Better error reporting for CE match!

docs/release-notes/.FSharp.Compiler.Service/9.0.200.md

@@ -10,5 +10,6 @@
 * Make ILTypeDef interface impls calculation lazy. ([PR #17392](https://github.com/dotnet/fsharp/pull/17392))
 * Better ranges for CE `let!` and `use!` error reporting. ([PR #17712](https://github.com/dotnet/fsharp/pull/17712))
 * Better ranges for CE `do!` error reporting. ([PR #17779](https://github.com/dotnet/fsharp/pull/17779))
+* Better ranges for CE `match!`. ([PR #17789](https://github.com/dotnet/fsharp/pull/17789))
 
 ### Breaking Changes

src/Compiler/Checking/Expressions/CheckExpressions.fs

@@ -6004,7 +6004,7 @@ and TcExprUndelayed (cenv: cenv) (overallTy: OverallTy) env tpenv (synExpr: SynE
         error(Error(FSComp.SR.tcConstructRequiresSequenceOrComputations(), m))
 
     | SynExpr.DoBang (trivia = { DoBangKeyword = m })
-    | SynExpr.MatchBang (range = m)
+    | SynExpr.MatchBang (trivia = { MatchBangKeyword = m })
     | SynExpr.WhileBang (range = m)
     | SynExpr.LetOrUseBang (trivia = { LetOrUseBangKeyword = m }) ->
         error(Error(FSComp.SR.tcConstructRequiresComputationExpression(), m))

tests/FSharp.Compiler.ComponentTests/Language/ComputationExpressionTests.fs

@@ -442,4 +442,55 @@ query {
         |> shouldFail
         |> withDiagnostics [
             (Error 3143, Line 4, Col 5, Line 4, Col 9, "'let!', 'use!' and 'do!' expressions may not be used in queries")
+        ]
+
+    [<Fact>]
+    let ``This control construct may only be used if the computation expression builder defines a 'Bind' method(match!)`` () =
+        Fsx """
+module Result =
+    let zip x1 x2 =
+        match x1,x2 with
+        | Ok x1res, Ok x2res -> Ok (x1res, x2res)
+        | Error e, _ -> Error e
+        | _, Error e -> Error e
+
+type ResultBuilder() =
+    member _.MergeSources(t1: Result<'T,'U>, t2: Result<'T1,'U>) = Result.zip t1 t2
+    member _.BindReturn(x: Result<'T,'U>, f) = Result.map f x
+    member _.Delay(f) = f()
+
+    member _.TryWith(r: Result<'T,'U>, f) =
+        match r with
+        | Ok x -> Ok x
+        | Error e -> f e
+
+let result = ResultBuilder()
+
+let run r2 r3 =
+    result {
+        match! r2 with
+        | Ok x -> return x
+        | Error e -> return e
+    }
+        """
+        |> ignoreWarnings
+        |> typecheck
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 708, Line 23, Col 9, Line 23, Col 15, "This control construct may only be used if the computation expression builder defines a 'Bind' method")
+        ]
+
+    [<Fact>]
+    let ``This construct may only be used within computation expressions(match!)`` () =
+        Fsx """
+let run r2 r3 =
+    match! r2 with
+    | Ok x -> x
+    | Error e -> e
+        """
+        |> ignoreWarnings
+        |> typecheck
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 750, Line 3, Col 5, Line 3, Col 11, "This construct may only be used within computation expressions")
         ]

tests/fsharp/typecheck/sigs/neg104.vsbsl

@@ -19,9 +19,9 @@ neg104.fs(35,19,35,20): parse error FS0010: Unexpected symbol '}' in definition.
 
 neg104.fs(36,1,36,1): parse error FS0010: Incomplete structured construct at or before this point in implementation file
 
-neg104.fs(8,9,8,30): typecheck error FS0750: This construct may only be used within computation expressions
+neg104.fs(8,9,8,15): typecheck error FS0750: This construct may only be used within computation expressions
 
-neg104.fs(10,9,10,30): typecheck error FS0750: This construct may only be used within computation expressions
+neg104.fs(10,9,10,15): typecheck error FS0750: This construct may only be used within computation expressions
 
 neg104.fs(20,9,20,15): typecheck error FS0025: Incomplete pattern matches on this expression.