Objective-C Blocks Don't Check Parameters' Generic Types
Originator: | heath.borders | ||
Number: | rdar://27014664 | Date Originated: | 25-Jun-2016 02:03 PM |
Status: | Open | Resolved: | |
Product: | Developer Tools | Product Version: | Version 8.0 beta (8S128d) |
Classification: | Serious Bug | Reproducible: | Always |
Summary: If a block accepts a parameter that contains a generic type, the block may be assigned to a variable with an incompatible generic type Steps to Reproduce: - (void)testExample { void (^blockWithNSArrayOfNSStrings)(NSArray<NSString *> *stringArray) = ^(NSArray<NSNumber *> *numberArray) { NSLog(@"numberArray: %@", numberArray); }; blockWithNSArrayOfNSStrings([NSArray<NSString *> arrayWithObjects: @"foo", @"bar", nil]); } Expected Results: The assignment should fail to compile because `blockWithNSArrayOfNSStrings` accepts an `NSArray` containing `NSString`s, but it’s assigned a block accepting an `NSArray` containing `NSNumber`s, and `NSNumber` is not a supertype of `NSString`. Actual Results: The assignment compiles without warnings from either clang or the analyzer.
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