A dynamic compiler determines whether to inline methods in place of virtual method calls by inspecting such calls' receiver expressions. If a given call site meets other criteria for inlining, the method is inlined if its receiver expression can be proved to have a property called "pre-existence." One kind of expression whose pre-existence is easily proved is a calling-procedure argument to which the body of the calling procedure makes no assignment. One of the other criteria is that the argument's static type is a class whose definition of the callee method has not been overridden, and the compiler employs a dependency data structure to record against both the caller and the callee that the caller contains code whose validity depends on the assumption that this criterion has been met. If the compiler thereafter compiles another implementation of the callee method, it inspects the dependency structures in which dependencies have been recorded against the callee method, and it recompiles the callers whose object code's validity is indicated by such structures to depend on that callee method's not having been overridden. The restriction of inlining to pre-existing receiver expression allows currently running invocations of the original compilation of the caller method to continue without fear of error.