AST: Introduce AnyFunctionType::containsPackExpansionType()

Author: slavapestov

include/swift/AST/Types.h

@@ -3359,6 +3359,8 @@ class AnyFunctionType : public TypeBase {
   /// replaced.
   AnyFunctionType *withExtInfo(ExtInfo info) const;
 
+  static bool containsPackExpansionType(ArrayRef<Param> params);
+
   static void printParams(ArrayRef<Param> Params, raw_ostream &OS,
                           const PrintOptions &PO = PrintOptions());
   static void printParams(ArrayRef<Param> Params, ASTPrinter &Printer,

lib/AST/Type.cpp

@@ -4282,6 +4282,15 @@ bool AnyFunctionType::hasSameExtInfoAs(const AnyFunctionType *otherFn) {
   return getExtInfo().isEqualTo(otherFn->getExtInfo(), useClangTypes(this));
 }
 
+bool AnyFunctionType::containsPackExpansionType(ArrayRef<Param> params) {
+  for (auto param : params) {
+    if (param.getPlainType()->is<PackExpansionType>())
+      return true;
+  }
+
+  return false;
+}
+
 ClangTypeInfo SILFunctionType::getClangTypeInfo() const {
   if (!Bits.SILFunctionType.HasClangTypeInfo)
     return ClangTypeInfo();