Merge pull request #5722 from Microsoft/merges/master-to-dev16.0

Merge master to dev16.0

Merge pull request #5722 from Microsoft/merges/master-to-dev16.0
Merge master to dev16.0
2f5befa8 · dotnet-automerge-bot · GitHub · 1cc5bd9d · f79da205 · 2f5befa8
10 changed file
--- a/VisualFSharp.sln
+++ b/VisualFSharp.sln

 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
-VisualStudioVersion = 15.0.27130.2036
+VisualStudioVersion = 15.0.28010.2036
 MinimumVisualStudioVersion = 10.0.40219.1
+Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "FSharp.VS.FSI", "vsintegration\src\FSharp.VS.FSI\FSharp.VS.FSI.fsproj", "{991DCF75-C2EB-42B6-9A0D-AA1D2409D519}"
+EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FSharp.Compiler.Private", "src\fsharp\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj", "{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}"
 EndProject
-Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "FSharp.VS.FSI", "vsintegration\src\FSharp.VS.FSI\FSharp.VS.FSI.fsproj", "{991DCF75-C2EB-42B6-9A0D-AA1D2409D519}"
-	ProjectSection(ProjectDependencies) = postProject
-		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3} = {2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}
-	EndProjectSection
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "VisualFSharpFull", "vsintegration\Vsix\VisualFSharpFull\VisualFSharpFull.csproj", "{59ADCE46-9740-4079-834D-9A03A3494EBC}"
 EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FSharp.Compiler.Server.Shared", "src\fsharp\FSharp.Compiler.Server.Shared\FSharp.Compiler.Server.Shared.fsproj", "{D5870CF0-ED51-4CBC-B3D7-6F56DA84AC06}"
 EndProject
@@ -65,14 +64,8 @@ EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FSharp.Compiler.Interactive.Settings", "src\fsharp\FSharp.Compiler.Interactive.Settings\FSharp.Compiler.Interactive.Settings.fsproj", "{649FA588-F02E-457C-9FCF-87E46407481E}"
 EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FsiAnyCPU", "src\fsharp\fsiAnyCpu\FsiAnyCPU.fsproj", "{8B3E283D-B5FE-4055-9D80-7E3A32F3967B}"
-	ProjectSection(ProjectDependencies) = postProject
-		{649FA588-F02E-457C-9FCF-87E46407481E} = {649FA588-F02E-457C-9FCF-87E46407481E}
-	EndProjectSection
 EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "Fsi", "src\fsharp\fsi\Fsi.fsproj", "{D0E98C0D-490B-4C61-9329-0862F6E87645}"
-	ProjectSection(ProjectDependencies) = postProject
-		{649FA588-F02E-457C-9FCF-87E46407481E} = {649FA588-F02E-457C-9FCF-87E46407481E}
-	EndProjectSection
 EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FSharp.Tests.FSharpSuite", "tests\fsharp\FSharp.Tests.FSharpSuite.fsproj", "{C163E892-5BF7-4B59-AA99-B0E8079C67C4}"
 EndProject
@@ -115,10 +108,6 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TextFile", "vsintegration\I
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "XMLFile", "vsintegration\ItemTemplates\XMLFile\XMLFile.csproj", "{1FB1DD07-06AA-45B4-B5AC-20FF5BEE98B6}"
 EndProject
-Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Vsix", "Vsix", "{141F6C23-E1B1-4D89-9F10-F0B8AD58E71F}"
-EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "VisualFSharpFull", "vsintegration\Vsix\VisualFSharpFull\VisualFSharpFull.csproj", "{59ADCE46-9740-4079-834D-9A03A3494EBC}"
-EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "HostedCompilerServer", "tests\fsharpqa\testenv\src\HostedCompilerServer\HostedCompilerServer.fsproj", "{4239EFEA-E746-446A-BF7A-51FCBAB13946}"
 EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "ILComparer", "tests\fsharpqa\testenv\src\ILComparer\ILComparer.fsproj", "{2E60864A-E3FF-4BCC-810F-DC7C34E6B236}"
@@ -155,14 +144,6 @@ Global
 		Release|x86 = Release|x86
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Debug|x86.Build.0 = Debug|Any CPU
-		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Release|Any CPU.Build.0 = Release|Any CPU
-		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Release|x86.ActiveCfg = Release|Any CPU
