diff --git a/hts.c b/hts.c
index caf85e64a..42be3f21f 100644
--- a/hts.c
+++ b/hts.c
@@ -3826,7 +3826,7 @@ void hts_itr_destroy(hts_itr_t *iter)
     }
 }
 
-static inline long long push_digit(long long i, char c)
+static inline unsigned long long push_digit(unsigned long long i, char c)
 {
     // ensure subtraction occurs first, avoiding overflow for >= MAX-48 or so
     int digit = c - '0';
@@ -3835,7 +3835,7 @@ static inline long long push_digit(long long i, char c)
 
 long long hts_parse_decimal(const char *str, char **strend, int flags)
 {
-    long long n = 0;
+    unsigned long long n = 0;
     int digits = 0, decimals = 0, e = 0, lost = 0;
     char sign = '+', esign = '+';
     const char *s, *str_orig = str;
diff --git a/hts_expr.c b/hts_expr.c
index 5e5a132ea..0fdb3bc8b 100644
--- a/hts_expr.c
+++ b/hts_expr.c
@@ -527,8 +527,10 @@ static int bitand_expr(hts_filter_t *filt, void *data, hts_expr_sym_func *fn,
             } else if (res->is_str || val.is_str) {
                 hts_expr_val_free(&val);
                 return -1;
+            } else {
+                res->is_true =
+                    (res->d = ((int64_t)res->d & (int64_t)val.d)) != 0;
             }
-            res->is_true = (res->d = ((int64_t)res->d & (int64_t)val.d)) != 0;
         } else {
             break;
         }
@@ -560,8 +562,10 @@ static int bitxor_expr(hts_filter_t *filt, void *data, hts_expr_sym_func *fn,
             } else if (res->is_str || val.is_str) {
                 hts_expr_val_free(&val);
                 return -1;
+            } else {
+                res->is_true =
+                    (res->d = ((int64_t)res->d ^ (int64_t)val.d)) != 0;
             }
-            res->is_true = (res->d = ((int64_t)res->d ^ (int64_t)val.d)) != 0;
         } else {
             break;
         }
@@ -593,8 +597,10 @@ static int bitor_expr(hts_filter_t *filt, void *data, hts_expr_sym_func *fn,
             } else if (res->is_str || val.is_str) {
                 hts_expr_val_free(&val);
                 return -1;
+            } else {
+                res->is_true =
+                    (res->d = ((int64_t)res->d | (int64_t)val.d)) != 0;
             }
-            res->is_true = (res->d = ((int64_t)res->d | (int64_t)val.d)) != 0;
         } else {
             break;
         }
diff --git a/vcf.c b/vcf.c
index 53f2b7a92..daedad34d 100644
--- a/vcf.c
+++ b/vcf.c
@@ -4020,7 +4020,10 @@ int vcf_format(const bcf_hdr_t *h, const bcf1_t *v, kstring_t *s)
 
     kputc_('\t', s); // INFO
     if (v->n_info) {
-        uint8_t *ptr = (uint8_t *)v->shared.s + v->unpack_size[0] + v->unpack_size[1] + v->unpack_size[2];
+        uint8_t *ptr = v->shared.s
+            ? (uint8_t *)v->shared.s + v->unpack_size[0] +
+               v->unpack_size[1] + v->unpack_size[2]
+            : NULL;
         int first = 1;
         bcf_info_t *info = v->d.info;