Just for the off hand chance that you are unaware of this, the option -fdump-tree-optimized on GCC and the other -fdump-tree.* options will do some of what you

Just for the off hand chance that you are unaware of this, the option -fdump-tree-optimized on GCC and the other -fdump-tree.* options will do some of what you are asking for. GCC isnt hipster hot nowadays but it has quite a few nice things. For C++ templates I still prefer G++ error messages over Clang++'s. I find the former a lot more informative, but without Clang breathing down their neck I doubt if they would have improved their error messages.