-		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Release|x86.Build.0 = Release|Any CPU
 		{991DCF75-C2EB-42B6-9A0D-AA1D2409D519}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{991DCF75-C2EB-42B6-9A0D-AA1D2409D519}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{991DCF75-C2EB-42B6-9A0D-AA1D2409D519}.Debug|x86.ActiveCfg = Debug|Any CPU
@@ -171,6 +152,22 @@ Global
 		{991DCF75-C2EB-42B6-9A0D-AA1D2409D519}.Release|Any CPU.Build.0 = Release|Any CPU
 		{991DCF75-C2EB-42B6-9A0D-AA1D2409D519}.Release|x86.ActiveCfg = Release|Any CPU
 		{991DCF75-C2EB-42B6-9A0D-AA1D2409D519}.Release|x86.Build.0 = Release|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Debug|x86.Build.0 = Debug|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Release|Any CPU.Build.0 = Release|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Release|x86.ActiveCfg = Release|Any CPU
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}.Release|x86.Build.0 = Release|Any CPU
+		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Debug|x86.Build.0 = Debug|Any CPU
+		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Release|Any CPU.Build.0 = Release|Any CPU
+		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Release|x86.ActiveCfg = Release|Any CPU
+		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Release|x86.Build.0 = Release|Any CPU
 		{D5870CF0-ED51-4CBC-B3D7-6F56DA84AC06}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{D5870CF0-ED51-4CBC-B3D7-6F56DA84AC06}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{D5870CF0-ED51-4CBC-B3D7-6F56DA84AC06}.Debug|x86.ActiveCfg = Debug|Any CPU
@@ -483,14 +480,6 @@ Global
 		{1FB1DD07-06AA-45B4-B5AC-20FF5BEE98B6}.Release|Any CPU.Build.0 = Release|Any CPU
 		{1FB1DD07-06AA-45B4-B5AC-20FF5BEE98B6}.Release|x86.ActiveCfg = Release|Any CPU
 		{1FB1DD07-06AA-45B4-B5AC-20FF5BEE98B6}.Release|x86.Build.0 = Release|Any CPU
-		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Debug|x86.Build.0 = Debug|Any CPU
-		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Release|Any CPU.Build.0 = Release|Any CPU
-		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Release|x86.ActiveCfg = Release|Any CPU
-		{59ADCE46-9740-4079-834D-9A03A3494EBC}.Release|x86.Build.0 = Release|Any CPU
 		{4239EFEA-E746-446A-BF7A-51FCBAB13946}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{4239EFEA-E746-446A-BF7A-51FCBAB13946}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{4239EFEA-E746-446A-BF7A-51FCBAB13946}.Debug|x86.ActiveCfg = Debug|Any CPU
@@ -584,8 +573,9 @@ Global
 		HideSolutionNode = FALSE
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
-		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3} = {3881429D-A97A-49EB-B7AE-A82BA5FE9C77}
 		{991DCF75-C2EB-42B6-9A0D-AA1D2409D519} = {4C7B48D7-19AF-4AE7-9D1D-3BB289D5480D}
+		{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3} = {3881429D-A97A-49EB-B7AE-A82BA5FE9C77}
+		{59ADCE46-9740-4079-834D-9A03A3494EBC} = {4C7B48D7-19AF-4AE7-9D1D-3BB289D5480D}
 		{D5870CF0-ED51-4CBC-B3D7-6F56DA84AC06} = {B8DDA694-7939-42E3-95E5-265C2217C142}
 		{DED3BBD7-53F4-428A-8C9F-27968E768605} = {3058BC79-8E79-4645-B05D-48CC182FA8A6}
 		{EE85AAB7-CDA0-4C4E-BDA0-A64CCC413E3F} = {4C7B48D7-19AF-4AE7-9D1D-3BB289D5480D}
@@ -629,8 +619,6 @@ Global
 		{E3FDD4AC-46B6-4B9F-B672-317D1202CC50} = {F6DAEE9A-8BE1-4C4A-BC83-09215517C7DA}
 		{D11FC318-8F5D-4C8C-9287-AB40A016D13C} = {F6DAEE9A-8BE1-4C4A-BC83-09215517C7DA}
 		{1FB1DD07-06AA-45B4-B5AC-20FF5BEE98B6} = {F6DAEE9A-8BE1-4C4A-BC83-09215517C7DA}
-		{141F6C23-E1B1-4D89-9F10-F0B8AD58E71F} = {4C7B48D7-19AF-4AE7-9D1D-3BB289D5480D}
-		{59ADCE46-9740-4079-834D-9A03A3494EBC} = {141F6C23-E1B1-4D89-9F10-F0B8AD58E71F}
 		{4239EFEA-E746-446A-BF7A-51FCBAB13946} = {CFE3259A-2D30-4EB0-80D5-E8B5F3D01449}
 		{2E60864A-E3FF-4BCC-810F-DC7C34E6B236} = {CFE3259A-2D30-4EB0-80D5-E8B5F3D01449}
 		{D086C8C6-D00D-4C3B-9AB2-A4286C9F5922} = {4C7B48D7-19AF-4AE7-9D1D-3BB289D5480D}

