alt Hacker NewsThis is one example why being a guest language isn't optimal.
They should have made use of JVM bytecodes that allow to optimize lambdas away and make JIT aware of them, via invokedynamic and MethodHandle optimizations.
Naturally they cannot rely on them being there, because Kotlin also needs to target ART, JS runtimes, WebAssembly and its own native version.
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gavinray • last Sunday at 9:10 PM
There are Kotlin compiler flags to default to "indy" optimization, and which may be enabled by default for some time now?
Also not all Kotlin inlines are lambdas or even include method calls
Kotlin existed before Java 7 and kept support JVM 1.6 for a long time (mainly because of Android)
Even then, they benchmarked it, and inlining was still faster* than invokedynamic and friends, so they aren't changing it now JVM 1.8+ is a requirement.
* at the expense of expanded bytecode size