diff --git a/Source/CarthageKit/FrameworkExtensions.swift b/Source/CarthageKit/FrameworkExtensions.swift
index 755ef75714..cfac72e370 100644
--- a/Source/CarthageKit/FrameworkExtensions.swift
+++ b/Source/CarthageKit/FrameworkExtensions.swift
@@ -22,7 +22,7 @@ extension String {
 	/// Strips off a trailing string, if present.
 	internal func stripping(suffix: String) -> String {
 		if hasSuffix(suffix) {
-			let end = characters.index(endIndex, offsetBy: -suffix.count)
+			let end = index(endIndex, offsetBy: -suffix.count)
 			return String(self[startIndex..<end])
 		} else {
 			return self
diff --git a/Source/carthage/Extensions.swift b/Source/carthage/Extensions.swift
index 5864d5b625..48974c16f4 100644
--- a/Source/carthage/Extensions.swift
+++ b/Source/carthage/Extensions.swift
@@ -43,8 +43,7 @@ internal func print<T>(_ object: T) {
 extension String {
 	/// Split the string into substrings separated by the given separators.
 	internal func split(maxSplits: Int = .max, omittingEmptySubsequences: Bool = true, separators: [Character] = [ ",", " " ]) -> [String] {
-		return characters
-			.split(maxSplits: maxSplits, omittingEmptySubsequences: omittingEmptySubsequences, whereSeparator: separators.contains)
+		return split(maxSplits: maxSplits, omittingEmptySubsequences: omittingEmptySubsequences, whereSeparator: separators.contains)
 			.map(String.init)
 	}
 }