|
|
Match translation was incorrect for:
case t => new t.C
case D(t) => new d.C
We would end up with Types in TypeTrees referring to the wrong
symbols, e.g:
// t7459a.scala
((x0$1: this.LM) => {
case <synthetic> val x1: this.LM = x0$1;
case4(){
matchEnd3(new tttt.Node[Any]())
};
matchEnd3(x: Any){
x
}
Or:
// t7459b.scala
((x0$1: CC) => {
case <synthetic> val x1: CC = x0$1;
case4(){
if (x1.ne(null))
matchEnd3(new tttt.Node[Any]())
else
case5()
};
This commit:
- Changes `bindSubPats` to traverse types, as well as terms,
in search of references to bound symbols
- Changes `Substitution` to reuse `Tree#substituteSymbols` rather
than the home-brew substitution from `Tree`s to `Tree`s, if the
`to` trees are all `Ident`s
- extends `substIdentsForTrees` to substitute selections like
`x1.caseField` into types.
I had to dance around the awkward handling of "swatches" (exception
handlers that can be implemented with JVM native type switches) by
duplicating trees to avoid seeing the results of `substituteSymbols`
in `caseDefs` after we abandon that approach if we detect the
patterns are too complex late in the game.
I also had to add an escape hatch for the "type selection from
volatile type" check in the type checker. Without this, the
translation of `pos/t7459c.scala`:
case <synthetic> val x1: _$1 = (null: Test.Mirror[_]).universe;
case5(){
if (x1.isInstanceOf[Test.JavaUniverse])
{
<synthetic> val x2: _$1 with Test.JavaUniverse = (x1.asInstanceOf[_$1 with Test.JavaUniverse]: _$1 with Test.JavaUniverse);
matchEnd4({
val ju1: Test.JavaUniverse = x2;
val f: () => x2.Type = (() => (null: x2.TypeTag[Nothing]).tpe);
.. triggers that error at `x2.TypeTag`.
|
