TypeParamRef

The type representing

T[U1, ..., Un]

where

The basetype of this type with given class symbol.

Returns NoType if this type does not have base in any of its base types.

Is this type exactly Nothing (no vars, aliases, refinements etc allowed)?

Is this type close enough to that type so that members with the two types would override each other?

This means:

• Either both types are polytypes with the same number of type parameters and their result types match after renaming corresponding type parameters
• Or both types are method types with =:=-equivalent(*) parameter types and matching result types after renaming corresponding parameter types if the method types are dependent.
• Or both types are =:=-equivalent
• Or neither type takes term or type parameters.

(*) when matching with a Java method, we also regard Any and Object as equivalent parameter types. (TODO)

This function will always use unsafe-nulls semamtics to check the types. This is because we are using a relaxed rule (ignoring Null types) to check overriding Java methods.

This is the same as matches except that it also matches => T with T and vice versa.

The member with the given name.

The normalized prefix of this type is:

• For a type alias, the normalized prefix of its alias.
• For all other named type and class infos: the prefix.
• Inherited by all other type proxies.
• NoType for all other types.

The closest supertype of this type.

This is the same as underlying, except that

• instead of a TypeBounds type it returns its upper bound, and
• for applied types it returns the upper bound of the constructor re-applied to the arguments.

Same as superType, except for two differences:

• opaque types are treated as transparent aliases
• applied type are matchtype-reduced if possible

Note: the reason to reduce match type aliases here and not in superType is that superType is context-independent and cached, whereas matchtype reduction depends on context and should not be cached (at least not without the very specific cache invalidation condition for matchtypes).

Widen singleton types, ExprTypes, AnnotatedTypes and RefinedTypes.

Widen from ExprType type to its result type.

For all other types, return this.