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

src/fsharp/TypeChecker.fs

@@ -7658,17 +7658,24 @@ and TcComputationExpression cenv env overallTy mWhole (interpExpr: Expr) builder
 
                     Some (nm, maintainsVarSpaceUsingBind, maintainsVarSpace, allowInto, isLikeZip, isLikeJoin, isLikeGroupJoin, joinConditionWord, methInfo))
 
-    let customOperationMethodsIndexedByKeyword = 
+    let customOperationMethodsIndexedByKeyword =
         customOperationMethods
         |> Seq.groupBy (fun (nm, _, _, _, _, _, _, _, _) -> nm)
-        |> Seq.map (fun (nm, g) -> (nm, Seq.toList g))
+        |> Seq.map (fun (nm, g) ->
+            (nm,
+                g
+                |> Seq.distinctBy (fun (_, _, _, _, _, _, _, _, methInfo) -> methInfo.LogicalName)
+                |> Seq.toList))
         |> 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))
+        |> Seq.groupBy (fun (_, _, _, _, _, _, _, _, methInfo) -> methInfo.LogicalName)        
+        |> Seq.map (fun (nm, g) ->
+            (nm,
+                g 
+                |> Seq.distinctBy (fun (nm, _, _, _, _, _, _, _, _) -> nm) |> Seq.toList ))
         |> dict
 
 
@@ -8299,6 +8306,66 @@ and TcComputationExpression cenv env overallTy mWhole (interpExpr: Expr) builder
             // Now run the consumeCustomOpClauses
             Some (consumeCustomOpClauses q varSpace dataCompPriorToOp comp false mClause)
 
+                        let dataCompAfterOp = 
+                            match opExpr with 
+                            | StripApps(SingleIdent nm, args) -> 
+                                // Check for the [<ProjectionParameter>] attribute on each argument position
+                                let args = args |> List.mapi (fun i arg -> if isCustomOperationProjectionParameter (i+1) nm then SynExpr.Lambda (false, false, varSpaceSimplePat, arg, arg.Range.MakeSynthetic()) else arg)
+                                mkSynCall methInfo.DisplayName mClause (dataCompPrior :: args)
+                            | _ -> failwith "unreachable"
+
+                        match optionalCont with 
+                        | None -> 
+                            match optionalIntoPat  with 
+                            | Some intoPat -> errorR(Error(FSComp.SR.tcIntoNeedsRestOfQuery(), intoPat.Range))
+                            | None -> ()
+                            dataCompAfterOp
+
+                        | Some contExpr -> 
+
+                                // select a.Name into name; ...
+                                // distinct into d; ...
+                                //
+                                // Rebind the into pattern and process the rest of the clauses
+                                match optionalIntoPat with 
+                                | Some intoPat -> 
+                                    if not (customOperationAllowsInto nm) then 
+                                        error(Error(FSComp.SR.tcOperatorDoesntAcceptInto(nm.idText), intoPat.Range))
+
+                                    // Rebind using either for ... or let!....
+                                    let rebind = 
+                                        if maintainsVarSpaceUsingBind then 
+                                            SynExpr.LetOrUseBang(NoSequencePointAtLetBinding, false, false, intoPat, dataCompAfterOp, contExpr, intoPat.Range) 
+                                        else 
+                                            SynExpr.ForEach (NoSequencePointAtForLoop, SeqExprOnly false, false, intoPat, dataCompAfterOp, contExpr, intoPat.Range)
+
+                                    trans true q emptyVarSpace rebind id
+
+                                // select a.Name; ...
+                                // distinct; ...
+                                //
+                                // Process the rest of the clauses
+                                | None -> 
+                                    if maintainsVarSpace || maintainsVarSpaceUsingBind then
+                                        consumeClauses varSpace dataCompAfterOp contExpr maintainsVarSpaceUsingBind
+                                    else
+                                        consumeClauses emptyVarSpace dataCompAfterOp contExpr false 
+
+                // No more custom operator clauses in compClausesExpr, but there may be clauses like join, yield etc. 
+                // Bind/iterate the dataCompPrior and use compClausesExpr as the body.
+                | _ -> 
+                    // Rebind using either for ... or let!....
+                    let rebind = 
+                        if lastUsesBind then 
+                            SynExpr.LetOrUseBang(NoSequencePointAtLetBinding, false, false, varSpacePat, dataCompPrior, compClausesExpr, compClausesExpr.Range) 
+                        else 
+                            SynExpr.ForEach (NoSequencePointAtForLoop, SeqExprOnly false, false, varSpacePat, dataCompPrior, compClausesExpr, compClausesExpr.Range)
+
+                    trans true q varSpace rebind id
+
+            // Now run the consumeClauses
+            Some (consumeClauses varSpace dataCompPriorToOp comp false)
+
         | SynExpr.Sequential (sp, true, innerComp1, innerComp2, m) -> 
 
