Merge pull request #10114 from practicalswift/swiftc-28769-conformance-gettypewitness-assoctype-nullptr-isequal-type-conflicting-type-witne

[swiftc (34 vs. 5544)] Add crasher in swift::TypeChecker::resolveWitness

Author: practicalswift

validation-test/compiler_crashers/28769-conformance-gettypewitness-assoctype-nullptr-isequal-type-conflicting-type-witne.swift

@@ -0,0 +1,10 @@
+// This source file is part of the Swift.org open source project
+// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+
+// REQUIRES: asserts
+// RUN: not --crash %target-swift-frontend %s -emit-ir
+protocol P{{}func a{}typealias e}struct A:P{typealias e:Self.a{}typealias e:Self.a{}typealias e:P