Get rid of BodyDeclList

Issue #166 resolved
Jesper Öqvist
created an issue

BodyDeclList is a node type used to build substituted member declarations in generic types. The problem with BodyDeclList is that inherited attributes don't work as expected since BodyDeclList is a List subtype. Inherited equations cause problems because they may not be able to compute a real child index for the body decl list children:

eq ClassDecl.getBodyDecl(int i).x() { ... } // ERROR: index i can't be computed for NTA children of BodyDeclList

As the above example illustrates, when the x() attribute is computed for an NTA child of BodyDeclList, then the child index becomes incorrectly computed in the generated code for the inherited equation.

An example from generated code in ExtendJ:

  public SimpleSet<TypeDecl> Define_lookupType(ASTNode _callerNode, ASTNode _childNode, String name) {
    if (_callerNode == getBodyDeclListNoTransform()) {
      // @declaredat /Users/jesper/git/extendj/java5/frontend/Generics.jrag:764
      int index = _callerNode.getIndexOfChild(_childNode);
      {
          SimpleSet<TypeDecl> result = memberTypes(name);
          if (getBodyDecl(index).visibleTypeParameters()) { // ERROR: Null pointer exception when _childNode is an NTA child of BodyDeclList.
            result = addTypeVariables(result, name);

Comments (4)

  1. Jesper Öqvist reporter

    This test case currently fails because of a NullPointerException caused by using BodyDeclList:

    // Test parameter type substitution and type lookup.
    // .result=COMPILE_PASS
    class Combined<U, V> {
      public Combined(U u, V v) {
      }
    }
    
    class Test<A> {
      Test<A> val;
      class Op<B> {
        Combined<A, B> op(Test<B> x) {
          return (val.new Op<B>()).combine(x.val);
        }
        Combined<A, B> combine(Test<B> x) {
          return new Combined<A, B>(val, x.val);
        }
      }
    }
    

    The NullPointerException occurs on the line commented above in Define_lookupType.

  2. Jesper Öqvist reporter

    Replace List subtype BodyDeclList

    BodyDeclList was used for on-demand creation of substituted body declarations in parameterized types. This has been replaced by using rewrites instead. This fixes a NullPointerException caused by evaluating inherited attributes on the NTA children of a BodyDeclList node.

    fixes #166 (bitbucket)

    → <<cset 4f7e08dee6cb>>

  3. Jesper Öqvist reporter

    Replace List subtype BodyDeclList

    BodyDeclList was used for on-demand creation of substituted body declarations in parameterized types. This has been replaced by using rewrites instead. This fixes a NullPointerException caused by evaluating inherited attributes on the NTA children of a BodyDeclList node.

    fixes #166 (bitbucket)

    → <<cset b4b9a85c4873>>

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