Xcode Explicitly Built Modules

Xcode 16 introduces experimental "explicitly built modules" to address the issue of implicitly built modules blocking build tasks. This new approach involves Xcode scanning source files to build a dependency graph for all modules, enabling it to build modules with ready dependencies without delays. While explicitly built modules are currently enabled by default for C and Objective-C code, they require an experimental setting for Swift code. Build timelines show that explicit module builds start compiling modules earlier, but initial testing suggests they may be slower than implicit builds. Explicitly built modules also share built modules with the debugger, potentially reducing delays when evaluating expressions. This feature is still experimental in Xcode 16 and may undergo changes in future betas. For more information, refer to Apple's WWDC24 session and article on building with explicit module dependencies.