Sema: Fix crash when accessing nominal member of protocol

Author: slavapestov

lib/Sema/TypeCheckType.cpp

@@ -3035,16 +3035,22 @@ Type TypeChecker::substMemberTypeWithBase(ModuleDecl *module,
   // The declared interface type for a generic type will have the type
   // arguments; strip them off.
   if (auto *nominalDecl = dyn_cast<NominalTypeDecl>(member)) {
+    // If the base type is not a nominal type, we might be looking up a
+    // nominal member of a generic parameter. This is not supported right
+    // now, but at least don't crash.
+    if (member->getDeclContext()->getAsProtocolOrProtocolExtensionContext())
+      return nominalDecl->getDeclaredType();
+
     if (!isa<ProtocolDecl>(nominalDecl) &&
         nominalDecl->getGenericParams()) {
       return UnboundGenericType::get(
           nominalDecl, baseTy,
           nominalDecl->getASTContext());
-    } else {
-      return NominalType::get(
-          nominalDecl, baseTy,
-          nominalDecl->getASTContext());
     }
+    
+    return NominalType::get(
+        nominalDecl, baseTy,
+        nominalDecl->getASTContext());
   }
 
   auto *aliasDecl = dyn_cast<TypeAliasDecl>(member);

test/decl/nested/protocol.swift

@@ -73,3 +73,9 @@ class OtherGenericClass<T> {
   protocol InnerProtocol : OtherGenericClass { }
   // expected-error@-1{{protocol 'InnerProtocol' cannot be nested inside another declaration}}
 }
+
+protocol SelfDotTest {
+  func f(_: Self.Class)
+  class Class {}
+  // expected-error@-1{{type 'Class' cannot be nested in protocol 'SelfDotTest'}}
+}

validation-test/compiler_crashers/28779-parent-parent-is-nominaltype-parent-is-boundgenerictype-parent-is-unboundgeneric.swift renamed to validation-test/compiler_crashers_fixed/28779-parent-parent-is-nominaltype-parent-is-boundgenerictype-parent-is-unboundgeneric.swift

@@ -5,6 +5,6 @@
 // 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
+
+// RUN: not %target-swift-frontend %s -emit-ir
 protocol P{func a:Self.a.a{}class a{class a

validation-test/compiler_crashers/28849-hasval.swift renamed to validation-test/compiler_crashers_fixed/28849-hasval.swift

@@ -5,8 +5,8 @@
 // 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
+
+// RUN: not %target-swift-frontend %s -emit-ir
 protocol A:P{}
 protocol P{{}typealias a:A
 class a:A