Add skeleton for contract level checker.

libsolidity/CMakeLists.txt

@@ -1,6 +1,7 @@
 # Until we have a clear separation, libyul has to be included here
 set(sources
 	analysis/ConstantEvaluator.cpp
+	analysis/ContractLevelChecker.cpp
 	analysis/ControlFlowAnalyzer.cpp
 	analysis/ControlFlowBuilder.cpp
 	analysis/ControlFlowGraph.cpp

libsolidity/analysis/ContractLevelChecker.cpp

@@ -0,0 +1,37 @@
+/*
+	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/>.
+*/
+/**
+ * Component that verifies overloads, abstract contracts, function clashes and others
+ * checks at contract or function level.
+ */
+
+#include <libsolidity/analysis/ContractLevelChecker.h>
+#include <libsolidity/ast/AST.h>
+
+#include <liblangutil/ErrorReporter.h>
+
+
+using namespace std;
+using namespace dev;
+using namespace langutil;
+using namespace dev::solidity;
+
+
+bool ContractLevelChecker::check(ContractDefinition const&)
+{
+	return Error::containsOnlyWarnings(m_errorReporter.errors());
+}

libsolidity/analysis/ContractLevelChecker.h

@@ -0,0 +1,59 @@
+/*
+	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/>.
+*/
+/**
+ * Component that verifies overloads, abstract contracts, function clashes and others
+ * checks at contract or function level.
+ */
+
+#pragma once
+
+#include <libsolidity/ast/ASTForward.h>
+
+#include <map>
+
+namespace langutil
+{
+class ErrorReporter;
+}
+
+namespace dev
+{
+namespace solidity
+{
+
+/**
+ * Component that verifies overloads, abstract contracts, function clashes and others
+ * checks at contract or function level.
+ */
+class ContractLevelChecker
+{
+public:
+	/// @param _errorReporter provides the error logging functionality.
+	explicit ContractLevelChecker(langutil::ErrorReporter& _errorReporter):
+		m_errorReporter(_errorReporter)
+	{}
+
+	/// Performs checks on the given contract.
+	/// @returns true iff all checks passed. Note even if all checks passed, errors() can still contain warnings
+	bool check(ContractDefinition const& _contract);
+
+private:
+	langutil::ErrorReporter& m_errorReporter;
+};
+
+}
+}

libsolidity/interface/CompilerStack.cpp

@@ -28,6 +28,7 @@
 #include <libsolidity/analysis/SemVerHandler.h>
 #include <libsolidity/ast/AST.h>
 #include <libsolidity/parsing/Parser.h>
+#include <libsolidity/analysis/ContractLevelChecker.h>
 #include <libsolidity/analysis/ControlFlowAnalyzer.h>
 #include <libsolidity/analysis/ControlFlowGraph.h>
 #include <libsolidity/analysis/GlobalContext.h>
@@ -225,8 +226,21 @@ bool CompilerStack::analyze()
 						m_contracts[contract->fullyQualifiedName()].contract = contract;
 				}
 
-		// This cannot be done in the above loop, because cross-contract types couldn't be resolved.
+		// Next, we check inheritance, overrides, function collisions and other things at
-		// A good example is `LibraryName.TypeName x;`.
+		// contract or function level.
+		// This also calculates whether a contract is abstract, which is needed by the
+		// type checker.
+		ContractLevelChecker contractLevelChecker(m_errorReporter);
+		for (Source const* source: m_sourceOrder)
+			for (ASTPointer<ASTNode> const& node: source->ast->nodes())
+				if (ContractDefinition* contract = dynamic_cast<ContractDefinition*>(node.get()))
+					if (!contractLevelChecker.check(*contract))
+						noErrors = false;
+
+		// New we run full type checks that go down to the expression level. This
+		// cannot be done earlier, because we need cross-contract types and information
+		// about whether a contract is abstract for the `new` expression.
+		// This populates the `type` annotation for all expressions.
 		//
 		// Note: this does not resolve overloaded functions. In order to do that, types of arguments are needed,
 		// which is only done one step later.