%= @grammar.prefix %>parse(<%= @grammar.prefix %>context_t * context)
             else if (parser_reduce_table[reduce_index].n_states > 0)
             {
                 size_t n_fields = parser_reduce_table[reduce_index].rule_set_node_field_array_size;
-                ASTNode * node = (ASTNode *)malloc(sizeof(ASTNode) + n_fields * sizeof(void *));
+                size_t bytes = sizeof(ASTNode) + n_fields * sizeof(void *);
+                ASTNode * node = (ASTNode *)malloc(bytes);
+                memset(node, 0, bytes);
                 node->position = INVALID_POSITION;
                 node->end_position = INVALID_POSITION;
-                for (size_t i = 0; i < n_fields; i++)
-                {
-                    node->fields[i] = NULL;
-                }
+                node->n_fields = n_fields;
                 if (parser_reduce_table[reduce_index].rule_set_node_field_index_map == NULL)
                 {
                     for (size_t i = 0; i < parser_reduce_table[reduce_index].n_states; i++)
                     {
-                        node->fields[i] = state_values_stack_index(&statevalues, -(int)parser_reduce_table[reduce_index].n_states + (int)i)->ast_node;
+                        node->fields[i] = (ASTNode *)state_values_stack_index(&statevalues, -(int)parser_reduce_table[reduce_index].n_states + (int)i)->ast_node;
                     }
                 }
                 else
                 {
                     for (size_t i = 0; i < parser_reduce_table[reduce_index].n_states; i++)
                     {
-                        node->fields[parser_reduce_table[reduce_index].rule_set_node_field_index_map[i]] = state_values_stack_index(&statevalues, -(int)parser_reduce_table[reduce_index].n_states + (int)i)->ast_node;
+                        node->fields[parser_reduce_table[reduce_index].rule_set_node_field_index_map[i]] = (ASTNode *)state_values_stack_index(&statevalues, -(int)parser_reduce_table[reduce_index].n_states + (int)i)->ast_node;
                     }
                 }
                 bool position_found = false;
                 for (size_t i = 0; i < n_fields; i++)
                 {
-                    ASTNode * child = (ASTNode *)node->fields[i];
+                    ASTNode * child = node->fields[i];
                     if ((child != NULL) && <%= @grammar.prefix %>position_valid(child->position))
                     {
                         if (!position_found)
@@ -1074,6 +1077,7 @@ size_t <%= @grammar.prefix %>parse(<%= @grammar.prefix %>context_t * context)
             memset(&reduced_parser_value2, 0, sizeof(reduced_parser_value2));
             if (parser_user_code(&reduced_parser_value2, parser_reduce_table[reduce_index].rule, &statevalues, parser_reduce_table[reduce_index].n_states, context) == P_USER_TERMINATED)
             {
+                state_values_stack_free(&statevalues);
                 return P_USER_TERMINATED;
             }
             reduced_parser_value = reduced_parser_value2;
@@ -1153,3 +1157,32 @@ size_t <%= @grammar.prefix %>user_terminate_code(<%= @grammar.prefix %>context_t
 {
     return context->token;
 }
+<% if @grammar.ast %>
+
+static void free_ast_node(ASTNode * node)
+{
+    if (node->is_token)
+    {
+        /* TODO: free value_t */
+    }
+    else if (node->n_fields > 0u)
+    {
+        for (size_t i = 0u; i < node->n_fields; i++)
+        {
+            if (node->fields[i] != NULL)
+            {
+                free_ast_node(node->fields[i]);
+            }
+        }
+    }
+    free(node);
+}
+
+/**
+ * Free all AST node memory.
+ */
+void <%= @grammar.prefix %>free_ast(<%= @grammar.ast_prefix %><%= @grammar.start_rule %><%= @grammar.ast_suffix %> * ast)
+{
+    free_ast_node((ASTNode *)ast);
+}
+<% end %>
diff --git a/assets/parser.h.erb b/assets/parser.h.erb
index 058371c..86a8b1e 100644
--- a/assets/parser.h.erb
+++ b/assets/parser.h.erb
@@ -75,9 +75,11 @@ typedef union
 /** AST node types. @{ */
 typedef struct <%= @grammar.ast_prefix %>Token<%= @grammar.ast_suffix %>
 {
-    /* ASTNode fields must be present in the same order here. */
+    <% # ASTNode fields must be present in the same order here. # %>
     <%= @grammar.prefix %>position_t position;
     <%= @grammar.prefix %>position_t end_position;
+    uint16_t n_fields;
+    uint8_t is_token;
     <%= @grammar.prefix %>token_t token;
     <%= @grammar.prefix %>value_t pvalue;
 } <%= @grammar.ast_prefix %>Token<%= @grammar.ast_suffix %>;
@@ -93,8 +95,11 @@ struct <%= name %>;
 <%     next if rule_set.optional? %>
 typedef struct <%= @grammar.ast_prefix %><%= name %><%= @grammar.ast_suffix %>
 {
+    <% # ASTNode fields must be present in the same order here. # %>
     <%= @grammar.prefix %>position_t position;
     <%= @grammar.prefix %>position_t end_position;
+    uint16_t n_fields;
+    uint8_t is_token;
 <%     rule_set.ast_fields.each do |fields| %>
     union
     {
@@ -187,6 +192,8 @@ size_t <%= @grammar.prefix %>parse(<%= @grammar.prefix %>context_t * context);
 
 <% if @grammar.ast %>
 <%= @grammar.ast_prefix %><%= @grammar.start_rule %><%= @grammar.ast_suffix %> * <%= @grammar.prefix %>result(<%= @grammar.prefix %>context_t * context);
+
+void <%= @grammar.prefix %>free_ast(<%= @grammar.ast_prefix %><%= @grammar.start_rule %><%= @grammar.ast_suffix %> * ast);
 <% else %>
 <%= start_rule_type[1] %> <%= @grammar.prefix %>result(<%= @grammar.prefix %>context_t * context);
 <% end %>
diff --git a/spec/propane_spec.rb b/spec/propane_spec.rb
index f9ef20e..f606381 100644
--- a/spec/propane_spec.rb
+++ b/spec/propane_spec.rb
@@ -78,9 +78,9 @@ EOF
     end
     case options[:language]
     when "c"
-      command = [*%w[gcc -Wall -o spec/run/testparser -Ispec -Ispec/run], *parsers, *test_files, "spec/testutils.c", "-lm"]
+      command = [*%w[gcc -g -Wall -o spec/run/testparser -Ispec -Ispec/run], *parsers, *test_files, "spec/testutils.c", "-lm"]
     when "cpp"
-      command = [*%w[g++ -x c++ -Wall -o spec/run/testparser -Ispec -Ispec/run], *parsers, *test_files, "spec/testutils.c", "-lm"]
+      command = [*%w[g++ -g -x c++ -Wall -o spec/run/testparser -Ispec -Ispec/run], *parsers, *test_files, "spec/testutils.c", "-lm"]
     when "d"
       command = [*%w[ldc2 -g --unittest -of spec/run/testparser -Ispec], *parsers, *test_files, "spec/testutils.d"]
     end
@@ -88,12 +88,13 @@ EOF
     expect(result).to be_truthy
   end
 
-  def run_test
+  def run_test(options)
     stdout, stderr, status = Open3.capture3("spec/run/testparser")
     File.binwrite("spec/run/.stderr", stderr)
     File.binwrite("spec/run/.stdout", stdout)
     stderr.sub!(/^.*modules passed unittests\n/, "")
-    Results.new(stdout, stderr, status)
+    results = Results.new(stdout, stderr, status)
+    results
   end
 
   def lines(str)
@@ -286,7 +287,7 @@ Foo -> plus <<>>
 EOF
         run_propane(language: language)
         compile("spec/test_lexer.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -324,7 +325,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_lexer_unknown_character.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -418,7 +419,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_basic_math_grammar.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -444,7 +445,7 @@ R2 -> a b;
 EOF
         run_propane(language: language)
         compile("spec/test_parser_identical_rules_lookahead.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.status).to eq 0
       end
 
@@ -459,7 +460,7 @@ R1 -> b;
 EOF
         run_propane(language: language)
         compile("spec/test_parser_rule_from_multiple_states.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.status).to eq 0
       end
 
@@ -494,7 +495,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_user_code.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.status).to eq 0
         verify_lines(results.stdout, [
           "abc!",
@@ -530,7 +531,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_pattern.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.status).to eq 0
         verify_lines(results.stdout, [
           "def!",
@@ -572,7 +573,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_return_token_from_pattern.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.status).to eq 0
         verify_lines(results.stdout, [
           "def!",
@@ -630,7 +631,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_lexer_modes.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.status).to eq 0
         verify_lines(results.stdout, [
           "begin string mode",
@@ -688,7 +689,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_lexer_multiple_modes.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.status).to eq 0
         verify_lines(results.stdout, [
           "ident: d",
@@ -725,7 +726,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_parser_rule_user_code.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.status).to eq 0
         verify_lines(results.stdout, [
           "A!",
@@ -744,7 +745,7 @@ As -> As a << $$ = $1 + 1u; >>
 EOF
         run_propane(language: language)
         compile("spec/test_parsing_lists.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.status).to eq 0
         expect(results.stderr).to eq ""
       end
@@ -798,7 +799,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_lexer_match_text.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.status).to eq 0
         verify_lines(results.stdout, [
           "Matched token is identifier_123",
@@ -831,7 +832,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_lexer_result_value.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -846,7 +847,7 @@ Start -> a num;
 EOF
         run_propane(language: language)
         compile("spec/test_error_positions.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -875,7 +876,7 @@ Start -> b c b;
 EOF
         run_propane(name: "myp2", language: language)
         compile("spec/test_multiple_parsers.#{language}", parsers: %w[myp1 myp2], language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -894,7 +895,7 @@ Any -> c;
 EOF
         run_propane(language: language)
         compile("spec/test_user_terminate_lexer.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -912,7 +913,7 @@ Any -> ;
 EOF
         run_propane(language: language)
         compile("spec/test_user_terminate.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -956,7 +957,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_match_backslashes.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
         verify_lines(results.stdout, [
@@ -1021,7 +1022,7 @@ Two -> two;
 EOF
         run_propane(language: language)
         compile("spec/test_ast.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -1065,7 +1066,7 @@ Two -> two;
 EOF
         run_propane(language: language)
         compile("spec/test_ast_ps.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -1139,7 +1140,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_optional_rule_component.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
         verify_lines(results.stdout, [
@@ -1191,7 +1192,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_optional_rule_component_ast.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -1232,7 +1233,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_named_optional_rule_component_ast.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -1252,7 +1253,7 @@ T -> c;
 EOF
         run_propane(language: language)
         compile("spec/test_ast_token_positions.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -1272,7 +1273,7 @@ A -> bb? c?;
 EOF
         run_propane(language: language)
         compile("spec/test_ast_invalid_positions.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -1292,7 +1293,7 @@ T -> c;
 EOF
         run_propane(language: language)
         compile("spec/test_ast_field_aliases.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -1315,7 +1316,7 @@ T -> c;
 EOF
         run_propane(language: language)
         compile("spec/test_ast_field_aliases.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
@@ -1358,7 +1359,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_field_aliases.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
         expect(results.stdout).to match /first is foo1.*second is bar2/m
@@ -1408,7 +1409,7 @@ EOF
         end
         run_propane(language: language)
         compile("spec/test_field_aliases.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
         expect(results.stdout).to match /first is foo1.*second is bar2/m
@@ -1419,7 +1420,7 @@ EOF
         write_grammar(File.read("spec/ast_node_memory_remains.#{ext}.propane"))
         run_propane(language: language)
         compile("spec/test_ast_node_memory_remains.#{language}", language: language)
-        results = run_test
+        results = run_test(language: language)
         expect(results.stderr).to eq ""
         expect(results.status).to eq 0
       end
diff --git a/spec/test_ast.c b/spec/test_ast.c
index 73e60cc..dd055bd 100644
--- a/spec/test_ast.c
+++ b/spec/test_ast.c
@@ -33,12 +33,16 @@ int main()
     assert_eq(22, itemsmore->pItem->pToken1->pvalue);
     assert(itemsmore->pItemsMore == NULL);
 
