[Musser] Compiler error messages are often terrible when generic programs are involved. This issue was mentioned a number of times during Dagstuhl seminar. It is stated as an open problem because it is not clear how it can be effectively solved without more language support than is provided by C++ and other major languages. Without the ability to state and enforce requirements, even syntactic ones, at template declaration time, it is very difficult detect and properly report errors: An error made by a programmer in using a library component may not be seen by the compiler until it is examining code deep within library components. Practical solutions seem to require a language level above that of current major languages, but still taking advantage of commercial compiler technology by using major language compilers for back-end code production (as in, for example, the SuchThat project, which is using C++ as a backend).