LaTeX does report this as a problem, of course - the refrain of "overfull hbox" is near universal (and ignoring the warning is just as universal). Where it fai

LaTeX does report this as a problem, of course - the refrain of "overfull hbox" is near universal (and ignoring the warning is just as universal). Where it fails is in reporting the problem in a meaningful way. This is, of course, very difficult to accomplish, since there is no nice mapping from line-of-TeX to visual error. What's more, any tool which could provide such an error would be so constrained as to be useless for typesetting.