Introduce MetadataSource as a way to store the original descriptor for
any element (before any lowerings) and maintain it until the end of the
codegen where it's used in generating the metadata. Note that JVM
signatures written to the metadata are formed from the _resulting_
generated elements, not by mapping the original descriptors.
Some corner cases are not supported yet, namely properties declared in
companion objects, synthetic methods for property annotations,
JvmPackageName, etc.
#KT-29119 Fixed
Dynamic expressions are represented as either operator expressions -
e.g., `d1 + d2`, `d[e]`, `d(e1, e2, e3)`, `d += e` -
where "operator" is a one of the known operators,
or as member reference expressions - e.g., `d.memberName` - where
member name is some arbitrary name (unresolved at compile-time and
represented as String).
Simplify ifs when branches have condition true/false.
Simplify blocks containing only a variable declaration
and a variable get of the same variable. Simplify to
just the condition.
Do not introduce temporary variables for constants for
null checks. Constants have no side-effects and can be
reloaded freely instead of going through a local.
This simplifies code such as "42.toLong()!!" so that the
resulting code has no branches and uses no locals. The
simplifications happen as follows:
```
block
temp = 42.toLong()
when
(temp == null) throw NPE
(true) load temp
---> null test simplification
block
temp = 42.toLong()
when
(false) throw NPE
(true) load temp
---> when simplification
block
temp = 42.toLong()
load temp
---> block simplification
42.toLong()
```
* if enum class has abstract members, then it is ABSTRACT
* otherwise, if enum class has entries with members, then it is OPEN
* otherwise, it is FINAL.
Introduce lowering to remove null checks for primitive type
expressions and replace them with true/false. Side-effects
are preserved.
Generate ifnull/ifnonnull instructions for null checks instead
of materializing a null literal for an equality check.
Use signature of function 'target' (a real function that will
be called instad of fake override) to make boxing/unboxing decision for
return value and type parameters on call site.
Input and output types are crucial for type variable fixation order and
analysis of postponed arguments (callable references, lambdas).
Specifically, if there is non-fixed type variable inside input types of
a callable reference, then we'll postpone resolution for such callable
reference.
Initial example with the expected type `KMutableProperty1<*, F>` caused
problems because input types were computed incorrectly (while there
aren't input types here)
#KT-25431 Fixed
Svyatoslav Kuzmich