backend error with case destructuring

[jvasileff]

This type-checks:

    String[2] tup = ["one", "two"];
    switch(tup)
    case ([a,b]) { String x = b; }

but results in

source/simple/run.ceylon:7: error: compiler bug: unhandled declaration unknown with type UnknownType at com.redhat.ceylon.compiler.java.codegen.AbstractTransformer.makeTypeTest(AbstractTransformer.java:4538)
    switch(tup)
    ^
1 error
1 warning

[jvasileff]

@gavinking I assume this is a backend bug and not a typechecker bug?

[gavinking]

Well, yeah, I suppose. Though I'm not sure that it was really 100% intentionally intended that this would work, so I'm not surprised that it wasn't tested. Still, I see no good reason to actively prevent you from writing that.

[FroMage]

OK, so what's the thing that makes this special? I fail to see it. Apparently I have an IsCase with a iscase.type that is an UnknownType. I assume the typechecker should infer that type to be what's in iscase.variable, no?

[jvasileff]

That's similar to what I though (ceylon/ceylon.ast#116 (comment)), the ast seems incomplete

[FroMage]

Whatever, I use the type of the Variable, that works.