fix merge issues

Author: Martin521

docs/release-notes/.Language/preview.md

@@ -3,7 +3,6 @@
 * Better generic unmanaged structs handling. ([Language suggestion #692](https://github.com/fsharp/fslang-suggestions/issues/692), [PR #12154](https://github.com/dotnet/fsharp/pull/12154))
 * Deprecate places where `seq` can be omitted. ([Language suggestion #1033](https://github.com/fsharp/fslang-suggestions/issues/1033), [PR #17772](https://github.com/dotnet/fsharp/pull/17772))
 * Added type conversions cache, only enabled for compiler runs ([PR#17668](https://github.com/dotnet/fsharp/pull/17668))
-* Introduction of the `#warnon` compiler directive, enabling scoped nowarn / warnon sections according to [RFC FS-1146](https://github.com/fsharp/fslang-design/pull/782/files). ([Language suggestion #278](https://github.com/fsharp/fslang-suggestions/issues/278), [PR #17507](https://github.com/dotnet/fsharp/pull/17507))
 
 ### Fixed
 * Warn on uppercase identifiers in patterns. ([PR #15816](https://github.com/dotnet/fsharp/pull/15816))

src/Compiler/Driver/CompilerConfig.fs

@@ -92,16 +92,61 @@ let ResolveFileUsingPaths (paths, m, fileName) =
         let searchMessage = String.concat "\n " paths
         raise (FileNameNotResolved(fileName, searchMessage, m))
 
-let GetWarningNumber (numberString) =
-    let trimPrefix (s: string) =
-        if s.StartsWithOrdinal "FS" then s[2..] else s
+[<RequireQualifiedAccess>]
+type WarningNumberSource =
+    | CommandLineOption
+    | CompilerDirective
+
+[<RequireQualifiedAccess>]
+type WarningDescription =
+    | Int32 of int
+    | String of string
+    | Ident of Ident
+
+let GetWarningNumber (m, description: WarningDescription, langVersion: LanguageVersion, source: WarningNumberSource) =
+    let argFeature = LanguageFeature.ParsedHashDirectiveArgumentNonQuotes
+
+    let parse (numStr: string) =
+        let trimPrefix (s: string) =
+            if s.StartsWithOrdinal "FS" then s[2..] else s
+
+        let tryParseIntWithFailAction (s: string) (failAction: unit -> unit) =
+            match Int32.TryParse s with
+            | true, n -> Some n
+            | false, _ ->
+                failAction ()
+                None
+
+        let warnInvalid () =
+            warning (Error(FSComp.SR.buildInvalidWarningNumber numStr, m))
 
-    let tryParseInt (s: string) =
-        match Int32.TryParse s with
-        | true, n -> Some n
-        | false, _ -> None
+        if source = WarningNumberSource.CommandLineOption then
+            tryParseIntWithFailAction (trimPrefix numStr) id
+        elif langVersion.SupportsFeature(argFeature) then
+            tryParseIntWithFailAction (trimPrefix numStr) warnInvalid
+        else
+            tryParseIntWithFailAction numStr id
 
-    tryParseInt (trimPrefix numberString)
+    match description with
+    | WarningDescription.Int32 n ->
+        if tryCheckLanguageFeatureAndRecover langVersion argFeature m then
+            Some n
+        else
+            None
+    | WarningDescription.String s ->
+        if
+            source = WarningNumberSource.CompilerDirective
+            && not (langVersion.SupportsFeature argFeature)
+            && s.StartsWithOrdinal "FS"
+        then
+            warning (Error(FSComp.SR.buildInvalidWarningNumber s, m))
+
+        parse s
+    | WarningDescription.Ident ident ->
+        if tryCheckLanguageFeatureAndRecover langVersion argFeature m then
+            parse ident.idText
+        else
+            None
 
 let ComputeMakePathAbsolute implicitIncludeDir (path: string) =
     try
@@ -927,7 +972,7 @@ type TcConfigBuilder =
     member tcConfigB.TurnWarningOff(m: range, s: string) =
         use _ = UseBuildPhase BuildPhase.Parameter
 
-        match GetWarningNumber s with
+        match GetWarningNumber(m, WarningDescription.String s, tcConfigB.langVersion, WarningNumberSource.CommandLineOption) with
         | None -> ()
         | Some n ->
             // nowarn:62 turns on mlCompatibility, e.g. shows ML compat items in intellisense menus
@@ -942,7 +987,7 @@ type TcConfigBuilder =
     member tcConfigB.TurnWarningOn(m: range, s: string) =
         use _ = UseBuildPhase BuildPhase.Parameter
 
-        match GetWarningNumber s with
+        match GetWarningNumber(m, WarningDescription.String s, tcConfigB.langVersion, WarningNumberSource.CommandLineOption) with
         | None -> ()
         | Some n ->
             // warnon 62 turns on mlCompatibility, e.g. shows ML compat items in intellisense menus

src/Compiler/Driver/CompilerConfig.fsi

@@ -927,7 +927,20 @@ val TryResolveFileUsingPaths: paths: string seq * m: range * fileName: string ->
 
 val ResolveFileUsingPaths: paths: string seq * m: range * fileName: string -> string
 
-val GetWarningNumber: string -> int option
+[<RequireQualifiedAccess>]
+type WarningNumberSource =
+    | CommandLineOption
+    | CompilerDirective
+
+[<RequireQualifiedAccess>]
+type WarningDescription =
+    | Int32 of int
+    | String of string
+    | Ident of Ident
+
+val GetWarningNumber:
+    m: range * description: WarningDescription * langVersion: LanguageVersion * source: WarningNumberSource ->
+        int option
 
 /// Get the name used for FSharp.Core
 val GetFSharpCoreLibraryName: unit -> string