Remove superfluous rec keywords and untangle some functions (#16544)

* remove some superfluous rec keywords and untangle two functions that aren't mutually recursive.

src/Compiler/Checking/CheckExpressions.fs

@@ -1895,7 +1895,7 @@ let BuildFieldMap (cenv: cenv) env isPartial ty (flds: ((Ident list * Ident) * '
                 | _ -> error(Error(FSComp.SR.tcRecordFieldInconsistentTypes(), m)))
     Some(tinst, tcref, fldsmap, List.rev rfldsList)
 
-let rec ApplyUnionCaseOrExn (makerForUnionCase, makerForExnTag) m (cenv: cenv) env overallTy item =
+let ApplyUnionCaseOrExn (makerForUnionCase, makerForExnTag) m (cenv: cenv) env overallTy item =
     let g = cenv.g
     let ad = env.eAccessRights
     match item with

src/Compiler/CodeGen/IlxGen.fs

@@ -92,7 +92,7 @@ let ChooseParamNames fieldNamesAndTypes =
         ilParamName, ilFieldName, ilPropType)
 
 /// Approximation for purposes of optimization and giving a warning when compiling definition-only files as EXEs
-let rec CheckCodeDoesSomething (code: ILCode) =
+let CheckCodeDoesSomething (code: ILCode) =
     code.Instrs
     |> Array.exists (function
         | AI_ldnull
@@ -476,7 +476,7 @@ let CompLocForPrivateImplementationDetails cloc =
     }
 
 /// Compute an ILTypeRef for a CompilationLocation
-let rec TypeRefForCompLoc cloc =
+let TypeRefForCompLoc cloc =
     match cloc.Enclosing with
     | [] -> mkILTyRef (cloc.Scope, TypeNameForPrivateImplementationDetails cloc)
     | [ h ] ->

src/Compiler/Optimize/Optimizer.fs

@@ -1457,11 +1457,11 @@ let AbstractExprInfoByVars (boundVars: Val list, boundTyVars) ivalue =
           | UnknownValue -> ivalue
           | SizeValue (_vdepth, vinfo) -> MakeSizedValueInfo (abstractExprInfo vinfo)
 
-      and abstractValInfo v = 
+      let abstractValInfo v = 
           { ValExprInfo=abstractExprInfo v.ValExprInfo 
             ValMakesNoCriticalTailcalls=v.ValMakesNoCriticalTailcalls }
 
-      and abstractModulInfo ss =
+      let rec abstractModulInfo ss =
          { ModuleOrNamespaceInfos = ss.ModuleOrNamespaceInfos |> NameMap.map (InterruptibleLazy.force >> abstractModulInfo >> notlazy) 
            ValInfos = ss.ValInfos.Map (fun (vref, e) -> 
                check vref (abstractValInfo e) ) }
@@ -1592,7 +1592,7 @@ let ValueIsUsedOrHasEffect cenv fvs (b: Binding, binfo) =
     // No discarding for things that are used
     Zset.contains v (fvs())
 
-let rec SplitValuesByIsUsedOrHasEffect cenv fvs x = 
+let SplitValuesByIsUsedOrHasEffect cenv fvs x = 
     x |> List.filter (ValueIsUsedOrHasEffect cenv fvs) |> List.unzip
 
 let IlAssemblyCodeInstrHasEffect i = 
@@ -2016,7 +2016,7 @@ let TryRewriteBranchingTupleBinding g (v: Val) rhs tgtSeqPtOpt body m =
         mkLetsBind m binds rhsAndTupleBinding |> Some
     | _ -> None
 
-let rec ExpandStructuralBinding cenv expr =
+let ExpandStructuralBinding cenv expr =
     let g = cenv.g
 
     assert cenv.settings.ExpandStructuralValues()

src/Compiler/TypedTree/TypedTreeOps.fs

@@ -3597,7 +3597,7 @@ let isSpanTyconRef g m tcref =
 let isSpanTy g m ty =
     ty |> stripTyEqns g |> (function TType_app(tcref, _, _) -> isSpanTyconRef g m tcref | _ -> false)
 
-let rec tryDestSpanTy g m ty =
+let tryDestSpanTy g m ty =
     match tryAppTy g ty with
     | ValueSome(tcref, [ty]) when isSpanTyconRef g m tcref -> Some(tcref, ty)
     | _ -> None
@@ -4626,11 +4626,11 @@ module DebugPrint =
         let body = moduleOrNamespaceTypeL ms.ModuleOrNamespaceType
         (header @@-- body) @@ footer
 
-    let rec implFilesL implFiles =
-        aboveListL (List.map implFileL implFiles)
-
-    and implFileL (CheckedImplFile (signature=implFileTy; contents=implFileContents)) =
+    let implFileL (CheckedImplFile (signature=implFileTy; contents=implFileContents)) =
         aboveListL [(wordL(tagText "top implementation ")) @@-- mexprL implFileTy implFileContents]
+
+    let implFilesL implFiles =
+        aboveListL (List.map implFileL implFiles)
 
     let showType x = showL (typeL x)
 
@@ -5097,6 +5097,33 @@ let tryGetFreeVarsCacheValue opts cache =
     if opts.canCache then tryGetCacheValue cache
     else ValueNone
 
