Use even more ArrayRefs

No functional change is intended, just a small refactoring.

llvm-svn: 273650
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 6a22f66..ed0a262 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -1019,9 +1019,8 @@
   Record.AddStmt(D->getBody());
   Record.AddTypeSourceInfo(D->getSignatureAsWritten());
   Record.push_back(D->param_size());
-  for (FunctionDecl::param_iterator P = D->param_begin(), PEnd = D->param_end();
-       P != PEnd; ++P)
-    Record.AddDeclRef(*P);
+  for (ParmVarDecl *P : D->parameters())
+    Record.AddDeclRef(P);
   Record.push_back(D->isVariadic());
   Record.push_back(D->blockMissingReturnType());
   Record.push_back(D->isConversionFromLambda());