Update IfCaseLet.swift (pointfreeco#22)

* Update IfCaseLet.swift

* Conform ElseContent to View

Author: junebash

Sources/SwiftUINavigation/IfCaseLet.swift

@@ -36,7 +36,7 @@ import SwiftUI
 ///
 /// To exhaustively handle every case of a binding to an enum, see ``Switch``. Or, to unwrap a
 /// binding to an optional, see ``IfLet``.
-public struct IfCaseLet<Enum, Case, IfContent, ElseContent>: View where IfContent: View {
+public struct IfCaseLet<Enum, Case, IfContent, ElseContent>: View where IfContent: View, ElseContent: View {
   public let `enum`: Binding<Enum>
   public let casePath: CasePath<Enum, Case>
   public let ifContent: (Binding<Case>) -> IfContent
@@ -69,7 +69,11 @@ public struct IfCaseLet<Enum, Case, IfContent, ElseContent>: View where IfConten
   }
 
   public var body: some View {
-    Binding(unwrapping: self.enum, case: self.casePath).map(self.ifContent)
+    if let caseBinding = Binding(unwrapping: self.enum, case: self.casePath) {
+      ifContent(caseBinding)
+    } else {
+      elseContent()
+    }
   }
 }