Open Radar

 
Summary:

When a method prototype contains a block parameter whose type is provided as a typedef, Xcode Objective-C autocompletion does not work correctly and prevents from directly (and thus conveniently!) implementing the block.

Steps to Reproduce:

Create a source file with the following contents:

NS_ASSUME_NONNULL_BEGIN
typedef void (^SomeBlockSignature)(NSString * __nullable param);

@interface SomeClass ()

- (void)someMethodWithABlock:(SomeBlockSignature)block;

@end
NS_ASSUME_NONNULL_END

@implementation SomeClass

- (void)someMethodWithABlock:(SomeBlockSignature)block
{
	// Implementation is irrelevant here
}

@end

Then begin implementing another method which calls -someMethodWithABlock, by typing ‘[self someMethod’  and pressing Enter twice. Xcode fills the remaining of the prototype and attempts to fill in the block signature. You get the following annoying result, though:

@implementation SomeClass

// … see above

- (void)otherMethod
{
	[self someMethodWithABlock:(SomeBlockSignature __nonnull()block
}

@end

instead of the result

@implementation SomeClass

// … see above

- (void)otherMethod
{
	[self someMethodWithABlock:^(NSString * __nullable) {
		<#code#>
	}
}

@end

you would get if no block signature typedef was used, i.e. if the block signature was directly inlined in the method prototype itself:

NS_ASSUME_NONNULL_BEGIN
@interface SomeClass ()

- (void)someMethodWithABlock:(void (^)(NSString * __nullable param))block;

@end
NS_ASSUME_NONNULL_END

Note that the ‘param’ parameter incorrectly disappears from the autocompleted result in this case, though. If the NONNULL region is removed:

@interface SomeClass ()

- (void)someMethodWithABlock:(void (^)(NSString *param))block;

@end

autocompletion namely provides the usual convenient result:

@implementation SomeClass

// … see above

- (void)otherMethod
{
	[self someMethodWithABlock:^(NSString *param) {
		<#code#>
	}
}

which can immediately be used for implementation.

@end

Expected Results:

Autocompletion correctly fills in the block signature, with immediately available parameters:

@implementation SomeClass

// … see above

- (void)otherMethod
{
	[self someMethodWithABlock:^(NSString * __nullable param) {
		<#code#>
	}
}

@end

Actual Results:

The autocompletion result is useless:

@implementation SomeClass

// … see above

- (void)otherMethod
{
	[self someMethodWithABlock:(SomeBlockSignature __nonnull()block
}

@end

Configuration:

Xcode 6.3

Notes: This is a duplicate of rdar://20723086