[flang] Address review comment

Original-commit: flang-compiler/f18@65dc8d4996
Reviewed-on: https://github.com/flang-compiler/f18/pull/732

flang/lib/semantics/check-declarations.cc

@@ -14,7 +14,10 @@
 
 // Static declaration checking
 
+#include "check-declarations.h"
+#include "scope.h"
 #include "semantics.h"
+#include "symbol.h"
 #include "tools.h"
 
 namespace Fortran::semantics {

flang/lib/semantics/check-declarations.h

@@ -0,0 +1,23 @@
+// Copyright (c) 2019, NVIDIA CORPORATION.  All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Static declaration checks
+
+#ifndef FORTRAN_SEMANTICS_CHECK_DECLARATIONS_H_
+#define FORTRAN_SEMANTICS_CHECK_DECLARATIONS_H_
+namespace Fortran::semantics {
+class SemanticsContext;
+void CheckDeclarations(SemanticsContext &);
+}
+#endif

flang/lib/semantics/semantics.cc

@@ -20,6 +20,7 @@
 #include "check-arithmeticif.h"
 #include "check-coarray.h"
 #include "check-deallocate.h"
+#include "check-declarations.h"
 #include "check-do.h"
 #include "check-if-stmt.h"
 #include "check-io.h"

flang/lib/semantics/semantics.h

@@ -193,8 +193,5 @@ struct BaseChecker {
   template<typename N> void Enter(const N &) {}
   template<typename N> void Leave(const N &) {}
 };
-
-// Static declaration checks
-void CheckDeclarations(SemanticsContext &);
 }
 #endif