# Unnecessary Bit Operations
# Detects bit operations that have no effect
id: unnecessary-bit-ops
name: Unnecessary Bit Operations Should Not Be Performed
severity: error
category: maintainability
defect_class: correctness
inline_tier: blocking
language: cpp

message: "Unnecessary bit operation - has no effect"

description: |
  Operations like (x | 0), (x & -1), (x ^ 0) have no effect.
  They indicate confusion or incomplete refactoring. Remove them.

  ✅ FIX: Remove unnecessary operation

  ```cpp
  int y = x;  // GOOD - simplified
  ```

query: |
  (binary_expression
    (identifier) @VAR
    "|" @OP
    (number_literal) @ZERO (#eq? @ZERO "0"))
  (binary_expression
    (identifier) @VAR
    "&" @OP
    (number_literal) @VAL (#match? @VAL "^-?1+$"))
  (binary_expression
    (identifier) @VAR
    "^" @OP
    (number_literal) @ZERO (#eq? @ZERO "0"))

metavars:
  - VAR
  - OP
  - ZERO
  - VAL

tags:
  - maintainability
  - cpp
  - suspicious

examples:
  bad: |
    int y = x | 0;   // BAD - no effect
    int z = x & -1;  // BAD - no effect
    int w = x ^ 0;   // BAD - no effect

  good: |
    int y = x;       // GOOD - simplified

has_fix: true
fix_action: remove_bit_operation