Question

We have a comparison operator which has a operator ‘===’. Can someone guide, what is evaluated first, the “type” or the value equality?

Answer 1

Sure it’s the Type,
normally when you use the == operator ,

1. it will check the type first, if they are different it will convert one of them to be identical,
2. then it will check if the values are equals,

so always the Type will be evaluated first.

EDIT

Referring to artragis answer
below is the full source code of the is_identical_function php 5.4.8 ( thanks to artragis )

ZEND_API int is_identical_function(zval *result, zval *op1, zval *op2 TSRMLS_DC) /* {{{ */
    {
        Z_TYPE_P(result) = IS_BOOL;
        if (Z_TYPE_P(op1) != Z_TYPE_P(op2)) {
            Z_LVAL_P(result) = 0;
            return SUCCESS;
        }
        switch (Z_TYPE_P(op1)) { // here it will check the Type and below it will check the value
            case IS_NULL:
                Z_LVAL_P(result) = 1;
                break;
            case IS_BOOL:
            case IS_LONG:
            case IS_RESOURCE:
                Z_LVAL_P(result) = (Z_LVAL_P(op1) == Z_LVAL_P(op2));
                break;
            case IS_DOUBLE:
                Z_LVAL_P(result) = (Z_DVAL_P(op1) == Z_DVAL_P(op2));
                break;
            case IS_STRING:
                Z_LVAL_P(result) = ((Z_STRLEN_P(op1) == Z_STRLEN_P(op2))
                    && (!memcmp(Z_STRVAL_P(op1), Z_STRVAL_P(op2), Z_STRLEN_P(op1))));
                break;
            case IS_ARRAY:
                Z_LVAL_P(result) = (Z_ARRVAL_P(op1) == Z_ARRVAL_P(op2) ||
                    zend_hash_compare(Z_ARRVAL_P(op1), Z_ARRVAL_P(op2), (compare_func_t) hash_zval_identical_function, 1 TSRMLS_CC)==0);
                break;
            case IS_OBJECT:
                if (Z_OBJ_HT_P(op1) == Z_OBJ_HT_P(op2)) {
                    Z_LVAL_P(result) = (Z_OBJ_HANDLE_P(op1) == Z_OBJ_HANDLE_P(op2));
                } else {
                    Z_LVAL_P(result) = 0;
                }
                break;
            default:
                Z_LVAL_P(result) = 0;
                return FAILURE;
        }
        return SUCCESS;
    }