Add a new command line switch to skip analyzer execution

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -4680,6 +4680,7 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/CommandLine/CSharpCommandLineParser.cs

@@ -127,6 +127,7 @@ internal sealed override CommandLineArguments CommonParse(IEnumerable<string> ar
             string? runtimeMetadataVersion = null;
             bool errorEndLocation = false;
             bool reportAnalyzer = false;
+            bool skipAnalyzers = false;
             ArrayBuilder<InstrumentationKind> instrumentationKinds = ArrayBuilder<InstrumentationKind>.GetInstance();
             CultureInfo? preferredUILang = null;
             string? touchedFilesPath = null;
@@ -1179,6 +1180,21 @@ internal sealed override CommandLineArguments CommonParse(IEnumerable<string> ar
                             reportAnalyzer = true;
                             continue;
 
+                        case "skipanalyzers":
+                        case "skipanalyzers+":
+                            if (value != null)
+                                break;
+
+                            skipAnalyzers = true;
+                            continue;
+
+                        case "skipanalyzers-":
+                            if (value != null)
+                                break;
+
+                            skipAnalyzers = false;
+                            continue;
+
                         case "nostdlib":
                         case "nostdlib+":
                             if (value != null)
@@ -1503,6 +1519,7 @@ internal sealed override CommandLineArguments CommonParse(IEnumerable<string> ar
                 ShouldIncludeErrorEndLocation = errorEndLocation,
                 PreferredUILang = preferredUILang,
                 ReportAnalyzer = reportAnalyzer,
+                SkipAnalyzers = skipAnalyzers,
                 EmbeddedFiles = embeddedFiles.AsImmutable()
             };
         }

src/Compilers/CSharp/Portable/CommandLine/CSharpCompiler.cs

@@ -361,10 +361,11 @@ protected override bool TryGetCompilerDiagnosticCode(string diagnosticId, out ui
         protected override void ResolveAnalyzersFromArguments(
             List<DiagnosticInfo> diagnostics,
             CommonMessageProvider messageProvider,
+            bool skipAnalyzers,
             out ImmutableArray<DiagnosticAnalyzer> analyzers,
             out ImmutableArray<ISourceGenerator> generators)
         {
-            Arguments.ResolveAnalyzersFromArguments(LanguageNames.CSharp, diagnostics, messageProvider, AssemblyLoader, out analyzers, out generators);
+            Arguments.ResolveAnalyzersFromArguments(LanguageNames.CSharp, diagnostics, messageProvider, AssemblyLoader, skipAnalyzers, out analyzers, out generators);
         }
 
         protected override void ResolveEmbeddedFilesFromExternalSourceDirectives(

src/Compilers/CSharp/Portable/xlf/CSharpResources.cs.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.de.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.es.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.fr.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.it.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.ja.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.ko.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.pl.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.pt-BR.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.ru.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.tr.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.zh-Hans.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Portable/xlf/CSharpResources.zh-Hant.xlf

@@ -1016,6 +1016,7 @@
                               both mean SARIF version 2.1.0.
 -reportanalyzer               Report additional analyzer information, such as
                               execution time.
+-skipanalyzers[+|-]           Skip execution of diagnostic analyzers.
 
                        - LANGUAGE -
 -checked[+|-]                 Generate overflow checks

src/Compilers/CSharp/Test/CommandLine/CommandLineTests.cs

@@ -9129,6 +9129,66 @@ public void ReportAnalyzerOutput()
             CleanupAllGeneratedFiles(srcFile.Path);
         }
 
