- 首先看一个常见的警告
-Wunguarded-availability-new
- 在Build Setting 里的
OTHER_CFLAGS添加-Werror=unguarded-availability-new，
- 注意是以
-Werror=开头
- 再编译看是否能变Error
参考链接
常见的警告
（1）-Wunguarded-availability（在工程中设置了忽略）
警告提示：warning: 'setResumingHandler:' is only available on iOS 9.0 or newer [-Wunguarded-availability]
警告原因：使用了支持的所有iOS版本不兼容的api时会发出警告
（2）-Wunknown-warning-option
警告提示：warning: unknown warning group '-Wreceiver-is-weak', ignored [-Wunknown-warning-option]
警告原因：使用了-Wreceiver-is-weak警告选项
（3）-Wstrict-prototypes（在工程中设置了忽略）
警告提示：warning: this block declaration is not a prototype [-Wstrict-prototypes] 或者 warning: this function declaration is not a prototype [-Wstrict-prototypes]
警告原因：在block或者函数定义，参数为空没写void时会发出警告；这个设置忽略的原因是因为，block的参数为空写为（）时，可以接受数量不定的参数，有些第三库是故意这样写的。
（4）-Wsometimes-uninitialized
警告提示：warning: variable 'overshootPoint' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
警告原因：变量在某些情况下可能未被初始化时发出警告
（5）-Wobjc-protocol-method-implementation
警告提示：warning: category is implementing a method which will also be implemented by its primary class [-Wobjc-protocol-method-implementation]
警告原因：在类别中重写原类方法时发出警告
（6）-Wobjc-literal-conversion
警告提示：warning: object of type 'NSNumber *' is not compatible with dictionary value type 'NSString *' [-Wobjc-literal-conversion]
警告原因：赋值类型不匹配时发出警告
（7）-Wmacro-redefined
警告提示：warning: 'MARGIN' macro redefined [-Wmacro-redefined]
警告原因：宏定义重复定义时发出警告
（8）-Wobjc-designated-initializers
警告提示：warning: method override for the designated initializer of the superclass '-initWithFrame:collectionViewLayout:' not found [-Wobjc-designated-initializers]
警告原因：在初始化方法的定义后面添加了NS_DESIGNATED_INITIALIZER宏，没有满足指定构造器的条件时会发出警告
（9）-Wnonnull
警告提示：warning: null passed to a callee that requires a non-null argument [-Wnonnull]
警告原因：null传递给非空参数时发出警告
（10）-Wunused-getter-return-value
警告提示：warning: property access result unused - getters should not be used for side effects [-Wunused-getter-return-value]
（11）-Wincomplete-implementation
警告提示：warning: method definition for 'modifyAddress:' not found [-Wincomplete-implementation]
警告原因：在.h定义了，没有在.m实现时发出警告
（12）-Wunused-variable
警告提示：warning: unused variable 'lineSpacing' [-Wunused-variable]
警告原因：变量没有使用时，发出警告
（13）-Warc-performSelector-leaks （在工程中设置了忽略）
警告提示：warning: performSelector may cause a leak because its selector is unknown [-Warc-performSelector-leaks]
警告原因：使用- (id)performSelector:(SEL)aSelector
（14）-Undeclared-Selector （在工程中设置了忽略）
警告提示：warning: undeclared selector 'rewardRuleTouched:' [-Wundeclared-selector]
警告原因：使用@selector(rewardRuleTouched:)时，如果rewardRuleTouched：方法在当前类没有声明则发出警告
（15）-Wobjc-literal-conversion
警告提示：warning: implicit boolean conversion of Objective-C object literal always evaluates to true [-Wobjc-literal-conversion]
警告原因：把oc对象字面量赋值给bool类型时总是为true，工程中有这种情况时发出警告
（16）-Wnon-literal-null-conversion
警告提示：warning: expression which evaluates to zero treated as a null pointer constant of type 'NSString * _Nullable' [-Wnon-literal-null-conversion]
（17）-Wproperty-attribute-mismatch
警告提示：warning: 'copy' attribute on property 'tailCode' does not match the property inherited from 'RouteDetailProtocol' [-Wproperty-attribute-mismatch]
警告原因：当代理方实现的@property属性和委托方定义的描述不一致时，发出警告
（18）-Wincompatible-pointer-types
警告提示：warning: incompatible pointer types assigning to 'TestDetailDateChooseCell *' from 'UITableViewCell *' [-Wincompatible-pointer-types]
警告原因：赋值时，等号两边指针类型不一致时发出警告
（19）-Wnullability-completeness
警告提示：warning: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Wnullability-completeness]
警告原因：@propery描述的属性缺少nullability类型的修饰时发出警告
（20）-Wprotocol
警告提示：warning: class 'TestDetailViewController' does not conform to protocol 'TestDetailPresenterProtocol' [-Wprotocol]
警告原因：没有实现尖括号中协议的方法时发出警告
（21）-Wobjc-missing-super-calls
警告提示：warning: method possibly missing a [super prepareForReuse] call [-Wobjc-missing-super-calls]
警告原因：缺少父类实现时发出警告
（22）-Wdocumentation
警告提示：warning: empty paragraph passed to '@param' command [-Wdocumentation]
警告原因：警告相关的警告
（23）-Wformat
警告提示：warning: format specifies type 'long' but the argument has type 'int'
（24）-Wshorten-64-to-32
警告提示：warning: implicit conversion loses integer precision: 'long long' to 'NSInteger' (aka 'int') [-Wshorten-64-to-32]
（25）-Wdeprecated-declarations
警告提示：warning: 'SSDKSetupSinaWeiboShareParamsByText:title:image:url:latitude:longitude:objectID:type:' is deprecated: discard form v4.0.4
（26）-Wint-conversion
警告提示：warning: incompatible pointer to integer conversion initializing 'BOOL' (aka 'signed char') with an expression of type 'NSString *'
