HasCallStack SrcLoc doesn't include function name.

Motivation

SrcLoc tells you where in a file you were called, but not what was calling you. This is quite useful information, since very often, the CallStack is only one level deep. You can after all get the function name for the first n-1 levels if you have n levels of stack information.

Proposal

Add srcLocDefName field or similar.

An alternative solution is to add another level of callstack information with the name of the calling function. the SrcLoc would however be bogus.