Turn unused value warnings on by default

src/fsharp/CompilerDiagnostics.fs

@@ -372,8 +372,7 @@ let warningOn err level specificWarnOn =
     let n = GetDiagnosticNumber err
     List.contains n specificWarnOn ||
     // Some specific warnings are never on by default, i.e. unused variable warnings
-    match n with 
-    | 1182 -> false // chkUnusedValue - off by default
+    match n with
     | 3180 -> false // abImplicitHeapAllocation - off by default
     | _ -> level >= GetWarningLevel err 
 

src/fsharp/FSharp.Build/CreateFSharpManifestResourceName.fs

@@ -19,7 +19,7 @@ type CreateFSharpManifestResourceName public () =
                     (linkFileName:string),
                     (rootNamespace:string), (* may be null *)  
                     (dependentUponFileName:string), (* may be null *) 
-                    (binaryStream:System.IO.Stream) (* may be null *)) : string = 
+                    (_:System.IO.Stream) (* may be null *)) : string = 
 
         // The Visual CSharp and XBuild CSharp toolchains transform resource names like this:
         //     SubDir\abc.resx --> SubDir.abc.resources

src/fsharp/FSharp.Build/FSharpEmbedResourceText.fs

@@ -356,7 +356,7 @@ open Printf
             printMessage (sprintf "Reading %s" filename)
             let lines = File.ReadAllLines(filename) 
                         |> Array.mapi (fun i s -> i,s) // keep line numbers
-                        |> Array.filter (fun (i,s) -> not(s.StartsWith "#"))  // filter out comments
+                        |> Array.filter (fun (_,s) -> not(s.StartsWith "#"))  // filter out comments
 
             printMessage (sprintf "Parsing %s" filename)
             let stringInfos = lines |> Array.map (fun (i,s) -> ParseLine filename i s)
@@ -391,7 +391,7 @@ open Printf
 
             printMessage (sprintf "Generating resource methods for %s" outFilename)
             // gen each resource method
-            stringInfos |> Seq.iter (fun (lineNum, (optErrNum,ident), str, holes, netFormatString) ->
+            stringInfos |> Seq.iter (fun (lineNum, (optErrNum,ident), str, holes, _) ->
                 let formalArgs = new System.Text.StringBuilder()
                 let actualArgs = new System.Text.StringBuilder()
                 let mutable firstTime = true
@@ -428,14 +428,14 @@ open Printf
             // gen validation method
             fprintfn out "    /// Call this method once to validate that all known resources are valid; throws if not"
             fprintfn out "    static member RunStartupValidation() ="
-            stringInfos |> Seq.iter (fun (lineNum, (optErrNum,ident), str, holes, netFormatString) ->
+            stringInfos |> Seq.iter (fun (_, (_,ident), _, _, _) ->
                 fprintfn out "        ignore(GetString(\"%s\"))" ident
             )
             fprintfn out "        ()"  // in case there are 0 strings, we need the generated code to parse
             // gen to resx
             let xd = new System.Xml.XmlDocument()
             xd.LoadXml(xmlBoilerPlateString)
-            stringInfos |> Seq.iter (fun (lineNum, (optErrNum,ident), str, holes, netFormatString) ->
+            stringInfos |> Seq.iter (fun (_, (_,ident), _, _, netFormatString) ->
                 let xn = xd.CreateElement("data")
                 xn.SetAttribute("name",ident) |> ignore
                 xn.SetAttribute("xml:space","preserve") |> ignore

src/fsharp/FSharp.Build/Fsc.fs

@@ -63,7 +63,6 @@ type public Fsc () as this =
     let mutable tailcalls : bool = true
     let mutable targetProfile : string = null
     let mutable targetType : string = null
-    let mutable toolExe : string = "fsc.exe"
     let defaultToolPath =
         let locationOfThisDll =
             try Some(Path.GetDirectoryName(typeof<Fsc>.Assembly.Location))
@@ -556,7 +555,6 @@ type public Fsc () as this =
             match host with
             | null -> base.ExecuteTool(pathToTool, responseFileCommands, commandLineCommands)
             | _ ->
-                let sources = sources|>Array.map(fun i->i.ItemSpec)
                 let invokeCompiler baseCallDelegate =
                     try
                         let ret =
@@ -568,7 +566,7 @@ type public Fsc () as this =
                     | :? TargetInvocationException as tie when (match tie.InnerException with | :? Microsoft.Build.Exceptions.BuildAbortedException -> true | _ -> false) ->
                         fsc.Log.LogError(tie.InnerException.Message, [| |])
                         -1  // ok, this is what happens when VS IDE cancels the build, no need to assert, just log the build-canceled error and return -1 to denote task failed
-                    | e -> reraise()
+                    | _ -> reraise()
 
