NCGenerics: improve assertion messages

Author: kavon

lib/AST/Decl.cpp

@@ -4897,7 +4897,7 @@ InverseMarking TypeDecl::getMarking(InvertibleProtocolKind ip) const {
 static TypeDecl::CanBeInvertible::Result
 conformanceExists(TypeDecl const *decl, InvertibleProtocolKind ip) {
   auto *proto = decl->getASTContext().getProtocol(getKnownProtocolKind(ip));
-  assert(proto);
+  assert(proto && "missing Copyable/Escapable from stdlib!");
 
   // Handle protocols specially, without building a GenericSignature.
   if (auto *protoDecl = dyn_cast<ProtocolDecl>(decl))

lib/AST/Requirement.cpp

@@ -358,8 +358,7 @@ void InverseRequirement::expandDefaults(
     auto protos = InverseRequirement::expandDefault(gp);
     for (auto ip : protos) {
       auto proto = ctx.getProtocol(getKnownProtocolKind(ip));
-      if (!proto)
-        llvm_unreachable("failed to load Copyable/Escapable/etc from stdlib!");
+      assert(proto && "missing Copyable/Escapable from stdlib!");
 
       auto protoTy = proto->getDeclaredInterfaceType();
       result.push_back({{RequirementKind::Conformance, gp, protoTy},

lib/AST/Type.cpp

@@ -388,7 +388,7 @@ static void expandDefaultProtocols(
       continue;
 
     auto proto = ctx.getProtocol(getKnownProtocolKind(ip));
-    assert(proto);
+    assert(proto && "missing Copyable/Escapable from stdlib!");
 
     protocols.push_back(proto);
   }

lib/Sema/TypeCheckInvertible.cpp

@@ -161,8 +161,8 @@ static void tryEmitContainmentFixits(InFlightDiagnostic &&diag,
 static bool conformsToInvertible(CanType type, InvertibleProtocolKind ip) {
   auto &ctx = type->getASTContext();
 
-  auto *invertible = ctx.getProtocol(getKnownProtocolKind(ip));
-  assert(invertible && "failed to load Copyable/Escapable from stdlib!");
+  auto *proto = ctx.getProtocol(getKnownProtocolKind(ip));
+  assert(proto && "missing Copyable/Escapable from stdlib!");
 
   // Must not have a type parameter!
   assert(!type->hasTypeParameter() && "caller forgot to mapTypeIntoContext!");
@@ -177,8 +177,8 @@ static bool conformsToInvertible(CanType type, InvertibleProtocolKind ip) {
                     SILTokenType>()));
 
   const bool conforms =
-      (bool) invertible->getParentModule()->checkConformance(
-          type, invertible,
+      (bool) proto->getParentModule()->checkConformance(
+          type, proto,
           /*allowMissing=*/false);
 
   return conforms;