diff --git a/SSZipArchive/SSZipArchive.m b/SSZipArchive/SSZipArchive.m
index 7730057..d2f831c 100755
--- a/SSZipArchive/SSZipArchive.m
+++ b/SSZipArchive/SSZipArchive.m
@@ -848,8 +848,10 @@
         NSString *temporaryDirectoryName = [[NSUUID UUID] UUIDString];
         NSString *temporaryDirectory = [NSTemporaryDirectory() stringByAppendingPathComponent:temporaryDirectoryName];
         BOOL directoryCreated = [[NSFileManager defaultManager] createDirectoryAtPath:temporaryDirectory withIntermediateDirectories:YES attributes:nil error:nil];
-        discardableFilePath = directoryCreated ? [temporaryDirectory stringByAppendingPathComponent:discardableFileName] : nil;
-        [@"" writeToFile:discardableFilePath atomically:YES encoding:NSUTF8StringEncoding error:nil];
+        if (directoryCreated) {
+            discardableFilePath = [temporaryDirectory stringByAppendingPathComponent:discardableFileName];
+            [@"" writeToFile:discardableFilePath atomically:YES encoding:NSUTF8StringEncoding error:nil];
+        }
     });
     return discardableFilePath;
 }
diff --git a/ZipArchive.xcodeproj/project.pbxproj b/ZipArchive.xcodeproj/project.pbxproj
index eece749..d5a3be7 100644
--- a/ZipArchive.xcodeproj/project.pbxproj
+++ b/ZipArchive.xcodeproj/project.pbxproj
@@ -463,6 +463,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
@@ -476,7 +477,7 @@
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
-				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN_UNREACHABLE_CODE = YES_AGGRESSIVE;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = NO;
 				CURRENT_PROJECT_VERSION = 1;
@@ -511,6 +512,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
@@ -524,7 +526,7 @@
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
-				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN_UNREACHABLE_CODE = YES_AGGRESSIVE;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = YES;
 				CURRENT_PROJECT_VERSION = 1;