diff --git a/Sources/Node.swift b/Sources/Node.swift
index df27fb4a..33862112 100644
--- a/Sources/Node.swift
+++ b/Sources/Node.swift
@@ -71,15 +71,9 @@ public class VariableNode: NodeType {
 
     if hasToken("if", at: 1) {
       let components = components.suffix(from: 2)
-      #if swift(<5.0)
-      let elseIndex = components.index(of: "else")
-      #else
-      let elseIndex = components.firstIndex(of: "else")
-      #endif
-
-      if let safeElseIndex = elseIndex {
-        condition = try parser.compileExpression(components: Array(components.prefix(upTo: safeElseIndex)), token: token)
-        let elseToken = components.suffix(from: safeElseIndex.advanced(by: 1)).joined(separator: " ")
+      if let elseIndex = components.firstIndex(of: "else") {
+        condition = try parser.compileExpression(components: Array(components.prefix(upTo: elseIndex)), token: token)
+        let elseToken = components.suffix(from: elseIndex.advanced(by: 1)).joined(separator: " ")
         elseExpression = try parser.compileResolvable(elseToken, containedIn: token)
       } else {
         condition = try parser.compileExpression(components: Array(components), token: token)
diff --git a/Sources/_SwiftSupport.swift b/Sources/_SwiftSupport.swift
index 24413505..1faa5e47 100644
--- a/Sources/_SwiftSupport.swift
+++ b/Sources/_SwiftSupport.swift
@@ -36,3 +36,11 @@ public extension Variable {
   }
 }
 #endif
+
+#if !swift(>=4.1)
+extension ArraySlice where Element: Equatable {
+    func firstIndex(of element: Element) -> Int? {
+        return index(of: element)
+    }
+}
+#endif