SIL: Factor out shouldExpandParams() from DestructureInputs

I'm going to need this when emitting reabstraction thunks using
the new function pointer representation.

Author: slavapestov

include/swift/SIL/TypeLowering.h

@@ -64,6 +64,20 @@ inline bool shouldExpandTupleType(TupleType *type) {
   return false;
 }
 
+/// A version of the above for parameter lists.
+///
+/// FIXME: Should also remove this soon.
+inline bool shouldExpandParams(AnyFunctionType::CanParamArrayRef params) {
+  for (auto param : params)
+    if (param.getValueOwnership() != ValueOwnership::Default)
+      return true;
+
+  if (params.size() == 1)
+    return params[0].isVariadic();
+
+  return false;
+}
+
 /// The default convention for handling the callee object on thick
 /// callees.
 const ParameterConvention DefaultThickCalleeConvention =

lib/SIL/SILFunctionType.cpp

@@ -608,13 +608,7 @@ class DestructureInputs {
     // If the abstraction pattern is opaque and the parameter list is a valid
     // target for substitution, implode it into a single tuple parameter.
     if (!hasSelf) {
-      bool canImplode = true;
-      for (auto param : params)
-        canImplode &= (param.getValueOwnership() == ValueOwnership::Default);
-      if (params.size() == 1)
-        canImplode &= !params[0].isVariadic();
-
-      if (canImplode && origType.isTypeParameter()) {
+      if (origType.isTypeParameter() && !shouldExpandParams(params)) {
         CanType ty = AnyFunctionType::composeInput(M.getASTContext(), params,
                                                    /*canonicalVararg*/true)
                                                      ->getCanonicalType();