Show external metadata for enum fields in decompiled view (#18800)

Author: ThobiWanKenobi

docs/release-notes/.FSharp.Compiler.Service/10.0.100.md

@@ -18,6 +18,7 @@
 * Fix active pattern typechecking regression. ([Issue #18638](https://github.com/dotnet/fsharp/issues/18638), [PR #18642](https://github.com/dotnet/fsharp/pull/18642))
 * Fix nullness warnings when casting non-nullable values to `IEquatable<T>` to match C# behavior. ([Issue #18759](https://github.com/dotnet/fsharp/issues/18759))
 * Fix IsByRefLikeAttribute types being incorrectly suppressed in completion lists. Types like `Span<T>` and `ReadOnlySpan<T>` now appear correctly in IntelliSense.
+* Fix Show XML doc for enum fields in external metadata ([Issue #17939](https://github.com/dotnet/fsharp/issues/17939#issuecomment-3137410105), [PR #18800](https://github.com/dotnet/fsharp/pull/18800))
 
 ### Changed
 * Use `errorR` instead of `error` in `CheckDeclarations.fs` when possible. ([PR #18645](https://github.com/dotnet/fsharp/pull/18645))

src/Compiler/Checking/NicePrint.fs

@@ -305,7 +305,7 @@ module internal PrintUtilities =
     let layoutXmlDocOfILFieldInfo (denv: DisplayEnv) (infoReader: InfoReader) (finfo: ILFieldInfo) restL =
         if denv.showDocumentation then
             GetXmlDocSigOfILFieldInfo infoReader Range.range0 finfo
-            |> layoutXmlDocFromSig denv infoReader true XmlDoc.Empty restL             
+            |> layoutXmlDocFromSig denv infoReader true XmlDoc.Empty restL
         else
             restL
 
@@ -465,9 +465,11 @@ module PrintIL =
         | None -> WordL.equals ^^ (comment "value unavailable")
         | Some s -> WordL.equals ^^ wordL s
 
-    let layoutILEnumCase nm litVal =
+    let layoutILEnumCase nm litVal xmlDocOpt =
         let nameL = ConvertLogicalNameToDisplayLayout (tagEnum >> wordL) nm
-        WordL.bar ^^ nameL ^^ layoutILFieldInit litVal
+        match xmlDocOpt with
+        | Some layout -> layout @@ (WordL.bar ^^ nameL ^^ layoutILFieldInit litVal)
+        | None -> WordL.bar ^^ nameL ^^ layoutILFieldInit litVal
 
 module PrintTypes = 
     // Note: We need nice printing of constants in order to print literals and attributes 
@@ -2108,9 +2110,8 @@ module TastDefinitionPrinting =
 
         let ilFieldsL =
             ilFields
-            |> List.map (fun x -> (true, x.IsStatic, x.FieldName, 0, 0), layoutILFieldInfo denv infoReader m x)
-            |> List.sortBy fst
-            |> List.map snd
+            |> List.sortBy (fun x -> x.IsStatic, x.FieldName)
+            |> List.map (fun x -> layoutILFieldInfo denv infoReader m x)
 
         let staticVals =
             if isRecdTy g ty then
@@ -2225,6 +2226,14 @@ module TastDefinitionPrinting =
             else 
                 (lhsL ^^ WordL.equals) -* rhsL
 
+        let tryGetFieldXml (layoutList: Layout list) idxOpt =
+            match idxOpt with
+            | Some i when i >= 0 && i < layoutList.Length ->
+                match layoutList[i] with
+                | Node (Node (_, right, _), _, _) -> Some right
+                | _ -> None
+            | _ -> None
+
         let typeDeclL = 
 
             match repr with 
@@ -2327,9 +2336,14 @@ module TastDefinitionPrinting =
                 |> addLhs
 
             | TILObjectRepr _ when tycon.ILTyconRawMetadata.IsEnum ->
-                infoReader.GetILFieldInfosOfType (None, ad, m, ty) 
-                |> List.filter (fun x -> x.FieldName <> "value__")
-                |> List.map (fun x -> PrintIL.layoutILEnumCase x.FieldName x.LiteralValue)
+                let ilFieldsSorted = 
+                    ilFields
+                    |> List.sortBy (fun x -> x.IsStatic, x.FieldName)
+                infoReader.GetILFieldInfosOfType (None, ad, m, ty)
+                |> List.filter (fun (x: ILFieldInfo) -> x.FieldName <> "value__")
+                |> List.map (fun (x: ILFieldInfo) ->
+                    let xmlDocOpt = List.tryFindIndex (fun (e: ILFieldInfo) -> e.FieldName = x.FieldName) ilFieldsSorted |> tryGetFieldXml ilFieldsL
+                    PrintIL.layoutILEnumCase x.FieldName x.LiteralValue xmlDocOpt)
                 |> applyMaxMembers denv.maxMembers
                 |> aboveListL
                 |> addLhs

