Merge pull request #3386 from practicalswift/swiftc-28349-swift-typebase-gatherallsubstitutions

Add 💥 (😢 → 52, 😀 → 5107) in swift::TypeBase::gatherAllSubstitutions(…)

Author: practicalswift

validation-test/compiler_crashers/28349-swift-typebase-gatherallsubstitutions.swift

@@ -0,0 +1,9 @@
+// This source file is part of the Swift.org open source project
+// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+
+// RUN: not --crash %target-swift-frontend %s -parse
+class B}class B<T{class A{class B:A{var a{b}}func b