+        [Fact]
+        [WorkItem(40926, "https://github.com/dotnet/roslyn/issues/40926")]
+        public void SkipAnalyzersParse()
+        {
+            var parsedArgs = DefaultParse(new[] { "a.cs" }, WorkingDirectory);
+            parsedArgs.Errors.Verify();
+            Assert.False(parsedArgs.SkipAnalyzers);
+
+            parsedArgs = DefaultParse(new[] { "/skipanalyzers+", "a.cs" }, WorkingDirectory);
+            parsedArgs.Errors.Verify();
+            Assert.True(parsedArgs.SkipAnalyzers);
+
+            parsedArgs = DefaultParse(new[] { "/skipanalyzers", "a.cs" }, WorkingDirectory);
+            parsedArgs.Errors.Verify();
+            Assert.True(parsedArgs.SkipAnalyzers);
+
+            parsedArgs = DefaultParse(new[] { "/SKIPANALYZERS+", "a.cs" }, WorkingDirectory);
+            parsedArgs.Errors.Verify();
+            Assert.True(parsedArgs.SkipAnalyzers);
+
+            parsedArgs = DefaultParse(new[] { "/skipanalyzers-", "a.cs" }, WorkingDirectory);
+            parsedArgs.Errors.Verify();
+            Assert.False(parsedArgs.SkipAnalyzers);
+
+            parsedArgs = DefaultParse(new[] { "/skipanalyzers-", "/skipanalyzers+", "a.cs" }, WorkingDirectory);
+            parsedArgs.Errors.Verify();
+            Assert.True(parsedArgs.SkipAnalyzers);
+
+            parsedArgs = DefaultParse(new[] { "/skipanalyzers", "/skipanalyzers-", "a.cs" }, WorkingDirectory);
+            parsedArgs.Errors.Verify();
+            Assert.False(parsedArgs.SkipAnalyzers);
+        }
+
+        [Theory, CombinatorialData]
+        [WorkItem(40926, "https://github.com/dotnet/roslyn/issues/40926")]
+        public void SkipAnalyzersSemantics(bool skipAnalyzers)
+        {
+            var srcFile = Temp.CreateFile().WriteAllText(@"class C {}");
+            var srcDirectory = Path.GetDirectoryName(srcFile.Path);
+
+            var outWriter = new StringWriter(CultureInfo.InvariantCulture);
+            var skipAnalyzersFlag = "/skipanalyzers" + (skipAnalyzers ? "+" : "-");
+            var csc = CreateCSharpCompiler(null, srcDirectory, new[] { skipAnalyzersFlag, "/reportanalyzer", "/t:library", "/a:" + Assembly.GetExecutingAssembly().Location, srcFile.Path });
+            var exitCode = csc.Run(outWriter);
+            Assert.Equal(0, exitCode);
+            var output = outWriter.ToString();
+            if (skipAnalyzers)
+            {
+                Assert.DoesNotContain(CodeAnalysisResources.AnalyzerExecutionTimeColumnHeader, output, StringComparison.Ordinal);
+                Assert.DoesNotContain(new WarningDiagnosticAnalyzer().ToString(), output, StringComparison.Ordinal);
+            }
+            else
+            {
+                Assert.Contains(CodeAnalysisResources.AnalyzerExecutionTimeColumnHeader, output, StringComparison.Ordinal);
+                Assert.Contains(new WarningDiagnosticAnalyzer().ToString(), output, StringComparison.Ordinal);
+            }
+
+            CleanupAllGeneratedFiles(srcFile.Path);
+        }
+
         [Fact]
         [WorkItem(24835, "https://github.com/dotnet/roslyn/issues/24835")]
         public void TestCompilationSuccessIfOnlySuppressedDiagnostics()
@@ -12249,6 +12309,55 @@ class C
             CleanupAllGeneratedFiles(src.Path);
         }
 
+        [Theory, CombinatorialData]
+        [WorkItem(40926, "https://github.com/dotnet/roslyn/issues/40926")]
+        public void TestSourceGeneratorsWithAnalyzers(bool includeCurrentAssemblyAsAnalyzerReference, bool skipAnalyzers)
+        {
+            var dir = Temp.CreateDirectory();
+            var src = dir.CreateFile("temp.cs").WriteAllText(@"
+class C
+{
+}");
+
+            var generatedSource = "public class D { }";
+            var generator = new SingleFileTestGenerator(generatedSource, "generatedSource.cs");
+
+            // 'skipAnalyzers' should have no impact on source generator execution, but should prevent analyzer execution.
+            var skipAnalyzersFlag = "/skipAnalyzers" + (skipAnalyzers ? "+" : "-");
+
+            // Verify analyzers were executed only if both the following conditions were satisfied:
+            //  1. Current assembly was added as an analyzer reference, i.e. "includeCurrentAssemblyAsAnalyzerReference = true" and
+            //  2. We did not explicitly request skipping analyzers, i.e. "skipAnalyzers = false".
+            var expectedAnalayzerExecution = includeCurrentAssemblyAsAnalyzerReference && !skipAnalyzers;
+
+            // 'WarningDiagnosticAnalyzer' generates a warning for each named type.
+            // We expect two warnings for this test: type "C" defined in source and the source generator defined type.
+            // Additionally, we also have an analyzer that generates "warning CS8032: An instance of analyzer cannot be created"
+            var expectedWarningCount = expectedAnalayzerExecution ? 3 : 0;
+
+            var output = VerifyOutput(dir, src, includeCurrentAssemblyAsAnalyzerReference,
+                expectedWarningCount: expectedWarningCount,
+                additionalFlags: new[] { "/langversion:preview", "/debug:embedded", "/out:embed.exe", skipAnalyzersFlag },
+                generators: new[] { generator });
+
+            // Verify source generator was executed, regardless of the value of 'skipAnalyzers'.
+            var generatorPrefix = $"{generator.GetType().Module.ModuleVersionId}_{generator.GetType().FullName}";
+            ValidateEmbeddedSources_Portable(new Dictionary<string, string> { { Path.Combine(dir.Path, $"{generatorPrefix}_generatedSource.cs"), generatedSource } }, dir, true);
+
+            if (expectedAnalayzerExecution)
+            {
+                Assert.Contains("warning Warning01", output, StringComparison.Ordinal);
+                Assert.Contains("warning CS8032", output, StringComparison.Ordinal);
+            }
+            else
+            {
+                Assert.Empty(output);
+            }
+
+            // Clean up temp files
+            CleanupAllGeneratedFiles(src.Path);
+        }
+
         [Theory]
         [InlineData("partial class D {}", "file1.cs", "partial class E {}", "file2.cs")] // different files, different names
         [InlineData("partial class D {}", "file1.cs", "partial class E {}", "file1.cs")] // different files, same names

src/Compilers/Core/MSBuildTask/ManagedCompiler.cs

@@ -316,6 +316,12 @@ public string? SharedCompilationId
             get { return (string?)_store[nameof(SharedCompilationId)]; }
         }
 
+        public bool SkipAnalyzers
+        {
+            set { _store[nameof(SkipAnalyzers)] = value; }
+            get { return _store.GetOrDefault(nameof(SkipAnalyzers), false); }
+        }
+
         public bool SkipCompilerExecution
         {
             set { _store[nameof(SkipCompilerExecution)] = value; }
@@ -830,6 +836,7 @@ internal void AddResponseFileCommandsForSwitchesSinceInitialReleaseThatAreNeeded
             commandLine.AppendSwitchWithSplitting("/instrument:", Instrument, ",", ';', ',');
             commandLine.AppendSwitchIfNotNull("/sourcelink:", SourceLink);
             commandLine.AppendSwitchIfNotNull("/langversion:", LangVersion);
+            commandLine.AppendPlusOrMinusSwitch("/skipanalyzers", _store, nameof(SkipAnalyzers));
 
