textDocument/implementation doesn't resolve local classes

[njames93]

Take this annotated example, where implementation is called on the points $^ and returns the corresponding ranges $[[]]

class $Class^A {
public:
  virtual ~A();
  virtual void $Method^doSomething();
};

class $Class[[B]] : A {
public:
  void $Method[[doSomething]]() override {}
};

namespace Other {
class $Class[[C]] : A {
public:
  void $Method[[doSomething]]() override {}
};
} // namespace Other

void foo() {
  class D : A {
  public:
    void doSomething() override {}
  };
}

As can be seen, the implementation(D) in foo is not returned.
This behaviour appears to happen when everything is defined in the same file, or if the implementations are in their own cpp file.

[HighCommander4]

Type hierarchy has the same issue.

[usx95]

Thanks for filing this.
Both textDocument/typeHierarchy(for subclasses) and textDocument/implementation are driven by the index.
Currently the index does not collect local symbols (such as those declared inside a FunctionDecl, BlockDecl,..).
This was done primarily to reduce the size of the index and thus the results are not entirely accurate in such a case.

[njames93]

Would it be wise to index just polymorphic classes inside functions, blocks, lambdas etc. There may be a case to index all records, but i feel there could be too much of a penalty there.

[hokein]

As discussed offline with @usx95, indexing function-local classes (and its methods) looks like a reasonable fix.
Defining a class inside function body is not a super common pattern, so the increase of memory should not be large.

I think it is worth to try this solution and see how it goes (measuring the size of the index and the performance of the index).

[usx95]

Sent https://reviews.llvm.org/D94785 for review.

[njames93]

Thanks for fixing this 👍