FWIW modern C compilers recommend double-bracing exactly for that reason e.g. in clang, by default, it triggers:

    test.c:3:17: warning: using the result of an assignment as a condition without parentheses [-Wparentheses]
      if (statement = ref) {
          ~~~~~~~~~~^~~~~
    test.c:3:17: note: place parentheses around the assignment to silence this warning
      if (statement = ref) {
                    ^
          (              )
    test.c:3:17: note: use '==' to turn this assignment into an equality comparison
      if (statement = ref) {
                    ^
                    ==