Open Radar

 
Summary:
When a method takes a parameter of generic type S that has a constraint to inherit from a generic class (e.g. "S: GenericClass<U>") and this parameter is used as a method argument, the swift compiler crashes with Segmentation fault: 11

Steps to Reproduce:
Open the sample project and try to compile it

Expected Results:
The code should compile fine

Actual Results:
The swift compiler crashes with Segmentation fault: 11

Version:
Xcode 7.0 (7A218) and 7.1 beta (7B75)

Notes:
Adding an explicit cast of newOperation to ResultOperation<S> (i.e. replacing the method argument "newOperation" in main.swift:22 by "newOperation as! ResultOperation<S>") circumvents the problem. 

I believe the root cause is the same as in rdar://22870249 which takes the same configuration and has the same workarounds but only results in a compiler error and not a segmentation fault

Configuration:
This issue does not occur if ResultOperation is not a generic class

Attachments:
'SampleProject.zip' was successfully uploaded.

This contains the following file:

class ResultOperation<ResultType> {
}

class OperationChain<LastReturnType> {
	func chain<T, O: ResultOperation<T>>(newOperation: O) -> OperationChain<T>? {
		return nil
	}
}

func chain<L, S, U: ResultOperation<S>>(operationChain: OperationChain<L>, newOperation: U) -> OperationChain<S>? {
	let x: OperationChain<L>? = nil
	let a = x?.chain(newOperation)
	return nil
}