             // Check for 'where x > y' and other mis-applications of infix operators. If detected, give a good error message, and just ignore innerComp1

tests/fsharp/typecheck/sigs/neg60.bsl

@@ -55,8 +55,6 @@ neg60.fs(65,19,65,24): typecheck error FS3087: The custom operation 'where' refe
 
 neg60.fs(65,19,65,24): typecheck error FS3087: The custom operation 'where' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
 
-neg60.fs(65,19,65,24): typecheck error FS3087: The custom operation 'where' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
-
 neg60.fs(65,19,65,38): typecheck error FS0001: This expression was expected to have type
     'bool'    
 but here has type

tests/fsharp/typecheck/sigs/neg61.bsl

@@ -9,7 +9,10 @@ neg61.fs(22,13,22,16): typecheck error FS3145: This is not a known query operato
 
 neg61.fs(22,13,22,16): typecheck error FS0039: The value or constructor 'zip' is not defined.
 
-neg61.fs(26,13,26,19): typecheck error FS3099: 'select' 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.
+neg61.fs(25,13,25,28): typecheck error FS0001: This expression was expected to have type
+    'Linq.QuerySource<'a,'b> * ('a -> 'c)'    
+but here has type
+    'Linq.QuerySource<int,System.Collections.IEnumerable>'    
 
 neg61.fs(30,13,30,16): typecheck error FS3145: This is not a known query operator. Query operators are identifiers such as 'select', 'where', 'sortBy', 'thenBy', 'groupBy', 'groupValBy', 'join', 'groupJoin', 'sumBy' and 'averageBy', defined using corresponding methods on the 'QueryBuilder' type.
 
@@ -81,7 +84,10 @@ neg61.fs(148,20,148,23): typecheck error FS3147: This 'let' definition may not b
 
 neg61.fs(156,21,156,22): typecheck error FS3147: This 'let' definition may not be used in a query. Only simple value definitions may be used in queries.
 
-neg61.fs(171,13,171,18): typecheck error FS3099: 'sumBy' 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.
+neg61.fs(170,13,170,32): typecheck error FS0001: This expression was expected to have type
+    'Linq.QuerySource<'a,'b> * ('a -> 'c)'    
+but here has type
+    'Linq.QuerySource<int,System.Collections.IEnumerable>'    
 
 neg61.fs(174,22,174,23): typecheck error FS0041: No overloads match for method 'Source'.
 

tests/fsharp/typecheck/sigs/neg87.bsl

@@ -36,5 +36,3 @@ neg87.fsx(14,5,14,10): typecheck error FS3087: The custom operation 'test2' refe
 neg87.fsx(14,5,14,10): typecheck error FS3087: The custom operation 'test2' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
 
 neg87.fsx(14,5,14,10): typecheck error FS3087: The custom operation 'test2' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.
-
-neg87.fsx(14,5,14,10): typecheck error FS3087: The custom operation 'test2' refers to a method which is overloaded. The implementations of custom operations may not be overloaded.

tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/QueryExpressions/E_BadGroupValBy01.fs

