[FS-1056] Allow overloads of custom keywords in computation expressions

src/fsharp/FSComp.txt

@@ -1224,6 +1224,7 @@ invalidFullNameForProvidedType,"invalid full name for provided type"
 3085,tcCustomOperationMayNotBeUsedInConjunctionWithNonSimpleLetBindings,"A custom operation may not be used in conjunction with a non-value or recursive 'let' binding in another part of this computation expression"
 3086,tcCustomOperationMayNotBeUsedHere,"A custom operation may not be used in conjunction with 'use', 'try/with', 'try/finally', 'if/then/else' or 'match' operators within this computation expression"
 3087,tcCustomOperationMayNotBeOverloaded,"The custom operation '%s' refers to a method which is overloaded. The implementations of custom operations may not be overloaded."
+featureOverloadsForCustomOperations,"overloads for custom operations"
 3090,tcIfThenElseMayNotBeUsedWithinQueries,"An if/then/else expression may not be used within queries. Consider using either an if/then expression, or use a sequence expression instead."
 3091,ilxgenUnexpectedArgumentToMethodHandleOfDuringCodegen,"Invalid argument to 'methodhandleof' during codegen"
 3092,etProvidedTypeReferenceMissingArgument,"A reference to a provided type was missing a value for the static parameter '%s'. You may need to recompile one or more referenced assemblies."

src/fsharp/LanguageFeatures.fs

@@ -34,6 +34,7 @@ type LanguageFeature =
     | WitnessPassing
     | InterfacesWithMultipleGenericInstantiation
     | StringInterpolation
+    | OverloadsForCustomOperations
 
 /// LanguageVersion management
 type LanguageVersion (specifiedVersionAsString) =
@@ -73,6 +74,7 @@ type LanguageVersion (specifiedVersionAsString) =
             LanguageFeature.InterfacesWithMultipleGenericInstantiation, previewVersion
             LanguageFeature.NameOf, previewVersion
             LanguageFeature.StringInterpolation, previewVersion
+            LanguageFeature.OverloadsForCustomOperations, previewVersion
         ]
 
     let specified =
@@ -144,6 +146,7 @@ type LanguageVersion (specifiedVersionAsString) =
         | LanguageFeature.WitnessPassing -> FSComp.SR.featureWitnessPassing()
         | LanguageFeature.InterfacesWithMultipleGenericInstantiation -> FSComp.SR.featureInterfacesWithMultipleGenericInstantiation()
         | LanguageFeature.StringInterpolation -> FSComp.SR.featureStringInterpolation()
+        | LanguageFeature.OverloadsForCustomOperations -> FSComp.SR.featureOverloadsForCustomOperations()
 
     /// Get a version string associated with the given feature.
     member _.GetFeatureVersionString feature =

src/fsharp/LanguageFeatures.fsi

@@ -22,6 +22,7 @@ type LanguageFeature =
     | WitnessPassing
     | InterfacesWithMultipleGenericInstantiation
     | StringInterpolation
+    | OverloadsForCustomOperations
 
 /// LanguageVersion management
 type LanguageVersion =

src/fsharp/TypeChecker.fs

@@ -7905,19 +7905,36 @@ and TcComputationExpression cenv env overallTy mWhole (interpExpr: Expr) builder
                     Some (nm, maintainsVarSpaceUsingBind, maintainsVarSpace, allowInto, isLikeZip, isLikeJoin, isLikeGroupJoin, joinConditionWord, methInfo))
 
     let customOperationMethodsIndexedByKeyword = 
-        customOperationMethods
-        |> Seq.groupBy (fun (nm, _, _, _, _, _, _, _, _) -> nm)
-        |> Seq.map (fun (nm, g) -> (nm, Seq.toList g))
+        if cenv.g.langVersion.SupportsFeature LanguageFeature.OverloadsForCustomOperations then
+            customOperationMethods
+            |> Seq.groupBy (fun (nm, _, _, _, _, _, _, _, _) -> nm)
+            |> Seq.map (fun (nm, group) ->
+                (nm,
+                    group
+                    |> Seq.distinctBy (fun (_, _, _, _, _, _, _, _, methInfo) -> methInfo.LogicalName)
+                    |> Seq.toList))
+        else
+            customOperationMethods
+            |> Seq.groupBy (fun (nm, _, _, _, _, _, _, _, _) -> nm)
+            |> Seq.map (fun (nm, g) -> (nm, Seq.toList g))
         |> dict
 
     // Check for duplicates by method name (keywords and method names must be 1:1)
     let customOperationMethodsIndexedByMethodName = 
-        customOperationMethods
-        |> Seq.groupBy (fun (_, _, _, _, _, _, _, _, methInfo) -> methInfo.LogicalName)
-        |> Seq.map (fun (nm, g) -> (nm, Seq.toList g))
+        if cenv.g.langVersion.SupportsFeature LanguageFeature.OverloadsForCustomOperations then
+            customOperationMethods
+            |> Seq.groupBy (fun (_, _, _, _, _, _, _, _, methInfo) -> methInfo.LogicalName)
+            |> Seq.map (fun (nm, group) ->
+                (nm,
+                    group
+                    |> Seq.distinctBy (fun (nm, _, _, _, _, _, _, _, _) -> nm)
+                    |> Seq.toList))
+        else
+            customOperationMethods
+            |> Seq.groupBy (fun (_, _, _, _, _, _, _, _, methInfo) -> methInfo.LogicalName)
+            |> Seq.map (fun (nm, g) -> (nm, Seq.toList g))
         |> dict
 
