[FSharpToFable] hacky fix for unknown attribute constructors (solving #1839 (comment))

Author: krauthaufen

src/Fable.Transforms/FSharp2Fable.fs

@@ -281,11 +281,12 @@ let rec private transformDecisionTargets (com: IFableCompiler) (ctx: Context) ac
 
 let private skipAttribute (name : string) =
     // TODO: skip all attributes where definiton not known???
-    name.StartsWith "Microsoft.FSharp.Core" ||
-    name.StartsWith "System.Reflection" ||
-    name.StartsWith "System.Runtime.CompilerServices" ||
-    name.StartsWith "System.ObsoleteAttribute" ||
-    name.StartsWith "System.Diagnostics"
+    // name.StartsWith "Microsoft.FSharp.Core" ||
+    // name.StartsWith "System.Reflection" ||
+    // name.StartsWith "System.Runtime.CompilerServices" ||
+    // name.StartsWith "System.ObsoleteAttribute" ||
+    // name.StartsWith "System.Diagnostics"
+    false
 
 let private transformAttribute (com: IFableCompiler) (ctx : Context) (a : FSharpAttribute) =
     match a.AttributeType.TryFullName with
@@ -310,11 +311,29 @@ let private transformAttribute (com: IFableCompiler) (ctx : Context) (a : FSharp
                 a.ConstructorArguments |> Seq.toList |> List.map (fun (t,v) ->
                     match v with
                     | :? string as str -> Fable.Value(Fable.StringConstant str, None)
+                    | :? int8 as v -> Fable.Value(Fable.NumberConstant(float v, NumberKind.Int8), None)
+                    | :? uint8 as v -> Fable.Value(Fable.NumberConstant(float v, NumberKind.UInt8), None)
+                    | :? int16 as v -> Fable.Value(Fable.NumberConstant(float v, NumberKind.Int16), None)
+                    | :? uint16 as v -> Fable.Value(Fable.NumberConstant(float v, NumberKind.UInt16), None)
+                    | :? int32 as v -> Fable.Value(Fable.NumberConstant(float v, NumberKind.Int32), None)
+                    | :? uint32 as v -> Fable.Value(Fable.NumberConstant(float v, NumberKind.UInt32), None)
+                    | :? float32 as v -> Fable.Value(Fable.NumberConstant(float v, NumberKind.Float32), None)
+                    | :? float as v -> Fable.Value(Fable.NumberConstant(v, NumberKind.Float64), None)
                     | _ -> Fable.Value(Fable.StringConstant (string v), None)
                 )
+            
+            
             let typ = makeTypeFromDef com ctx.GenericArgs (System.Collections.Generic.List() :> IList<_>) a.AttributeType
-            let x = makeCallFrom com ctx None typ false [] None args ctor
-            Some (fullname,x)
+            try
+                let x = makeCallFrom com ctx None typ false [] None args ctor
+                match x with
+                | AST.Fable.Value(AST.Fable.Null AST.Fable.Any, None) ->
+                    com.RemoveLastError()
+                    None
+                | _ ->                
+                    Some (fullname,x)
+            with _ ->
+                None                   
         | _ ->
             None
     | _ ->
@@ -1545,6 +1564,9 @@ type FableCompiler(com: ICompiler, implFiles: IDictionary<string, FSharpImplemen
         member __.AddLog(msg, severity, ?range, ?fileName:string, ?tag: string) =
             com.AddLog(msg, severity, ?range=range, ?fileName=fileName, ?tag=tag)
 
+        member __.RemoveLastError() = 
+            com.RemoveLastError()
+
 let getRootModuleFullName (file: FSharpImplementationFileContents) =
     let rootEnt, _ = getRootModuleAndDecls file.Declarations
     match rootEnt with

src/Fable.Transforms/Fable2Babel.fs

@@ -1901,6 +1901,8 @@ module Compiler =
             member __.GetOrAddInlineExpr(fullName, generate) = com.GetOrAddInlineExpr(fullName, generate)
             member __.AddLog(msg, severity, ?range, ?fileName:string, ?tag: string) =
                 com.AddLog(msg, severity, ?range=range, ?fileName=fileName, ?tag=tag)
+            member __.RemoveLastError() =
+                com.RemoveLastError()
 
     let makeCompiler com = new BabelCompiler(com)
 

src/Fable.Transforms/Global/Compiler.fs

@@ -34,3 +34,4 @@ type ICompiler =
     abstract GetOrAddInlineExpr: string * (unit->InlineExpr) -> InlineExpr
     abstract AddLog: msg:string * severity: Severity * ?range:SourceLocation
                         * ?fileName:string * ?tag: string -> unit
+    abstract RemoveLastError : unit -> unit                    

src/Fable.Transforms/State.fs

@@ -94,6 +94,13 @@ type Compiler(currentFile, project: Project, options, fableLibraryDir: string) =
               Range = range
               FileName = fileName }
             |> logs.Add
+
+        member __.RemoveLastError() =
+            let mutable i = logs.Count - 1
+            while i >= 0 && logs.[i].Severity <> Severity.Error do
+                i <- i - 1
+            if i >= 0 then logs.RemoveAt i  
+               
         // TODO: If name includes `$$2` at the end, remove it
         member __.GetUniqueVar(name) =
             id <- id + 1

tests/Main/ReflectionTests.fs

@@ -23,6 +23,7 @@ type TestType =
 type TestType2 =
     | Union2 of string
 
+[<System.Runtime.CompilerServices.Extension>]
 type TestType3 = class end
 type TestType4 = class end
 type TestType5 = class end