The input validation for caching currently relies on having a stack of `scala.math.Equiv`, which is questionable since it can fallback to universal equality.
This is likely related to the intermittent caching behavior we are seeing in https://github.com/sbt/sbt/issues/3226
`F0`, `F1` and `Maybe` have become useless since Java 8 introduced
`Supplier`, `Function` and `Optional` in the default Java 8 standard
library.
Therefore, they are not necessary anymore. This change is required to
change some Zinc's and sbt APIs. They are not widely used, so the
changes will be small.
While running scripted, you see
```
ERROR StatusLogger Unable to create custom ContextSelector. Falling back to default.
java.lang.ClassCastException: Cannot cast org.apache.logging.log4j.core.async.AsyncLoggerContextSelector to org.apache.logging.log4j.core.selector.ContextSelector
at java.lang.Class.cast(Class.java:3369)
at org.apache.logging.log4j.util.LoaderUtil.newCheckedInstanceOf(LoaderUtil.java:201)
at org.apache.logging.log4j.util.LoaderUtil.newCheckedInstanceOfProperty(LoaderUtil.java:226)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.createContextSelector(Log4jContextFactory.java:97)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.<init>(Log4jContextFactory.java:58)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at java.lang.Class.newInstance(Class.java:442)
at org.apache.logging.log4j.LogManager.<clinit>(LogManager.java:94)
at org.apache.logging.log4j.spi.ThreadContextMapFactory.createThreadContextMap(ThreadContextMapFactory.java:73)
at org.apache.logging.log4j.ThreadContext.init(ThreadContext.java:223)
at org.apache.logging.log4j.ThreadContext.<clinit>(ThreadContext.java:202)
at org.apache.logging.log4j.core.impl.ContextDataInjectorFactory.createDefaultInjector(ContextDataInjectorFactory.java:83)
at org.apache.logging.log4j.core.impl.ContextDataInjectorFactory.createInjector(ContextDataInjectorFactory.java:67)
at org.apache.logging.log4j.core.lookup.ContextMapLookup.<init>(ContextMapLookup.java:34)
at org.apache.logging.log4j.core.lookup.Interpolator.<init>(Interpolator.java:117)
at org.apache.logging.log4j.core.config.AbstractConfiguration.<init>(AbstractConfiguration.java:125)
at org.apache.logging.log4j.core.config.DefaultConfiguration.<init>(DefaultConfiguration.java:46)
at org.apache.logging.log4j.core.layout.PatternLayout$Builder.build(PatternLayout.java:650)
at org.apache.logging.log4j.core.layout.PatternLayout.createDefaultLayout(PatternLayout.java:487)
at sbt.internal.util.ConsoleAppender.<init>(ConsoleAppender.scala:245)
```
This aims to workaround the casting error during PatternLayout.createDefaultLayout()
that was originally used for ConsoleAppender.
The stacktrace shows it's having issue initializing default DefaultConfiguration.
Since we currently do not use Layout inside ConsoleAppender, the actual pattern is not relevant.
We still publish parts of sbt for Scala 2.10 for compiler-bridge reasons
in Zinc. However util-collection is now becoming an sbt-only module, so
it won't need to continue to cross-build to Scala 2.10! Its new
dependency util-position which is used by lm also isn't a dependency of
the compiler-bridge, so also doesn't need to be cross-built to Scala
2.10.
Looks like the reason that util-cache depended on util-collection was to
define the sjson-new formats (HListFormats) for util-collection's HList.
Given that util-collection already depends on sjsonnew, HListFormats can
also be defined in util-collection.
All that was left then was (a) HListFormatSpec requires
sjsonnewScalaJson, so that was added in test scope, and (b) HListFormats
had to be dropped from sbt.util.CacheImplicits - HListFormats will have
to be imported and/or mixed-in where required downstream. For importing
convenience I defined a companion object.