--- a/src/absil/il.fs
+++ b/src/absil/il.fs
@@ -154,12 +154,11 @@ let unsplitTypeName (ns, n) =
    | [] -> String.concat "." ns + "." + n 
    | _ -> n 

-let splitTypeNameRightAux nm = 
-    if String.contains nm '.' then 
-      let idx = String.rindex nm '.'
-      let s1, s2 = splitNameAt nm idx
-      Some s1, s2 
-    else None, nm
+let splitTypeNameRightAux (nm:string) = 
+    let idx = nm.LastIndexOf '.'
+    if idx = -1 then None, nm else
+    let s1, s2 = splitNameAt nm idx
+    Some s1, s2

 let splitTypeNameRight nm =
    memoizeNamespaceRightTable.GetOrAdd(nm, splitTypeNameRightAux)
@@ -4189,23 +4188,6 @@ let resolveILMethodRef td mref = resolveILMethodRefWithRescope id td mref
 let mkRefToILModule m =
  ILModuleRef.Create(m.Name, true, None)

-
-let ungenericizeTypeName n = 
-  let sym = '`'
-  if 
-    String.contains n sym && 
-      (* check what comes after the symbol is a number *)
-    (let m = String.rindex n sym
-     let res = ref (m < n.Length - 1)
-     for i = m + 1 to n.Length - 1 do
-       res := !res && n.[i] >= '0' && n.[i] <= '9'
-     !res)
-  then 
-      let pos = String.rindex n sym
-      String.sub n 0 pos
-  else n
-
-
 type ILEventRef =
    { erA: ILTypeRef; erB: string }
    static member Create(a, b) = {erA=a;erB=b}

--- a/src/absil/il.fsi
+++ b/src/absil/il.fsi
@@ -1540,9 +1540,6 @@ val typeNameForGlobalFunctions: string

 val isTypeNameForGlobalFunctions: string -> bool

-val ungenericizeTypeName: string -> string (* e.g. List`1 --> List *)
-
-
 // ====================================================================
 // PART 2
 // 

--- a/src/absil/illib.fs
+++ b/src/absil/illib.fs
@@ -452,23 +452,13 @@ type String with
    member inline x.EndsWithOrdinal(value) =
        x.EndsWith(value, StringComparison.Ordinal)

