Source:
<code>public Optional<ScalarFunctionImplementation> specialize(Signature boundSignature, BoundVariables boundVariables, TypeManager typeManager, FunctionRegistry functionRegistry, boolean isDeterministic) { List<ScalarImplementationChoice> implementationChoices = new ArrayList<>(); for (Map.Entry<String, Class<?>> entry : specializedTypeParameters.entrySet()) { if (!entry.getValue().isAssignableFrom(boundVariables.getTypeVariable(entry.getKey()).getJavaType())) { return Optional.empty(); } } if (returnNativeContainerType != Object.class && !returnNativeContainerType.equals(typeManager.getType(boundSignature.getReturnType()).getJavaType())) { return Optional.empty(); } for (int i = 0; i < boundSignature.getArgumentTypes().size(); i++) { if (boundSignature.getArgumentTypes().get(i).getBase().equals(FunctionType.NAME)) { if (argumentNativeContainerTypes.get(i).isPresent()) { return Optional.empty(); } } else { if (!argumentNativeContainerTypes.get(i).isPresent()) { return Optional.empty(); } Class<?> argumentType = typeManager.getType(boundSignature.getArgumentTypes().get(i)).getJavaType(); Class<?> argumentNativeContainerType = argumentNativeContainerTypes.get(i).get(); if (argumentNativeContainerType != Object.class && !argumentNativeContainerType.isAssignableFrom(argumentType)) { return Optional.empty(); } } } for (ParametricScalarImplementationChoice choice : choices) { MethodHandle boundMethodHandle = bindDependencies(choice.getMethodHandle(), choice.getDependencies(), boundVariables, typeManager, functionRegistry); Optional<MethodHandle> boundConstructor = choice.getConstructor().map(constructor -> { MethodHandle result = bindDependencies(constructor, choice.getConstructorDependencies(), boundVariables, typeManager, functionRegistry); checkCondition( <START> result.type().parameterList().isEmpty(), <END> FUNCTION_IMPLEMENTATION_ERROR, "All parameters of a constructor in a function definition class must be Dependencies. Signature: %s", boundSignature); return result; }); implementationChoices.add(new ScalarImplementationChoice( choice.nullable, choice.argumentProperties, boundMethodHandle.asType(javaMethodType(choice, boundSignature, typeManager)), boundConstructor)); } return Optional.of(new ScalarFunctionImplementation(implementationChoices, isDeterministic)); }</code><technical_language>I assume changes a separate refactor commit</technical_language>

Target:
public Optional<ScalarFunctionImplementation> specialize(Signature boundSignature, BoundVariables boundVariables, TypeManager typeManager, FunctionRegistry functionRegistry, boolean isDeterministic) { List<ScalarImplementationChoice> implementationChoices = new ArrayList<>(); for (Map.Entry<String, Class<?>> entry : specializedTypeParameters.entrySet()) { if (entry.getValue() != boundVariables.getTypeVariable(entry.getKey()).getJavaType()) { return Optional.empty(); } } if (returnNativeContainerType != Object.class && returnNativeContainerType != typeManager.getType(boundSignature.getReturnType()).getJavaType()) { return Optional.empty(); } for (int i = 0; i < boundSignature.getArgumentTypes().size(); i++) { if (boundSignature.getArgumentTypes().get(i).getBase().equals(FunctionType.NAME)) { if (argumentNativeContainerTypes.get(i).isPresent()) { return Optional.empty(); } } else { if (!argumentNativeContainerTypes.get(i).isPresent()) { return Optional.empty(); } Class<?> argumentType = typeManager.getType(boundSignature.getArgumentTypes().get(i)).getJavaType(); Class<?> argumentNativeContainerType = argumentNativeContainerTypes.get(i).get(); if (argumentNativeContainerType != Object.class && argumentNativeContainerType != argumentType) { return Optional.empty(); } } } for (ParametricScalarImplementationChoice choice : choices) { MethodHandle boundMethodHandle = bindDependencies(choice.getMethodHandle(), choice.getDependencies(), boundVariables, typeManager, functionRegistry); Optional<MethodHandle> boundConstructor = choice.getConstructor().map(constructor -> { MethodHandle result = bindDependencies(constructor, choice.getConstructorDependencies(), boundVariables, typeManager, functionRegistry); checkCondition( result.type().parameterList().isEmpty(), FUNCTION_IMPLEMENTATION_ERROR, "All parameters of a constructor in a function definition class must be Dependencies. Signature: %s", boundSignature); return result; }); implementationChoices.add(new ScalarImplementationChoice( choice.nullable, choice.argumentProperties, boundMethodHandle.asType(javaMethodType(choice, boundSignature, typeManager)), boundConstructor)); } return Optional.of(new ScalarFunctionImplementation(implementationChoices, isDeterministic)); }