xcode shows alert when my table view footer view's subview use masonry to do auotolayout

[beautylim]

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Issue Info

Info	Value
Platform	ios
Platform Version	9.0
Masonry Version	1.0.1
Integration Method	cocoapods

Issue Description

⚠️I init a footer view and have set its frame. The footer view's subview (such as UILabel,UIButton) use masonry to do constrain their left and right margin , but Xcode say i shouldn't set subview's right margin, why? And after i set it's width, everything become ok, but it 's not elegant

footer view init code

_addCashierFooterView = [[MposAddCashierFooterView alloc] initWithFrame:CGRectMake(0, 0, WIDTH_SCREEN, 300.f)];

footer view subview use masonry

[self.noteLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(self).with.offset(5.f);
        make.left.equalTo(self).with.offset(25.f);
        make.right.equalTo(self).with.offset(-25.f);
    }];

    [self.submmitButton mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(self.noteLabel.mas_bottom).with.offset(20.f);
        make.left.equalTo(self).offset(50.f);
        make.right.equalTo(self).offset(-50.f);
        make.height.mas_equalTo(50.f);
    }];

Xcode alert message

2017-03-22 18:02:54.427511 UMSMposI[57173:313304] [LayoutConstraints] 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. 
(
    "<MASLayoutConstraint:0x6000002af2a0 UIButton:0x7f9c63581d70.left == MposAddCashierFooterView:0x7f9c63581500.left + 50>",
    "<MASLayoutConstraint:0x6000002b0140 UIButton:0x7f9c63581d70.right == MposAddCashierFooterView:0x7f9c63581500.right - 50>",
    "<NSLayoutConstraint:0x60800009d6f0 MposAddCashierFooterView:0x7f9c63581500.width == 0>"
)

Will attempt to recover by breaking constraint 
<MASLayoutConstraint:0x6000002b0140 UIButton:0x7f9c63581d70.right == MposAddCashierFooterView:0x7f9c63581500.right - 50>

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.
2017-03-22 18:02:54.430166 UMSMposI[57173:313304] [LayoutConstraints] 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. 
(
    "<MASLayoutConstraint:0x6080002aaaa0 UILabel:0x7f9c63581ae0.left == MposAddCashierFooterView:0x7f9c63581500.left + 25>",
    "<MASLayoutConstraint:0x6080002aaec0 UILabel:0x7f9c63581ae0.right == MposAddCashierFooterView:0x7f9c63581500.right - 25>",
    "<NSLayoutConstraint:0x60800009d6f0 MposAddCashierFooterView:0x7f9c63581500.width == 0>"
)

Will attempt to recover by breaking constraint 
<MASLayoutConstraint:0x6080002aaec0 UILabel:0x7f9c63581ae0.right == MposAddCashierFooterView:0x7f9c63581500.right - 25>

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.

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