Revert TcSymbolUseData cleanup per dotnet#6084 (dotnet#6089)

src/fsharp/NameResolution.fs

@@ -1574,7 +1574,7 @@ let LookupTypeNameInEnvMaybeHaveArity fq nm (typeNameResInfo: TypeNameResolution
 //-------------------------------------------------------------------------
 
 /// Represents the kind of the occurrence when reporting a name in name resolution
-[<RequireQualifiedAccess; Struct>]
+[<RequireQualifiedAccess>]
 type ItemOccurence =
     /// This is a binding / declaration of the item
     | Binding
@@ -1872,24 +1872,17 @@ type TcSymbolUseData =
 /// This is a memory-critical data structure - allocations of this data structure and its immediate contents
 /// is one of the highest memory long-lived data structures in typical uses of IDEs. Not many of these objects
 /// are allocated (one per file), but they are large because the allUsesOfAllSymbols array is large.
-type TcSymbolUses(g, capturedNameResolutions: ResizeArray<CapturedNameResolution>, formatSpecifierLocations: (range * int)[]) =
-
+type TcSymbolUses(g, capturedNameResolutions: ResizeArray<CapturedNameResolution>, formatSpecifierLocations: (range * int)[]) = 
+    
     // Make sure we only capture the information we really need to report symbol uses
-    let allUsesOfSymbols =
-        capturedNameResolutions
-        |> ResizeArray.mapToSmallArrayChunks (fun cnr -> { Item=cnr.Item; ItemOccurence=cnr.ItemOccurence; DisplayEnv=cnr.DisplayEnv; Range=cnr.Range })
-
+    let allUsesOfSymbols = [| for cnr in capturedNameResolutions -> { Item=cnr.Item; ItemOccurence=cnr.ItemOccurence; DisplayEnv=cnr.DisplayEnv; Range=cnr.Range } |]
     let capturedNameResolutions = ()
     do ignore capturedNameResolutions // don't capture this!
 
     member this.GetUsesOfSymbol item =
-        // This member returns what is potentially a very large array, which may approach the size constraints of the Large Object Heap.
-        // This is unlikely in practice, though, because we filter down the set of all symbol uses to those specifically for the given `item`.
-        // Consequently we have a much lesser chance of ending up with an array large enough to be promoted to the LOH.
-        [| for symbolUseChunk in allUsesOfSymbols do
-            for symbolUse in symbolUseChunk do
-                if protectAssemblyExploration false (fun () -> ItemsAreEffectivelyEqual g item symbolUse.Item) then
-                    yield symbolUse |]
+        [| for symbolUse in allUsesOfSymbols do
+               if protectAssemblyExploration false (fun () -> ItemsAreEffectivelyEqual g item symbolUse.Item) then
+                  yield symbolUse |]
 
     member this.AllUsesOfSymbols = allUsesOfSymbols
 

src/fsharp/NameResolution.fsi

@@ -294,7 +294,7 @@ type TypeNameResolutionInfo =
   static member ResolveToTypeRefs : TypeNameResolutionStaticArgsInfo -> TypeNameResolutionInfo
 
 /// Represents the kind of the occurrence when reporting a name in name resolution
-[<RequireQualifiedAccess; Struct>]
+[<RequireQualifiedAccess>]
 type internal ItemOccurence = 
     | Binding 
     | Use 
@@ -375,7 +375,7 @@ type internal TcSymbolUses =
     member GetUsesOfSymbol : Item -> TcSymbolUseData[]
 
     /// All the uses of all items within the file
-    member AllUsesOfSymbols : TcSymbolUseData[][]
+    member AllUsesOfSymbols : TcSymbolUseData[]
 
     /// Get the locations of all the printf format specifiers in the file
     member GetFormatSpecifierLocationsAndArity : unit -> (range * int)[]

src/fsharp/absil/illib.fs

@@ -474,6 +474,9 @@ module ResizeArray =
         /// in order to prevent long-term storage of those values
         chunkBySize maxArrayItemCount f inp
 
+/// Because FSharp.Compiler.Service is a library that will target FSharp.Core 4.5.2 for the forseeable future,
+/// we need to stick these functions in this module rather than using the module functions for ValueOption
+/// that come after FSharp.Core 4.5.2.
 module ValueOptionInternal =
 
     let inline ofOption x = match x with Some x -> ValueSome x | None -> ValueNone

src/fsharp/service/FSharpCheckerResults.fs

@@ -1893,12 +1893,11 @@ type FSharpCheckFileResults
             (fun scope ->
                 let cenv = scope.SymbolEnv
                 seq {
-                    for symbolUseChunk in scope.ScopeSymbolUses.AllUsesOfSymbols do
-                        for symbolUse in symbolUseChunk do
-                            cancellationToken |> Option.iter (fun ct -> ct.ThrowIfCancellationRequested())
-                            if symbolUse.ItemOccurence <> ItemOccurence.RelatedText then
-                                let symbol = FSharpSymbol.Create(cenv, symbolUse.Item)
-                                FSharpSymbolUse(scope.TcGlobals, symbolUse.DisplayEnv, symbol, symbolUse.ItemOccurence, symbolUse.Range)
+                    for symbolUse in scope.ScopeSymbolUses.AllUsesOfSymbols do
+                        cancellationToken |> Option.iter (fun ct -> ct.ThrowIfCancellationRequested())
+                        if symbolUse.ItemOccurence <> ItemOccurence.RelatedText then
+                            let symbol = FSharpSymbol.Create(cenv, symbolUse.Item)
+                            FSharpSymbolUse(scope.TcGlobals, symbolUse.DisplayEnv, symbol, symbolUse.ItemOccurence, symbolUse.Range)
                 })
 
     member __.GetUsesOfSymbolInFile(symbol:FSharpSymbol, ?cancellationToken: CancellationToken) = 
@@ -2117,7 +2116,6 @@ type FSharpCheckProjectResults
         [| for r in tcSymbolUses do
             for symbolUseChunk in r.AllUsesOfSymbols do
                 for symbolUse in symbolUseChunk do
-                    cancellationToken |> Option.iter (fun ct -> ct.ThrowIfCancellationRequested())
                     if symbolUse.ItemOccurence <> ItemOccurence.RelatedText then
                       let symbol = FSharpSymbol.Create(cenv, symbolUse.Item)
                       yield FSharpSymbolUse(tcGlobals, symbolUse.DisplayEnv, symbol, symbolUse.ItemOccurence, symbolUse.Range) |]