Open Radar

 
Summary:
Accessing an object's own properties and methods should require prefixing with "self." The current implicit addition of self makes code more difficult to understand and maintain.

Consider a class like

   class Foo {
     var a:String = "Bob"
     func printInfo(a:String) -> () { 
       println(a) 
     }
   }

When looking at the line "println(a)" in isolation, it is not self-evident if I am accessing self.a or the local argument a, which shadows it. 

Similarly, faced with a line like

    sort(myElements)

It is unclear whether this refers to the stdlib function sort, or to an implicit self.sort(). In the presence of subclasses, this can become even more confusing.

Method calls in ObjC have always required self, and best practice for accessing properties in ObjC is to use self. Swift should continue this practice.

In addition, I would suggest that explicit self is even *more* valuable in Swift than in ObjC, because Swift has many features which will make it more likely that people will define functions, variables, and constants in the top-level scope, outside of type definitions. I'm thinking of namespaces, its support for directly running .swift files, its REPL, and general support for functional programming idioms (where generic top-level functions typically act on objects, as opposed to being narrowly scoped as methods).

When people define more functions identifiers at the top-level, it becomes more crucial that code distinguish between top-level identifiers and type-scoped identifiers.

Steps to Reproduce:
1. define a type with a property and/or method
2. access the property and/or method

Expected Results:
3. I use a "self." prefix to access the property and/or method

Actual Results:
3. I can implicitly access the property and/or method

Version:
Xcode6-Beta

Notes:


Configuration:
always

Attachments: