Signature

The signature of a denotation.

Same-named denotations with different signatures are considered to be overloads, see SingleDenotation#matches for more details.

A method signature (a value of type Signature, excluding NotAMethod and OverloadedSignature) is composed of a list of parameter signatures, plus a type signature for the final result type.

A parameter signature (a value of type ParamSig) is either an integer, representing the number of type parameters in a type parameter section, or the type signature of a term parameter.

A type signature is the fully qualified name of the type symbol of the type's erasure.

For instance a definition

def f[T, S](x: Int)(y: List[T]): S

would have signature

Signature(
  List(2, "scala.Int".toTypeName, "scala.collection.immutable.List".toTypeName),
  "java.lang.Object".toTypeName)

Note that paramsSig has one entry for a whole type parameter section but one entry for each term parameter (currently, methods in Dotty can only have one type parameter section but this encoding leaves the door open for supporting multiple sections).

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