Swiftのビューにプログラムで制約を追加するとエラーが発生する

Swiftのビューにプログラムで制約を追加すると、同時に満たすことができない競合する制約があることを示すエラーがログに表示されますが、UIは、シミュレーターを実行するときに意図したとおりに表示されます。スクリーンショットで。左ボタンの前縁はセグメント化されたコントロールの前縁と位置合わせされ、右ボタンの後縁はセグメント化されたコントロールの後縁と位置合わせされます。

これらの制約が問題を引き起こしていると思います。これらの2つをコメントアウトすると、エラーがスローされるのを防ぐことができますが、UIが意図したとおりに表示されません。

誰かが私が間違ったことを理解するのを手伝ってくれませんか？

Conversion View Controller loaded
2016-07-29 22:51:34.555 WorldTrotter[800:41503] Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want. 
Try this: 
    (1) look at each constraint and try to figure out which you don't expect; 
    (2) find the code that added the unwanted constraint or constraints and fix it. 
(
"<NSLayoutConstraint:0x7fd836313550 UIButton:0x7fd836312e60'Current Location'.left == UILayoutGuide:0x7fd83630fc20'UIViewLayoutMarginsGuide'.left>",
"<NSLayoutConstraint:0x7fd836313660 UIButton:0x7fd836312e60'Current Location'.trailing == UILayoutGuide:0x7fd83630fc20'UIViewLayoutMarginsGuide'.centerX - 8>",
"<NSLayoutConstraint:0x7fd836318800 'UIView-Encapsulated-Layout-Width' H:[MKMapView:0x7fd83351d900(0)]>",
"<NSLayoutConstraint:0x7fd836312e00 'UIView-leftMargin-guide-constraint' H:|-(0)-[UILayoutGuide:0x7fd83630fc20'UIViewLayoutMarginsGuide'](LTR)   (Names: '|':MKMapView:0x7fd83351d900 )>",
"<NSLayoutConstraint:0x7fd833794d30 'UIView-rightMargin-guide-constraint' H:[UILayoutGuide:0x7fd83630fc20'UIViewLayoutMarginsGuide']-(0)-|(LTR)   (Names: '|':MKMapView:0x7fd83351d900 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x7fd836313660 UIButton:0x7fd836312e60'Current Location'.trailing == UILayoutGuide:0x7fd83630fc20'UIViewLayoutMarginsGuide'.centerX - 8>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
2016-07-29 22:51:34.556 WorldTrotter[800:41503] Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want. 
Try this: 
    (1) look at each constraint and try to figure out which you don't expect; 
    (2) find the code that added the unwanted constraint or constraints and fix it. 
(
"<NSLayoutConstraint:0x7fd836313ee0 UIButton:0x7fd8363136b0'Next Pin'.leading == UILayoutGuide:0x7fd83630fc20'UIViewLayoutMarginsGuide'.centerX + 8>",
"<NSLayoutConstraint:0x7fd836313fb0 UIButton:0x7fd8363136b0'Next Pin'.trailing == UILayoutGuide:0x7fd83630fc20'UIViewLayoutMarginsGuide'.trailing>",
"<NSLayoutConstraint:0x7fd836318800 'UIView-Encapsulated-Layout-Width' H:[MKMapView:0x7fd83351d900(0)]>",
"<NSLayoutConstraint:0x7fd836312e00 'UIView-leftMargin-guide-constraint' H:|-(0)-[UILayoutGuide:0x7fd83630fc20'UIViewLayoutMarginsGuide'](LTR)   (Names: '|':MKMapView:0x7fd83351d900 )>",
"<NSLayoutConstraint:0x7fd833794d30 'UIView-rightMargin-guide-constraint' H:[UILayoutGuide:0x7fd83630fc20'UIViewLayoutMarginsGuide']-(0)-|(LTR)   (Names: '|':MKMapView:0x7fd83351d900 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x7fd836313fb0 UIButton:0x7fd8363136b0'Next Pin'.trailing == UILayoutGuide:0x7fd83630fc20'UIViewLayoutMarginsGuide'.trailing>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.

import UIKit
import MapKit

class MapViewController: UIViewController, MKMapViewDelegate {

var mapView: MKMapView!
let locationManager = CLLocationManager()
var coordinates: [CLLocationCoordinate2D] = []
var counter: Int = 0

override func loadView() {
    mapView = MKMapView()
    mapView.delegate = self
    view = mapView


