[WICKET-5647] missing generic cast causes compile error on OS X / jdk 8

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 6.16.0, 7.0.0-M2
• Fix Version/s: 7.0.0-M3, 6.17.0
• Component/s: wicket
• Environment: OS X 10.9.4; JDK 1.8.0_11
• Assignee: Peter Ertl
• Reporter: Peter Ertl
• Created: 17/Jul/14 10:02
• Updated: 17/Jul/14 11:49
• Resolved: 17/Jul/14 10:18

Description

when trying to compile wicket-7 from HEAD it fails under OS X / JDK 1.8.0_11. Casting a NULL to generic type (T) solves the issues. This seems like some odd case of failing type inference.

The problematic source line is:

return getEnumImpl(key, eClass, null);

The compiler error is:

Error:(792, 35) java: incompatible types: inference variable T has incompatible upper bounds java.lang.Enum<T>,T

This will fix the issue:

return getEnumImpl(key, eClass, (T)null);

I found that there is a fix WICKET-5427 which does not work in most current JDK 1.8.0_11 anymore. -Could not change the wicket-6 branch since the change will break the clirr plugin (see WICKET-5427).-

Issue Links

• is related to: WICKET-5427 Building Wicket with JDK 1.8 fails with signatures like <T extends Enum<T>>