Fix bug in foldi for Map

src/FSharpPlus/Control/Indexable.fs

@@ -123,7 +123,7 @@ type FoldIndexed =
     inherit Default1
     static member FoldIndexed (x: list<_>   , f, z, _impl: FoldIndexed) = x |> List.fold  (fun (p, i) t -> (f p i t, i + 1)) (z, 0) |> fst
     static member FoldIndexed (x: _ []      , f, z, _impl: FoldIndexed) = x |> Array.fold (fun (p, i) t -> (f p i t, i + 1)) (z, 0) |> fst
-    static member FoldIndexed (_: Map<'k,'t>, f, z, _impl: FoldIndexed) = Map.fold f z
+    static member FoldIndexed (x: Map<'k,'t>, f, z, _impl: FoldIndexed) = Map.fold f z x
 
     static member inline Invoke (folder: 'State->'Key->'T->'State) (state: 'State) (foldable: '``Foldable<'T>``) : 'State =
         let inline call_2 (a: ^a, b: ^b, f, z) = ((^a or ^b) : (static member FoldIndexed : _*_*_*_ -> _) b, f, z, a)

tests/FSharpPlus.Tests/FSharpPlus.Tests.fsproj

@@ -21,6 +21,7 @@
     <Compile Include="Monoid.fs" />
     <Compile Include="Parsing.fs" />
     <Compile Include="Traversals.fs" />
+    <Compile Include="Indexables.fs" />
     <Compile Include="Validations.fs" />
     <Compile Include="Task.fs" />
     <Compile Include="ValueTask.fs" />

tests/FSharpPlus.Tests/General.fs

@@ -915,48 +915,6 @@ module Foldable =
         areEqual sb' None
         ()
 
-module Indexable = 
-    [<Test>]
-    let testCompileAndExecuteItem () =
-
-        let a = Map.ofSeq [1, "one"; 2, "two"]
-        let _ = item 1 a
-
-        let b = dict [1, "one"; 2, "two"]
-        let _ = item 1 b
-
-        let c = "two"
-        let _ = item 1 c
-
-        let d = System.Text.StringBuilder "one"
-        let _ = item 1 d
-
-        let e = array2D [[1;2];[3;4];[5;6]]
-        let _ = item (1, 1) e
-
-        let f = [1, "one"; 2, "two"]
-        let _ = item 1 f
-
-        let g = [|1, "one"; 2, "two"|]
-        let _ = item 1 g
-
-        let h = ResizeArray [1, "one"; 2, "two"]
-        let _ = item 1 h
-
-        let i = Array3D.create 3 2 2 0
-        let _ = item (1, 1, 1) i
-
-        let j = Array4D.create 3 2 2 3 0
-        let _ = item (1, 1, 1, 1) j
-
-        let k = NonEmptyMap.Create (("a", 1), ("b", 2))
-        let _ = item "b" k
-
-        // This doesn't intentionally compile: seq is not Indexable. Not all foldables are Indexable, for example a Set is foldable but not Indexable. For seq use nth instead.
-        // let f = seq [1, "one"; 2, "two"]
-        // let _ = item 1 f
-
-        ()
 
