presto-main/src/main/java/io/prestosql/metadata/FunctionRegistry.java/FunctionRegistry/isMoreSpecificThan
class FunctionRegistry:    private boolean isMoreSpecificThan(ApplicableFunction left, ApplicableFunction right)
    {
        List<TypeSignatureProvider> resolvedTypes = fromTypeSignatures(left.getBoundSignature().getArgumentTypes());
        Optional<BoundVariables> boundVariables = new SignatureBinder(metadata, right.getDeclaredSignature(), true)
                .bindVariables(resolvedTypes);
        return boundVariables.isPresent();
    }