[AST] Construct iterator_range with the conversion constructor (NFC) (llvm#169004)

This patch simplifies iterator_range construction with the conversion
constructor.

Author: kazutakahirata

clang/include/clang/AST/ExprCXX.h

@@ -978,8 +978,7 @@ class MSPropertyRefExpr : public Expr {
   }
 
   const_child_range children() const {
-    auto Children = const_cast<MSPropertyRefExpr *>(this)->children();
-    return const_child_range(Children.begin(), Children.end());
+    return const_cast<MSPropertyRefExpr *>(this)->children();
   }
 
   static bool classof(const Stmt *T) {
@@ -1741,8 +1740,7 @@ class CXXConstructExpr : public Expr {
   }
 
   const_child_range children() const {
-    auto Children = const_cast<CXXConstructExpr *>(this)->children();
-    return const_child_range(Children.begin(), Children.end());
+    return const_cast<CXXConstructExpr *>(this)->children();
   }
 };
 

clang/include/clang/AST/ExprObjC.h

@@ -247,8 +247,7 @@ class ObjCArrayLiteral final
   }
 
   const_child_range children() const {
-    auto Children = const_cast<ObjCArrayLiteral *>(this)->children();
-    return const_child_range(Children.begin(), Children.end());
+    return const_cast<ObjCArrayLiteral *>(this)->children();
   }
 
   static bool classof(const Stmt *T) {
@@ -394,8 +393,7 @@ class ObjCDictionaryLiteral final
   }
 
   const_child_range children() const {
-    auto Children = const_cast<ObjCDictionaryLiteral *>(this)->children();
-    return const_child_range(Children.begin(), Children.end());
+    return const_cast<ObjCDictionaryLiteral *>(this)->children();
   }
 
   static bool classof(const Stmt *T) {
@@ -790,8 +788,7 @@ class ObjCPropertyRefExpr : public Expr {
   }
 
   const_child_range children() const {
-    auto Children = const_cast<ObjCPropertyRefExpr *>(this)->children();
-    return const_child_range(Children.begin(), Children.end());
+    return const_cast<ObjCPropertyRefExpr *>(this)->children();
   }
 
   static bool classof(const Stmt *T) {

clang/include/clang/AST/OpenACCClause.h

@@ -51,8 +51,7 @@ class OpenACCClause {
 
   child_range children();
   const_child_range children() const {
-    auto Children = const_cast<OpenACCClause *>(this)->children();
-    return const_child_range(Children.begin(), Children.end());
+    return const_cast<OpenACCClause *>(this)->children();
   }
 
   virtual ~OpenACCClause() = default;
@@ -474,8 +473,7 @@ class OpenACCSelfClause final
   }
 
   const_child_range children() const {
-    child_range Children = const_cast<OpenACCSelfClause *>(this)->children();
-    return const_child_range(Children.begin(), Children.end());
+    return const_cast<OpenACCSelfClause *>(this)->children();
   }
 
   static OpenACCSelfClause *Create(const ASTContext &C, SourceLocation BeginLoc,
@@ -523,9 +521,7 @@ class OpenACCClauseWithExprs : public OpenACCClauseWithParams {
   }
 
   const_child_range children() const {
-    child_range Children =
-        const_cast<OpenACCClauseWithExprs *>(this)->children();
-    return const_child_range(Children.begin(), Children.end());
+    return const_cast<OpenACCClauseWithExprs *>(this)->children();
   }
 };