Chapter 18 Unsafe code
Use of this in a primary-expression in a context other than the ones listed above is a compile-time error. In particular, it is not possible to refer to this in a static method, a static property accessor, or in a variable-initializer of a field declaration.
7.5.8 Base access
A base-access consists of the reserved word base followed by either a “.” token and an identifier or an expression-list enclosed in square brackets:
base-access: base . identifier base [ expression-list ]
A base-access is used to access base class members that are hidden by similarly named members in the current class or struct. A base-access is permitted only in the block of an instance constructor, an instance method, or an instance accessor. When base.I occurs in a class or struct, I must denote a member of the base class of that class or struct. Likewise, when base[E] occurs in a class, an applicable indexer must exist in the base class.
At compile-time, base-access expressions of the form base.I and base[E] are evaluated exactly as if they were written ((B)this).I and ((B)this)[E], where B is the base class of the class or struct in which the construct occurs. Thus, base.I and base[E] correspond to this.I and this[E], except this is viewed as an instance of the base class.
When a base-access references a virtual function member (a method, property, or indexer), the determination of which function member to invoke at run-time (§7.4.3) is changed. The function member that is invoked is determined by finding the most derived implementation (§10.5.3) of the function member with respect to B (instead of with respect to the run-time type of this, as would be usual in a non-base access). Thus, within an override of a virtual function member, a base-access can be used to invoke the inherited implementation of the function member. If the function member referenced by a base-access is abstract, a compile-time error occurs.
7.5.9 Postfix increment and decrement operators
post-increment-expression: primary-expression ++
post-decrement-expression: primary-expression --
The operand of a postfix increment or decrement operation must be an expression classified as a variable, a property access, or an indexer access. The result of the operation is a value of the same type as the operand.
If the operand of a postfix increment or decrement operation is a property or indexer access, the property or indexer must have both a get and a set accessor. If this is not the case, a compile-time error occurs.
Unary operator overload resolution (§7.2.3) is applied to select a specific operator implementation. Predefined ++ and -- operators exist for the following types: sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, decimal, and any enum type. The predefined ++ operators return the value produced by adding 1 to the operand, and the predefined -- operators return the value produced by subtracting 1 from the operand.
The run-time processing of a postfix increment or decrement operation of the form x++ or x-- consists of the following steps:
If x is classified as a variable:
x is evaluated to produce the variable.
The value of x is saved.
The selected operator is invoked with the saved value of x as its argument.
The value returned by the operator is stored in the location given by the evaluation of x.
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