@@ -1,7 +1,7 @@
 // #Conformance #DataExpressions #Query
 // DevDiv:179889, groupValBy was hard to use with poor diagnostics
-//<Expects status="error" span="(9,9-9,19)" id="FS3099">'groupValBy' is used with an incorrect number of arguments\. This is a custom operation in this query or computation expression\. Expected 2 argument\(s\), but given 0\.$</Expects>
-//<Expects status="error" span="(15,9-15,19)" id="FS3099">'groupValBy' is used with an incorrect number of arguments\. This is a custom operation in this query or computation expression\. Expected 2 argument\(s\), but given 1\.$</Expects>
+//<Expects status="error" span="(8,9-8,28)" id="FS0001">This expression was expected to have type.    'Linq\.QuerySource\<'a,'b\> \* \('a \-\> 'c\) \* \('a \-\> 'd\)'    .but here has type.    'Linq\.QuerySource\<int,System\.Collections\.IEnumerable\>'</Expects>
+//<Expects status="error" span="(15,9-15,21)" id="FS0501">The member or object constructor 'GroupValBy' takes 3 argument\(s\) but is here given 2\. The required signature is 'member Linq\.QueryBuilder\.GroupValBy \: source\:Linq\.QuerySource\<'T,'Q\> \* resultSelector\:\('T \-\> 'Value\) \* keySelector\:\('T \-\> 'Key\) \-\> Linq\.QuerySource\<System\.Linq\.IGrouping\<'Key,'Value\>,'Q\> when 'Key \: equality'\.$</Expects>
 
 let q1 = 
     query {

tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/QueryExpressions/E_BadGroupValBy02.fs

@@ -1,6 +1,6 @@
 // #Conformance #DataExpressions #Query
 // DevDiv:210830, groupValBy with poor diagnostics
-//<Expects status="error" span="(9,6-9,32)" id="FS0001">This expression was expected to have type.+'System\.Linq\.IGrouping<'a,'b>'.+but here has type.+'unit'</Expects>
+//<Expects status="error" span="(9,6-9,32)" id="FS0501">The member or object constructor 'GroupValBy' takes 3 argument\(s\) but is here given 4\. The required signature is 'member Linq\.QueryBuilder\.GroupValBy \: source\:Linq\.QuerySource\<'T,'Q\> \* resultSelector\:\('T \-\> 'Value\) \* keySelector\:\('T \-\> 'Key\) \-\> Linq\.QuerySource\<System\.Linq\.IGrouping\<'Key,'Value\>,'Q\> when 'Key \: equality'\.</Expects>
 
 let words = ["blueberry"; "chimpanzee"; ]
 let wordGroups =

tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/QueryExpressions/E_WhitespaceErrors01.fs

@@ -1,6 +1,6 @@
 // #Conformance #DataExpressions #Query
 // DevDiv:188241, just baselines errors around spacing
-//<Expects status="error" span="(15,13-15,18)" id="FS3099">'where' 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\.$</Expects>
+//<Expects status="error" span="(15,13-16,25)" id="FS0501">The member or object constructor 'Where' takes 2 argument\(s\) but is here given 4\. The required signature is 'member Linq\.QueryBuilder\.Where : source:Linq\.QuerySource<'T,'Q> \* predicate:\('T \-> bool\) \-> Linq\.QuerySource<'T,'Q>'\.$</Expects>
 
 let q1 = // no errors
     query {

tests/fsharpqa/Source/Conformance/Expressions/DataExpressions/QueryExpressions/env.lst

@@ -13,7 +13,7 @@ NoMT	SOURCE=ForWhereJoin01.fs                         SCFLAGS="--test:ErrorRange
 NoMT	SOURCE=E_WhitespaceErrors01.fs                   SCFLAGS="--test:ErrorRanges"			# E_WhitespaceErrors01.fs
 NoMT	SOURCE=E_WhitespaceErrors02.fs                   SCFLAGS="--test:ErrorRanges"			# E_WhitespaceErrors02.fs
 NoMT	SOURCE=E_WhitespaceErrors03.fs                   SCFLAGS="--test:ErrorRanges"			# E_WhitespaceErrors03.fs
-NoMT	SOURCE=E_BadGroupValBy01.fs                      SCFLAGS="--test:ErrorRanges"			# E_BadGroupValBy01.fs
+NoMT	SOURCE=E_BadGroupValBy01.fs                      SCFLAGS="--test:ErrorRanges --flaterrors"	# E_BadGroupValBy01.fs
 NoMT	SOURCE=E_BadGroupValBy02.fs                      SCFLAGS="--test:ErrorRanges --flaterrors"	# E_BadGroupValBy02.fs
 NoMT	SOURCE=E_FirstOrDefaultWithNulls01.fs            SCFLAGS="--test:ErrorRanges -r:Utils.dll"	# E_FirstOrDefaultWithNulls01.fs