+let accFreeLocalVal opts v fvs =
+    if not opts.includeLocals then fvs else
+    if Zset.contains v fvs.FreeLocals then fvs 
+    else 
+        let fvs = accFreevarsInVal opts v fvs
+        {fvs with FreeLocals=Zset.add v fvs.FreeLocals}
+
+let accFreeInValFlags opts flag acc =
+    let isMethLocal = 
+        match flag with 
+        | VSlotDirectCall 
+        | CtorValUsedAsSelfInit 
+        | CtorValUsedAsSuperInit -> true 
+        | PossibleConstrainedCall _
+        | NormalValUse -> false
+    let acc = accUsesFunctionLocalConstructs isMethLocal acc
+    match flag with 
+    | PossibleConstrainedCall ty -> accFreeTyvars opts accFreeInType ty acc
+    | _ -> acc
+
+let accLocalTyconRepr opts b fvs = 
+    if not opts.includeLocalTyconReprs then fvs else
+    if Zset.contains b fvs.FreeLocalTyconReprs then fvs
+    else { fvs with FreeLocalTyconReprs = Zset.add b fvs.FreeLocalTyconReprs }
+
+let inline accFreeExnRef _exnc fvs = fvs // Note: this exnc (TyconRef) should be collected the surround types, e.g. tinst of Expr.Op
+
 let rec accBindRhs opts (TBind(_, repr, _)) acc = accFreeInExpr opts repr acc
 
 and accFreeInSwitchCases opts csl dflt (acc: FreeVars) =
@@ -5123,31 +5150,6 @@ and accFreeInDecisionTree opts x (acc: FreeVars) =
     | TDSwitch(e1, csl, dflt, _) -> accFreeInExpr opts e1 (accFreeInSwitchCases opts csl dflt acc)
     | TDSuccess (es, _) -> accFreeInFlatExprs opts es acc
     | TDBind (bind, body) -> unionFreeVars (bindLhs opts bind (accBindRhs opts bind (freeInDecisionTree opts body))) acc
-
-and accFreeInValFlags opts flag acc =
-    let isMethLocal = 
-        match flag with 
-        | VSlotDirectCall 
-        | CtorValUsedAsSelfInit 
-        | CtorValUsedAsSuperInit -> true 
-        | PossibleConstrainedCall _
-        | NormalValUse -> false
-    let acc = accUsesFunctionLocalConstructs isMethLocal acc
-    match flag with 
-    | PossibleConstrainedCall ty -> accFreeTyvars opts accFreeInType ty acc
-    | _ -> acc
-
-and accFreeLocalVal opts v fvs =
-    if not opts.includeLocals then fvs else
-    if Zset.contains v fvs.FreeLocals then fvs 
-    else 
-        let fvs = accFreevarsInVal opts v fvs
-        {fvs with FreeLocals=Zset.add v fvs.FreeLocals}
-
-and accLocalTyconRepr opts b fvs = 
-    if not opts.includeLocalTyconReprs then fvs else
-    if Zset.contains b fvs.FreeLocalTyconReprs then fvs
-    else { fvs with FreeLocalTyconReprs = Zset.add b fvs.FreeLocalTyconReprs } 
 
 and accUsedRecdOrUnionTyconRepr opts (tc: Tycon) fvs =
     if (match tc.TypeReprInfo with TFSharpTyconRepr _ -> true | _ -> false) then
@@ -5170,8 +5172,7 @@ and accFreeRecdFieldRef opts rfref fvs =
         let fvs = fvs |> accUsedRecdOrUnionTyconRepr opts rfref.Tycon
         let fvs = fvs |> accFreevarsInTycon opts rfref.TyconRef 
         { fvs with FreeRecdFields = Zset.add rfref fvs.FreeRecdFields } 
-
-and accFreeExnRef _exnc fvs = fvs // Note: this exnc (TyconRef) should be collected the surround types, e.g. tinst of Expr.Op 
+
 and accFreeValRef opts (vref: ValRef) fvs = 
     match vref.IsLocalRef with 
     | true -> accFreeLocalVal opts vref.ResolvedTarget fvs
@@ -6609,7 +6610,7 @@ let isExpansiveUnderInstantiation g fty0 tyargs pargs argsl =
          | _ :: t -> not (isFunTy g fty) || loop (rangeOfFunTy g fty) t
      loop fty1 argsl)
 
-let rec mkExprAppAux g f fty argsl m =
+let mkExprAppAux g f fty argsl m =
     match argsl with 
     | [] -> f
     | _ -> 
@@ -6780,7 +6781,7 @@ let foldLinearBindingTargetsOfMatch tree (targets: _[]) =
             treeR, targetsR
 
 // Simplify a little as we go, including dead target elimination 
-let rec simplifyTrivialMatch spBind mExpr mMatch ty tree (targets : _[]) = 
+let simplifyTrivialMatch spBind mExpr mMatch ty tree (targets : _[]) = 
     match tree with 
     | TDSuccess(es, n) -> 
         if n >= targets.Length then failwith "simplifyTrivialMatch: target out of range"
@@ -10722,7 +10723,7 @@ let rec serializeNode (writer: IndentedTextWriter) (addTrailingComma:bool) (node
     else
         writer.WriteLine("}")
 
-let rec serializeEntity path (entity: Entity) =
+let serializeEntity path (entity: Entity) =
     let root = visitEntity entity
     use sw = new System.IO.StringWriter()
     use writer = new IndentedTextWriter(sw)