Multiple fixes to @static #1226
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As a funny side effect of those changes: import annotation.static
class T
object T {
@static val dummy: Unit = println("I am static initializer")
}Compiles to code equivalent to: public class T {
public static BoxedUnit dummy;
static {
Predef..MODULE$.println((Object)"I am static initializer");
dummy = BoxedUnit.UNIT;
}
} |
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@lrytz, would you kindly take a look? |
| import annotation.static | ||
| object T { | ||
| @static val foo = 10 // error: needs companion class | ||
| } |
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don't you need a .check file for this test?
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In dotty, our neg-tests test for presence of errors on lines containing // error:.
We don't check the error message.
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This pr revealed a bug in lazy vals. Fixing it. |
| override def transformStats(trees: List[Tree])(implicit ctx: Context, info: TransformerInfo): List[Tree] = { | ||
| if (ctx.owner.is(Flags.Package)) { | ||
| val (classes, others) = trees.partition(x => x.isInstanceOf[TypeDef] && x.symbol.isClass) | ||
| val pairs = classes.groupBy(_.symbol.name.stripModuleClassSuffix).asInstanceOf[Map[Name, List[TypeDef]]] |
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Static type is Map[Name, List[Tree]].
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oh i see now -- since you don't use others, you can write val classes = trees collect { case td: TypeDef if td.symbol.isClass => td } and don't need the cast
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I have several more fixes pending. This pr at the moment has problems with initialization of lazy vals. |
They aren't inherited and can be entered into frozen owners.
As a funny side-effect this allows to execute arbitrary code in static
initialisers:
@static val a: Unit = {println("loaded")}
It's not clear how they should be implemented.
There used to be a rare test when companion class and companion object would have gotten the very same offset, causing undefined behaviour in runtime.
Unlink the static from the old scope, and don't drop top-level trees that are not TypeDefs.
Helps to spot usage of unsafe that would lead to undefined behaviour.
Now moveStatics can correctly create static constructors for objects. Those static constructors would later be merged with synthetic module initialisers by GenBCode. This is a bit of magic, it would be good to move all this into this phase.
This method is only used to find static initialisers. Previously, it was always wrong, but we didn't care as we never had them.
Nicely spotted by Ycheck.
This broke lazy vals, as unsafe offsets were not initialised.
GenBCode checks if class already has static initialiser, the check is fooled if class inherited a static initialisers.
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@odersky please review. |
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LGTM |
This PR fixes multiple issues in
@staticand makes lazy vals use them instead of fields in companion classes.