                 let baseCallDelegate = Func<int>(fun () -> fsc.BaseExecuteTool(pathToTool, responseFileCommands, commandLineCommands) )
                 try

src/fsharp/FSharp.Build/Fsi.fs

@@ -37,15 +37,12 @@ type public Fsi () as this =
     let mutable provideCommandLineArgs = false
     let mutable references : ITaskItem[] = [||]
     let mutable referencePath : string = null
-    let mutable resources : ITaskItem[] = [||]
     let mutable skipCompilerExecution = false
     let mutable sources : ITaskItem[] = [||]
     let mutable loadSources : ITaskItem[] = [||]
     let mutable useSources : ITaskItem[] = [||]
     let mutable tailcalls : bool = true
     let mutable targetProfile : string = null
-    let mutable targetType : string = null
-    let mutable toolExe : string = "fsi.exe"
     let mutable toolPath : string =
         let locationOfThisDll =
             try Some(Path.GetDirectoryName(typeof<Fsi>.Assembly.Location))
@@ -85,11 +82,6 @@ type public Fsi () as this =
             for item in references do
                 builder.AppendSwitchIfNotNull("-r:", item.ItemSpec)
 
-        let referencePathArray = // create a array of strings
-            match referencePath with
-            | null -> null
-            | _ -> referencePath.Split([|';'; ','|], StringSplitOptions.RemoveEmptyEntries)
-
         // NoWarn
         match disabledWarnings with
         | null -> ()
@@ -293,7 +285,6 @@ type public Fsi () as this =
             match host with
             | null -> base.ExecuteTool(pathToTool, responseFileCommands, commandLineCommands)
             | _ ->
-                let sources = sources|>Array.map(fun i->i.ItemSpec)
                 let invokeCompiler baseCallDelegate =
                     try
                         let ret =
@@ -305,7 +296,7 @@ type public Fsi () as this =
                     | :? TargetInvocationException as tie when (match tie.InnerException with | :? Microsoft.Build.Exceptions.BuildAbortedException -> true | _ -> false) ->
                         fsi.Log.LogError(tie.InnerException.Message, [| |])
                         -1  // ok, this is what happens when VS IDE cancels the build, no need to assert, just log the build-canceled error and return -1 to denote task failed
-                    | e -> reraise()
+                    | _ -> reraise()
 
                 let baseCallDelegate = Func<int>(fun () -> fsi.BaseExecuteTool(pathToTool, responseFileCommands, commandLineCommands) )
                 try

src/fsharp/FSharp.Build/MapSourceRoots.fs

@@ -122,7 +122,7 @@ type MapSourceRoots () =
 
                     for root in mappedSourceRoots do
                         match root.GetMetadata SourceControl with
-                        | HasValue v when isSourceControlled -> mapNestedRootIfEmpty root
+                        | HasValue _ when isSourceControlled -> mapNestedRootIfEmpty root
                         | NullOrEmpty when not isSourceControlled -> mapNestedRootIfEmpty root
                         | _ -> ()
 

src/fsharp/FSharp.Compiler.Interactive.Settings/FSharp.Compiler.Interactive.Settings.fsproj

@@ -9,7 +9,7 @@
     <AssemblyName>FSharp.Compiler.Interactive.Settings</AssemblyName>
     <NoWarn>$(NoWarn);45;55;62;75;1182;1204</NoWarn>
     <AllowCrossTargeting>true</AllowCrossTargeting>
-    <OtherFlags>$(OtherFlags) --maxerrors:20 --extraoptimizationloops:1</OtherFlags>
+    <OtherFlags>$(OtherFlags) --maxerrors:20 --extraoptimizationloops:1 --warnaserror-:1182</OtherFlags>
     <NGenBinary>true</NGenBinary>
   </PropertyGroup>
 

src/fsharp/FSharp.Compiler.Server.Shared/FSharpInteractiveServer.fs

@@ -41,7 +41,7 @@ type internal FSharpInteractiveServer() =
         LifetimeServices.RenewOnCallTime      <- TimeSpan(7,0,0,0);
         LifetimeServices.SponsorshipTimeout   <- TimeSpan(7,0,0,0);
         ChannelServices.RegisterChannel(chan,false);
-        let objRef = RemotingServices.Marshal(server,"FSIServer") 
+        RemotingServices.Marshal(server,"FSIServer")  |> ignore
         ()
 
     static member StartClient(channelName) =

tests/FSharp.Build.UnitTests/MapSourceRootsTests.fs

@@ -14,7 +14,7 @@ type MockEngine() =
     member val Messages = ResizeArray() with get
 
     interface IBuildEngine with
-        member this.BuildProjectFile(projectFileName: string, targetNames: string [], globalProperties: System.Collections.IDictionary, targetOutputs: System.Collections.IDictionary): bool =
+        member this.BuildProjectFile(_: string, _: string [], _: System.Collections.IDictionary, _: System.Collections.IDictionary): bool =
             failwith "Not Implemented"
         member this.ColumnNumberOfTaskNode: int = 0
         member this.ContinueOnError: bool = true
@@ -141,7 +141,7 @@ type MapSourceRootsTests() =
                 Assert.IsTrue(errorMessages |> Seq.exists (fun err -> err.EndsWith expectedErrorPath),
                               sprintf "expected an error to end with '%s', none did.\nMessages were:\n%A" expectedErrorPath errorMessages)
             )
-        | Some mappings ->
+        | Some _ ->
             Assert.Fail("Expected to fail on the inputs")
 