+    p_free_ast(start);
+
     input = "";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert_eq(P_SUCCESS, p_parse(&context));
     start = p_result(&context);
     assert(start->pItems == NULL);
 
+    p_free_ast(start);
+
     input = "2 1";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert_eq(P_SUCCESS, p_parse(&context));
@@ -51,5 +55,7 @@ int main()
     assert(start->pItems->pItem->pDual->pTwo2 == NULL);
     assert(start->pItems->pItem->pDual->pOne1 == NULL);
 
+    p_free_ast(start);
+
     return 0;
 }
diff --git a/spec/test_ast_field_aliases.c b/spec/test_ast_field_aliases.c
index 5b3716a..fec19cc 100644
--- a/spec/test_ast_field_aliases.c
+++ b/spec/test_ast_field_aliases.c
@@ -15,5 +15,7 @@ int main()
     assert_eq(TOKEN_b, start->second->pToken->token);
     assert_eq(TOKEN_c, start->third->pToken->token);
 
+    p_free_ast(start);
+
     return 0;
 }
diff --git a/spec/test_ast_invalid_positions.c b/spec/test_ast_invalid_positions.c
index eaac60f..28beb7b 100644
--- a/spec/test_ast_invalid_positions.c
+++ b/spec/test_ast_invalid_positions.c
@@ -30,6 +30,8 @@ int main()
     assert_eq(3, start->end_position.row);
     assert_eq(8, start->end_position.col);
 
+    p_free_ast(start);
+
     input = "a\nbb";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert(p_parse(&context) == P_SUCCESS);
@@ -54,6 +56,8 @@ int main()
     assert_eq(2, start->end_position.row);
     assert_eq(2, start->end_position.col);
 
+    p_free_ast(start);
+
     input = "a\nc\nc";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert(p_parse(&context) == P_SUCCESS);
@@ -78,6 +82,8 @@ int main()
     assert_eq(3, start->end_position.row);
     assert_eq(1, start->end_position.col);
 
+    p_free_ast(start);
+
     input = "a";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert(p_parse(&context) == P_SUCCESS);
@@ -98,5 +104,7 @@ int main()
     assert_eq(1, start->end_position.row);
     assert_eq(1, start->end_position.col);
 
+    p_free_ast(start);
+
     return 0;
 }
diff --git a/spec/test_ast_node_memory_remains.c b/spec/test_ast_node_memory_remains.c
index d29284d..9c6cecb 100644
--- a/spec/test_ast_node_memory_remains.c
+++ b/spec/test_ast_node_memory_remains.c
@@ -411,5 +411,7 @@ int main(int argc, char * argv[])
         }
     }
 
+    p_free_ast(pmod);
+
     return 0;
 }
diff --git a/spec/test_ast_ps.c b/spec/test_ast_ps.c
index 69ebcae..516d164 100644
--- a/spec/test_ast_ps.c
+++ b/spec/test_ast_ps.c
@@ -33,12 +33,16 @@ int main()
     assert_eq(22, itemsmore->pItem->pToken1->pvalue);
     assert(itemsmore->pItemsMore == NULL);
 