-module String = 
-    let indexNotFound() = raise (new KeyNotFoundException("An index for the character was not found in the string"))
-
+module String =
    let make (n: int) (c: char) : string = new String(c, n)

    let get (str:string) i = str.[i]

    let sub (s:string) (start:int) (len:int) = s.Substring(start,len)

-    let index (s:string) (c:char) =  
-        let r = s.IndexOf(c) 
-        if r = -1 then indexNotFound() else r
-
-    let rindex (s:string) (c:char) =
-        let r =  s.LastIndexOf(c) 
-        if r = -1 then indexNotFound() else r
-
    let contains (s:string) (c:char) = s.IndexOf(c) <> -1

    let order = LanguagePrimitives.FastGenericComparer<string>

--- a/src/buildfromsource/FSharp.Compiler.Private/FSComp.resx
+++ b/src/buildfromsource/FSharp.Compiler.Private/FSComp.resx
@@ -3082,7 +3082,7 @@
    <value>This number is outside the allowable range for 32-bit floats</value>
  </data>
  <data name="lexInvalidNumericLiteral" xml:space="preserve">
-    <value>This is not a valid numeric literal. Valid numeric literals include 1, 0x1, 0b0001 (int), 1u (uint32), 1L (int64), 1UL (uint64), 1s (int16), 1y (sbyte), 1uy (byte), 1.0 (float), 1.0f (float32), 1.0m (decimal), 1I (BigInteger).</value>
+    <value>This is not a valid numeric literal. Valid numeric literals include 1, 0x1, 0b0001 (int), 1u (uint32), 1L (int64), 1UL (uint64), 1s (int16), 1us (uint16), 1y (sbyte), 1uy (byte), 1.0 (float), 1.0f (float32), 1.0m (decimal), 1I (BigInteger).</value>
  </data>
  <data name="lexInvalidByteLiteral" xml:space="preserve">
    <value>This is not a valid byte literal</value>
@@ -4378,4 +4378,4 @@
  <data name="chkInvalidFunctionReturnType" xml:space="preserve">
    <value>The function or method has an invalid return type '{0}'. This is not permitted by the rules of Common IL.</value>
  </data>
-</root>
\ No newline at end of file
+</root>
--- a/src/fsharp/CompileOps.fs
+++ b/src/fsharp/CompileOps.fs
@@ -2609,13 +2609,13 @@ type TcConfigBuilder =
    member tcConfigB.RemoveReferencedAssemblyByPath (m, path) =
        tcConfigB.referencedDLLs <- tcConfigB.referencedDLLs |> List.filter (fun ar-> ar.Range <> m || ar.Text <> path)
    
-    static member SplitCommandLineResourceInfo ri = 
-        if String.contains ri ',' then 
-            let p = String.index ri ',' 
+    static member SplitCommandLineResourceInfo (ri:string) =
+        let p = ri.IndexOf ','
+        if p <> -1 then
            let file = String.sub ri 0 p 
            let rest = String.sub ri (p+1) (String.length ri - p - 1) 
-            if String.contains rest ',' then 
-                let p = String.index rest ',' 
+            let p = rest.IndexOf ',' 
+            if p <> -1 then
                let name = String.sub rest 0 p+".resources" 
                let pubpri = String.sub rest (p+1) (rest.Length - p - 1) 
                if pubpri = "public" then file, name, ILResourceAccess.Public 

--- a/src/fsharp/NameResolution.fs
+++ b/src/fsharp/NameResolution.fs
@@ -985,10 +985,8 @@ type TypeNameResolutionStaticArgsInfo =

    // Get the first possible mangled name of the type, assuming the args are generic args
    member x.MangledNameForType nm = 
-        if IsMangledGenericName nm || x.NumStaticArgs = 0 then nm
-        else nm+"`"+string x.NumStaticArgs
-
-
+        if x.NumStaticArgs = 0 || TryDemangleGenericNameAndPos nm <> ValueNone then nm
+        else nm + "`" + string x.NumStaticArgs

