Except as described below, an expression used in a context where a constant expression is required is value-dependent if any subexpression is value-dependent.
An id-expression is value-dependent if:
it is type-dependent,
it is the name of a non-type template parameter,
it names a static data member that is a dependent member of the current instantiation and is not initialized in a member-declarator,
it names a static member function that is a dependent member of the current instantiation, or
it is a constant with literal type and is initialized with an expression that is value-dependent.
sizeof unary-expression sizeof ( type-id ) typeid ( expression ) typeid ( type-id ) alignof ( type-id ) noexcept ( expression )
[ Note: For the standard library macro offsetof, see [support.types]. — end note ]
simple-type-specifier ( expression-listopt ) static_cast < type-id > ( expression ) const_cast < type-id > ( expression ) reinterpret_cast < type-id > ( expression ) ( type-id ) cast-expression
An expression of the form &qualified-id where the qualified-id names a dependent member of the current instantiation is value-dependent. An expression of the form &cast-expression is also value-dependent if evaluating cast-expression as a core constant expression succeeds and the result of the evaluation refers to a templated entity that is an object with static or thread storage duration or a member function.