# std::scoped_lock With Constructor Args
# Detects std::scoped_lock created without constructor arguments
id: no-scoped-lock-without-args
name: std::scoped_lock Should Be Created With Constructor Arguments
severity: error
category: reliability
defect_class: correctness
inline_tier: blocking
language: cpp

message: "std::scoped_lock should be created with constructor arguments"

description: |
  std::scoped_lock is designed to lock multiple mutexes atomically.
  Creating one without arguments serves no purpose and is likely a bug.

  ✅ FIX: Pass mutexes to the constructor

  ```cpp
  std::mutex m1, m2;
  std::scoped_lock lock(m1, m2);  // GOOD - locks both
  ```

query: |
  (declaration
    type: (template_type
      name: (type_identifier) @TYPE (#eq? @TYPE "scoped_lock"))
    declarator: (init_declarator
      initializer: (argument_list) @ARGS))

metavars:
  - TYPE
  - ARGS

post_filter: scoped_lock_empty_args

tags:
  - reliability
  - cpp
  - since-cpp17
  - mutex
  - concurrency

examples:
  bad: |
    std::scoped_lock lock;  // BAD - no mutexes to lock!

  good: |
    std::mutex mtx;
    std::scoped_lock lock(mtx);  // GOOD - locks mutex

has_fix: false