 [<NoEquality; NoComparison>]
 /// Represents information which guides name resolution of types.
@@ -1018,7 +1016,11 @@ let LookupTypeNameInEntityHaveArity nm (staticResInfo: TypeNameResolutionStaticA
 /// Unqualified lookups of type names where the number of generic arguments is known 
 /// from context, e.g. List<arg>.  Rebindings due to 'open' may have rebound identifiers.
 let LookupTypeNameInEnvHaveArity fq nm numTyArgs (nenv:NameResolutionEnv) = 
-    let key = if IsMangledGenericName nm then DecodeGenericTypeName nm else NameArityPair(nm,numTyArgs)
+    let key =
+        match TryDemangleGenericNameAndPos nm with
+        | ValueSome pos -> DecodeGenericTypeName pos nm
+        | _ -> NameArityPair(nm,numTyArgs)
+
    match nenv.TyconsByDemangledNameAndArity(fq).TryFind(key)  with
    | Some res -> Some res
    | None -> nenv.TyconsByAccessNames(fq).TryFind nm |> Option.map List.head
@@ -1041,15 +1043,17 @@ let LookupTypeNameInEnvHaveArity fq nm numTyArgs (nenv:NameResolutionEnv) =
 // also be used to qualify access if needed, though this is almost never needed.  

 let LookupTypeNameNoArity nm (byDemangledNameAndArity: LayeredMap<NameArityPair,_>) (byAccessNames: LayeredMultiMap<string,_>) = 
-    if IsMangledGenericName nm then 
-      match byDemangledNameAndArity.TryFind (DecodeGenericTypeName nm) with 
-      | Some res -> [res]
-      | None -> 
-          match byAccessNames.TryFind nm with
-          | Some res -> res
-          | None -> []
-    else 
-      byAccessNames.[nm]
+    match TryDemangleGenericNameAndPos nm with
+    | ValueSome pos -> 
+        let demangled = DecodeGenericTypeName pos nm
+        match byDemangledNameAndArity.TryFind demangled with 
+        | Some res -> [res]
+        | None ->
+            match byAccessNames.TryFind nm with
+            | Some res -> res
+            | None -> []
+    | _ ->
+        byAccessNames.[nm]

 /// Qualified lookup of type names in the environment
 let LookupTypeNameInEnvNoArity fq nm (nenv: NameResolutionEnv) = 

--- a/src/fsharp/NicePrint.fs
+++ b/src/fsharp/NicePrint.fs
@@ -102,7 +102,7 @@ module private PrintIL =
    open Microsoft.FSharp.Compiler.AbstractIL.IL
        
    let fullySplitILTypeRef (tref:ILTypeRef) = 
-        (List.collect IL.splitNamespace (tref.Enclosing @ [IL.ungenericizeTypeName tref.Name])) 
+        (List.collect IL.splitNamespace (tref.Enclosing @ [PrettyNaming.DemangleGenericTypeName tref.Name])) 

    let layoutILTypeRefName denv path =
        let path = 
@@ -193,7 +193,7 @@ module private PrintIL =
        let args = signatur.ArgTypes |> List.map (layoutILType denv ilTyparSubst) 
        let res  = 
            match cons with
-            | Some className -> layoutILTypeRefName denv (SplitNamesForILPath (ungenericizeTypeName className)) ^^ (pruneParms className ilTyparSubst |> paramsL) // special case for constructor return-type (viz., the class itself)
+            | Some className -> layoutILTypeRefName denv (SplitNamesForILPath (PrettyNaming.DemangleGenericTypeName className)) ^^ (pruneParms className ilTyparSubst |> paramsL) // special case for constructor return-type (viz., the class itself)
            | None           -> signatur.ReturnType |> layoutILType denv ilTyparSubst
        match args with
        | []   -> WordL.structUnit ^^ WordL.arrow ^^ res
@@ -226,7 +226,7 @@ module private PrintIL =
        // return type be passed along as the `cons` parameter.)
        let res  = 
            match cons with
-            | Some className -> layoutILTypeRefName denv (SplitNamesForILPath (ungenericizeTypeName className)) ^^ (pruneParms className ilTyparSubst |> paramsL) // special case for constructor return-type (viz., the class itself)
+            | Some className -> layoutILTypeRefName denv (SplitNamesForILPath (PrettyNaming.DemangleGenericTypeName className)) ^^ (pruneParms className ilTyparSubst |> paramsL) // special case for constructor return-type (viz., the class itself)
            | None           -> retType |> layoutILType denv ilTyparSubst
        match parameters with
        | []   -> WordL.structUnit ^^ WordL.arrow ^^ res

