Parser: recover on missing items in tuple expression

src/Compiler/FSComp.txt

@@ -1644,4 +1644,5 @@ reprStateMachineInvalidForm,"The state machine has an unexpected form"
 3520,invalidXmlDocPosition,"XML comment is not placed on a valid language element."
 3521,tcInvalidMemberDeclNameMissingOrHasParen,"Invalid member declaration. The name of the member is missing or has parentheses."
 3522,tcAnonRecdDuplicateFieldId,"The field '%s' appears multiple times in this record expression."
-3523,tcAnonRecdTypeDuplicateFieldId,"The field '%s' appears multiple times in this anonymous record type."
+3523,tcAnonRecdTypeDuplicateFieldId,"The field '%s' appears multiple times in this anonymous record type."
+3524,parsExpectingExpressionInTuple,"Expecting expression"

src/Compiler/SyntaxTree/SyntaxTreeOps.fs

@@ -985,3 +985,12 @@ let mkDynamicArgExpr expr =
         SynExpr.Const(con, con.Range ident.idRange)
     | SynExpr.Paren (expr = e) -> e
     | e -> e
+
+let rec normalizeTupleExpr exprs commas : SynExpr list * range list =
+    match exprs with
+    | SynExpr.Tuple (false, innerExprs, innerCommas, _) :: rest ->
+        let innerExprs, innerCommas =
+            normalizeTupleExpr (List.rev innerExprs) (List.rev innerCommas)
+
+        innerExprs @ rest, innerCommas @ commas
+    | _ -> exprs, commas

src/Compiler/SyntaxTree/SyntaxTreeOps.fsi

@@ -340,3 +340,5 @@ val (|SynPipeRight3|_|): SynExpr -> (SynExpr * SynExpr * SynExpr * SynExpr) opti
 val prependIdentInLongIdentWithTrivia: ident: SynIdent -> dotm: range -> lid: SynLongIdent -> SynLongIdent
 
 val mkDynamicArgExpr: expr: SynExpr -> SynExpr
+
+val normalizeTupleExpr: exprs: SynExpr list -> commas: range list -> SynExpr list * range List

src/Compiler/pars.fsy

@@ -4028,6 +4028,13 @@ declExpr:
 
   | tupleExpr  %prec expr_tuple
      { let exprs, commas = $1
+       let exprs, commas =
+           // Nested non-struct tuple is only possible during error recovery,
+           // in other situations there are intermediate nodes.
+           match exprs with
+           | SynExpr.Tuple(false, _, _, _) :: _ -> normalizeTupleExpr exprs commas
+           | _ -> exprs, commas
+
        SynExpr.Tuple (false, List.rev exprs, List.rev commas, (commas.Head, exprs) ||> unionRangeWithListBy (fun e -> e.Range) ) }
 
   | declExpr JOIN_IN declExpr
@@ -4384,6 +4391,17 @@ tupleExpr:
   | declExpr COMMA declExpr  
       { [$3 ; $1], [rhs parseState 2] }
 
+  | COMMA declExpr
+      { let commaRange = rhs parseState 1
+        reportParseErrorAt commaRange (FSComp.SR.parsExpectingExpressionInTuple())
+        [$2; arbExpr ("tupleExpr3", commaRange.StartRange)], [commaRange] }
+
+  | COMMA ends_coming_soon_or_recover
+      { if not $2 then reportParseErrorAt (rhs parseState 2) (FSComp.SR.parsExpectedExpressionAfterToken())
+        let commaRange = rhs parseState 1
+        let zeroWidthAtNextToken = (rhs parseState 2).StartRange
+        [(arbExpr("tupleExpr4", zeroWidthAtNextToken)); arbExpr ("tupleExpr5", commaRange.StartRange)], [commaRange] }
+
 minusExpr: 
   | MINUS minusExpr   %prec expr_prefix_plus_minus
       { mkSynPrefix (rhs parseState 1) (unionRanges (rhs parseState 1) $2.Range) "~-" $2 }

src/Compiler/xlf/FSComp.txt.cs.xlf

@@ -517,6 +517,11 @@
         <target state="translated">Neočekávaný token v definici typu. Za typem {0} se očekává =.</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">Tento přístup člena je nejednoznačný. Při vytváření objektu použijte závorky, např. (new SomeType(args)).MemberName'</target>

