An annotated type tpe @ annot

A type map that approximates NoTypes by upper or lower known bounds depending on variance.

if variance > 0 : approximate by upper bound variance < 0 : approximate by lower bound variance = 0 : propagate NoType to next outer level

A marker trait for types that bind other types that refer to them. Instances are: LambdaType, RecType.

Instances of this class are cached and are not proxies.

Instances of this class are cached and are proxies.

A marker trait for cached types

Roughly: the info of a class during a period.

A constant type with single value.

A type map that maps also parents and self type of a ClassInfo

A by-name parameter type of the form => T, or the type of a method with no parameter list.

A common superclass of ErrorType and TryDynamicCallSite. Instances of this class are at the same time subtypes and supertypes of every other type.

A higher kinded type application C[T_1, ..., T_n]

A type lambda of the form [X_0 B_0, ..., X_n B_n] => T Variances are encoded in parameter names. A name starting with + designates a covariant parameter, a name starting with - designates a contravariant parameter, and every other name designates a non-variant parameter.

The type of an import clause tree

The type of an import clause tree

The type of an erased array

The parameter of a type lambda

The parameter of a type lambda

The lambda type square:

LambdaType | TermLambda | TypeLambda -------------+-------------------+------------------ HKLambda | HKTermLambda | HKTypeLambda MethodOrPoly | MethodType | PolyType

A ternary extractor for MethodType

A trait that mixes in functionality for signature caching

A name filter selects or discards a member name of a type pre. To enable efficient caching, name filters have to satisfy the following invariant: If keep is a name filter, and pre has class C as a base class, then

keep(pre, name) implies keep(C.this, name)

A NamedType of the form Prefix # name

Implementations of this trait cache the results of narrow.

Missing prefix

Sentinel for "missing type"

The type of a polymorphic method. It has the same form as HKTypeLambda, except it applies to terms and parameters do not have variances.

A trait for proto-types, used as expected types in typer

a self-reference to an enclosing recursive type.

a self-reference to an enclosing recursive type.

A refined type parent { refinement }

An extractor for single abstract method types. A type is a SAM type if it is a reference to a class or trait, which

• has a single abstract method with a method type (ExprType and PolyType not allowed!)
• can be instantiated without arguments or with just () as argument.

The pattern SAMType(denot) matches a SAM type, where denot is the denotation of the single abstract method as a member of the type.

A marker trait for types that are guaranteed to contain only a single non-null value (they might contain null in addition).

A skolem type reference with underlying type binder.

The type of a super reference cls.super where thistpe is cls.this and supertpe is the type of the value referenced by super.

A marker trait for types that apply only to term symbols or that represent higher-kinded types.

The type cls.this

Main class representing types.

The principal subclasses and sub-objects are as follows:

Type -+- ProxyType --+- NamedType ----+--- TypeRef
      |              |                 \
      |              +- SingletonType-+-+- TermRef
      |              |                |
      |              |                +--- ThisType
      |              |                +--- SuperType
      |              |                +--- ConstantType
      |              |                +--- TermParamRef
      |              |                +----RecThis
      |              |                +--- SkolemType
      |              +- TypeParamRef
      |              +- RefinedOrRecType -+-- RefinedType
      |              |                   -+-- RecType
      |              +- HKApply
      |              +- TypeBounds
      |              +- ExprType
      |              +- AnnotatedType
      |              +- TypeVar
      |              +- HKTypeLambda
      |
      +- GroundType -+- AndType
                     +- OrType
                     +- MethodOrPoly ---+-- PolyType
                                        +-- MethodType ---+- ImplicitMethodType
                     |                                    +- JavaMethodType
                     +- ClassInfo
                     |
                     +- NoType
                     +- NoPrefix
                     +- ErrorType
                     +- WildcardType

Note: please keep in sync with copy in docs/docs/internals/type-system.md.

Type bounds >: lo <: hi

A marker trait for type proxies. Each implementation is expected to redefine the underlying method.

A marker trait for types that apply only to type symbols

In a TypeApply tree, a TypeVar is created for each argument type to be inferred. Every type variable is referred to by exactly one inferred type parameter of some TypeApply tree.

A type variable is essentially a switch that models some part of a substitution. It is first linked to origin, a poly param that's in the current constraint set. It can then be (once) instantiated to some other type. The instantiation is recorded in the type variable itself, or else, if the current type state is different from the variable's creation state (meaning unrolls are possible) in the current typer state.

Instances of this class are uncached and are not proxies.

Instances of this class are uncached and are proxies.

A marker trait for types that can be types of values or that are higher-kinded

A marker trait for types that can be types of values or prototypes of value types

Wildcard type, possibly with bounds

A filter for names of deferred term definitions of a given type

A filter for names of abstract types of a given type

A filter for names of abstract types of a given type