"A declaration which can be contained in a [[Package]] or in another [[NestableDeclaration]].
 
 Functions, values, classes, interfaces and aliases are such declarations."​
​shared sealed interface NestableDeclaration of 
                                        FunctionOrValueDeclaration |
                                        ClassOrInterfaceDeclaration |
                                        ConstructorDeclaration |
                                        SetterDeclaration |
                                        AliasDeclaration​
        satisfies AnnotatedDeclaration & TypedDeclaration {
​
    "True if this declaration is annotated with [[actual|ceylon.language::actual]]."​
    shared formal Boolean actual;
​
    "True if this declaration is annotated with [[formal|ceylon.language::formal]]."​
    shared formal Boolean formal;
​
    "True if this declaration is annotated with [[default|ceylon.language::default]]."​
    shared formal Boolean default;
​
    "True if this declaration is annotated with [[shared|ceylon.language::shared]]."​
    shared formal Boolean shared;
    
    "True if this declaration is annotated with [[static|ceylon.language::static]]."​
    shared formal Boolean static;
    
    "This declaration's package container."​
    shared formal Package containingPackage;
    
    "This declaration's module container."​
    shared formal Module containingModule;
    
    "This declaration's immediate container, which can be either a [[NestableDeclaration]]
     or a [[Package]]."​
    shared formal NestableDeclaration|Package container;
    
    "True if this declaration is a toplevel declaration."​
    shared formal Boolean toplevel;
    
}
​