+    p_free_ast(start);
+
     input = "";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert_eq(P_SUCCESS, p_parse(&context));
     start = p_result(&context);
     assert(start->pItems == NULL);
 
+    p_free_ast(start);
+
     input = "2 1";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert_eq(P_SUCCESS, p_parse(&context));
@@ -51,5 +55,7 @@ int main()
     assert(start->pItems->pItem->pDual->pTwo2 == NULL);
     assert(start->pItems->pItem->pDual->pOne1 == NULL);
 
+    p_free_ast(start);
+
     return 0;
 }
diff --git a/spec/test_ast_token_positions.c b/spec/test_ast_token_positions.c
index 91c0437..6354996 100644
--- a/spec/test_ast_token_positions.c
+++ b/spec/test_ast_token_positions.c
@@ -43,6 +43,8 @@ int main()
     assert_eq(1, start->end_position.row);
     assert_eq(6, start->end_position.col);
 
+    p_free_ast(start);
+
     input = "\n\n  bb\nc\ncc\n\n     a";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert(p_parse(&context) == P_SUCCESS);
@@ -80,5 +82,7 @@ int main()
     assert_eq(7, start->end_position.row);
     assert_eq(6, start->end_position.col);
 
+    p_free_ast(start);
+
     return 0;
 }
diff --git a/spec/test_named_optional_rule_component_ast.c b/spec/test_named_optional_rule_component_ast.c
index 5bbb3fd..4244cf3 100644
--- a/spec/test_named_optional_rule_component_ast.c
+++ b/spec/test_named_optional_rule_component_ast.c
@@ -17,6 +17,8 @@ int main()
     assert(start->pR == NULL);
     assert(start->r == NULL);
 
+    p_free_ast(start);
+
     input = "abcd";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert(p_parse(&context) == P_SUCCESS);
@@ -31,6 +33,8 @@ int main()
     assert(start->pR == start->r);
     assert_eq(TOKEN_c, start->pR->pToken1->token);
 
+    p_free_ast(start);
+
     input = "bdc";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert(p_parse(&context) == P_SUCCESS);
@@ -40,6 +44,8 @@ int main()
     assert(start->r != NULL);
     assert_eq(TOKEN_d, start->pR->pToken1->token);
 
+    p_free_ast(start);
+
     return 0;
 }
 
diff --git a/spec/test_optional_rule_component_ast.c b/spec/test_optional_rule_component_ast.c
index 1885983..d88ea46 100644
--- a/spec/test_optional_rule_component_ast.c
+++ b/spec/test_optional_rule_component_ast.c
@@ -16,6 +16,8 @@ int main()
     assert(start->pR3 == NULL);
     assert(start->pR == NULL);
 
+    p_free_ast(start);
+
     input = "abcd";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert(p_parse(&context) == P_SUCCESS);
@@ -28,6 +30,8 @@ int main()
     assert(start->pR == start->pR3);
     assert_eq(TOKEN_c, start->pR->pToken1->token);
 
+    p_free_ast(start);
+
     input = "bdc";
     p_context_init(&context, (uint8_t const *)input, strlen(input));
     assert(p_parse(&context) == P_SUCCESS);
@@ -37,6 +41,8 @@ int main()
     assert(start->pR != NULL);
     assert_eq(TOKEN_d, start->pR->pToken1->token);
 
+    p_free_ast(start);
+
     return 0;
 }
 
diff --git a/spec/test_start_rule_ast.c b/spec/test_start_rule_ast.c
index 3d90812..d262143 100644
--- a/spec/test_start_rule_ast.c
+++ b/spec/test_start_rule_ast.c
@@ -13,5 +13,7 @@ int main()
     assert(top->pToken != NULL);
     assert_eq(TOKEN_hi, top->pToken->token);
 
+    p_free_ast(top);
+
     return 0;
 }