Merge pull request #31822 from mavasani/ConditionalDirectives

Add workaround to unused parameters/values analyzer for code with con…

src/EditorFeatures/CSharpTest/RemoveUnusedParametersAndValues/RemoveUnusedParametersTests.cs

@@ -861,6 +861,21 @@ public async Task Parameter_IndexerMethod()
 }");
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnusedParameters)]
+        public async Task Parameter_ConditionalDirective()
+        {
+            await TestDiagnosticMissingAsync(
+@"class C
+{
+    void M(int [|p|])
+    {
+#if DEBUG
+        System.Console.WriteLine(p);
+#endif
+    }
+}");
+        }
+
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnusedParameters)]
         public async Task Parameter_EventHandler_FirstParameter()
         {

src/EditorFeatures/CSharpTest/RemoveUnusedParametersAndValues/RemoveUnusedValueAssignmentTests.cs

@@ -5895,6 +5895,28 @@ void M()
     {
         List<int> [|x|] = null;
     }
+}", optionName);
+        }
+
+        [WorkItem(31583, "https://github.com/dotnet/roslyn/issues/31583")]
+        [Theory, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnusedValues)]
+        [InlineData(nameof(PreferDiscard))]
+        [InlineData(nameof(PreferUnusedLocal))]
+        public async Task UsedAssignment_ConditionalPreprocessorDirective(string optionName)
+        {
+            await TestMissingInRegularAndScriptAsync(
+@"#define DEBUG
+
+class C
+{
+    int M()
+    {
+        int [|x|] = 0;
+#if DEBUG
+        x = 1;
+#endif
+        return x;
+    }
 }", optionName);
         }
     }

src/EditorFeatures/VisualBasicTest/RemoveUnusedParametersAndValues/RemoveUnusedParametersTests.vb

@@ -73,6 +73,18 @@ $"Public Class C
 
     Public Sub M([|p|] As Integer) Handles field.E
     End Sub
+End Class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnusedParameters)>
+        Public Async Function Parameter_ConditionalDirective() As Task
+            Await TestDiagnosticMissingAsync(
+$"Public Class C
+    Public Sub M([|p|] As Integer)
+#If DEBUG Then
+        System.Console.WriteLine(p)
+#End If
+    End Sub
 End Class")
         End Function
     End Class

src/EditorFeatures/VisualBasicTest/RemoveUnusedParametersAndValues/RemoveUnusedValueAssignmentTests.vb

@@ -355,6 +355,20 @@ $"Class C
         [|count|] = count + 1
         Return False
     End Function
+End Class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnusedValues)>
+        Public Async Function UsedAssignment_ConditionalPreprocessorDirective() As Task
+            Await TestMissingInRegularAndScriptAsync(
+$"Class C
+    Function M() As Integer
+        Dim [|p|] = 0
+#If DEBUG Then
+        p = 1
+#End If
+        Return p
+    End Function
 End Class")
         End Function
     End Class

src/Features/CSharp/Portable/RemoveUnusedParametersAndValues/CSharpRemoveUnusedParametersAndValuesDiagnosticAnalyzer.cs

@@ -25,6 +25,9 @@ protected override bool SupportsDiscard(SyntaxTree tree)
         protected override bool MethodHasHandlesClause(IMethodSymbol method)
             => false;
 
+        protected override bool IsIfConditionalDirective(SyntaxNode node)
+            => node is IfDirectiveTriviaSyntax;
+
         // C# does not have an explicit "call" statement syntax for invocations with explicit value discard.
         protected override bool IsCallStatement(IExpressionStatementOperation expressionStatement)
             => false;

src/Features/Core/Portable/RemoveUnusedParametersAndValues/AbstractRemoveUnusedParametersAndValuesDiagnosticAnalyzer.SymbolStartAnalyzer.BlockAnalyzer.cs

@@ -68,6 +68,15 @@ public static void Analyze(OperationBlockStartAnalysisContext context, SymbolSta
                         return;
                     }
 
+                    // Bail out in presence of conditional directives
+                    // This is a workaround for https://github.com/dotnet/roslyn/issues/31820
+                    // Issue https://github.com/dotnet/roslyn/issues/31821 tracks
+                    // reverting this workaround.
+                    if (HasConditionalDirectives())
+                    {
+                        return;
+                    }
+
                     // All operation blocks for a symbol belong to the same tree.
                     var firstBlock = context.OperationBlocks[0];
                     if (!symbolStartAnalyzer._compilationAnalyzer.TryGetOptions(firstBlock.Syntax.SyntaxTree,
@@ -103,6 +112,20 @@ bool HasSyntaxErrors()
 
                         return false;
                     }
+
+                    bool HasConditionalDirectives()
+                    {
+                        foreach (var operationBlock in context.OperationBlocks)
+                        {
+                            if (operationBlock.Syntax.DescendantNodes(descendIntoTrivia: true)
+                                                     .Any(n => symbolStartAnalyzer._compilationAnalyzer.IsIfConditionalDirective(n)))
+                            {
+                                return true;
+                            }
+                        }
+
+                        return false;
+                    }
                 }
 
                 private void AnalyzeExpressionStatement(OperationAnalysisContext context)

src/Features/Core/Portable/RemoveUnusedParametersAndValues/AbstractRemoveUnusedParametersAndValuesDiagnosticAnalyzer.cs

@@ -89,6 +89,7 @@ protected AbstractRemoveUnusedParametersAndValuesDiagnosticAnalyzer()
         protected abstract Location GetDefinitionLocationToFade(IOperation unusedDefinition);
         protected abstract bool SupportsDiscard(SyntaxTree tree);
         protected abstract bool MethodHasHandlesClause(IMethodSymbol method);
+        protected abstract bool IsIfConditionalDirective(SyntaxNode node);
         protected abstract Option<CodeStyleOption<UnusedValuePreference>> UnusedValueExpressionStatementOption { get; }
         protected abstract Option<CodeStyleOption<UnusedValuePreference>> UnusedValueAssignmentOption { get; }
 

src/Features/VisualBasic/Portable/RemoveUnusedParametersAndValues/VisualBasicRemoveUnusedParametersAndValuesDiagnosticAnalyzer.vb

@@ -35,6 +35,10 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.RemoveUnusedParametersAndValues
                                                           End Function)
         End Function
 
+        Protected Overrides Function IsIfConditionalDirective(node As SyntaxNode) As Boolean
+            Return TryCast(node, IfDirectiveTriviaSyntax) IsNot Nothing
+        End Function
+
         Protected Overrides Function IsCallStatement(expressionStatement As IExpressionStatementOperation) As Boolean
             Return TryCast(expressionStatement.Syntax, CallStatementSyntax) IsNot Nothing
         End Function