An expression statement without side effects, such as a comparison without assigning its result to a variable, is useless, and must have been a mistake on the developer's part.

Noncompliant code example

var str = "long string split on multiple lines but" // without concatenation operator, statement implicitly ends at the linebreak
  " the concatenation operator + is missing";  // Noncompliant

a == 1;   // Noncompliant; was assignment intended?

See