Is it possible for the debugger (or the CLR exception handler) to show the line where the exception happened in Release mode using the pdb?
The code, in release mode
The debugger makes a best-effort guess at where the problem occurred. It is not guaranteed to be 100% accurate, and with fully optimized code, it often will be inaccurate - I've found the inaccuracies ranging anywhere from a few lines off to having an entirely wrong call stack.
How accurate the debugger is with optimized code really depends on the code itself and which optimizations you're making.