Annotate references with the name of the function in which they occur

[HighCommander4]

When performing Find References, it would be really useful if each reference was annotated with the name of the functin in which the reference occurs (in addition to the name of the file, which is already there).

[jacobdufault]

Can you share a screenshot? This is likely a vscode issue that cannot be fixed by cquery.

[HighCommander4]

Sure. Given this code:

void target();

void function1() {
  target();
}

void function2() {
  target();
}

when you perform "Find References" on target, and, say, the reference in function1() is selected:

I would like to see function1 either at the top beside "test.cpp - 3 references", or in the side panel next to the entry being viewed (in which case, it can be there even when the entry is not selected).

(In this case, you can see function1 in the code preview, but imagine it was a longer function so you couldn't see its name without scrolling up, potentially a lot.)

[HighCommander4]

I don't think it's a VSCode issue, because the server only sends the reference's character range:

    {
      "uri": "file:///home/nr/dev/projects/testing/test/test.cpp",
      "range": {
        "start": {
          "line": 3,
          "character": 2
        },
        "end": {
          "line": 3,
          "character": 8
        }
      }
    },

To implement this feature, the server would also need to send the name of the enclosing function for each reference.

[HighCommander4]

As a point of comparison, consider the search results pane in Eclipse CDT:

There is no preview window, just a copy of the line containing the reference, but the search result is annotated with the name of the function it's contained in.

[MaskRay]

interface ReferenceParams extends TextDocumentPositionParams { returns Location[] | null. I think TypeScript interfaces can be arbitrarily inherited so we can add extra fields to Location. But this requires UI support from language clients.

What is needed to be done on cquery's side:

• Extend struct VarDefDefinitionData to add semantic container (a named container)
• Support serialization of subclasses. This requires some pointer or std::unique_ptr to utilize virtual functions, or use ad-hoc type dispatching.

[jacobdufault]

Why can't we just add the information to TextDocumentPositionParams (or some derived type that the references message uses)? This approach eliminates the need for subclass serialization.

[HighCommander4]

Why can't we just add the information to TextDocumentPositionParams (or some derived type that the references message uses)? This approach eliminates the need for subclass serialization.

TextDocumentPositionParams is what the request message uses. We need a place to put the information in the response message, whose type is just Location[] | null.

[MaskRay]

this requires more info in QueryLocation and uses. I recently changed Id from size_t to uint32_t

// 12 bytes
struct QueryLocation {
  QueryFileId path; // 4 bytes
  Range range; // 8 bytes
};

struct QueryVar {
...
    std::vector<QueryLocation> uses;
};

We should think how to encode the parent symbol information without bloating the size too much.

struct IndexVar {
  ...
  std::vector<Range> uses;
};

[HighCommander4]

It looks like the necessary information is available from libclang via CXIdxEntityRefInfo::container. Currently, we only use it for functions, to populate IndexFuncRef::id inside IndexFunc::callers. To implement this fully, we will need to store the container for variable and type references as well.

[MaskRay]

For a symbol occurrence (uses variables in query.h and indexer.h), what we need to record:

• Range range;
• Maybe<Id<void>> parent; container information
• QueryFileId path;
• SymbolKind parent_kind for a variable, the container may be either a type or a function. there should be someway to differentiate them.
• CXSymbolRole read/write/call ...

QueryFileId path; looks to me the most useless one, but we may need to encode the file information in Query{Func,Type,Var} so that we can get the file associate with a uses entry by looking up its Query{Func,Type,Var} entry.

[HighCommander4]

I filed an LSP spec issue for this: microsoft/language-server-protocol#396.

[MaskRay]

Renamed {Index,Query}File::callers to uses because the uses can also be f = &foo;

360a4ca added config->extension.referenceContainer
but someone should turn all

  Maybe<typename F::Range> definition_spelling;
  Maybe<typename F::Range> definition_extent;

to
Use (because Use records the lexical parent information)

[MaskRay]

The uses of Query{Func,Type,Var} have been unified to std::vector<Use> uses;

struct IndexFunc {
...
  std::vector<Use> uses;
};

Use::kind Use::id represents the lexical parent.