Systems and methods of representing and extracting type information from typeless and dynamically-typed programming languages are provided. These systems and methods can be immune to source file edits and the order in which those edits are executed. Deriving type information from these languages allows tools to perform operations, for example, refactoring, intellisense, recognition of semantic errors, etc. These systems and methods can be implemented using processes that, implicitly or explicitly, gather type information for the program, and can also accept user input as well.