Hi Pythraners, I have just pushed a big commit that changes the way builtins are handled by pythran. They used to be available at global scope. Now the first pass of pythran turns them into members of the __builtin__ module (that exists in Python, and is read-only), and they are treated just as regular functions. Consequences: 1/ during code generation or ast manipulation, if you want to generate calls to builtins, use an ast.Attribute instead of an ast.Name. 2/ in pythonic, every builtins live in the __buitlin__ namespace I hope it does *not* wreak havoc in your current development, just rebase against master to check the consequences.