8.3.3: Clarify that a field cannot be referenced in its own initializer

The rules in 8.3.2.3 (8.3.3 in JLS 8) are designed to prevent circularity in the initialization of fields. This is accomplished by requiring that most references to a field in a field initializer (or initializer block) must happen _after_ the declaration of the field. But, strangely, I can't find an explicit rule prohibiting the simplest circularity of all: a field that refers to itself.

class Foo { int i = i+1; } // error in javac

JLS 1 8.3.2.2 said "A compile-time error occurs if an initialization expression for an instance variable contains a use by a simple name of that instance variable or of another instance variable whose declaration occurs to its right (that is, textually later) in the same class." And, "int k = k+1;" was exemplified as an error "because the initialization of k refers to k itself."

JLS 2 rewrote these sections and no longer explicitly prohibited a field from being used in its own initializer.

---

Suggested text:

Use of instance variables whose declarations ***contain or*** appear textually after the use is sometimes restricted, even though these instance variables are in scope. Specifically, it is a compile-time error if all of the following conditions hold:

• The declaration of an instance variable in a class or interface C ***either contains or*** appears textually after a use of the instance variable;

• The use is a simple name in either an instance variable initializer of C or an instance initializer of C;

• The use is not on the left hand side of an assignment;

• C is the innermost class or interface enclosing the use.

[May also want to update some informal descriptions of this rule appearing elsewhere in 8.3.2.]