--- a/src/fsharp/PrettyNaming.fs
+++ b/src/fsharp/PrettyNaming.fs
@@ -484,30 +484,36 @@ module public Microsoft.FSharp.Compiler.PrettyNaming
     
    let [<Literal>] private mangledGenericTypeNameSym = '`'

-    let IsMangledGenericName (n:string) = 
-        n.IndexOf mangledGenericTypeNameSym <> -1 &&
+    let TryDemangleGenericNameAndPos (n:string) =
        (* check what comes after the symbol is a number *)
-        let m = n.LastIndexOf mangledGenericTypeNameSym
-        let mutable res = m < n.Length - 1
-        for i = m + 1 to n.Length - 1 do
-            res <- res && n.[i] >= '0' && n.[i] <= '9'
-        res
+        let pos = n.LastIndexOf mangledGenericTypeNameSym
+        if pos = -1 then ValueNone else
+        let mutable res = pos < n.Length - 1
+        let mutable i = pos + 1
+        while res && i < n.Length do
+            let char = n.[i]
+            if not (char >= '0' && char <= '9') then
+                res <- false
+            i <- i + 1
+        if res then
+            ValueSome pos
+        else
+            ValueNone

    type NameArityPair = NameArityPair of string * int

-    let DecodeGenericTypeName n = 
-        if IsMangledGenericName n then 
-            let pos = n.LastIndexOf mangledGenericTypeNameSym
-            let res = n.Substring(0,pos)
-            let num = n.Substring(pos+1,n.Length - pos - 1)
-            NameArityPair(res, int32 num)
-        else NameArityPair(n,0)
-
-    let DemangleGenericTypeName n = 
-        if  IsMangledGenericName n then 
-            let pos = n.LastIndexOf mangledGenericTypeNameSym
-            n.Substring(0,pos)
-        else n
+    let DecodeGenericTypeName pos (mangledName:string) =
+        let res = mangledName.Substring(0,pos)
+        let num = mangledName.Substring(pos+1,mangledName.Length - pos - 1)
+        NameArityPair(res, int32 num)
+
+    let DemangleGenericTypeNameWithPos pos (mangledName:string) =
+        mangledName.Substring(0,pos)
+
+    let DemangleGenericTypeName (mangledName:string) =
+        match TryDemangleGenericNameAndPos mangledName with
+        | ValueSome pos -> DemangleGenericTypeNameWithPos pos mangledName
+        | _ -> mangledName

    let private chopStringTo (s:string) (c:char) =
        match s.IndexOf c with

--- a/src/fsharp/tast.fs
+++ b/src/fsharp/tast.fs
@@ -480,10 +480,11 @@ let KeyTyconByDemangledNameAndArity nm (typars: _ list) x =

 /// Generic types can be accessed either by 'List' or 'List`1'. This lists both keys. The second form should really be deprecated.
 let KeyTyconByAccessNames nm x = 
-    if IsMangledGenericName nm then 
-        let dnm = DemangleGenericTypeName nm 
+    match TryDemangleGenericNameAndPos nm with
+    | ValueSome pos ->
+        let dnm = DemangleGenericTypeNameWithPos pos nm 
        [| KeyValuePair(nm,x); KeyValuePair(dnm,x) |]
-    else
+    | _ ->
        [| KeyValuePair(nm,x) |]

 type ModuleOrNamespaceKind =