Dotty Documentation


case class Signature
extends Product

The signature of a denotation. Overloaded denotations with the same name are distinguished by their signatures. A signature of a method (of type PolyType,MethodType, or ExprType) is composed of a list of signature names, one for each parameter type, plus a signature for the result type. Methods are uncurried before taking their signatures. The signature name of a type is the fully qualified name of the type symbol of the type's erasure.

For instance a definition

def f(x: Int)(y: List[String]): String

would have signature

  List("scala.Int".toTypeName, "scala.collection.immutable.List".toTypeName),

The signatures of non-method types are always NotAMethod.

There are three kinds of "missing" parts of signatures:

  • tpnme.EMPTY Result type marker for NotAMethod and OverloadedSignature
  • tpnme.WILDCARD Arises from a Wildcard or error type
  • tpnme.Uninstantiated Arises from an uninstantiated type variable

[-] Constructors

Signature ( paramsSig: List [ TypeName ] , resSig: TypeName )

[-] Members

[+] val paramsSig : List [ TypeName ]
[+] val resSig : TypeName
[+] private def consistent ( name1: TypeName , name2: TypeName ) : Boolean

Two names are consistent if they are the same or one of them is tpnme.Uninstantiated

[+] final def consistentParams ( that: Signature ) : Boolean

Does this signature coincide with that signature on their parameter parts? This is the case if all parameter names are consistent, i.e. they are either equal or on of them is tpnme.Uninstantiated.

[+] def isUnderDefined ( implicit ctx: Context ) : Boolean

A signature is under-defined if its paramsSig part contains at least one tpnme.Uninstantiated. Under-defined signatures arise when taking a signature of a type that still contains uninstantiated type variables. They are eliminated by fixSignature in PostTyper.

[+] private def isWildcard ( name: TypeName ) : Boolean

name.toString == "" or name.toString == "_"

[+] final def matchDegree ( that: Signature ) ( implicit ctx: Context ) : MatchDegree

The degree to which this signature matches that. If parameter names are consistent and result types names match (i.e. they are the same or one is a wildcard), the result is FullMatch. If only the parameter names are consistent, the result is ParamMatch before erasure and NoMatch otherwise. If the parameters are inconsistent, the result is always NoMatch.

[+] def prepend ( params: List [ Type ] , isJava: Boolean ) ( implicit ctx: Context ) : Signature

Construct a signature by prepending the signature names of the given params to the parameter part of this signature.

[+] final def updateWith ( that: Signature ) : Signature

that signature, but keeping all corresponding parts of this signature.