diff --git a/libr/anal/data.c b/libr/anal/data.c
index 0608f33c0dc2c..6944ec012875f 100644
--- a/libr/anal/data.c
+++ b/libr/anal/data.c
@@ -4,6 +4,7 @@
 
 // TODO: integrate this code in a better way.. maybe reftype as name?
 R_API int r_anal_data_type(RAnal *anal, ut64 da) {
+	R_RETURN_VAL_IF_FAIL (anal, R_ANAL_REF_TYPE_NULL);
 	RIO *io = anal->iob.io;
 	if (!anal->iob.is_valid_offset (io, da, R_PERM_R)) {
 		return R_ANAL_REF_TYPE_ERROR;
@@ -198,14 +199,11 @@ static bool is_bin(const ut8 *buf, int size) {
 }
 
 // TODO: add is_flag, is comment?
-R_API char *r_anal_data_tostring(RAnalData *d, RConsPrintablePalette *pal) {
+R_API char *r_anal_data_tostring(RAnalData *d, R_NULLABLE RConsPrintablePalette *pal) {
+	R_RETURN_VAL_IF_FAIL (d, NULL);
 	int i, len, mallocsz = 1024;
 	ut32 n32;
 
-	if (!d) {
-		return NULL;
-	}
-
 	RStrBuf *sb = r_strbuf_new (NULL);
 	if (!sb || !r_strbuf_reserve (sb, mallocsz)) {
 		r_strbuf_free (sb);
@@ -334,6 +332,7 @@ R_API RAnalData *r_anal_data_new_string(ut64 addr, const char *p, int len, int t
 }
 
 R_API RAnalData *r_anal_data_new(ut64 addr, int type, ut64 n, const ut8 *buf, int len) {
+	R_RETURN_VAL_IF_FAIL (buf, NULL);
 	RAnalData *ad = R_NEW0 (RAnalData);
 	int l = R_MIN (len, 8);
 	if (!ad) {
@@ -537,9 +536,8 @@ R_API const char *r_anal_data_kind(RAnal *a, ut64 addr, const ut8 *buf, int len)
 }
 
 R_API const char *r_anal_datatype_tostring(RAnalDataType t) {
+	R_RETURN_VAL_IF_FAIL (t == R_ANAL_DATATYPE_NULL, NULL);
 	switch (t) {
-	case R_ANAL_DATATYPE_NULL:
-		return NULL;
 	case R_ANAL_DATATYPE_ARRAY:
 		return "array";
 	case R_ANAL_DATATYPE_OBJECT: // instance
@@ -558,6 +556,8 @@ R_API const char *r_anal_datatype_tostring(RAnalDataType t) {
 		return "int64";
 	case R_ANAL_DATATYPE_FLOAT:
 		return "float";
+	default:
+		break;
 	}
 	return NULL;
 }