Tweak record class spec

Author: RexJaeschke

standard/expressions.md

@@ -1559,11 +1559,13 @@ A *simple_name* is either of the form `I` or of the form `I<A₁, ..., Aₑ>`,
 - If `e` is zero and the *simple_name* appears within a local variable declaration space ([§7.3](basic-concepts.md#73-declarations)) that directly contains a local variable, parameter or constant with name `I`, then the *simple_name* refers to that local variable, parameter or constant and is classified as a variable or value.
 - If `e` is zero and the *simple_name* appears within a generic method declaration but outside the *attributes* of its *method_declaration*, and if that declaration includes a type parameter with name `I`, then the *simple_name* refers to that type parameter.
 - Otherwise, for each instance type `T` ([§15.3.2](classes.md#1532-the-instance-type)), starting with the instance type of the immediately enclosing type declaration and continuing with the instance type of each enclosing class or struct declaration (if any):
-  - If `e` is zero and the declaration of `T` includes a type parameter with name `I`, then the *simple_name* refers to that type parameter.
+  - If the declaration of `T` includes a primary constructor parameter `I` and the reference occurs within the `argument_list` of `T`’s `class_base` or within an initializer of a field, property or event of `T`, the result is the primary constructor parameter `I`.
+  - Otherwise, if `e` is zero and the declaration of `T` includes a type parameter with name `I`, then the *simple_name* refers to that type parameter.
   - Otherwise, if a member lookup ([§12.5](expressions.md#125-member-lookup)) of `I` in `T` with `e` type arguments produces a match:
     - If `T` is the instance type of the immediately enclosing class or struct type and the lookup identifies one or more methods, the result is a method group with an associated instance expression of `this`. If a type argument list was specified, it is used in calling a generic method ([§12.8.10.2](expressions.md#128102-method-invocations)).
     - Otherwise, if `T` is the instance type of the immediately enclosing class or struct type, if the lookup identifies an instance member, and if the reference occurs within the *block* of an instance constructor, an instance method, or an instance accessor ([§12.2.1](expressions.md#1221-general)), the result is the same as a member access ([§12.8.7](expressions.md#1287-member-access)) of the form `this.I`. This can only happen when `e` is zero.
     - Otherwise, the result is the same as a member access ([§12.8.7](expressions.md#1287-member-access)) of the form `T.I` or `T.I<A₁, ..., Aₑ>`.
+  - Otherwise, if the declaration of `T` includes a primary constructor parameter `I`, the result is the primary constructor parameter `I`.
 - Otherwise, for each namespace `N`, starting with the namespace in which the *simple_name* occurs, continuing with each enclosing namespace (if any), and ending with the global namespace, the following steps are evaluated until an entity is located:
   - If `e` is zero and `I` is the name of a namespace in `N`, then:
     - If the location where the *simple_name* occurs is enclosed by a namespace declaration for `N` and the namespace declaration contains an *extern_alias_directive* or *using_alias_directive* that associates the name `I` with a namespace or type, then the *simple_name* is ambiguous and a compile-time error occurs.