`A15-4-4`: Conservatively assuming throwing behaviour for externally defined functions

[lcartey]

Affected rules

• A15-4-4

Description

The exceptions library makes a conservative assumption about which functions will throw which exceptions. However, for this query that leads to false positives where an externally defined function is known to throw in certain circumstances, but this is not captured in the throw specification for the function.

Example

This function is erroneously identified as a candidate for noexcept even though append could throw an out_of_range error.

std::string concat(const std::string& s1, const std::string& s2) {
  std::string s3;
  s3.reserve(s1.size() +s2.size());
  s3.append(s1.c_str(), s1.size())
  s3.append(s2.c_str(), s2.size()));
  return s3;
}```