[Python] Misc fixes

src/Fable.Transforms/Python/Fable2Python.fs

@@ -2,6 +2,7 @@ module rec Fable.Transforms.Fable2Python
 
 open System
 open System.Collections.Generic
+open System.Text.RegularExpressions
 
 open Fable
 open Fable.AST
@@ -2224,11 +2225,6 @@ module Util =
         // printfn "transformGet: %A" (fableExpr.Type)
 
         match kind with
-        | Fable.ExprGet (Fable.Value(kind = Fable.StringConstant "length"))
-        | Fable.FieldGet { Name = "length" } ->
-            let func = Expression.name "len"
-            let left, stmts = com.TransformAsExpr(ctx, fableExpr)
-            Expression.call (func, [ left ]), stmts
         | Fable.FieldGet { Name = "message" } ->
             let func = Expression.name "str"
             let left, stmts = com.TransformAsExpr(ctx, fableExpr)
@@ -2243,7 +2239,7 @@ module Util =
             expr, stmts @ stmts' @ stmts''
 
         | Fable.FieldGet i ->
-            //printfn "Fable.FieldGet: %A" (fieldName, fableExpr.Type)
+            // printfn "Fable.FieldGet: %A" (i.Name, fableExpr.Type)
             let fieldName = i.Name |> Naming.toSnakeCase // |> Helpers.clean
 
             let fableExpr =
@@ -3249,6 +3245,9 @@ module Util =
 
         let args = discardUnitArg args
 
+        /// Removes `_mut` or `_mut_1` suffix from the identifier name
+        let cleanName (input: string) = Regex.Replace(input, @"_mut(_\d+)?$", "")
+
         // For Python we need to append the TC-arguments to any declared (arrow) function inside the while-loop of the
         // TCO. We will set them as default values to themselves e.g `i=i` to capture the value and not the variable.
         let tcArgs, tcDefaults =
@@ -3257,7 +3256,7 @@ module Util =
                 tc.Args
                 |> List.choose (fun arg ->
                     let (Identifier name) = arg.Arg
-                    let name = name.Substring(0, name.Length - 4)
+                    let name = cleanName name
                     match name with
                     | "tupled_arg_m" -> None // Remove these arguments (not sure why)
                     | _ ->

src/Fable.Transforms/Python/Replacements.fs

@@ -1578,7 +1578,7 @@ let strings (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisArg: Expr opt
 
 let stringModule (com: ICompiler) (ctx: Context) r t (i: CallInfo) (_: Expr option) (args: Expr list) =
     match i.CompiledName, args with
-    | "Length", [ arg ] -> getFieldWith r t arg "length" |> Some
+    | "Length", [ arg ] -> Helper.GlobalCall("len", t, [ arg ], [ t ], ?loc = r) |> Some
     | ("Iterate"
       | "IterateIndexed"
       | "ForAll"
@@ -1617,7 +1617,7 @@ let formattableString (com: ICompiler) (ctx: Context) r (t: Type) (i: CallInfo)
     | "Create", None, [ str; args ] -> objExpr [ "str", str; "args", args ] |> Some
     | "get_Format", Some x, _ -> getFieldWith r t x "str" |> Some
     | "get_ArgumentCount", Some x, _ ->
-        getFieldWith r t (getField x "args") "length"
+        Helper.GlobalCall("len", t, [ getField x "args" ], [ t ], ?loc = r)
         |> Some
     | "GetArgument", Some x, [ idx ] ->
         getExpr r t (getField x "args") idx
@@ -1696,7 +1696,7 @@ let resizeArrays (com: ICompiler) (ctx: Context) r (t: Type) (i: CallInfo) (this
         match ar.Type with
         // Fable translates System.Collections.Generic.List as Array
         // TODO: Check also IList?
-        | Array _ -> getFieldWith r t ar "length" |> Some
+        | Array _ -> Helper.GlobalCall("len", t, [ ar ], [ t ], ?loc = r) |> Some
         | _ ->
             Helper.LibCall(com, "util", "count", t, [ ar ], ?loc = r)
             |> Some
@@ -1889,7 +1889,7 @@ let arrayModule (com: ICompiler) (ctx: Context) r (t: Type) (i: CallInfo) (_: Ex
 
