RFR: 8361445: javac crashes on unresolvable constant in @SuppressWarnings [v3]

[Jan Lahoda]

> Consider this code:
> 
> @SuppressWarnings(CONST)
> public class Ann {
>     public static final String CONST = "";
> }
> 
> 
> javac will crash attempting to compile it:
> 
> $ javac -XDdev /tmp/Ann.java
> /tmp/Ann.java:1: error: cannot find symbol
> @SuppressWarnings(CONST)
>                   ^
>   symbol: variable CONST
> 1 error
> An exception has occurred in the compiler (26-internal). Please file a bug against the Java compiler via the Java bug reporting page (https://bugreport.java.com/) after checking the Bug Database (https://bugs.java.com/) for duplicates. Include your program, the following diagnostic, and the parameters passed to the Java compiler in your report. Thank you.
> java.lang.ClassCastException: class com.sun.tools.javac.code.Attribute$Error cannot be cast to class com.sun.tools.javac.code.Attribute$Constant (com.sun.tools.javac.code.Attribute$Error and com.sun.tools.javac.code.Attribute$Constant are in module jdk.compiler of loader 'app')
>         at jdk.compiler/com.sun.tools.javac.code.Lint.suppressionsFrom(Lint.java:533)
> ...
> 
> 
> The reason is that the unresolvable constant will be `Attribute.Error`, not `Attribute.Constant`, and there's an unguarded cast. The proposal herein is to improve error recovery by ignoring non-constant annotation attributes in `Lint.suppressionsFrom`. Such erroneous cases should have already been reported as compile-time errors anyway.

Jan Lahoda has updated the pull request incrementally with one additional commit since the last revision:

  Adding test for enum constants, as suggested.

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/26142/files
  - new: https://git.openjdk.org/jdk/pull/26142/files/db4d5686..9527969e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26142&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26142&range=01-02

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26142.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26142/head:pull/26142

PR: https://git.openjdk.org/jdk/pull/26142