diff --git a/lib/parse.c b/lib/parse.c
index 5d5f717..a5bdd22 100644
--- a/lib/parse.c
+++ b/lib/parse.c
@@ -5,6 +5,7 @@
 
 #include "parse.h"
 
+#include <assert.h>
 #include <stdlib.h>
 
 #define CLASS_START_CAPACITY 4
@@ -62,15 +63,13 @@ static int parse_class(const char *input, int rem, regex_class_t *out)
 	out->count = 0;
 	out->capacity = CLASS_START_CAPACITY;
 	out->contents = malloc(out->capacity);
-	if (NULL == out->contents)
-		return -1;
+	assert(NULL != out->contents);
 
 	while (used < rem) {
 		if (out->count >= out->capacity) {
 			out->capacity *= 2;
 			out->contents = realloc(out->contents, out->capacity);
-			if (NULL == out->contents)
-				return -1;
+			assert(NULL != out->contents);
 		}
 
 		result = parse_literal(
@@ -155,16 +154,14 @@ static int parse_sequence(const char *input, int rem, regex_sequence_t *out)
 	out->count = 0;
 	out->capacity = SEQUENCE_START_CAPACITY;
 	out->contents = malloc(out->capacity * sizeof(regex_term_t));
-	if (NULL == out->contents)
-		return -1;
+	assert(NULL != out->contents);
 
 	while (used < rem) {
 		if (out->count >= out->capacity) {
 			out->capacity *= 2;
 			out->contents = realloc(
 			    out->contents, out->capacity * sizeof(regex_term_t));
-			if (NULL == out->contents)
-				return -1;
+			assert(NULL != out->contents);
 		}
 
 		result = parse_term(
@@ -185,8 +182,7 @@ int parse_expr(const char *input, int rem, regex_t *out)
 	out->count = 0;
 	out->capacity = TREE_START_CAPACITY;
 	out->contents = malloc(out->capacity * sizeof(regex_sequence_t));
-	if (NULL == out->contents)
-		return -1;
+	assert(NULL != out->contents);
 
 	result = parse_sequence(input + used, rem - used, &out->contents[0]);
 	if (result < 0)
@@ -203,8 +199,7 @@ int parse_expr(const char *input, int rem, regex_t *out)
 			out->capacity *= 2;
 			out->contents = realloc(
 			    out->contents, out->capacity * sizeof(regex_sequence_t));
-			if (NULL == out->contents)
-				return -1;
+			assert(NULL != out->contents);
 		}
 
 		result = parse_sequence(