    //Adding pins to map
    let firstLocation = CLLocationCoordinate2DMake(5.000000, -5.000000)
    let secondLocation = CLLocationCoordinate2DMake(-5.000000, 5.000000)
    coordinates.append(firstLocation)
    coordinates.append(secondLocation)



    let segmentedControl = UISegmentedControl(items: ["Standard", "Hybrid", "Satellite"])
    segmentedControl.backgroundColor = UIColor.whiteColor().colorWithAlphaComponent(0.5)
    segmentedControl.selectedSegmentIndex = 0
    segmentedControl.translatesAutoresizingMaskIntoConstraints = false

    segmentedControl.addTarget(self, action: #selector(MapViewController.mapTypeChanged(_:)), forControlEvents: .ValueChanged)

    view.addSubview(segmentedControl)

    let margins = view.layoutMarginsGuide

    let topConstraint = segmentedControl.topAnchor.constraintEqualToAnchor(topLayoutGuide.bottomAnchor, constant: 8)

    let leadingConstraint = segmentedControl.leadingAnchor.constraintEqualToAnchor(margins.leadingAnchor)


    let trailingConstraint = segmentedControl.trailingAnchor.constraintEqualToAnchor(margins.trailingAnchor)
    topConstraint.active = true
    leadingConstraint.active = true
    trailingConstraint.active = true

    let userButton = UIButton()
    view.addSubview(userButton)
    userButton.translatesAutoresizingMaskIntoConstraints = false
    userButton.addTarget(self, action: #selector(MapViewController.userButtonSelected(_:)), forControlEvents: UIControlEvents.TouchUpInside)
    userButton.setTitle("Current Location", forState: .Normal)
    userButton.backgroundColor = UIColor.blueColor().colorWithAlphaComponent(0.7)


    let bTopConstraint = userButton.topAnchor.constraintEqualToAnchor(segmentedControl.bottomAnchor, constant: 8)

    //Problematic constraint I think
    let bLConstraint = userButton.leftAnchor.constraintEqualToAnchor(margins.leftAnchor)

    let bTConstraint = userButton.trailingAnchor.constraintEqualToAnchor(margins.centerXAnchor, constant: -8)
    bTopConstraint.active = true
    bLConstraint.active = true
    bTConstraint.active = true

    let pinsButton = UIButton()
    view.addSubview(pinsButton)
    pinsButton.translatesAutoresizingMaskIntoConstraints = false
    pinsButton.addTarget(self, action: #selector(MapViewController.pinsButtonSelected(_:)), forControlEvents: UIControlEvents.TouchUpInside)
    pinsButton.setTitle("Next Pin", forState: .Normal)
    pinsButton.backgroundColor = UIColor.blueColor().colorWithAlphaComponent(0.7)

    let pTopConstraint = pinsButton.topAnchor.constraintEqualToAnchor(segmentedControl.bottomAnchor, constant: 8)

    //Problematic constraint I think
    let pLConstraint = pinsButton.leadingAnchor.constraintEqualToAnchor(margins.centerXAnchor, constant: 8)

    let pTConstraint = pinsButton.trailingAnchor.constraintEqualToAnchor(margins.trailingAnchor)
    pTopConstraint.active = true
    pLConstraint.active = true
    pTConstraint.active = true

}

func mapTypeChanged(segControl: UISegmentedControl) {
    switch segControl.selectedSegmentIndex {
    case 0:
        mapView.mapType = .Standard
    case 1:
        mapView.mapType = .Hybrid
    case 2:
        mapView.mapType = .Satellite
    default:
        break
    }

}

override func viewDidLoad() {
    super.viewDidLoad()
}

func userButtonSelected(button: UIButton) {
    if mapView.showsUserLocation == false {
        mapView.showsUserLocation = true
    } else {
        mapView.showsUserLocation = false
    }
}

func pinsButtonSelected(button: UIButton) {
    if counter >= coordinates.count {
        counter = 0
    }
    let dropPin = MKPointAnnotation()
    dropPin.coordinate = coordinates[counter]
    counter += 1
    mapView.addAnnotation(dropPin)
    mapView.setCenterCoordinate(dropPin.coordinate, animated: false)
}

func mapViewWillStartLocatingUser(mapView: MKMapView) {
    // Ask for Authorisation from the User.
    self.locationManager.requestAlwaysAuthorization()

    // For use in foreground
    self.locationManager.requestWhenInUseAuthorization()
    if CLLocationManager.locationServicesEnabled() {
        locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters
        locationManager.startUpdatingLocation()
    }

    mapView.setUserTrackingMode(MKUserTrackingMode.Follow, animated: true)
    print("Tracking user")
}

}