[PATCH] D47687: fix: [Bug 18971] - Missing -Wparentheses warning

[eric via Phabricator via cfe-commits]

Higuoxing added a comment.

As for some test cases,

  $ cat a.cc
  
  #include <iostream>
  #include <cassert>
  
  #define bar(x) \
    ( \
      ( std::cout << x ) \
    )
  
  bool x;
  int val;
  
  void foo(bool b) {
    std::cout << b << std::endl;
  }
  
  int main () {
  
  
    foo(x && val == 4 || (!x && val == 5));
    bar(x && val == 4 || (!x && val == 5));
    assert(x && val == 4 || (!x && val == 5));
    assert(x || val == 4 && "test");
    return 0;
  }

And clang will emits

  a.cc:20:9: warning: '&&' within '||' [-Wlogical-op-parentheses]
    foo(x && val == 4 || (!x && val == 5));
        ~~^~~~~~~~~~~ ~~
  a.cc:20:9: note: place parentheses around the '&&' expression to silence this warning
    foo(x && val == 4 || (!x && val == 5));
          ^
        (            )
  a.cc:21:9: warning: '&&' within '||' [-Wlogical-op-parentheses]
    bar(x && val == 4 || (!x && val == 5));
    ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  a.cc:7:20: note: expanded from macro 'bar'
      ( std::cout << x ) \
        ~~~~~~~~~~~~~^
  a.cc:21:9: note: place parentheses around the '&&' expression to silence this warning
    bar(x && val == 4 || (!x && val == 5));
    ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  a.cc:7:20: note: expanded from macro 'bar'
      ( std::cout << x ) \
        ~~~~~~~~~~~~~^
  a.cc:22:12: warning: '&&' within '||' [-Wlogical-op-parentheses]
    assert(x && val == 4 || (!x && val == 5));
           ~~^~~~~~~~~~~ ~~
  /usr/include/assert.h:93:25: note: expanded from macro 'assert'
      (__builtin_expect(!(e), 0) ? __assert_rtn(__func__, __FILE__, __LINE__, #e) : (void)0)
                          ^
  a.cc:22:12: note: place parentheses around the '&&' expression to silence this warning
    assert(x && val == 4 || (!x && val == 5));
           ~~^~~~~~~~~~~
  /usr/include/assert.h:93:25: note: expanded from macro 'assert'
      (__builtin_expect(!(e), 0) ? __assert_rtn(__func__, __FILE__, __LINE__, #e) : (void)0)
                          ^
  3 warnings generated.


Repository:
  rC Clang

https://reviews.llvm.org/D47687