diff --git a/src/json.hpp.re2c b/src/json.hpp.re2c
index 5b2dc8d2d..208489eab 100644
--- a/src/json.hpp.re2c
+++ b/src/json.hpp.re2c
@@ -8252,7 +8252,7 @@ class basic_json
 
                 if (!p) 
                 {
-                    return false;
+                    return false; // LCOV_EXCL_LINE
                 }
 
                 if (*p == '-' or *p == '+') 
@@ -8262,7 +8262,7 @@ class basic_json
 
                 if (p == m_end) 
                 {
-                    return false;
+                    return false; // LCOV_EXCL_LINE
                 }
 
                 while (p < m_end and *p >= '0' 
@@ -8401,11 +8401,11 @@ class basic_json
                 value = static_cast<T>(x);
 
                 return x == static_cast<decltype(x)>(value) // x fits into destination T
+                   and (x < 0) == (value < 0)               // preserved sign
                    and (x != 0 or is_integral())            // strto[u]ll did nto fail
                    and errno == 0                           // strto[u]ll did not overflow
                    and m_start < m_end                      // token was not empty
-                   and endptr == m_end                      // parsed entire token exactly
-                   and (x < 0) == (*m_start == '-');        // input was sign-compatible
+                   and endptr == m_end;                      // parsed entire token exactly
             }
 
 #else // parsing integral types manually