         newArray (makeIntConst 0) t |> Some
     | "IsEmpty", [ ar ] ->
-        eq (getFieldWith r (Int32.Number) ar "length") (makeIntConst 0)
+        eq (Helper.GlobalCall("len", t, [ ar ], [ t ], ?loc = r)) (makeIntConst 0)
         |> Some
 
     | "SortInPlaceWith", args ->
@@ -2480,7 +2480,9 @@ let intrinsicFunctions (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisAr
       [ ar; lower; upper ] ->
         let upper =
             match upper with
-            | Value (NewOption (None, _, _), _) -> getExpr None (Int32.Number) ar (makeStrConst "length")
+            | Value (NewOption (None, _, _), _) ->
+                Helper.GlobalCall("len", t, [ ar ], [ t ], ?loc = r)
+                //getExpr None (Int32.Number) ar (makeStrConst "length2")
             | _ -> add upper (makeIntConst 1)
 
         Helper.InstanceCall(ar, "slice", t, [ lower; upper ], ?loc = r)
@@ -3185,10 +3187,10 @@ let regex com (ctx: Context) r t (i: CallInfo) (thisArg: Expr option) (args: Exp
             propInt 0 thisArg.Value |> Some
     | "get_Length" ->
         if isGroup then
-            propStr "length" thisArg.Value |> Some
+            Helper.GlobalCall("len", t, [ thisArg.Value ], [ t ], ?loc = r) |> Some
         else
-            propInt 0 thisArg.Value
-            |> propStr "length"
+            let prop = propInt 0 thisArg.Value
+            Helper.GlobalCall("len", t, [ prop ], [ t ], ?loc = r)
             |> Some
     // Group
     | "get_Success" ->
@@ -3198,7 +3200,7 @@ let regex com (ctx: Context) r t (i: CallInfo) (thisArg: Expr option) (args: Exp
         Helper.LibCall(com, "RegExp", "get_item", t, [ thisArg.Value; args.Head ], [ thisArg.Value.Type ], ?loc = r)
         |> Some
     | "get_Item" -> getExpr r t thisArg.Value args.Head |> Some
-    | "get_Count" -> propStr "length" thisArg.Value |> Some
+    | "get_Count" -> Helper.GlobalCall("len", t, [ thisArg.Value ], [ t ], ?loc = r)  |> Some
     | "GetEnumerator" -> getEnumerator com r t thisArg.Value |> Some
     | meth ->
         let meth =

tests/Python/Fable.Tests.Python.fsproj

@@ -72,6 +72,7 @@
     <Compile Include="TestUri.fs" />
     <Compile Include="TestPyInterop.fs" />
 
+    <Compile Include="TestNonRegression.fs" />
     <Compile Include="Main.fs" />
   </ItemGroup>
 </Project>

tests/Python/TestNonRegression.fs

@@ -0,0 +1,17 @@
+module Fable.Tests.NonRegression
+
+open Util.Testing
+
+module Issue3496 =
+  type Class(length: int) =
+    member x.Length = length
+    static member StaticLength (length: int) = length
+  let returnLength (length: int) = length
+
+
+  [<Fact>]
+  let testLengthPassedToCtorIsOk() =
+    let c = Class(1)
+    equal 1 c.Length
+    equal 1 (returnLength 1)
+    equal 1 (Class.StaticLength 1)

tests/Python/TestPyInterop.fs

@@ -53,6 +53,7 @@ type Props =
 [<Global("Array")>]
 type PyArray =
     abstract push: item: obj -> unit
+    [<Emit("len($0)")>]
     abstract length: int
 
 [<Fable.Core.AttachMembers>]
@@ -162,4 +163,4 @@ let factorial (count : int) : int =
 let ``test emitPyStatement works with parameters`` () =
     factorial 5 |> equal 120
 
-#endif
+#endif