Definitive assignment of a final field in instance initializer not found in the constructor

Issue #128 resolved
Loïc Girault created an issue

extendj v8.0.1-4-gcc1f6e3

I tried to compile jEdit5.2.0 using extendj. While javac accept it, extendj find an error in org/gjt/sp/jedit/buffer/ Here is a minimal example :

class B {   int value(){return 0;}    }

class A {
    //instance initializer
        b=new B();

    int j;

        j = b.value();

    final B b;

A final field assigned in an instance intializer and used in a constructor is not recognized as already assigned. This error appears when the field is declared after the initializer and the constructor.

I fixed it using the joined Assign aspect and by adding the following lines in java4/frontend /DefiniteAssignment.jrag l 300

if (b instanceof ConstructorDecl) {
          for (BodyDecl bdecl : getBodyDeclList()){
            if (bdecl instanceof InstanceInitializer
                && ((InstanceInitializer)bdecl).assign(v))
              return true;

        search = false;

However I fear that the Assign aspect is not written in an idiomatic way. I would be happy to see it rewritten.

Comments (6)

  1. Jesper Öqvist

    Interesting! I was able to shrink the test case a bit more:

    class B1 {
            b = 0;
        B1() {
        void m(int x) {
        final int b;

    The definite assignment analysis has definitely been in need of cleanup a long while now. I actually pushed a commit earlier today that tidies up the code a little.

  2. Jesper Öqvist

    Thank you for the bug report! Bug reports really help to improve ExtendJ!

    I have fixed this issue now. The issue was caused in part by incorrect equations for assignedAfter and unassignedAfter on FieldDeclaration, and in part by incorrect handling of constructor calls in the definite assignment analysis. See the fix commit for more details (should be linked here soon).

  3. Loïc Girault reporter

    You're welcome. Actually I'm phd student building a refactoring tool on top of the frontend of extendj (with the name locking aspect done by Max Schäfer). So I really appreciate any improvement. (It's already a pretty cool compiler)

  4. Jesper Öqvist

    Fix definite assignment error for blank finals

    Fixed a definite assignment analysis error for blank final instance variables.

    The problem was caused by not searching all instance initializers and instance variable initializers for assignments to the given variable. Partly this was caused by not incorrect handling of alternate constructor and implicit and explicit super constructor calls, partly it was caused by FieldDeclaration having incorrect equations for assignedAfter and unassignedAfter.

    fixes #128 (bitbucket)

    → <<cset 472713ca9e9d>>

  5. Log in to comment