Misleading compiler errors when using lambda expressions

OS version: Microsoft Windows [Version 6.1.7601]

Java version:
java version "1.8.0_40"
Java(TM) SE Runtime Environment (build 1.8.0_40-b25)
Java HotSpot(TM) 64-Bit Server VM (build 25.40-b25, mixed mode)

Also get identical output on JDK8 update 0, JDK 8 update 40 and JDK 9 (1.9.0-ea-b55)

More concretely, the issues are:

   1. With respect to case 1, javac reification converts Testcase<String> to Testcase<Object>.
       Not sure if this is a bug or a limitation in the current reification implementation.

   2. With respect to case 2:
         1. If you compile the file without "-Xlint" you get a warning:

[WARNING]
/C:/Users/<userid>/Documents/NetBeansProjects/Testcase/src/main/java/Testcase.java:
C:\Users\<userid>\Documents\NetBeansProjects\Testcase\src\main\java\Testcase.java uses unchecked or unsafe operations.
[WARNING]
/C:/Users/<userid>/Documents/NetBeansProjects/Testcase/src/main/java/Testcase.java: Recompile with -Xlint:unchecked for details.

         2. But, if you then enable "-Xlint:unchecked" the compiler does not produce any warnings at all. Expecting the compiler to provide detailed warnings in this case.