Go 1.26 introduces a source-level inliner feature in the go fix command that enables API migrations and deprecations by automatically inlining function calls marked with //go:fix inline directives. The inliner, originally developed for gopls refactoring tools, can replace deprecated function calls with their new counterparts while handling complex correctness issues.
This article argues that concerns about function call overhead in Rust async code are often unfounded, demonstrating that modern compilers inline small functions in release builds, making indirection cost negligible compared to actual I/O and system-level operations. The author emphasizes that code readability and maintainability should take priority over micro-optimizations, and provides concrete benchmarking and profiling techniques to measure real performance impact.