llvm/clang-tools-extra/docs/clang-tidy/checks/bugprone/assignment-in-if-condition.rst

.. title:: clang-tidy - bugprone-assignment-in-if-condition

bugprone-assignment-in-if-condition
===================================

Finds assignments within conditions of `if` statements.
Such assignments are bug-prone because they may have been intended as equality tests.

This check finds all assignments within `if` conditions, including ones that are not flagged
by `-Wparentheses` due to an extra set of parentheses, and including assignments that call
an overloaded `operator=()`. The identified assignments violate 
`BARR group "Rule 8.2.c" <https://barrgroup.com/embedded-systems/books/embedded-c-coding-standard/statement-rules/if-else-statements>`_.

.. code-block:: c++

  int f = 3;
  if(f = 4) { // This is identified by both `Wparentheses` and this check - should it have been: `if (f == 4)` ?
    f = f + 1;
  }

  if((f == 5) || (f = 6)) { // the assignment here `(f = 6)` is identified by this check, but not by `-Wparentheses`. Should it have been `(f == 6)` ?
    f = f + 2;
  }