Definite un-assignedness for assignment expression

[Erik Hogeman]

JLS version 7, Chapter 16.1.8 states:

 V is definitely unassigned after the assignment expression iff a is not V and V is definitely unassigned after b.

The attribute for assignment expression definite unassignedness does not comply with the specification:

eq AssignExpr.isDUafter(Variable v) = getSource().isDUafter(v);

The attribute only checks the source unassignedness.

Proposed fix:

eq AssignExpr.isDUafter(Variable v) {
    //Bug in java 4 implementation, see 16.1.8 second bullet. Must check that v != a 
    if(getDest().isVariable() && getDest().varDecl() == v) 
        return false;
    else
        return getSource().isDUafter(v);
}

[Jesper Öqvist]

Test case for this bug:

public class Test {
        public void m() {
                final int f;
                f = 3;
                f = 4;// expect error because f not definitely unassigned
                System.out.println(""+f);
        }
}

[Jesper Öqvist]

Fixed definite assignment error

fixes issue #51 (bitbucket)

→ <<cset 62c7dc33fa23>>