Merge pull request #28012 from zoecarver/fix/optimizer-and-SR-11624

Fix crash when optimizing protocol composition

Author: atrick

lib/SILOptimizer/SILCombiner/SILCombinerApplyVisitors.cpp

@@ -907,7 +907,7 @@ SILCombiner::buildConcreteOpenedExistentialInfoFromSoleConformingType(
         (archetypeTy->getConformsTo().size() == 1)) {
       PD = archetypeTy->getConformsTo()[0];
     } else if (ArgType.isExistentialType() && !ArgType.isAnyObject() &&
-               !SwiftArgType->isAny()) {
+               !SwiftArgType->isAny() && SwiftArgType->getAnyNominal()) {
       PD = dyn_cast<ProtocolDecl>(SwiftArgType->getAnyNominal());
     }
   }

validation-test/compiler_crashers_2_fixed/sr11624.swift

@@ -0,0 +1,20 @@
+// 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
+
+// RUN: not %target-swift-frontend %s -O -whole-module-optimization
+
+class ClassA<T> { }
+protocol ProtocolA { }
+
+class MainClass<H> {
+    init(x: ClassA<H> & ProtocolA) { }
+}
+
+final class ClassB: ClassA<String> { }
+extension ClassB: ProtocolA { }
+
+_ = MainClass(x: ClassB())