Merge pull request ethereum#10744 from ethereum/useDropEx

Use drop_exactly.

libsolidity/analysis/TypeChecker.cpp

@@ -34,12 +34,14 @@
 
 #include <libsolutil/Algorithms.h>
 #include <libsolutil/StringUtils.h>
+#include <libsolutil/Views.h>
 
 #include <boost/algorithm/string/join.hpp>
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/range/adaptor/reversed.hpp>
 
 #include <range/v3/view/zip.hpp>
+#include <range/v3/view/drop_exactly.hpp>
 
 #include <memory>
 #include <vector>
@@ -1001,9 +1003,8 @@ void TypeChecker::endVisit(TryStatement const& _tryStatement)
 	TryCatchClause const* panicClause = nullptr;
 	TryCatchClause const* errorClause = nullptr;
 	TryCatchClause const* lowLevelClause = nullptr;
-	for (size_t i = 1; i < _tryStatement.clauses().size(); ++i)
+	for (auto const& clause: _tryStatement.clauses() | ranges::views::drop_exactly(1) | views::dereferenceChecked)
 	{
-		TryCatchClause const& clause = *_tryStatement.clauses()[i];
 		if (clause.errorName() == "")
 		{
 			if (lowLevelClause)

libsolutil/CMakeLists.txt

@@ -34,6 +34,7 @@ set(sources
 	UTF8.cpp
 	UTF8.h
 	vector_ref.h
+	Views.h
 	Visitor.h
 	Whiskers.cpp
 	Whiskers.h

libsolutil/Views.h

@@ -0,0 +1,39 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+// SPDX-License-Identifier: GPL-3.0
+
+#pragma once
+
+#include <range/v3/view/transform.hpp>
+
+#include <liblangutil/Exceptions.h>
+
+
+namespace solidity::util::views
+{
+
+static constexpr auto dereference = ranges::views::transform([](auto&& x) -> decltype(auto) { return *x; });
+
+static constexpr auto dereferenceChecked = ranges::views::transform(
+	[](auto&& x) -> decltype(auto)
+	{
+		solAssert(x, "");
+		return *x;
+	}
+);
+
+}