This rule is deprecated; use {rule:php:S6600} instead.

Why is this an issue?

echo can be called with or without parentheses, but it is best practice to leave parentheses off the call because using parentheses with multiple arguments will result in a parse error.

Noncompliant code example

echo("Hello");  // Noncompliant, but it works
echo("Hello", "World"); // Noncompliant. Parse error

Compliant solution

echo "Hello";
echo "Hello","World!";