Computer code is received that is written using a dynamic Domain Specific Language (DSL) running in a General Purpose Language (GPL) computing environment. A compiler performs static compiler analysis on the computer code. The static compiler analysis includes referencing a security policy defining one or more unacceptable program behaviors. During compile time at the compiler, runtime security checking functionality is performed leveraging compiler extensions, type information, and environment specific compile context. Results of the static compiler analysis are used to indicate when execution of the computer code would result in performance of the one or more unacceptable program behaviors. The one or more unacceptable program behaviors include modifying preexisting computer code to incorporate the computer code written using the DSL.