Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-4214318

explicit constructor invocation as a right-hand operand of assignment

    Details

    • Subcomponent:
    • CPU:
      sparc
    • OS:
      solaris_2.5.1

      Description



      Name: laC46010 Date: 02/23/99



      Constructor invocation can not be the right-hand operand of an assignment
      since it doesn't return anything :

      (field = field).this(); // legal
      field = field.this(); // illegal but javac allows it

      (See latest 'Clarifications and Amendments to the Inner Classes Specification' and
       JLS 19.8.5 :
      ExplicitConstructorInvocation: ...
      Primary . this ( ArgumentList opt ) ;
      Primary . super ( ArgumentList opt ) ;
      this ( ArgumentList opt ) ;
      super ( ArgumentList opt ) ;
      )

      Javac seems to treat unparenthesized assignment here as a Primary, what contradicts the
      grammar (JLS 19.12).

      Javac (1.2fcs, 1.2.2) compiles the following programs without reporting any errors,
      while earlier versions (1.1.x, 1.2beta1,2,3,4) give compilation errors :

      1)
      ------------- test.java -----------
      public class test {
      static test field = new test();
      int var = 0;

      class C extends test {
      C() {}
      C(int a) {
      field = field.this(); // compiler should emit an error here
      field.var = a;
      }
      }

      public static void main( String args[] ) {
      test v1 = new test();
      C v2 = v1.new C(10);
      System.out.println("v2.var = " + v2.var);
      }
      }
      --------- end of test.java --------

      This program outputs :
      -----------
      > java test
      v2.var = 0
      -----------

      2)
      ------------- test.java -----------
      public class test {
      static test field = new test();
      int var = 0;
      }

      class C extends test {
      C() {}
      C(int a) {
      field = field.this(); // compiler should emit an error here
      field.var = a;
      }
      }
      --------- end of test.java --------

      ======================================================================

        Attachments

          Activity

            People

            • Assignee:
              wmaddoxsunw William Maddox (Inactive)
              Reporter:
              leosunw Leo Leo (Inactive)
            • Votes:
              0 Vote for this issue
              Watchers:
              0 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved:
                Imported:
                Indexed: