[patterns] __matches __matches __matches

[Tagir Valeev]

Hello!

Thank you for fixing this!

public class Name {
  static final boolean __matches = false;

  public static void main(String[] args) {
    if(__matches __matches __matches) {
      System.out.println("Matches!");
    }
  }
}

Compiles fine, prints "Matches!" as expected, cool. Now let's go deeper!

public class Name {
  static final boolean __matches = false;

  public static void main(String[] args) {
    if((__matches __matches __matches) __matches __matches) {
      System.out.println("Matches!");
    }
  }
}

Name.java:5: error: ',', ')', or '[' expected
    if((__matches __matches __matches) __matches __matches) {
                           ^
Name.java:5: error: illegal start of expression
    if((__matches __matches __matches) __matches __matches) {
                                                          ^
Name.java:5: error: not a statement
    if((__matches __matches __matches) __matches __matches) {
                                                 ^
3 errors

Why so?

With best regards,
Tagir Valeev.

On Wed, Oct 11, 2017 at 10:44 PM, Gavin Bierman
<gavin.bierman at oracle.com> wrote:
> Thanks Tagir. Of course, this is a somewhat “transient” problem, but we’ve
> pushed a patch to address it.
>
> http://hg.openjdk.java.net/amber/amber/rev/fad77d011e0c
>
> Many thanks,
> Gavin
>
> On 11 Oct 2017, at 11:04, Tagir Valeev <amaembo at gmail.com> wrote:
>
> Hello!
>
> Tried the following source code:
>
> public class Name {
>  static final int __matches = 1;
>
>  public static void main(String[] args) {
>    if(__matches __matches __matches) {
>      System.out.println("Matches!");
>    }
>  }
> }
>
> I assumed that __matches is a restricted keyword which is recognized
> as a keyword only at specific syntactic position, thus this program
> should be correct. Well, this could be debated, but the actual result
> is somewhat unpleasant:
>
>
> The system is out of resources.
> Consult the following stack trace for details.
> java.lang.StackOverflowError
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.lambda$new$0(JavacParser.java:1038)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.peekToken(JavacParser.java:321)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.peekToken(JavacParser.java:317)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.optag(JavacParser.java:4250)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.lambda$new$0(JavacParser.java:1043)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.peekToken(JavacParser.java:321)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.peekToken(JavacParser.java:317)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.optag(JavacParser.java:4250)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.lambda$new$0(JavacParser.java:1043)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.peekToken(JavacParser.java:321)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.peekToken(JavacParser.java:317)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.optag(JavacParser.java:4250)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.lambda$new$0(JavacParser.java:1043)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.peekToken(JavacParser.java:321)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.peekToken(JavacParser.java:317)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.optag(JavacParser.java:4250)
>        at
> jdk.compiler/com.sun.tools.javac.parser.JavacParser.lambda$new$0(JavacParser.java:1043)
> ...
>
> With best regards,
> Tagir Valeev
>
>