Better anonymous record error reporting

src/Compiler/Checking/CheckExpressions.fs

@@ -1808,7 +1808,6 @@ let BuildFieldMap (cenv: cenv) env isPartial ty (flds: ((Ident list * Ident) * '
     if isNil flds then invalidArg "flds" "BuildFieldMap"
 
     let fldCount = flds.Length
-
     let fldResolutions =
         let allFields = flds |> List.map (fun ((_, ident), _) -> ident)
         flds
@@ -7383,21 +7382,41 @@ and TcRecdExpr cenv overallTy env tpenv (inherits, withExprOpt, synRecdFields, m
                 | _ -> List.frontAndBack synLongId.LongIdent, exprBeingAssigned)
 
         let flds = if hasOrigExpr then GroupUpdatesToNestedFields flds else flds
+        // Check if the overall type is an anon record type and if so raise an copy-update syntax error
+        // let f (r: {| A: int; C: int |}) = { r with A = 1; B = 2; C = 3 }
+        if isAnonRecdTy cenv.g overallTy || isStructAnonRecdTy cenv.g overallTy then
+            for fld, _ in flds do
+                let _, fldId = fld
+                match TryFindAnonRecdFieldOfType g overallTy fldId.idText with
+                | Some item ->
+                    CallNameResolutionSink cenv.tcSink (fldId.idRange, env.eNameResEnv, item, emptyTyparInst, ItemOccurence.UseInType, env.eAccessRights)
+                | None -> ()
 
-        match flds with
-        | [] -> []
-        | _ ->
-            match BuildFieldMap cenv env hasOrigExpr overallTy flds mWholeExpr with
-            | None -> []
-            | Some(tinst, tcref, _, fldsList) ->
+            try
+                let firstPartRange = mkRange mWholeExpr.FileName mWholeExpr.Start (mkPos mWholeExpr.StartLine (mWholeExpr.StartColumn + 1))
+                // Use the  left { in the expression
+                error(Error(FSComp.SR.chkCopyUpdateSyntaxInAnonRecords(), firstPartRange))
+            with _ ->
+                // Use the  right } in the expression
+                let lastPartRange = mkRange mWholeExpr.FileName (mkPos mWholeExpr.StartLine (mWholeExpr.EndColumn - 1)) (mkPos mWholeExpr.StartLine (mWholeExpr.EndColumn))
+                error(Error(FSComp.SR.chkCopyUpdateSyntaxInAnonRecords(), lastPartRange))
+            []
+        else
+            // If the overall type is a record type build a map of the fields
+            match flds with
+            | [] -> []
+            | _ ->
+                match BuildFieldMap cenv env hasOrigExpr overallTy flds mWholeExpr with
+                | None -> []
+                | Some(tinst, tcref, _, fldsList) ->
 
-            let gtyp = mkAppTy tcref tinst
-            UnifyTypes cenv env mWholeExpr overallTy gtyp
+                let gtyp = mkAppTy tcref tinst
+                UnifyTypes cenv env mWholeExpr overallTy gtyp
 
-            [ for n, v in fldsList do
-                match v with
-                | Some v -> yield n, v
-                | None -> () ]
+                [ for n, v in fldsList do
+                    match v with
+                    | Some v -> yield n, v
+                    | None -> () ]
 
     let withExprInfoOpt =
         match withExprOptChecked with

src/Compiler/Checking/NameResolution.fs

@@ -3685,8 +3685,7 @@ let ResolveFieldPrim sink (ncenv: NameResolver) nenv ad ty (mp, id: Ident) allFi
                     error(ErrorWithSuggestions(errorText, m, id.idText, suggestLabels))
                 else
                     lookup()
-        | _ ->
-            lookup()
+        | ValueNone -> lookup()
     | _ ->
         let lid = (mp@[id])
         let tyconSearch ad () =

src/Compiler/FSComp.txt

@@ -1710,4 +1710,5 @@ featureAccessorFunctionShorthand,"underscore dot shorthand for accessor only fun
 3569,chkNotTailRecursive,"The member or function '%s' has the 'TailCallAttribute' attribute, but is not being used in a tail recursive way."
 3570,tcStaticBindingInExtrinsicAugmentation,"Static bindings cannot be added to extrinsic augmentations. Consider using a 'static member' instead."
 3571,pickleFsharpCoreBackwardsCompatible,"Newly added pickle state cannot be used in FSharp.Core, since it must be working in older compilers+tooling as well. The time window is at least 3 years after feature introduction. Violation: %s . Context: \n %s "
-3577,tcOverrideUsesMultipleArgumentsInsteadOfTuple,"This override takes a tuple instead of multiple arguments. Try to add an additional layer of parentheses at the method definition (e.g. 'member _.Foo((x, y))'), or remove parentheses at the abstract method declaration (e.g. 'abstract member Foo: 'a * 'b -> 'c')."
+3577,tcOverrideUsesMultipleArgumentsInsteadOfTuple,"This override takes a tuple instead of multiple arguments. Try to add an additional layer of parentheses at the method definition (e.g. 'member _.Foo((x, y))'), or remove parentheses at the abstract method declaration (e.g. 'abstract member Foo: 'a * 'b -> 'c')."
+3578,chkCopyUpdateSyntaxInAnonRecords,"This expression is an anonymous record, use {{|...|}} instead of {{...}}."

