At its most general, Top is a framework for constructing abstract interpretations which focuses on giving good feedback on why an abstract interpretation does not give any useful information. In a mathematical notation this is usually made explicit by returning the top element of a (complete) lattice. This is also one of the reasons for the name of the project. We have obtained good results with our first subproject, delivering good type error messages for a language quite similar to Haskell (a restricted implementation can be found in the Helium compiler). For this reason, Top may also be read as Typing Our Programs. However, the approach that we used can also be deployed for other program analyses for which good feedback is desirable. The sources can be obtained from .