tests/FSharp.Compiler.Service.Tests/Symbols.fs

@@ -1249,3 +1249,19 @@ module Delegates =
 
         symbols["EventHandler"].IsDelegate |> shouldEqual true
         symbols["Action"].IsDelegate |> shouldEqual true
+
+module MetadataAsText =
+    [<Fact>]
+    let ``TryGetMetadataAsText returns metadata for external enum field`` () =
+        let _, checkResults = getParseAndCheckResults """
+let test = System.DateTimeKind.Utc
+"""
+        let symbolUse = checkResults |> findSymbolUseByName "DateTimeKind"
+        match symbolUse.Symbol with
+        | :? FSharpEntity as symbol ->
+            match symbol.TryGetMetadataText() with
+            | Some metadataText ->
+                metadataText.ToString() |> shouldContain "The time represented is UTC"
+            | None ->
+                failwith "Expected metadata text, got None"
+        | _ -> failwith "Expected FSharpEntity symbol"

tests/ILVerify/ilverify_FSharp.Compiler.Service_Debug_netstandard2.0.bsl

@@ -60,7 +60,7 @@
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.CompilerConfig+TcConfig::.ctor([FSharp.Compiler.Service]FSharp.Compiler.CompilerConfig+TcConfigBuilder, bool)][offset 0x00000634][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.PatternMatchCompilation::isProblematicClause([FSharp.Compiler.Service]FSharp.Compiler.PatternMatchCompilation+MatchClause)][offset 0x00000065][found Byte] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$FSharp.Compiler.PatternMatchCompilation::.cctor()][offset 0x00000015][found Boolean] Unexpected type on the stack.
-[IL]: Error [StackUnexpected]: : FSharp.Compiler.NicePrint+TastDefinitionPrinting+meths@2070-3::Invoke([FSharp.Compiler.Service]FSharp.Compiler.Infos+MethInfo)][offset 0x000000BE][found Char] Unexpected type on the stack.
+[IL]: Error [StackUnexpected]: : FSharp.Compiler.NicePrint+TastDefinitionPrinting+meths@2072-3::Invoke([FSharp.Compiler.Service]FSharp.Compiler.Infos+MethInfo)][offset 0x000000BE][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.NicePrint+PrintUtilities::layoutXmlDoc([FSharp.Compiler.Service]FSharp.Compiler.TypedTreeOps+DisplayEnv, bool, [FSharp.Compiler.Service]FSharp.Compiler.Xml.XmlDoc, [FSharp.Compiler.Service]FSharp.Compiler.Text.Layout)][offset 0x00000033][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.TypeProviders::ValidateNamespaceName(string, [FSharp.Compiler.Service]FSharp.Compiler.Tainted`1<Microsoft.FSharp.Core.CompilerServices.ITypeProvider>, [FSharp.Compiler.Service]FSharp.Compiler.Text.Range, string)][offset 0x00000063][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.TypeProviders::ValidateExpectedName([FSharp.Compiler.Service]FSharp.Compiler.Text.Range, string[], string, [FSharp.Compiler.Service]FSharp.Compiler.Tainted`1<FSharp.Compiler.TypeProviders+ProvidedType>)][offset 0x000000AD][found Char] Unexpected type on the stack.

tests/ILVerify/ilverify_FSharp.Compiler.Service_Release_netstandard2.0.bsl

@@ -65,7 +65,7 @@
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.IlxGen::HashRangeSorted([S.P.CoreLib]System.Collections.Generic.IDictionary`2<!!0,System.Tuple`2<int32,!!1>>)][offset 0x00000012][found ref '[FSharp.Compiler.Service]FSharp.Compiler.IlxGen+HashRangeSorted@1875<T1>'][expected ref '[FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`2<int32,T0>,T0>'] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.PatternMatchCompilation::isProblematicClause([FSharp.Compiler.Service]FSharp.Compiler.PatternMatchCompilation+MatchClause)][offset 0x00000040][found Byte] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$FSharp.Compiler.PatternMatchCompilation::.cctor()][offset 0x0000000B][found Boolean] Unexpected type on the stack.
-[IL]: Error [StackUnexpected]: : FSharp.Compiler.NicePrint+TastDefinitionPrinting+meths@2070-3::Invoke([FSharp.Compiler.Service]FSharp.Compiler.Infos+MethInfo)][offset 0x000000B3][found Char] Unexpected type on the stack.
+[IL]: Error [StackUnexpected]: : FSharp.Compiler.NicePrint+TastDefinitionPrinting+meths@2072-3::Invoke([FSharp.Compiler.Service]FSharp.Compiler.Infos+MethInfo)][offset 0x000000B3][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.NicePrint+PrintUtilities::layoutXmlDoc([FSharp.Compiler.Service]FSharp.Compiler.TypedTreeOps+DisplayEnv, bool, [FSharp.Compiler.Service]FSharp.Compiler.Xml.XmlDoc, [FSharp.Compiler.Service]FSharp.Compiler.Text.Layout)][offset 0x00000034][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.TypeProviders::ValidateNamespaceName(string, [FSharp.Compiler.Service]FSharp.Compiler.Tainted`1<Microsoft.FSharp.Core.CompilerServices.ITypeProvider>, [FSharp.Compiler.Service]FSharp.Compiler.Text.Range, string)][offset 0x00000074][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.TypeProviders::ValidateExpectedName([FSharp.Compiler.Service]FSharp.Compiler.Text.Range, string[], string, [FSharp.Compiler.Service]FSharp.Compiler.Tainted`1<FSharp.Compiler.TypeProviders+ProvidedType>)][offset 0x000000A8][found Char] Unexpected type on the stack.