src/Compiler/xlf/FSComp.txt.de.xlf

@@ -517,6 +517,11 @@
         <target state="translated">Unerwartetes Token in Typdefinition. Nach Typ "{0}" wurde "=" erwartet.</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">Dieser Memberzugriff ist mehrdeutig. Setzen Sie Klammern um die Objekterstellung, z. B. "(new SomeType(args)). MemberName“</target>

src/Compiler/xlf/FSComp.txt.es.xlf

@@ -517,6 +517,11 @@
         <target state="translated">Token inesperado en la definición de tipo. Se esperaba "=" después del tipo "{0}".</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">Este acceso de miembro es ambiguo. Use paréntesis alrededor de la creación del objeto, por ejemplo, '(nuevo AlgúnTipo(args)).NombreMiembro'</target>

src/Compiler/xlf/FSComp.txt.fr.xlf

@@ -517,6 +517,11 @@
         <target state="translated">Jeton inattendu dans la définition de type. Signe '=' attendu après le type '{0}'.</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">L’accès à ce membre est ambigu. Utilisez des parenthèses autour de la création de l’objet, par exemple' (New SomeType (args)). MemberName</target>

src/Compiler/xlf/FSComp.txt.it.xlf

@@ -517,6 +517,11 @@
         <target state="translated">Token imprevisto nella definizione del tipo. Dopo il tipo '{0}' è previsto '='.</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">L'accesso ai membri è ambiguo. Utilizzare le parentesi intorno alla creazione oggetto, ad esempio “(New SomeType (args)). MemberName”</target>

src/Compiler/xlf/FSComp.txt.ja.xlf

@@ -517,6 +517,11 @@
         <target state="translated">型定義に予期しないトークンがあります。型 '{0}' の後には '=' が必要です。</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">このメンバーへのアクセスはあいまいです。オブジェクト作成の前後にはかっこを使用してください。例: '(new SomeType(args)).MemberName'</target>

src/Compiler/xlf/FSComp.txt.ko.xlf

@@ -517,6 +517,11 @@
         <target state="translated">형식 정의에 예기치 않은 토큰이 있습니다. '{0}' 형식 뒤에 '='가 필요합니다.</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">이 구성원 액세스가 모호합니다. 개체 생성 주위에 괄호를 사용하세요. 예: '(새로운 SomeType(인수)).MemberName'</target>

src/Compiler/xlf/FSComp.txt.pl.xlf

@@ -517,6 +517,11 @@
         <target state="translated">Nieoczekiwany token w definicji typu. Oczekiwano znaku „=” po typie „{0}”.</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">Dostęp tego elementu członkowskiego jest niejednoznaczny. W celu utworzenia obiektu użyj nawiasów, na przykład „(nowy SomeType(args)).MemberName”</target>

src/Compiler/xlf/FSComp.txt.pt-BR.xlf

@@ -517,6 +517,11 @@
         <target state="translated">Token inesperado na definição de tipo. Esperava-se '=' após o tipo '{0}'.</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">Este acesso de membro é ambíguo. Use parênteses em torno da criação do objeto, por exemplo, '(new SomeType(args)).MemberName''.</target>

src/Compiler/xlf/FSComp.txt.ru.xlf

@@ -517,6 +517,11 @@
         <target state="translated">Неожиданный токен в определении типа. После типа "{0}" ожидается "=".</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">Неоднозначный доступ к этому элементу. Заключите операцию создания объекта в круглые скобки, например (new Объект(аргументы)).Элемент</target>

src/Compiler/xlf/FSComp.txt.tr.xlf

@@ -517,6 +517,11 @@
         <target state="translated">Tür tanımında beklenmeyen belirteç var. '{0}' türünden sonra '=' bekleniyordu.</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">Bu üye erişimi belirsiz. Lütfen nesne oluşturma etrafında parantez kullanın, örneğin '(yeni SomeType (args)).MemberName’</target>

src/Compiler/xlf/FSComp.txt.zh-Hans.xlf

@@ -517,6 +517,11 @@
         <target state="translated">类型定义中出现意外标记。类型“{0}”后应为 "="。</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">此成员访问权限不明确。请在对象创建周围使用括号，例如 “(new SomeType(args)).MemberName”</target>

src/Compiler/xlf/FSComp.txt.zh-Hant.xlf

@@ -517,6 +517,11 @@
         <target state="translated">型別定義中出現非預期的權杖。類型 '{0}' 之後應該要有 '='。</target>
         <note />
       </trans-unit>
+      <trans-unit id="parsExpectingExpressionInTuple">
+        <source>Expecting expression</source>
+        <target state="new">Expecting expression</target>
+        <note />
+      </trans-unit>
       <trans-unit id="parsNewExprMemberAccess">
         <source>This member access is ambiguous. Please use parentheses around the object creation, e.g. '(new SomeType(args)).MemberName'</source>
         <target state="translated">此成員存取不明確。請在物件建立前後加上括弧，例如「(new SomeType(args)).MemberName」</target>

tests/service/Common.fs

@@ -226,6 +226,11 @@ let getSingleExprInModule (input: ParsedInput) =
     | SynModuleDecl.Expr (expr, _) -> expr
     | _ -> failwith "Unexpected expression"
 
