diff --git a/libyul/AsmScopeFiller.cpp b/libyul/AsmScopeFiller.cpp
index 3a8e548b8..4c37bf5ec 100644
--- a/libyul/AsmScopeFiller.cpp
+++ b/libyul/AsmScopeFiller.cpp
@@ -151,13 +151,13 @@ bool ScopeFiller::registerVariable(TypedName const& _name, SourceLocation const&
 
 bool ScopeFiller::registerFunction(FunctionDefinition const& _funDef)
 {
-	vector<Scope::YulType> arguments;
-	for (auto const& _argument: _funDef.parameters)
-		arguments.emplace_back(_argument.type.str());
+	vector<Scope::YulType> parameters;
+	for (auto const& parameter: _funDef.parameters)
+		parameters.emplace_back(parameter.type);
 	vector<Scope::YulType> returns;
-	for (auto const& _return: _funDef.returnVariables)
-		returns.emplace_back(_return.type.str());
-	if (!m_currentScope->registerFunction(_funDef.name, std::move(arguments), std::move(returns)))
+	for (auto const& returnVariable: _funDef.returnVariables)
+		returns.emplace_back(returnVariable.type);
+	if (!m_currentScope->registerFunction(_funDef.name, std::move(parameters), std::move(returns)))
 	{
 		//@TODO secondary location
 		m_errorReporter.declarationError(
diff --git a/libyul/backends/evm/EVMDialect.cpp b/libyul/backends/evm/EVMDialect.cpp
index 3274f440f..39fc65632 100644
--- a/libyul/backends/evm/EVMDialect.cpp
+++ b/libyul/backends/evm/EVMDialect.cpp
@@ -221,6 +221,15 @@ EVMDialectTyped::EVMDialectTyped(langutil::EVMVersion _evmVersion, bool _objectA
 	boolType = "bool"_yulstring;
 	types = {defaultType, boolType};
 
+	// Set all types to ``defaultType``
+	for (auto& fun: m_functions)
+	{
+		for (auto& p: fun.second.parameters)
+			p = defaultType;
+		for (auto& r: fun.second.returns)
+			r = defaultType;
+	}
+
 	m_functions["lt"_yulstring].returns = {"bool"_yulstring};
 	m_functions["gt"_yulstring].returns = {"bool"_yulstring};
 	m_functions["slt"_yulstring].returns = {"bool"_yulstring};
@@ -260,6 +269,7 @@ EVMDialectTyped::EVMDialectTyped(langutil::EVMVersion _evmVersion, bool _objectA
 		_visitArguments();
 	}));
 	m_functions["bool_to_u256"_yulstring].parameters = {"bool"_yulstring};
+	m_functions["bool_to_u256"_yulstring].returns = {"u256"_yulstring};
 	m_functions.insert(createFunction("u256_to_bool", 1, 1, {}, false, [](
 		FunctionCall const&,
 		AbstractAssembly& _assembly,
@@ -276,6 +286,7 @@ EVMDialectTyped::EVMDialectTyped(langutil::EVMVersion _evmVersion, bool _objectA
 		_assembly.appendInstruction(evmasm::Instruction::INVALID);
 		_assembly.appendLabel(inRange);
 	}));
+	m_functions["u256_to_bool"_yulstring].parameters = {"u256"_yulstring};
 	m_functions["u256_to_bool"_yulstring].returns = {"bool"_yulstring};
 }