Segfault if use Self.typealias from protocol

protocol P {
    associatedtype AT
    typealias T = UnsafePointer<AT>
    
    var a: T { get }
}
public struct S<AT>: P {
    // var a: Self.T // ok
    var a: Self.T { fatalError() }
    let b: UnsafePointer<T>
}

xCode 11.4. Apple Swift version 5.2 (swiftlang-1103.0.32.1 clang-1103.0.32.29)

Error from Apple Swift version 5.2-dev (LLVM 26ec4a6878, Swift 6adc3e6258):

Assertion failed: (GenericSig && "Dependent type in pattern without generic signature?"), function requiresClass, file /Users/buildnode/jenkins/workspace/oss-swift-package-osx/swift/lib/SIL/AbstractionPattern.cpp, line 231.

Do you mind filing a bug on bugs.swift.org?

Done