diff --git a/src/fsharp/FSharp.Core/list.fs b/src/fsharp/FSharp.Core/list.fs
index bf37ab08a1..920f0f0d9f 100644
--- a/src/fsharp/FSharp.Core/list.fs
+++ b/src/fsharp/FSharp.Core/list.fs
@@ -171,13 +171,13 @@ namespace Microsoft.FSharp.Collections
         [<CompiledName("Initialize")>]
         let init length initializer = Microsoft.FSharp.Primitives.Basics.List.init length initializer
 
-        let rec initConstAcc n x acc =
-            if n <= 0 then acc else initConstAcc (n-1) x (x :: acc)
-
         [<CompiledName("Replicate")>]
         let replicate count initial =
             if count < 0 then invalidArg "count" (SR.GetString(SR.inputMustBeNonNegative))
-            initConstAcc count initial []
+            let mutable result = []
+            for i in 0..count-1 do
+               result <- initial :: result
+            result
 
         [<CompiledName("Iterate2")>]
         let iter2 action list1 list2 =
diff --git a/src/fsharp/FSharp.Core/local.fs b/src/fsharp/FSharp.Core/local.fs
index 8e1b17ea91..3d812fc72c 100644
--- a/src/fsharp/FSharp.Core/local.fs
+++ b/src/fsharp/FSharp.Core/local.fs
@@ -83,7 +83,7 @@ open System.Collections.Generic
 
 module internal List =
 
-    let arrayZeroCreate (n:int) = (# "newarr !0" type ('T) n : 'T array #)
+    let inline arrayZeroCreate (n:int) = (# "newarr !0" type ('T) n : 'T array #)
 
     [<SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")>]
     let nonempty x = match x with [] -> false | _ -> true
diff --git a/src/fsharp/TypeChecker.fs b/src/fsharp/TypeChecker.fs
index 5d7a170c2c..58d3b2d87b 100644
--- a/src/fsharp/TypeChecker.fs
+++ b/src/fsharp/TypeChecker.fs
@@ -5482,7 +5482,7 @@ and TcPat warnOnUpper cenv env topValInfo vFlags (tpenv, names, takenNames) ty p
               | [SynPatErrorSkip(SynPat.Tuple (false, args, _)) | SynPatErrorSkip(SynPat.Paren(SynPatErrorSkip(SynPat.Tuple (false, args, _)), _))] when numArgTys > 1 -> args
 
               // note: we allow both 'C _' and 'C (_)' regardless of number of argument of the pattern 
-              | [SynPatErrorSkip(SynPat.Wild _ as e) | SynPatErrorSkip(SynPat.Paren(SynPatErrorSkip(SynPat.Wild _ as e), _))] -> Array.toList (Array.create numArgTys e)
+              | [SynPatErrorSkip(SynPat.Wild _ as e) | SynPatErrorSkip(SynPat.Paren(SynPatErrorSkip(SynPat.Wild _ as e), _))] -> List.replicate numArgTys e 
               | [arg] -> [arg] 
               | _ when numArgTys = 0 -> error(Error(FSComp.SR.tcUnionCaseDoesNotTakeArguments(), m)) 
               | _ when numArgTys = 1 -> error(Error(FSComp.SR.tcUnionCaseRequiresOneArgument(), m))