In cases when the test has the JVM_TARGET directive, use that one for
Java compilation as well.
Otherwise, for box tests, the corresponding test in `JvmTarget6OnJvm6`
(module `:compiler:tests-different-jdk`) will fail. However, it affects
all codegen tests, so fix a bunch of them which use Java 8+ features to
explicitly compile with JVM target 1.8. In particular, this obsoletes
the SKIP_JDK6 directive in those tests because "JVM_TARGET: 1.8" also
skips it for JDK 6.
The check for IS_SOURCE_6_STILL_SUPPORTED is needed in order to still be
able to run tests in the project while only having a single JDK > 11
installed, and having all of the env vars JDK_16, JDK_17, JDK_18
pointing to that JDK.
This commit includes three changes:
1. 'EnhancedNullability' is no more set for declaration types
2. It is no more used for conversion types in translator
3. Translator inserts implicit not-null cast only when enhanced type is cast to not-null type.
Before this commit, extension receivers were declared only for
properties with container source, which is strange & inconsistent.
Now we declare accessor extension receiver iff corresponding property
has extension receiver.
See KT-35849.
1. When expected lambda return type is a type parameter, don't generate
introduce implicit casts (even if the corresponding type parameter has
an upper bound that would otherwise require such cast).
2. Do not generate implicit null check for lambda return value of
@EnhancedNullability type.
Most of these tests used this directive as a way to opt in to a new
language feature, and most of those features are already stable for a
long time, so no opt-in is needed. Some other tests used the directive
to opt out from a language feature, replace those by the `LANGUAGE`
directive. One test used the directive to test behavior that actually
depended on the API version; use `API_VERSION` directive there instead.
The implementation is a bit obscure because this worked on JS since
Kotlin 1.0 and we should not break that; however, on JVM, a diagnostic
will be reported with old language/API version
#KT-25241 Fixed
Alexander Udalov