[Bug libgcj/16677] New: GCJ fails to reject invalid code

["vadimn at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>]

In the process of producing a test case for PR16675, we ran across
another bug.  See below.

Bryce points out that it is similar to PR9884.  As far as I can tell,
it's the exact same issue, in which case please mark this as a
duplicate.  Here goes.

The following snippet of code is not valid.

  | $ cat Test.java 
  | public class Test {
  |     public static void main(String[] s) {
  |         new Object() {
  |             public String toString() {
  |                 return "enclosing class: " + Test.this.getClass();
  |             }
  |         }.toString();
  |     }
  | }

Sun's javac compiler correctly rejects it like so:

  | $ java -version
  | java version "1.4.2_04"
  | Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_04-b05)
  | Java HotSpot(TM) Client VM (build 1.4.2_04-b05, mixed mode)
  | $ javac Test.java
  | Test.java:5: non-static variable this cannot be referenced from a static context
  |                 return "enclosing class: " + Test.this.getClass();
  |                                                  ^
  | 1 error
  | $ echo $?
  | 1

GCJ accepts it:

  | $ gcj -C Test.java
  | $ echo $?
  | 0

The generated bytecode produces a runtime error:

  | $ gij Test
  | Exception in thread "main" java.lang.NullPointerException
  |    at Test$1.toString() (Unknown Source)
  |    at Test.main(java.lang.String[]) (Unknown Source)

-- 
           Summary: GCJ fails to reject invalid code
           Product: gcc
           Version: 3.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: libgcj
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: vadimn at redhat dot com
                CC: gcc-bugs at gcc dot gnu dot org,java-prs at gcc dot gnu
                    dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16677