     [<Test>]
@@ -219,7 +219,7 @@ type MapSourceRootsTests() =
             |> Seq.iter (fun expectedErrorPath ->
                 Assert.IsTrue(errorMessages |> Seq.exists (fun err -> err.EndsWith expectedErrorPath), sprintf "expected an error to end with '%s', none did.\nMessages were:\n%A" expectedErrorPath errorMessages)
             )
-        | Some mappings ->
+        | Some _ ->
             Assert.Fail("Expected to fail on the inputs")
 
     [<TestCase(true)>]
@@ -348,7 +348,7 @@ type MapSourceRootsTests() =
             |> Seq.iter (fun expectedErrorPath ->
                 Assert.IsTrue(errorMessages |> Seq.exists (fun err -> err.EndsWith expectedErrorPath), sprintf "expected an error to end with '%s', none did.\nMessages were:\n%A" expectedErrorPath errorMessages)
             )
-        | Some mappings ->
+        | Some _ ->
             Assert.Fail("Expected to fail on the inputs")
 
     [<Test>]
@@ -379,7 +379,7 @@ type MapSourceRootsTests() =
             |> Seq.iter (fun expectedErrorPath ->
                 Assert.IsTrue(errorMessages |> Seq.exists (fun err -> err.EndsWith expectedErrorPath), sprintf "expected an error to end with '%s', none did.\nMessages were:\n%A" expectedErrorPath errorMessages)
             )
-        | Some mappings ->
+        | Some _ ->
             Assert.Fail("Expected to fail on the inputs")
 
     [<TestCase(true)>]

tests/FSharp.Compiler.ComponentTests/ErrorMessages/WarnExpressionTests.fs

@@ -82,8 +82,9 @@ let changeProperty() =
         """
         |> typecheck
         |> shouldFail
-        |> withSingleDiagnostic (Warning 20, Line 9, Col 5, Line 9, Col 23,
-                                 "The result of this equality expression has type 'bool' and is implicitly discarded. Consider using 'let' to bind the result to a name, e.g. 'let result = expression'.")
+        |> withDiagnostics [
+            (Warning 20, Line 9, Col 5, Line 9, Col 23, "The result of this equality expression has type 'bool' and is implicitly discarded. Consider using 'let' to bind the result to a name, e.g. 'let result = expression'.")
+            (Warning 1182,  Line 2, Col 14, Line 2, Col 23, "The value 'property1' is unused")]
 
     [<Fact>]
     let ``Warn If Implicitly Discarded``() =

tests/FSharp.Compiler.ComponentTests/FSharp.Compiler.ComponentTests.fsproj

@@ -18,6 +18,10 @@
     <Content Include="resources\**" CopyToOutputDirectory="Never" CopyToPublishDirectory="Never" />
   </ItemGroup>
 
+  <ItemGroup>
+    <EmbeddedResource Remove="NewFolder\**" />
+  </ItemGroup>
+
   <ItemGroup>
     <Compile Include="EmittedIL\Operators.fs" />
     <Compile Include="EmittedIL\Literals.fs" />
@@ -57,8 +61,4 @@
     <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Core\FSharp.Core.fsproj" />
     <ProjectReference Include="$(FSharpTestsRoot)\FSharp.Test.Utilities\FSharp.Test.Utilities.fsproj" />
   </ItemGroup>
-
-  <ItemGroup>
-    <Folder Include="NewFolder\" />
-  </ItemGroup>
 </Project>

tests/FSharp.Compiler.Private.Scripting.UnitTests/DependencyManagerInteractiveTests.fs

@@ -34,11 +34,6 @@ type DependencyManagerInteractiveTests() =
         | Ok(value) -> value
         | Error ex -> raise ex
 
-    let getErrors ((_value: Result<FsiValue option, exn>), (errors: FSharpErrorInfo[])) =
-        errors
-
-    let ignoreValue = getValue >> ignore
-
     [<Fact>]
     member __.``SmokeTest - #r nuget``() =
         let text = """
@@ -56,7 +51,7 @@ type DependencyManagerInteractiveTests() =
 #r @"nuget:System.Collections.Immutable.DoesNotExist, version=1.5.0"
 0"""
         use script = new scriptHost()
-        let opt, errors = script.Eval(text)
+        let _, errors = script.Eval(text)
         Assert.Equal(errors.Length, 1)
 
