C# Language Specification

Type parameters

A type parameter is a simple identifier that denotes a placeholder for a type argument supplied to create a constructed type. A type parameter is a formal placeholder for a type that will be supplied later. By constrast, a type argument (§4.4.1) is the actual type that is substituted for the type parameter when a constructed type is created.

type-parameter-list:
< type-parameters >

type-parameters:
attributes_opt type-parameter
type-parameters , attributes_opt type-parameter

type-parameter:
identifier

Each type parameter in a class declaration defines a name in the declaration space (§3.3) of that class. Thus, it cannot have the same name as another type parameter or a member declared in that class. A type parameter cannot have the same name as the type itself.

4.