             AddFeatures(commandLine, Features);
             AddEmbeddedFilesToCommandLine(commandLine);

src/Compilers/Core/MSBuildTask/Microsoft.CSharp.Core.targets

@@ -126,6 +126,7 @@
          ResponseFiles="$(CompilerResponseFile)"
          RuntimeMetadataVersion="$(RuntimeMetadataVersion)"
          SharedCompilationId="$(SharedCompilationId)"
+         SkipAnalyzers="$(_SkipAnalyzers)"
          SkipCompilerExecution="$(SkipCompilerExecution)"
          Sources="@(Compile)"
          SubsystemVersion="$(SubsystemVersion)"

src/Compilers/Core/MSBuildTask/Microsoft.Managed.Core.targets

@@ -50,6 +50,28 @@
     </PropertyGroup>
   </Target>
 
+  <Target Name="_ComputeSkipAnalyzers" BeforeTargets="CoreCompile">
+    <!-- First, force clear non-user facing property '_SkipAnalyzers'. -->
+    <PropertyGroup>
+      <_SkipAnalyzers></_SkipAnalyzers>
+    </PropertyGroup>
+
+    <!--
+        Then, determine if '_SkipAnalyzers' needs to be 'true' based on user facing property 'RunAnalyzers'.
+        If 'RunAnalyzers' is not set, then fallback to user facing property 'RunAnalyzersDuringBuild'.
+        Latter property allows users to disable analyzers only for non-design time builds.
+        Design time builds are background builds inside Visual Studio,
+        see details here: https://github.com/dotnet/project-system/blob/master/docs/design-time-builds.md.
+        Setting 'RunAnalyzersDuringBuild' to false, without setting 'RunAnalyzers', allows users to
+        continue running analyzers in the background in Visual Studio while typing (i.e. intellisense),
+        while disabling analyzer execution on explicitly invoked non-design time builds.
+      -->
+    <PropertyGroup Condition="'$(RunAnalyzers)' == 'false' or
+                              ('$(RunAnalyzers)' == '' and '$(RunAnalyzersDuringBuild)' == 'false')">
+      <_SkipAnalyzers>true</_SkipAnalyzers>
+    </PropertyGroup>
+  </Target>
+
   <!--
     ========================
     .editorconfig Support

src/Compilers/Core/MSBuildTask/Microsoft.VisualBasic.Core.targets

@@ -103,6 +103,7 @@
          RuntimeMetadataVersion="$(RuntimeMetadataVersion)"
          SdkPath="$(FrameworkPathOverride)"
          SharedCompilationId="$(SharedCompilationId)"
+         SkipAnalyzers="$(_SkipAnalyzers)"
          SkipCompilerExecution="$(SkipCompilerExecution)"
          Sources="@(Compile)"
          SubsystemVersion="$(SubsystemVersion)"

src/Compilers/Core/MSBuildTaskTests/CscTests.cs

@@ -481,5 +481,24 @@ public void EditorConfig()
             csc.AnalyzerConfigFiles = MSBuildUtil.CreateTaskItems("..\\.editorconfig", "sub dir\\.editorconfig");
             Assert.Equal(@"/out:test.exe /analyzerconfig:..\.editorconfig /analyzerconfig:""sub dir\.editorconfig"" test.cs", csc.GenerateResponseFileContents());
         }
+
+        [Fact]
+        [WorkItem(40926, "https://github.com/dotnet/roslyn/issues/40926")]
+        public void SkipAnalyzersFlag()
+        {
+            var csc = new Csc();
+            csc.Sources = MSBuildUtil.CreateTaskItems("test.cs");
+            csc.SkipAnalyzers = true;
+            Assert.Equal("/out:test.exe /skipanalyzers+ test.cs", csc.GenerateResponseFileContents());
+
+            csc = new Csc();
+            csc.Sources = MSBuildUtil.CreateTaskItems("test.cs");
+            csc.SkipAnalyzers = false;
+            Assert.Equal("/out:test.exe /skipanalyzers- test.cs", csc.GenerateResponseFileContents());
+
+            csc = new Csc();
+            csc.Sources = MSBuildUtil.CreateTaskItems("test.cs");
+            Assert.Equal("/out:test.exe test.cs", csc.GenerateResponseFileContents());
+        }
     }
 }