Extend using-for.

libsolidity/analysis/DeclarationTypeChecker.cpp

@@ -25,6 +25,7 @@
 #include <liblangutil/ErrorReporter.h>
 
 #include <libsolutil/Algorithms.h>
+#include <libsolutil/Visitor.h>
 
 #include <range/v3/view/transform.hpp>
 
@@ -451,12 +452,39 @@ void DeclarationTypeChecker::endVisit(VariableDeclaration const& _variable)
 
 bool DeclarationTypeChecker::visit(UsingForDirective const& _usingFor)
 {
-	ContractDefinition const* library = dynamic_cast<ContractDefinition const*>(
-		_usingFor.libraryName().annotation().referencedDeclaration
-	);
+	if (_usingFor.usesBraces())
+	{
+		for (ASTPointer<IdentifierPath> const& function: _usingFor.functionsOrLibrary())
+			if (auto functionDefinition = dynamic_cast<FunctionDefinition const*>(function->annotation().referencedDeclaration))
+			{
+				if (!functionDefinition->isFree() && !(
+					dynamic_cast<ContractDefinition const*>(functionDefinition->scope()) &&
+					dynamic_cast<ContractDefinition const*>(functionDefinition->scope())->isLibrary()
+				))
+					m_errorReporter.typeError(
+						4167_error,
+						function->location(),
+						"Only file-level functions and library functions can be bound to a type in a \"using\" statement"
+					);
+			}
+			else
+				m_errorReporter.fatalTypeError(8187_error, function->location(), "Expected function name." );
+	}
+	else
+	{
+		ContractDefinition const* library = dynamic_cast<ContractDefinition const*>(
+			_usingFor.functionsOrLibrary().front()->annotation().referencedDeclaration
+		);
+		if (!library || !library->isLibrary())
+			m_errorReporter.fatalTypeError(
+				4357_error,
+				_usingFor.functionsOrLibrary().front()->location(),
+				"Library name expected. If you want to attach a function, use '{...}'."
+			);
+	}
 
-	if (!library || !library->isLibrary())
-		m_errorReporter.fatalTypeError(4357_error, _usingFor.libraryName().location(), "Library name expected.");
+	// We do not visit _usingFor.functions() because it will lead to an error since
+	// library names cannot be mentioned stand-alone.
 
 	if (_usingFor.typeName())
 		_usingFor.typeName()->accept(*this);

libsolidity/analysis/SyntaxChecker.cpp

@@ -403,6 +403,30 @@ void SyntaxChecker::endVisit(ContractDefinition const&)
 	m_currentContractKind = std::nullopt;
 }
 
+bool SyntaxChecker::visit(UsingForDirective const& _usingFor)
+{
+	if (!m_currentContractKind && !_usingFor.typeName())
+		m_errorReporter.syntaxError(
+			8118_error,
+			_usingFor.location(),
+			"The type has to be specified explicitly at file level (cannot use '*')."
+		);
+	else if (_usingFor.usesBraces() && !_usingFor.typeName())
+		m_errorReporter.syntaxError(
+			3349_error,
+			_usingFor.location(),
+			"The type has to be specified explicitly when attaching specific functions."
+		);
+	if (m_currentContractKind == ContractKind::Interface)
+		m_errorReporter.syntaxError(
+			9088_error,
+			_usingFor.location(),
+			"The \"using for\" directive is not allowed inside interfaces."
+		);
+
+	return true;
+}
+
 bool SyntaxChecker::visit(FunctionDefinition const& _function)
 {
 	solAssert(_function.isFree() == (m_currentContractKind == std::nullopt), "");

libsolidity/analysis/SyntaxChecker.h

@@ -88,6 +88,9 @@ private:
 
 	bool visit(ContractDefinition const& _contract) override;
 	void endVisit(ContractDefinition const& _contract) override;
+
+	bool visit(UsingForDirective const& _usingFor) override;
+
 	bool visit(FunctionDefinition const& _function) override;
 	bool visit(FunctionTypeName const& _node) override;
 

libsolidity/analysis/TypeChecker.cpp

@@ -35,6 +35,7 @@
 #include <libsolutil/Algorithms.h>
 #include <libsolutil/StringUtils.h>
 #include <libsolutil/Views.h>
+#include <libsolutil/Visitor.h>
 
 #include <boost/algorithm/string/join.hpp>
 #include <boost/algorithm/string/predicate.hpp>
@@ -3626,12 +3627,67 @@ void TypeChecker::endVisit(Literal const& _literal)
 
 void TypeChecker::endVisit(UsingForDirective const& _usingFor)
 {
-	if (m_currentContract->isInterface())
-		m_errorReporter.typeError(
-			9088_error,
-			_usingFor.location(),
-			"The \"using for\" directive is not allowed inside interfaces."
+	if (!_usingFor.usesBraces())
+	{
+		solAssert(_usingFor.functionsOrLibrary().size() == 1);
+		ContractDefinition const* library = dynamic_cast<ContractDefinition const*>(
+				_usingFor.functionsOrLibrary().front()->annotation().referencedDeclaration
 		);
+		solAssert(library && library->isLibrary());
+		// No type checking for libraries
+		return;
+	}
+
+	if (!_usingFor.typeName())
+	{
+		solAssert(m_errorReporter.hasErrors());
+		return;
+	}
+
+	solAssert(_usingFor.typeName()->annotation().type);
+	Type const* normalizedType = TypeProvider::withLocationIfReference(
+		DataLocation::Storage,
+		_usingFor.typeName()->annotation().type
+	);
+	solAssert(normalizedType);
+
+	for (ASTPointer<IdentifierPath> const& path: _usingFor.functionsOrLibrary())
+	{
+		solAssert(path->annotation().referencedDeclaration);
+		FunctionDefinition const& functionDefinition =
+			dynamic_cast<FunctionDefinition const&>(*path->annotation().referencedDeclaration);
+
+		solAssert(functionDefinition.type());
+
+		if (functionDefinition.parameters().empty())
+			m_errorReporter.fatalTypeError(
+				4731_error,
+				path->location(),
+				"The function \"" + joinHumanReadable(path->path(), ".") + "\" " +
+				"does not have any parameters, and therefore cannot be bound to the type \"" +
+				(normalizedType ? normalizedType->toString(true) : "*") + "\"."
+			);
+
+		FunctionType const* functionType = dynamic_cast<FunctionType const&>(*functionDefinition.type()).asBoundFunction();
+		solAssert(functionType && functionType->selfType(), "");
+		BoolResult result = normalizedType->isImplicitlyConvertibleTo(
+			*TypeProvider::withLocationIfReference(DataLocation::Storage, functionType->selfType())
+		);
+		if (!result)
+			m_errorReporter.typeError(
+				3100_error,
+				path->location(),
+				"The function \"" + joinHumanReadable(path->path(), ".") + "\" "+
+				"cannot be bound to the type \"" + _usingFor.typeName()->annotation().type->toString() +
+				"\" because the type cannot be implicitly converted to the first argument" +
+				" of the function (\"" + functionType->selfType()->toString() + "\")" +
+				(
+					result.message().empty() ?
+					"." :
+					": " +  result.message()
+				)
+			);
+	}
 }
 
 void TypeChecker::checkErrorAndEventParameters(CallableDeclaration const& _callable)