Future programming languages could have (IIRC some current PLs allow for such syntax, some of them I believe using 'let'):

    if (p_non_null = (p != NULL)) && (char_non_space = (*p != ' ')) { ... }

But where the IDE only shows the LHS of the expression as:

    if p_non_null && char_ non_space { ... }

But also where the IDE makes it easier to write the earlier full expression above.

Also, the initial code:

    bool p_non_null = (p != NULL);
    bool char_non_space = (*p != ' ');
    if p_non_null && char_ non_space { ... }

This could simply be analyzed by the compiler to not store the named boolean variables in the first place, and to evaluate them inline in the if-condition so as to allow for the short-circuiting to occur fine.