Bugzilla – Full Text Bug Listing
| Summary: | [1.5][compiler] M2: Unnecessary cast is necessary | ||||||
|---|---|---|---|---|---|---|---|
| Product: | [Eclipse Project] JDT | Reporter: | David Saff <david> | ||||
| Component: | Core | Assignee: | Philipe Mulet <philippe_mulet> | ||||
| Status: | VERIFIED FIXED | QA Contact: | |||||
| Severity: | normal | ||||||
| Priority: | P3 | CC: | jcsahnwaldt, zorzella | ||||
| Version: | 3.3 | ||||||
| Target Milestone: | 3.3 M3 | ||||||
| Hardware: | PC | ||||||
| OS: | Windows XP | ||||||
| Whiteboard: | |||||||
| Attachments: |
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Which build ID are you using ? I20060922-0010 Reproduced.
class X {
void addChildren(Widget w) {
if (w instanceof Composite) {
Composite composite = (Composite) w;
addAll((Widget[]) composite.getChildren());
addAll(composite.getChildren());
}
}
void addAll(Widget... widgets) {
}
}
class Widget {}
class Control extends Widget {}
class Composite extends Control {
Control[] getChildren() {
return null;
}
}
We perform ok in following direct case:
class X {
void addChildren(Widget w) {
if (w instanceof Composite) {
Composite composite = (Composite) w;
addAll((Control[]) composite.getChildren());
addAll(composite.getChildren());
}
}
void addAll(Control... widgets) {
}
}
class Widget {}
class Control extends Widget {}
class Composite extends Control {
Control[] getChildren() {
return null;
}
}
I would expect the offending cast to be unnecessary. And when unnecessary cast is removed, no varargs warning should occur either. Created attachment 51397 [details]
Proposed patch
Fixed in HEAD Released for 3.3M3 Added VarargsTest#test052-053 Verified for 3.3 M3 using build I20061030-0010 *** Bug 163889 has been marked as a duplicate of this bug. *** *** Bug 170765 has been marked as a duplicate of this bug. *** |
In the following code: class WidgetChildren { void addChildren(Widget w) { if (w instanceof Composite) { Composite composite = (Composite) w; addAll((Widget[]) composite.getChildren()); } } void addAll(Widget... widgets) { } } Eclipse flags the last line with the warning "Unnecessary cast from Control[] to Widget[]". Removing the cast, however, results in the warning "The argument of type Control[] should explicitly be cast to Widget[] for the invocation of the varargs method addAll(Widget...) from type WidgetChildren. It could alternatively be cast to Widget for a varargs invocation" Is it possible to remove one of these warnings?