 (*
@@ -151,8 +146,6 @@ type DependencyManagerInteractiveTests() =
 
     [<Fact>]
     member __.``Multiple Instances of DependencyProvider should be isolated``() =
-
-        let assemblyProbingPaths () = Seq.empty<string>
         let nativeProbingRoots () = Seq.empty<string>
 
         use dp1 = new DependencyProvider(NativeResolutionProbe(nativeProbingRoots))
@@ -277,7 +270,6 @@ TorchSharp.Tensor.LongTensor.From([| 0L .. 100L |]).Device
                 | ErrorReportType.Warning -> printfn "PackageManagementWarning %d : %s" code message
             ResolvingErrorReport (report)
 
-        let mutable resolverPackageRoots = Seq.empty<string>
         let mutable resolverPackageRoots = Seq.empty<string>
         let mutable resolverReferences = Seq.empty<string>
 
@@ -374,11 +366,9 @@ printfn ""%A"" result
             ResolvingErrorReport (report)
 
         let mutable resolverPackageRoots = Seq.empty<string>
-        let mutable resolverPackageRoots = Seq.empty<string>
 
         let mutable resolverReferences = Seq.empty<string>
         let nativeProbingRoots () = resolverPackageRoots
-        let assemblyPaths () = resolverReferences
 
         // Restore packages, Get Reference dll paths and package roots
         let result =
@@ -513,10 +503,8 @@ x |> Seq.iter(fun r ->
             ResolvingErrorReport (report)
 
         let mutable resolverPackageRoots = Seq.empty<string>
-        let mutable resolverReferences = Seq.empty<string>
 
         let nativeProbingRoots () = resolverPackageRoots
-        let assemblyProbingPaths () = resolverReferences
 
         // Restore packages, Get Reference dll paths and package roots
         let result =
@@ -539,10 +527,8 @@ x |> Seq.iter(fun r ->
             ResolvingErrorReport (report)
 
         let mutable resolverPackageRoots = Seq.empty<string>
-        let mutable resolverReferences = Seq.empty<string>
 
         let nativeProbingRoots () = resolverPackageRoots
-        let assemblyProbingPaths () = resolverReferences
 
         // Restore packages, Get Reference dll paths and package roots
         let result =
@@ -645,7 +631,7 @@ x |> Seq.iter(fun r ->
 
         // Set up AssemblyResolver to resolve dll's
         do
-            use dp = new AssemblyResolveHandler(AssemblyResolutionProbe(assemblyProbingPaths))
+            use __ = new AssemblyResolveHandler(AssemblyResolutionProbe(assemblyProbingPaths))
 
             // Invoking a non-existent assembly causes a probe. which should invoke the call back
             try Assembly.Load("NoneSuchAssembly") |> ignore with _ -> ()
@@ -741,16 +727,15 @@ x |> Seq.iter(fun r ->
             lines.Add(line)
             match expected |> Array.tryFind(compareLine) with
             | None -> ()
-            | Some t ->
+            | Some _ ->
                 found <- found + 1
                 if found = expected.Length then sawExpectedOutput.Set() |> ignore
 
         let text = "#help"
         use output = new RedirectConsoleOutput()
         use script = new FSharpScript(quiet = false, langVersion = LangVersion.V47)
-        let mutable found = 0
         output.OutputProduced.Add (fun line -> verifyOutput line)
-        let opt = script.Eval(text) |> getValue
+        let _ = script.Eval(text) |> getValue
         Assert.True(sawExpectedOutput.WaitOne(TimeSpan.FromSeconds(5.0)), sprintf "Expected to see error sentinel value written\nexpected:%A\nactual:%A" expected lines)
 
 
@@ -790,14 +775,13 @@ x |> Seq.iter(fun r ->
             lines.Add(line)
             match expected |> Array.tryFind(compareLine) with
             | None -> ()
-            | Some t ->
+            | Some _ ->
                 found <- found + 1
                 if found = expected.Length then sawExpectedOutput.Set() |> ignore
 
         let text = "#help"
         use output = new RedirectConsoleOutput()
         use script = new FSharpScript(quiet = false, langVersion = LangVersion.Preview)
-        let mutable found = 0
         output.OutputProduced.Add (fun line -> verifyOutput line)
-        let opt = script.Eval(text) |> getValue
+        let _ = script.Eval(text) |> getValue
         Assert.True(sawExpectedOutput.WaitOne(TimeSpan.FromSeconds(5.0)), sprintf "Expected to see error sentinel value written\nexpected:%A\nactual:%A" expected lines)