[ConstraintSystem] Make binding producer responsible for attemping Any last

Instead of doing that while collecting bindings, let's move `Any`
to the end of the list when type variable has been selected to be
attempted next.

Author: xedin

lib/Sema/CSBindings.cpp

@@ -566,21 +566,6 @@ void ConstraintSystem::PotentialBindings::finalize(
 
     addPotentialBinding(PotentialBinding::forHole(TypeVar, locator));
   }
-
-  // Let's always consider `Any` to be a last resort binding because
-  // it's always better to infer concrete type and erase it if required
-  // by the context.
-  if (Bindings.size() > 1) {
-    auto AnyTypePos =
-        llvm::find_if(Bindings, [](const PotentialBinding &binding) {
-          return binding.BindingType->isAny() &&
-                 !binding.isDefaultableBinding();
-        });
-
-    if (AnyTypePos != Bindings.end()) {
-      std::rotate(AnyTypePos, AnyTypePos + 1, Bindings.end());
-    }
-  }
 }
 
 Optional<ConstraintSystem::PotentialBindings>

lib/Sema/ConstraintSystem.cpp

@@ -5366,14 +5366,30 @@ TypeVarBindingProducer::TypeVarBindingProducer(
         return false;
       };
 
+  // A binding to `Any` which should always be considered as a last resort.
+  Optional<Binding> Any;
+
   for (const auto &binding : bindings.Bindings) {
+    auto type = binding.BindingType;
+
+    if (!CanBeNil && type->isAny()) {
+      Any.emplace(binding);
+      continue;
+    }
+
     // Adjust optionality of existing bindings based on presence of
     // `ExpressibleByNilLiteral` requirement.
     if (CanBeNil && requiresOptionalAdjustment(binding)) {
-      Bindings.push_back(
-          binding.withType(OptionalType::get(binding.BindingType)));
+      Bindings.push_back(binding.withType(OptionalType::get(type)));
     } else {
       Bindings.push_back(binding);
     }
   }
+
+  // Let's always consider `Any` to be a last resort binding because
+  // it's always better to infer concrete type and erase it if required
+  // by the context.
+  if (Any) {
+    Bindings.push_back(*Any);
+  }
 }