Merge pull request #32752 from mavasani/Issue32702

Account for both parts of partial methods while computing dependent s…

src/Compilers/CSharp/Test/Semantic/Diagnostics/DiagnosticAnalyzerTests.cs

@@ -2913,5 +2913,69 @@ public void TestSymbolStartAnalyzer_NestedOperationAction_Inside_AllSymbolKinds(
                 Diagnostic("SymbolStartRuleId").WithArguments("e1", "Analyzer5").WithLocation(1, 1),
                 Diagnostic("SymbolStartRuleId").WithArguments("f1", "Analyzer6").WithLocation(1, 1));
         }
+
+        [Fact, WorkItem(32702, "https://github.com/dotnet/roslyn/issues/32702")]
+        public void TestInvocationInPartialMethod()
+        {
+            string source1 = @"
+static partial class B
+{
+    static partial void PartialMethod();
+}";
+            string source2 = @"
+static partial class B
+{
+    static partial void PartialMethod()
+    {
+        M();
+    }
+
+    private static void M() { }
+}";
+
+            var compilation = CreateCompilationWithMscorlib45(new[] { source1, source2 });
+            compilation.VerifyDiagnostics();
+
+            var analyzers = new DiagnosticAnalyzer[] { new SymbolStartAnalyzer(topLevelAction: false, SymbolKind.NamedType, OperationKind.Invocation) };
+
+            var expected = new[] {
+                Diagnostic("OperationRuleId").WithArguments("B", "PartialMethod", "M()", "Analyzer1").WithLocation(1, 1),
+                Diagnostic("SymbolStartRuleId").WithArguments("B", "Analyzer1").WithLocation(1, 1)
+            };
+
+            compilation.VerifyAnalyzerDiagnostics(analyzers, expected: expected);
+        }
+
+        [Fact, WorkItem(32702, "https://github.com/dotnet/roslyn/issues/32702")]
+        public void TestFieldReferenceInPartialMethod()
+        {
+            string source1 = @"
+static partial class B
+{
+    static partial void PartialMethod();
+}";
+            string source2 = @"
+static partial class B
+{
+    static partial void PartialMethod()
+    {
+        var x = _field;
+    }
+
+    private static int _field = 0;
+}";
+
+            var compilation = CreateCompilationWithMscorlib45(new[] { source1, source2 });
+            compilation.VerifyDiagnostics();
+
+            var analyzers = new DiagnosticAnalyzer[] { new SymbolStartAnalyzer(topLevelAction: true, SymbolKind.NamedType, OperationKind.FieldReference) };
+
+            var expected = new[] {
+                Diagnostic("OperationRuleId").WithArguments("B", "PartialMethod", "_field", "Analyzer1").WithLocation(1, 1),
+                Diagnostic("SymbolStartTopLevelRuleId").WithArguments("B", "Analyzer1").WithLocation(1, 1)
+            };
+
+            compilation.VerifyAnalyzerDiagnostics(analyzers, expected: expected);
+        }
     }
 }

src/Compilers/Core/Portable/DiagnosticAnalyzer/AnalyzerManager.AnalyzerExecutionContext.cs

@@ -173,6 +173,13 @@ void processMembers(IEnumerable<ISymbol> members)
                             {
                                 memberSet = memberSet ?? new HashSet<ISymbol>();
                                 memberSet.Add(member);
+
+                                // Ensure that we include symbols for both parts of partial methods.
+                                if (member is IMethodSymbol method &&
+                                    !(method.PartialImplementationPart is null))
+                                {
+                                    memberSet.Add(method.PartialImplementationPart);
+                                }
                             }
 
                             if (member.Kind != symbol.Kind &&

src/EditorFeatures/CSharpTest/RemoveUnusedMembers/RemoveUnusedMembersTests.cs

@@ -2257,6 +2257,35 @@ partial class MyClass
 
 static class MyClass3
 {
+}
+        </Document>
+    </Project>
+</Workspace>");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnusedMembers)]
+        [WorkItem(32702, "https://github.com/dotnet/roslyn/issues/32702")]
+        public async Task UsedExtensionMethod_ReferencedFromPartialMethod()
+        {
+            await TestDiagnosticMissingAsync(
+@"
+<Workspace>
+    <Project Language=""C#"" AssemblyName=""Assembly1"" CommonReferences=""true"">
+        <Document>
+static partial class B
+{
+    static partial void PartialMethod();
+}
+        </Document>
+        <Document>
+static partial class B
+{
+    static partial void PartialMethod()
+    {
+        UsedMethod();
+    }
+
+    private static void [|UsedMethod|]() { }
 }
         </Document>
     </Project>