What does static class mean?
What does this construction mean
static class Class {};
If the design doesn't make sense then why does the studio compile it.
2 answers
The meaning can appear if a variable is defined together with the class definition, that is, the code is transformed into the following:
static class Class {} var;
This will mean that a variable of the newly defined class is being created. The fact that Visual Studio allows such a construction, i.e. it only issues a warning, and not a compilation error, is a feature of the compiler.
Moreover, var, depending on the context, can be either a definition of a global variable that is available only within the current file, if it is written at the global namespace level. Or it can be a declaration of a static variable of the enclosing class, if written inside the class definition:
struct X {
static class Class {} var;
};
In this case, to use var, it will still need to be defined outside X:
X::Class X::var;
Such a construction means nothing - it is not compiled in principle. C++ has always allowed storage class specifiers (static in this case) only in object or function declarations.
10.1.1 Storage class specifiers
4 The static specifier can be applied only to names of variables and functions and to anonymous unions [...]
Http://eel.is/c++draft/dcl.stc#4
This construction does not declare any no object, no function. Any C++ compiler is required to issue a diagnostic message in response to such a construction.
The concept of "compiles" or "does not compile" does not exist in the C++ world. The correctness of C++ code is determined primarily by the presence or absence of compiler diagnostic messages.
In this case, the compiler's decision to continue compiling after issuing a diagnostic message may be caused by the legacy of the C language, in which such pointless storage class specifiers are valid (though also meaningless).