That will limit the usefulness but on the other hand avoid
the illegal configurations all over.
+ If "select" <symbol> is followed by "if" <expr>, <symbol> will be
+ selected by the logical AND of the value of the current menu symbol
+ and <expr>. This means, the lower limit can be downgraded due to the
+ presence of "if" <expr>. This behavior may seem weird, but we rely on
+ it. (The future of this behavior is undecided.)
+
- weak reverse dependencies: "imply" <symbol> ["if" <expr>]
This is similar to "select" as it enforces a lower limit on another
imply BAR
imply BAZ
+ Note: If "imply" <symbol> is followed by "if" <expr>, the default of <symbol>
+ will be the logical AND of the value of the current menu symbol and <expr>.
+ (The future of this behavior is undecided.)
+
- limiting menu display: "visible if" <expr>
This attribute is only applicable to menu blocks, if the condition is