+let getSingleParenInnerExpr expr =
+    match expr with
+    | SynModuleDecl.Expr(SynExpr.Paren(expr, _, _, _), _) -> expr
+    | _ -> failwith "Unexpected tree"
+
 let parseSourceCodeAndGetModule (source: string) =
     parseSourceCode ("test.fsx", source) |> getSingleModuleLikeDecl
 
@@ -449,6 +454,8 @@ let coreLibAssemblyName =
     "mscorlib"
 #endif
 
+let getRange (e: SynExpr) = e.Range
+
 let assertRange
     (expectedStartLine: int, expectedStartColumn: int)
     (expectedEndLine: int, expectedEndColumn: int)

tests/service/ParserTests.fs

@@ -3,6 +3,7 @@
 open FSharp.Compiler.Service.Tests.Common
 open FSharp.Compiler.Syntax
 open FSharp.Compiler.Text
+open FsUnit
 open NUnit.Framework
 
 [<Test>]
@@ -187,3 +188,137 @@ let f (x,
         | SynPat.FromParseError (SynPat.Paren (SynPat.FromParseError (SynPat.Wild _, _), _), _) -> ()
         | _ -> failwith "Unexpected tree"
     | _ -> failwith "Unexpected tree"
+
+let assertIsBefore (f: _ -> range) (a, b) =
+    let r1 = f a
+    let r2 = f b
+    Position.posGeq r2.Start r1.End |> shouldEqual true
+
+let checkExprOrder exprs =
+    exprs
+    |> List.pairwise
+    |> List.iter (assertIsBefore getRange)
+
+let checkRangeCountAndOrder commas =
+    commas
+    |> List.iter (fun (commas, length) ->
+        List.length commas |> shouldEqual length
+
+        commas
+        |> List.pairwise
+        |> List.iter (assertIsBefore id))
+
+[<Test>]
+let ``Expr - Tuple 01`` () =
+    let parseResults = getParseResults """
+(,)
+(,,)
+(,,,)
+"""
+    let exprs = getSingleModuleMemberDecls parseResults |> List.map getSingleParenInnerExpr
+    match exprs with
+    | [ SynExpr.Tuple(_, [SynExpr.ArbitraryAfterError _ as e11; SynExpr.ArbitraryAfterError _ as e12], c1, _)
+        SynExpr.Tuple(_, [SynExpr.ArbitraryAfterError _ as e21; SynExpr.ArbitraryAfterError _ as e22; SynExpr.ArbitraryAfterError _ as e23], c2, _)
+        SynExpr.Tuple(_, [SynExpr.ArbitraryAfterError _ as e31; SynExpr.ArbitraryAfterError _ as e32; SynExpr.ArbitraryAfterError _ as e33; SynExpr.ArbitraryAfterError _ as e34], c3, _) ] ->
+            [ e11; e12; e21; e22; e23; e31; e32; e33; e34 ] |> checkExprOrder
+            [ c1, 1; c2, 2; c3, 3 ] |> checkRangeCountAndOrder
+
+    | _ -> failwith "Unexpected tree"
+
+[<Test>]
+let ``Expr - Tuple 02`` () =
+    let parseResults = getParseResults """
+(1,)
+(,1)
+(1,1)
+"""
+    let exprs = getSingleModuleMemberDecls parseResults |> List.map getSingleParenInnerExpr    
+    match exprs with
+    | [ SynExpr.Tuple(_, [SynExpr.Const _ as e11; SynExpr.ArbitraryAfterError _ as e12], c1, _)
+        SynExpr.Tuple(_, [SynExpr.ArbitraryAfterError _  as e21; SynExpr.Const _  as e22], c2, _)
+        SynExpr.Tuple(_, [SynExpr.Const _  as e31; SynExpr.Const _  as e32], c3, _) ] ->
+            [ e11; e12; e21; e22; e31; e32 ] |> checkExprOrder
+            [ c1, 1; c2, 1; c3, 1 ] |> checkRangeCountAndOrder
+
+    | _ -> failwith "Unexpected tree"
+
+[<Test>]
+let ``Expr - Tuple 03`` () =
+    let parseResults = getParseResults """
+(1,,)
+(,1,)
+(,,1)
+
+(1,1,)
+(,1,1)
