Address feedback + fix test

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

@@ -9153,11 +9153,11 @@ public void SkipAnalyzersParse()
             parsedArgs.Errors.Verify();
             Assert.False(parsedArgs.SkipAnalyzers);
 
-            parsedArgs = DefaultParse(new[] { "/skipanalyzers- /skipanalyzers+", "a.cs" }, WorkingDirectory);
+            parsedArgs = DefaultParse(new[] { "/skipanalyzers-", "/skipanalyzers+", "a.cs" }, WorkingDirectory);
             parsedArgs.Errors.Verify();
             Assert.True(parsedArgs.SkipAnalyzers);
 
-            parsedArgs = DefaultParse(new[] { "/skipanalyzers /skipanalyzers-", "a.cs" }, WorkingDirectory);
+            parsedArgs = DefaultParse(new[] { "/skipanalyzers", "/skipanalyzers-", "a.cs" }, WorkingDirectory);
             parsedArgs.Errors.Verify();
             Assert.False(parsedArgs.SkipAnalyzers);
         }
@@ -12288,8 +12288,30 @@ public void TestAnalyzerFilteringBasedOnSeverity(DiagnosticSeverity defaultSever
             }
         }
 
+        [Fact]
+        public void SourceGenerators_EmbeddedSources()
+        {
+            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");
+
+            VerifyOutput(dir, src, includeCurrentAssemblyAsAnalyzerReference: false, additionalFlags: new[] { "/langversion:preview", "/debug:embedded", "/out:embed.exe" }, generators: new[] { generator }, analyzers: null);
+
+            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);
+
+            // Clean up temp files
+            CleanupAllGeneratedFiles(src.Path);
+        }
+
         [Theory, CombinatorialData]
-        public void SourceGenerators_EmbeddedSources(bool skipAnalyzers)
+        [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(@"
@@ -12300,14 +12322,38 @@ class C
             var generatedSource = "public class D { }";
             var generator = new SingleFileTestGenerator(generatedSource, "generatedSource.cs");
 
-            // Skip analyzers should have no impact on source generator execution.
+            // 'skipAnalyzers' should have no impact on source generator execution, but should prevent analyzer execution.
             var skipAnalyzersFlag = "/skipAnalyzers" + (skipAnalyzers ? "+" : "-");
 
-            VerifyOutput(dir, src, includeCurrentAssemblyAsAnalyzerReference: false, additionalFlags: new[] { "/langversion:preview", "/debug:embedded", "/out:embed.exe", skipAnalyzersFlag }, generators: new[] { generator }, analyzers: null);
+            // 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);
         }