18.104.22.168.5 Implicit Type Determination
An <IDENTIFIER> that is not explicitly associated with a declared type via either a <type-spec> or a <type-suffix> might be implicitly associated with a declared type. The implicit declared type of such a name is defined as follows:
If the first letter of the name value of the <IDENTIFIER> has is in the character span of a <letter-spec> that is part of a <def-directive> within the module containing the <IDENTIFIER> then its declared type is as specified in section 5.2.2.
Otherwise its implicit declared type is Variant.