+(1,,1)
+
+(1,1,1)
+"""
+    let exprs = getSingleModuleMemberDecls parseResults |> List.map getSingleParenInnerExpr    
+    match exprs with
+    | [ SynExpr.Tuple(_, [SynExpr.Const _ as e11; SynExpr.ArbitraryAfterError _  as e12; SynExpr.ArbitraryAfterError _  as e13], c1, _)
+        SynExpr.Tuple(_, [SynExpr.ArbitraryAfterError _ as e21; SynExpr.Const _ as e22; SynExpr.ArbitraryAfterError _ as e23], c2, _)
+        SynExpr.Tuple(_, [SynExpr.ArbitraryAfterError _ as e31; SynExpr.ArbitraryAfterError _ as e32; SynExpr.Const _ as e33], c3, _)
+
+        SynExpr.Tuple(_, [SynExpr.Const _ as e41; SynExpr.Const _ as e42; SynExpr.ArbitraryAfterError _ as e43], c4, _)
+        SynExpr.Tuple(_, [SynExpr.ArbitraryAfterError _ as e51; SynExpr.Const _ as e52; SynExpr.Const _ as e53], c5, _)
+        SynExpr.Tuple(_, [SynExpr.Const _ as e61; SynExpr.ArbitraryAfterError _ as e62; SynExpr.Const _ as e63], c6, _)
+
+        SynExpr.Tuple(_, [SynExpr.Const _ as e71; SynExpr.Const _ as e72; SynExpr.Const _ as e73], c7, _) ] ->
+            [ e11; e12; e13; e21; e22; e23; e31; e32; e33
+              e41; e42; e43; e51; e52; e53; e61; e62; e63
+              e71; e72; e73 ]
+            |> checkExprOrder
+
+            [ c1, 2; c2, 2; c3, 2
+              c4, 2; c5, 2; c6, 2
+              c7, 2 ]
+            |> checkRangeCountAndOrder
+
+    | _ -> failwith "Unexpected tree"
+
+
+[<Test>]
+let ``Expr - Tuple 04`` () =
+    let parseResults = getParseResults """
+(,1,,2,3,,4,)
+"""
+    let exprs = getSingleModuleMemberDecls parseResults |> List.map getSingleParenInnerExpr
+    match exprs with
+    | [ SynExpr.Tuple(_, [ SynExpr.ArbitraryAfterError _ as e1
+                           SynExpr.Const _ as e2
+                           SynExpr.ArbitraryAfterError _ as e3
+                           SynExpr.Const _ as e4
+                           SynExpr.Const _ as e5
+                           SynExpr.ArbitraryAfterError _  as e6
+                           SynExpr.Const _ as e7
+                           SynExpr.ArbitraryAfterError _  as e8 ], c, _) ] ->
+            [ e1; e2; e3; e4; e5; e6; e7; e8 ]
+            |> checkExprOrder
+
+            [ c, 7 ] |> checkRangeCountAndOrder
+
+    | _ -> failwith "Unexpected tree"
+
+[<Test>]
+let ``Expr - Tuple 05`` () =
+    let parseResults = getParseResults """
+(1,
+"""
+    match getSingleModuleMemberDecls parseResults |> List.map getSingleParenInnerExpr with
+    | [ SynExpr.FromParseError(SynExpr.Tuple(_, [SynExpr.Const _; SynExpr.ArbitraryAfterError _], _, _), _) ] -> ()
+    | _ -> failwith "Unexpected tree"
+
+[<Test>]
+let ``Expr - Tuple 06`` () =
+    let parseResults = getParseResults """
+(1,,,2)
+"""
+    let synExprs = getSingleModuleMemberDecls parseResults |> List.map getSingleParenInnerExpr
+    match synExprs with
+    | [ SynExpr.Tuple(_, [ SynExpr.Const _
+                           SynExpr.ArbitraryAfterError _
+                           SynExpr.ArbitraryAfterError _
+                           SynExpr.Const _ ], _, _) ] -> ()
+    | _ -> failwith "Unexpected tree"