condition inside Depends doesn't work properly

Although having a condition inside a Depends {} block appears to be implemented, and a simple condition:true or condition:false works as expected, it doesn't evaluate properly with more complex things. It doesn't seem to see the scope of the condition correctly:

    Application {
        property bool someProp: true
        Depends {
            condition: someProp
            name: 'cpp';
        }
        ...
    }

The above give the error:

d:\workitems\qbs-bugs>qbs -f conditionaldepends.qbp
Found project file D:\workitems\qbs-bugs\conditionaldepends.qbp
ERROR: D:\workitems\qbs-bugs\conditionaldepends.qbp:9 Error while evaluating Depends.condition: Error: Undefined property 'someProp'

It behaves even more weirdly when you use properties from derived products - the base definition is seen but changing its value in the derived has no effect. The attached conditionaldepends_derived.qbp should compile cleanly because someProp is true. (It does compile if you set someProp as true in conditionaldepends_base.qbs). Instead it errors as if the condition was still false:

d:\workitems\qbs-bugs>qbs architecture:x86_64 -f conditionaldepends_derived.qbp
Found project file D:\workitems\qbs-bugs\conditionaldepends_derived.qbp
loading project took:  31 ms
ERROR: No artifacts generated for product 'conditionaldepends_derived'.

(I've trimmed these examples down to the bone - I do have a genuine use-case for wanting conditional depends to work, but I'd never be conditional on cpp or Qt.core!)