约束冲突记录

1、如果出现约束冲突（如下提示），检查是不是给错误的视图加了约束：

[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:0x600000e32640 UIImageView:0x7f8155416420.top == UIView:0x7f8155415f60.top>",
    "<MASLayoutConstraint:0x600000e33840 UIImageView:0x7f8155418780.top == UIImageView:0x7f8155416420.bottom + 55>",
    "<MASLayoutConstraint:0x600000e345a0 UIView:0x7f8155415f60.centerY == UIImageView:0x7f8155418780.centerY>",
    "<MASLayoutConstraint:0x600000e34720 UIView:0x7f8155415f60.height == 14>"
)

原代码如下，原本应该给self.nameLabel添加约束，它的父视图是UICollectionViewCell.contentView，结果错误地给其父视图加了约束。

self.nameLabel = [[UILabel alloc] init];
self.nameLabel.font = [UIFont systemFontOfSize:10];
[self.contentView mas_makeConstraints:^(MASConstraintMaker *make) {
    make.left.equalTo(self.avatarImageView.mas_right).offset(6);
    make.right.equalTo(self.coverImageView);
    make.centerY.equalTo(self.avatarImageView);
    make.height.equalTo(@(self.nameLabel.font.lineHeight));
}];