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Summary:
The Swift 2 book comments the use of the parameter "block" to the decorator "@convention" as such:

> “The block argument is used to indicate an Objective-C compatible block reference. The function value is represented as a reference to the block object, which is an id-compatible Objective-C object that embeds its invocation function within the object. The invocation function uses the C calling convention.”

This is not currently true; a block type cannot be converted to "AnyObject"

Steps to Reproduce:
1. Typealias a function type to include "@convention(block)" in Swift 2
2. Create a function taking a parameter of that function type
3. Attempt to cast the block to "AnyObject" using "as"
4. Follow compiler warning to use "as!" instead
5. Code traps at runtime

Expected Results:
The block type is converted to "AnyObject".

Actual Results:
Precondition failure: "Could not cast value of type '@convention(block) () -> ()' (0xSOMEADDR) to 'Swift.AnyObject' (0xSOMEADDR)."

Version:
Xcode 7.0 (7A218)/Apple Swift 2.0 (swiftlang-700.0.59 clang-700.0.72)

Notes:
A block can be passed to/casted from "id" in Objective-C, or bridged to Core Foundation as appropriate. In non-ObjC C, blocks are always pointer types.

Configuration:
Occurs on all releases of Swift.

Attachments: