[NFC] non-null assertion for inheritsFrom

Author: kavon

lib/AST/Decl.cpp

@@ -6558,6 +6558,8 @@ bool ProtocolDecl::walkInheritedProtocols(
 }
 
 bool ProtocolDecl::inheritsFrom(const ProtocolDecl *super) const {
+  assert(super);
+
   if (this == super)
     return false;
 

lib/Sema/TypeCheckConcurrency.cpp

@@ -165,6 +165,9 @@ bool IsActorRequest::evaluate(
   if (auto protocol = dyn_cast<ProtocolDecl>(nominal)) {
     auto &ctx = protocol->getASTContext();
     auto *actorProtocol = ctx.getProtocol(KnownProtocolKind::Actor);
+    if (!actorProtocol)
+      return false;
+
     return (protocol == actorProtocol ||
             protocol->inheritsFrom(actorProtocol));
   }

lib/Sema/TypeCheckDistributed.cpp

@@ -188,6 +188,9 @@ bool IsDistributedActorRequest::evaluate(
   if (auto protocol = dyn_cast<ProtocolDecl>(nominal)) {
     auto &ctx = protocol->getASTContext();
     auto *distributedActorProtocol = ctx.getDistributedActorDecl();
+    if (!distributedActorProtocol)
+      return false;
+
     return (protocol == distributedActorProtocol ||
             protocol->inheritsFrom(distributedActorProtocol));
   }