Augmented assignment operator (e.g., '+=') can be resolved to simple
function call ('plusAssign'). In that case, augmented assignment LHS
can be an arbitrary expression, and may have no associated ResolvedCall.
For example:
(a as MutableList<Int>) += 42
Note that it can happen only in case of augmented assignment operator
convention resolution, because all other forms of assignment-like
operator desugaring require some kind of 'store' operation
(property setter, 'set' operator for array element expression, etc),
and should resolve to some combination of calls.
In that case we simply generate LHS on 'load', and throw assertion on
'store'.
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
This is needed to get rid of the code that appends "$companion" to
properties moved from companion, because it caused inconsistencies in
the ABI and in JVM signatures stored in the metadata
For comparison intrinsics and for instanceof checks, make
it possible to get the the stack value produced and branch
on that directly instead of materializing a boolean to
branch on from it.
That reduces code such as
```
IF_CMPEQ L1
CONST_0
GOTO L2
L1: CONST_1
L2: IFEQ L3
```
to just one IF_CMP instruction.
The generated code is more inline with java, and we avoid the error of
accessing package-private field outside of the package.
However, this changes semantics a bit. Now, a user should set assertion
status of inline-site's package, instead of inline function's one.
#KT-28317: Fixed
In constructs such as 'd[i] += x', where both indexed get and indexed
set are dynamic calls, it's safe to generate augmented assignment body
directly, without temporary variables for array ('d') and index ('i').
Note that corresponding IntermediateValue's are OnceExpressionValue's,
which would throw an exception if this assumption is violated.
NB1 Not every dynamic unary or binary expression is translated to
dynamic operator expressions literally. For example, assignments and
increments can have safe calls in LHS, which require some extra logic.
NB2 There are some open design questions left regarding how dynamic
expressions should actually be translated.
Svyatoslav Kuzmich