     [<Test>]
     let testCompileAndExecuteTryItem () =

tests/FSharpPlus.Tests/Indexables.fs

@@ -0,0 +1,80 @@
+namespace FSharpPlus.Tests
+
+#nowarn "686"
+
+open System
+open System.Collections.Generic
+open FSharpPlus
+open FSharpPlus.Data
+open FSharpPlus.Control
+open NUnit.Framework
+open Helpers
+
+
+module Indexables =
+
+    [<Test>]
+    let testCompileAndExecuteItem () =
+
+        let a = Map.ofSeq [1, "one"; 2, "two"]
+        let _ = item 1 a
+
+        let b = dict [1, "one"; 2, "two"]
+        let _ = item 1 b
+
+        let c = "two"
+        let _ = item 1 c
+
+        let d = System.Text.StringBuilder "one"
+        let _ = item 1 d
+
+        let e = array2D [[1;2];[3;4];[5;6]]
+        let _ = item (1, 1) e
+
+        let f = [1, "one"; 2, "two"]
+        let _ = item 1 f
+
+        let g = [|1, "one"; 2, "two"|]
+        let _ = item 1 g
+
+        let h = ResizeArray [1, "one"; 2, "two"]
+        let _ = item 1 h
+
+        let i = Array3D.create 3 2 2 0
+        let _ = item (1, 1, 1) i
+
+        let j = Array4D.create 3 2 2 3 0
+        let _ = item (1, 1, 1, 1) j
+
+        let k = NonEmptyMap.Create (("a", 1), ("b", 2))
+        let _ = item "b" k
+
+        // This doesn't intentionally compile: seq is not Indexable. Not all foldables are Indexable, for example a Set is foldable but not Indexable. For seq use nth instead.
+        // let f = seq [1, "one"; 2, "two"]
+        // let _ = item 1 f
+
+        ()
+
+    [<Test>]
+    let foldIndexed () =
+        Assert.AreEqual (123, foldi (fun a b c -> a + b + c) 0 (seq [20; 40; 60]))
+        Assert.AreEqual (123, foldi (fun a b c -> a + b + c) 0 [20; 40; 60])
+        Assert.AreEqual (123, foldi (fun a b c -> a + b + c) 0 (Map.ofSeq [0, 20; 1, 40; 2, 60]))
+
+
+    [<Test>]
+    let traverseIndexed () =
+        let m1 = Map.ofList [(1, [1;1;1]); (2, [2;2;2])]
+        let r1 = m1 |> traversei (fun _ _ -> None)
+        let r2 = m1 |> traversei (fun i v -> if List.forall ((=) i) v then Some (i :: v) else None)
+        Assert.AreEqual (None, r1)
+        CollectionAssert.AreEqual (Map.ofList [(1, [1; 1; 1; 1]); (2, [2; 2; 2; 2])], r2.Value)
+        Assert.IsInstanceOf<Option<Map<int,int list>>> (Some r2.Value)
+
+        let r3 = seq [ ( [0; 0; 0]); ( [1; 1; 1]); ( [2; 2; 2])] |> traversei (fun i v -> if List.forall ((=) i) v then Some (i :: v) else None)
+        CollectionAssert.AreEqual (seq [[0; 0; 0; 0]; [1; 1; 1; 1]; [2; 2; 2; 2]], r3.Value)
+        Assert.IsInstanceOf<Option<seq<int list>>> (Some r3.Value)
+
+        let r4 = [ ( [0; 0; 0]); ( [1; 1; 1]); ( [2; 2; 2])] |> traversei (fun i v -> if List.forall ((=) i) v then Some (i :: v) else None)
+        CollectionAssert.AreEqual ([[0; 0; 0; 0]; [1; 1; 1; 1]; [2; 2; 2; 2]], r4.Value)
+        Assert.IsInstanceOf<Option<int list list>> (Some r4.Value)

tests/FSharpPlus.Tests/Traversals.fs

@@ -273,11 +273,6 @@ module Traversable =
         CollectionAssert.AreEqual (r2.Value, m)
 
         let m1 = Map.ofList [(1, [1;1;1]); (2, [2;2;2])]
-        let r1 = m1 |> traversei (fun _ _ -> None)
-        let r2 = m1 |> traversei (fun i v -> if List.forall ((=) i) v then Some (i :: v) else None)
-        Assert.AreEqual(None, r1)
-        CollectionAssert.AreEqual (Map.ofList [(1, [1;1;1;1]); (2, [2;2;2;2])], r2.Value)
-
         let expected = [Map.ofList [(1, 1); (2, 2)]; Map.ofList [(1, 1); (2, 2)]; Map.ofList [(1, 1); (2, 2)];
                         Map.ofList [(1, 1); (2, 2)]; Map.ofList [(1, 1); (2, 2)]; Map.ofList [(1, 1); (2, 2)];
                         Map.ofList [(1, 1); (2, 2)]; Map.ofList [(1, 1); (2, 2)]; Map.ofList [(1, 1); (2, 2)]]