Honor --nowarn for command-line option warnings

docs/release-notes/.FSharp.Compiler.Service/11.0.100.md

@@ -1,5 +1,6 @@
 ### Fixed
 
+* Honor `--nowarn` and `--warnaserror` for warnings emitted during command-line option parsing ([Issue #19576](https://github.com/dotnet/fsharp/issues/19576), [PR #19776](https://github.com/dotnet/fsharp/pull/19776))
 * Fix `[<return: X>]` prefix attributes being silently dropped on class members, and fix false-positive `AllowMultiple=false` errors when `[<X>]` and `[<return: X>]` are applied to the same binding. ([Issue #17904](https://github.com/dotnet/fsharp/issues/17904), [Issue #19020](https://github.com/dotnet/fsharp/issues/19020), [PR #19738](https://github.com/dotnet/fsharp/pull/19738))
 * Fix attributes on return type of unparenthesized tuple methods being silently dropped from IL. ([Issue #462](https://github.com/dotnet/fsharp/issues/462), [PR #19714](https://github.com/dotnet/fsharp/pull/19714))
 * Fix internal error FS0073 "Undefined or unsolved type variable" in IlxGen when nested inline SRTP functions with multiple overloads leave unsolved typars in the non-witness codegen path. ([Issue #19709](https://github.com/dotnet/fsharp/issues/19709), [PR #19710](https://github.com/dotnet/fsharp/pull/19710))

src/Compiler/Driver/fsc.fs

@@ -119,10 +119,9 @@ type IDiagnosticsLoggerProvider =
 
 type CapturingDiagnosticsLogger with
 
-    /// Commit the delayed diagnostics via a fresh temporary logger of the right kind.
     member x.CommitDelayedDiagnostics(diagnosticsLoggerProvider: IDiagnosticsLoggerProvider, tcConfigB, exiter) =
         let diagnosticsLogger = diagnosticsLoggerProvider.CreateLogger(tcConfigB, exiter)
-        x.CommitDelayedDiagnostics diagnosticsLogger
+        x.CommitDelayedDiagnostics(GetDiagnosticsLoggerFilteringByScopedNowarn(tcConfigB.diagnosticsOptions, diagnosticsLogger))
 
 /// The default DiagnosticsLogger implementation, reporting messages to the Console up to the maxerrors maximum
 type ConsoleLoggerProvider() =
@@ -578,7 +577,9 @@ let main1
     SetThreadDiagnosticsLoggerNoUnwind diagnosticsLogger
 
     // Forward all errors from flags
-    delayForFlagsLogger.CommitDelayedDiagnostics diagnosticsLogger
+    delayForFlagsLogger.CommitDelayedDiagnostics(
+        GetDiagnosticsLoggerFilteringByScopedNowarn(tcConfigB.diagnosticsOptions, diagnosticsLogger)
+    )
 
     if not tcConfigB.continueAfterParseFailure then
         AbortOnError(diagnosticsLogger, exiter)

tests/FSharp.Compiler.ComponentTests/CompilerOptions/fsc/warn/nowarn_for_cmdline_warnings.fs

@@ -0,0 +1,78 @@
+// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
+
+namespace CompilerOptions.Fsc
+
+open Xunit
+open FSharp.Test
+open FSharp.Test.Compiler
+
+/// Regression tests for https://github.com/dotnet/fsharp/issues/19576
+module ``Nowarn for command-line option warnings`` =
+
+    [<Fact>]
+    let ``command-line option warning is emitted`` () =
+        FSharp "module Module"
+        |> withOptions [ "--extraoptimizationloops:1" ]
+        |> ignoreWarnings
+        |> compile
+        |> shouldSucceed
+        |> withWarningCode 75
+        |> ignore
+
+    [<Fact>]
+    let ``--nowarn suppresses command-line option warning`` () =
+        FSharp "module Module"
+        |> withOptions [ "--extraoptimizationloops:1"; "--nowarn:75" ]
+        |> compile
+        |> shouldSucceed
+
+    [<Fact>]
+    let ``--nowarn suppresses only the targeted warning`` () =
+        FSharp "module Module"
+        |> withOptions [ "--extraoptimizationloops:1"; "--test:NoSuchTestFlag"; "--nowarn:75" ]
+        |> ignoreWarnings
+        |> compile
+        |> shouldSucceed
+        |> withWarningCode 1063
+        |> ignore
+
+    [<Fact>]
+    let ``--nowarn 3551 suppresses duplicate source file warning`` () =
+        let file =
+            SourceCodeFileKind.Fs(
+                { FileName = "test.fs"
+                  SourceText = Some """printfn "Hello" """ }
+            )
+
+        fsFromString file
+        |> FS
+        |> asExe
+        |> withAdditionalSourceFile file
+        |> withNoWarn 3551
+        |> compile
+        |> shouldSucceed
+
+    [<Fact>]
+    let ``--warnaserror+ promotes command-line option warning to error`` () =
+        FSharp "module Module"
+        |> withOptions [ "--warnaserror+"; "--extraoptimizationloops:1" ]
+        |> compile
+        |> shouldFail
+        |> withErrorCode 75
+        |> ignore
+
+    [<Fact>]
+    let ``--warnaserror+ with --nowarn suppresses rather than errors`` () =
+        FSharp "module Module"
+        |> withOptions [ "--warnaserror+"; "--extraoptimizationloops:1"; "--nowarn:75" ]
+        |> compile
+        |> shouldSucceed
+
+    [<Fact>]
+    let ``--warnaserror 75 with --nowarn 75 still errors because specific warnaserror wins`` () =
+        FSharp "module Module"
+        |> withOptions [ "--warnaserror:75"; "--extraoptimizationloops:1"; "--nowarn:75" ]
+        |> compile
+        |> shouldFail
+        |> withErrorCode 75
+        |> ignore

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

@@ -419,6 +419,7 @@
     <Compile Include="CompilerOptions\fsc\Platform.fs" />
     <Compile Include="CompilerOptions\fsc\times\times.fs" />
     <Compile Include="CompilerOptions\fsc\warn\warn.fs" />
+    <Compile Include="CompilerOptions\fsc\warn\nowarn_for_cmdline_warnings.fs" />
     <Compile Include="CompilerOptions\fsc\warnon\warnon.fs" />
     <Compile Include="CompilerOptions\fsc\reference.fs" />
     <Compile Include="CompilerOptions\fsc\reflectionfree.fs" />