- Add marker for the experimental type inference features
- Add annotation that will control builder-like inference
- Require that annotation on corresponding parameters and extensions
- Allow to use builder inference without suspendability
Changes in tests and refactorings (rename mainly) are going to be
introduced in further commits
If a declaration is annotated both with SinceKotlin and WasExperimental
and the SinceKotlin version makes it inaccessible, the experimental
checker must regard it as experimental, with markers specified in the
WasExperimental annotation arguments. So only errors/warnings about the
experimentality are going to be reported in this case, and no error that
the declaration is unavailable because of a low API version
Usages of declarations annotated with WasExperimental are allowed even
if the API version requirement is not satisfied, provided that the
opt-in to all mentioned markers is given. This is needed for smooth
graduation of API in kotlin-stdlib
Since we're not yet sure of the design of Experimental/UseExperimental,
we're making them "experimental" themselves in some sense, in that the
user is required to provide the magic argument
"-Xuse-experimental=kotlin.Experimental" to be allowed to use either
Experimental or UseExperimental. This is more convenient than the
previous approach of "-language-version 1.3
-Xskip-metadata-version-check" because it's simpler and does not cause
pre-release binaries to be produced