-
     /// Decide if the identifier represents a use of a custom query operator
     let tryGetDataForCustomOperation (nm: Ident) = 
         match customOperationMethodsIndexedByKeyword.TryGetValue nm.idText with 
@@ -8899,12 +8916,12 @@ and TcComputationExpression cenv env overallTy mWhole (interpExpr: Expr) builder
                         let maintainsVarSpace = customOperationMaintainsVarSpace nm
                         let maintainsVarSpaceUsingBind = customOperationMaintainsVarSpaceUsingBind nm
 
-                        let expectedArgCount = expectedArgCountForCustomOperator nm 
+                        let expectedArgCount = expectedArgCountForCustomOperator nm
 
                         let dataCompAfterOp = 
                             match opExpr with 
-                            | StripApps(SingleIdent nm, args) -> 
-                                if args.Length = expectedArgCount then 
+                            | StripApps(SingleIdent nm, args) ->
+                                if args.Length = expectedArgCount || cenv.g.langVersion.SupportsFeature LanguageFeature.OverloadsForCustomOperations then
                                     // Check for the [<ProjectionParameter>] attribute on each argument position
                                     let args = args |> List.mapi (fun i arg -> 
                                         if isCustomOperationProjectionParameter (i+1) nm then 
@@ -8913,7 +8930,7 @@ and TcComputationExpression cenv env overallTy mWhole (interpExpr: Expr) builder
                                     mkSynCall methInfo.DisplayName mClause (dataCompPrior :: args)
                                 else 
                                     errorR(Error(FSComp.SR.tcCustomOperationHasIncorrectArgCount(nm.idText, expectedArgCount, args.Length), nm.idRange))
-                                    mkSynCall methInfo.DisplayName mClause ([ dataCompPrior ] @ List.init expectedArgCount (fun i -> arbExpr("_arg" + string i, mClause))) 
+                                    mkSynCall methInfo.DisplayName mClause ([ dataCompPrior ] @ List.init expectedArgCount (fun i -> arbExpr("_arg" + string i, mClause)))
                             | _ -> failwith "unreachable"
 
                         match optionalCont with 

tests/fsharp/Compiler/Conformance/DataExpressions/ComputationExpressions.fs

@@ -710,3 +710,129 @@ let ceResult =
 check "grwerjkrwejgk42" ceResult.Value 2
     """
 
