* In blocks, discard the result of any statement that has a return
type other than void. This was previously done by wrapping each
statement into an "implicit Unit conversion" that was actually
compiled down to a stack pop instead. If an expression happened to
already have type Unit, however, such a conversion was not inserted,
resulting in a stray reference on the stack. These conversions are
now redundant and should probably be removed.
* In assignments and non-exhaustive conditionals, materialize a Unit
on the stack to avoid depth mismatches that trip up the bytecode
validator. Because such expressions are generally used at block level
(and, indeed, the frontend will reject a non-exhaustive conditional
used as an expression), combined with the above change this results
in no additional GETSTATIC opcodes, as they are immediately removed
by the peephole optimizer.
Reuse StringBuilder instances for nested subexpressions.
(NB StringBuilder instance for string template with a string
concatenation inside an expression entry, such as `"${"a" + "b"}"`,
will not be reused, although that doesn't seem to be a real-life issue).
#KT-18558 Fixed Target versions 1.1.4
#KT-13682 Fixed Target versions 1.1.4
Join adjacent strings literals, escaped strings, and constant values
(in a language version that supports const val inlining).
Use StringBuilder#append(char) for single-character constants
(e.g., " " in "$a $b").
#KT-17280 Fixed Target versions 1.1.4
#KT-15235 Fixed Target versions 1.1.4