tests/FSharp.Compiler.ComponentTests/Conformance/Types/RecordTypes/AnonymousRecords.fs

@@ -19,7 +19,18 @@ module AnonRecd =
         |> shouldFail
         |> withErrorCode 3522
         |> withMessage "The field 'A' appears multiple times in this record expression."
-
+
+    [<Fact>]
+    let ``Anonymous Records incomplete`` () =
+        Fsx """
+let x () : {| A: int; B: string  |} =  {| A = 123 |}
+"""
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 1, Line 2, Col 40, Line 2, Col 53, "This anonymous record does not have enough fields. Add the missing fields [B].")
+        ]
+
     [<Fact>]
     let ``Anonymous Records with duplicate labels - Copy and update expression`` () =
         FSharp """
@@ -65,7 +76,57 @@ type ErrorResponse =
             Error 10, Line 7, Col 12, Line 7, Col 14, "Unexpected symbol '|}' in field declaration. Expected identifier or other token."
             Error 10, Line 10, Col 17, Line 10, Col 21, "Incomplete structured construct at or before this point in field declaration. Expected identifier or other token."
         ]
+
+    [<Fact>]
+    let ``Anonymous Record type annotation with with fields defined in a record`` () =
+        Fsx """
+type T = { ff : int }
 
+let t3 (t1: {| gu: string; ff: int |}) = { t1 with ff = 3 }
+        """
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 3578, Line 4, Col 42, Line 4, Col 43, "This expression is an anonymous record, use {|...|} instead of {...}.")
+            (Error 3578, Line 4, Col 59, Line 4, Col 60, "This expression is an anonymous record, use {|...|} instead of {...}.")
+        ]
+
+    [<Fact>]
+    let ``This expression was expected to have an anonymous Record but has a record`` () =
+        Fsx """
+let t3 (t1: {| gu: string; ff: int |}) = { t1 with ff = 3 }
+        """
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 3578, Line 2, Col 42, Line 2, Col 43, "This expression is an anonymous record, use {|...|} instead of {...}.")
+            (Error 3578, Line 2, Col 59, Line 2, Col 60, "This expression is an anonymous record, use {|...|} instead of {...}.")
+        ]
+
+    [<Fact>]
+    let ``This expression was expected to have an struct anonymous Record but has a record`` () =
+        Fsx """
+let t3 (t1: struct {| gu: string; ff: int |}) = { t1 with ff = 3 }
+        """
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 3578, Line 2, Col 49, Line 2, Col 50, "This expression is an anonymous record, use {|...|} instead of {...}.")
+            (Error 3578, Line 2, Col 66, Line 2, Col 67, "This expression is an anonymous record, use {|...|} instead of {...}.")
+        ]
+
+    [<Fact>]
+    let ``This expression was expected to have an anonymous with various properties Record but has a record`` () =
+        Fsx """
+let f (r: {| A: int; C: int |}) = { r with A = 1; B = 2; C = 3 }
+        """
+        |> compile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 3578, Line 2, Col 35, Line 2, Col 36, "This expression is an anonymous record, use {|...|} instead of {...}.")
+            (Error 3578, Line 2, Col 64, Line 2, Col 65, "This expression is an anonymous record, use {|...|} instead of {...}.")
+        ]
+
     [<Fact>]
     let ``Nested anonymous records where outer label = concatenated inner labels (see secondary issue reported in 6411)`` () =
         FSharp """
@@ -75,16 +136,3 @@ let x = {| abcd = {| ab = 4; cd = 1 |} |}
 """
         |> compile
         |> shouldSucceed
-
-    [<Fact>]
-    let ``Wrong update syntax`` () =
-        Fsx """
-let f (r: {| A: int |}) =
-    { r with A = 1 }
-"""
-        |> ignoreWarnings
-        |> compile
-        |> shouldFail
-        |> withDiagnostics [
-            (Error 39, Line 3, Col 14, Line 3, Col 15, "The record label 'A' is not defined.")
-        ]