microsoft / microsoft/vscode-cpptools

Find All References on a variable template returns nothing

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bug Feature: Find All References Language Service
Dominant language
TypeScript
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Description

Environment

cpptools — Find All References on the variable template ex::zeroValue returns nothing

Field Value
Symbol (spec id) var-template-zeroValue
Declaration template <class T> constexpr T zeroValue = T(0); (variable template)
Query position src/extras.h:22:13 (cursor on zeroValue)
Affected LSP request textDocument/references
Repro archive P1-var-template-zeroValue.zip (this folder)

Summary

Find All References on the variable template ex::zeroValue returns no references in VS Code with the C/C++ extension (cpptools), missing both instantiation uses. The symbol appears unused even though it is instantiated twice.

Environment

  • Editor: Visual Studio Code 1.33.5
  • Extension: C/C++ (ms-vscode.cpptools), default IntelliSense engine
  • Language standard: C++20 (freestanding fixture; no STL/toolchain required)

Steps to reproduce

  1. Extract P1-var-template-zeroValue.zip and open the cpp-project folder in VS Code (C/C++ extension enabled).
  2. Optionally configure with CMake Tools (preset cdb); the fixture also parses under default C++20 IntelliSense.
  3. Open src/extras.h, place the cursor on zeroValue in constexpr T zeroValue = T(0); (line 22, col 13).
  4. Invoke Find All References (Shift+Alt+F12).

Expected vs actual

Source Result count
Expected 3
VS Code / cpptools 0 (no references)

Expected (3): the template declaration (extras.h:22) and its two instantiation uses in main()ex::zeroValue<int> (main.cpp:150) and ex::zeroValue<double> (main.cpp:151).

Actual (0): "Find All References" reports no results (the instantiation uses are not found).

Why it matters

A false "no references" on a live symbol is high risk: an automated agent (or a developer) can conclude the variable template is dead and delete it, breaking the two instantiations.

Bug Summary and Steps to Reproduce

P1-var-template-zeroValue.zip

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with P1-var-template-zeroValue.zip and inspect src/extras.h:22 and the uses in main.cpp:150-151. Trace the textDocument/references handling for the variable-template symbol and compare the reported result with the expected three references. Done means Find All References returns the declaration and both instantiation uses.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp, typescript
Domain
compilers, devtools
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Clearly specified
Newbie friendliness
62/100

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