+    let overloadLib includeInternalExtensions includeExternalExtensions = 
+        """
+open System
+
+type Content = ArraySegment<byte> list
+
+type ContentBuilder() =
+    member this.Run(c: Content) =
+        let crlf = "\r\n"B
+        [|for part in List.rev c do
+            yield! part.Array.[part.Offset..(part.Count+part.Offset-1)]
+            yield! crlf |]
+
+    member this.Yield(_) = []
+
+    [<CustomOperation("body")>]
+    member this.Body(c: Content, segment: ArraySegment<byte>) =
+        segment::c
+        """ + (if includeInternalExtensions then """
+
+type ContentBuilder with
+    // unattributed internal type extension with same arity
+    member this.Body(c: Content, bytes: byte[]) =
+        ArraySegment<byte>(bytes, 0, bytes.Length)::c
+
+    // internal type extension with different arity
+    [<CustomOperation("body")>]
+    member this.Body(c: Content, bytes: byte[], offset, count) =
+        ArraySegment<byte>(bytes, offset, count)::c
+        """ else """
+
+    // unattributed type member with same arity
+    member this.Body(c: Content, bytes: byte[]) =
+        ArraySegment<byte>(bytes, 0, bytes.Length)::c
+
+    // type member with different arity
+    [<CustomOperation("body")>]
+    member this.Body(c: Content, bytes: byte[], offset, count) =
+        ArraySegment<byte>(bytes, offset, count)::c
+        """) + (if includeExternalExtensions then """
+
+module Extensions =
+    type ContentBuilder with
+        // unattributed external type extension with same arity
+        member this.Body(c: Content, content: System.IO.Stream) =
+            let mem = new System.IO.MemoryStream()
+            content.CopyTo(mem)
+            let bytes = mem.ToArray()
+            ArraySegment<byte>(bytes, 0, bytes.Length)::c
+
+        // external type extensions as ParamArray
+        [<CustomOperation("body")>]
+        member this.Body(c: Content, [<ParamArray>] contents: string[]) =
+            List.rev [for c in contents -> let b = Text.Encoding.ASCII.GetBytes c in ArraySegment<_>(b,0,b.Length)] @ c
+open Extensions
+        """ else """
+
+    // unattributed type member with same arity
+    member this.Body(c: Content, content: System.IO.Stream) =
+        let mem = new System.IO.MemoryStream()
+        content.CopyTo(mem)
+        let bytes = mem.ToArray()
+        ArraySegment<byte>(bytes, 0, bytes.Length)::c
+
+    // type members
+    [<CustomOperation("body")>]
+    member this.Body(c: Content, [<ParamArray>] contents: string[]) =
+        List.rev [for c in contents -> let b = Text.Encoding.ASCII.GetBytes c in ArraySegment<_>(b,0,b.Length)] @ c
+        """) + """
+
+let check msg actual expected = if actual <> expected then failwithf "FAILED %s, expected %A, got %A" msg expected actual
+        """
+
+    let OverloadLibTest inclInternalExt inclExternalExt source =
+        CompilerAssert.CompileExeAndRunWithOptions [| "/langversion:preview" |] (overloadLib inclInternalExt inclExternalExt + source)
+
+    [<Test>]
+    let ``OverloadLib accepts overloaded methods`` () =
+        OverloadLibTest false false """
+let mem = new System.IO.MemoryStream("Stream"B)
+let content = ContentBuilder()
+let ceResult =
+    content {
+        body "Name"
+        body (ArraySegment<_>("Email"B, 0, 5))
+        body "Password"B 2 4
+        body "BYTES"B
+        body mem
+        body "Description" "of" "content"
+    }
+check "TmFtZVxyXG5FbWF1" ceResult "Name\r\nEmail\r\nsswo\r\nBYTES\r\nStream\r\nDescription\r\nof\r\ncontent\r\n"B
+    """
+
+    [<Test>]
+    let ``OverloadLib accepts overloaded internal extension methods`` () =
+        OverloadLibTest true false """
+let mem = new System.IO.MemoryStream("Stream"B)
+let content = ContentBuilder()
+let ceResult =
+    content {
+        body "Name"
+        body (ArraySegment<_>("Email"B, 0, 5))
+        body "Password"B 2 4
+        body "BYTES"B
+        body mem
+        body "Description" "of" "content"
+    }
+check "TmFtZVxyXG5FbWF2" ceResult "Name\r\nEmail\r\nsswo\r\nBYTES\r\nStream\r\nDescription\r\nof\r\ncontent\r\n"B
+    """
+
+    [<Test>]
+    let ``OverloadLib accepts overloaded internal and external extensions`` () =
+        OverloadLibTest true true """
+let mem = new System.IO.MemoryStream("Stream"B)
+let content = ContentBuilder()
+let ceResult =
+    content {
+        body "Name"
+        body (ArraySegment<_>("Email"B, 0, 5))
+        body "Password"B 2 4
+        body "BYTES"B
+        body mem
+        body "Description" "of" "content"
+    }
+check "TmFtZVxyXG5FbWF3" ceResult "Name\r\nEmail\r\nsswo\r\nBYTES\r\nStream\r\nDescription\r\nof\r\ncontent\r\n"B
+    """

tests/fsharp/typecheck/sigs/neg60.bsl

@@ -79,3 +79,83 @@ neg60.fs(80,19,80,20): typecheck error FS0043: Expecting a type supporting the o
 neg60.fs(81,22,81,34): typecheck error FS0002: This function takes too many arguments, or is used in a context where a function is not expected
 
 neg60.fs(87,10,87,13): typecheck error FS0043: The type 'System.Nullable<int>' does not support the operator '?=?'. Consider opening the module 'Microsoft.FSharp.Linq.NullableOperators'.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(128,9,128,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(129,9,129,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(129,9,129,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(129,9,129,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(129,9,129,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(129,9,129,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(129,9,129,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(130,9,130,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(130,9,130,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(130,9,130,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(130,9,130,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(130,9,130,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(130,9,130,13): typecheck error FS3099: 'body' is used with an incorrect number of arguments. This is a custom operation in this query or computation expression. Expected 1 argument(s), but given 3.
+
+neg60.fs(131,9,131,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(131,9,131,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(131,9,131,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(131,9,131,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(131,9,131,13): typecheck error FS3087: The custom operation 'body' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
+
+neg60.fs(131,9,131,13): typecheck error FS3099: 'body' is used with an incorrect number of arguments. This is a custom operation in this query or computation expression. Expected 1 argument(s), but given 3.
+
+neg60.fs(177,9,177,13): typecheck error FS3099: 'text' is used with an incorrect number of arguments. This is a custom operation in this query or computation expression. Expected 1 argument(s), but given 0.
+
+neg60.fs(186,9,186,24): typecheck error FS3099: 'with_validators' is used with an incorrect number of arguments. This is a custom operation in this query or computation expression. Expected 1 argument(s), but given 2.
+
+neg60.fs(195,9,195,24): typecheck error FS3099: 'with_validators' is used with an incorrect number of arguments. This is a custom operation in this query or computation expression. Expected 1 argument(s), but given 3.