Fix/RCS1031 and RCS1208

ChangeLog.md

@@ -27,12 +27,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix ([RCS1206](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1206.md)) ([#1049](https://github.com/JosefPihrt/Roslynator/pull/1049)).
 - Prevent possible recursion in ([RCS1235](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1235.md)) ([#1054](https://github.com/JosefPihrt/Roslynator/pull/1054)).
 - Fix ([RCS1223](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1223.md)) ([#1051](https://github.com/JosefPihrt/Roslynator/pull/1051)).
-- Do not remove braces in the cases where there are overlapping local variables. ([RCS1031](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1013.md), [RCS1211](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1211.md), [RCS1208](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1208.md)) ([#1039](https://github.com/JosefPihrt/Roslynator/pull/1039)).
+- Do not remove braces in the cases where there are overlapping local variables. ([RCS1031](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1013.md), [RCS1211](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1211.md), [RCS1208](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1208.md)) ([#1039](https://github.com/JosefPihrt/Roslynator/pull/1039),[#1058](https://github.com/JosefPihrt/Roslynator/pull/1058)).
 - [CLI] Analyze command does not create the XML output file and returns incorrect exit code when only compiler diagnostics are reported ([#1056](https://github.com/JosefPihrt/Roslynator/pull/1056) by @PeterKaszab).
 - [CLI] Fix exit code when multiple projects are processed ([#1061](https://github.com/JosefPihrt/Roslynator/pull/1061) by @PeterKaszab).
 - Fix code fix for CS0164 ([#1031](https://github.com/JosefPihrt/Roslynator/pull/1031)).
 
-
 ## [4.2.0] - 2022-11-27
 
 ### Added

src/Analyzers/CSharp/Analysis/RemoveUnnecessaryBracesInSwitchSectionAnalyzer.cs

@@ -121,11 +121,20 @@ private static bool LocallyDeclaredVariablesOverlapWithAnyOtherSwitchSections(Sw
 
         foreach (var otherSection in switchStatement.Sections)
         {
-            // If the other section is not a block then we do not need to check as if there were overlapping variables then there would already be a error.
-            if (otherSection.Statements.SingleOrDefault(shouldThrow: false) is not BlockSyntax otherBlock)
+            if (otherSection.Span.Contains(switchBlock.Span))
                 continue;
 
-            if (otherBlock.Span == switchBlock.Span)
+            foreach (var label in otherSection.Labels)
+            {
+                if (label is not CasePatternSwitchLabelSyntax casePatternSwitchLabelSyntax)
+                    continue;
+
+                if (PattenMatchingVariableDeclarationHelper.GetVariablesDeclared(casePatternSwitchLabelSyntax.Pattern).Intersect(sectionDeclaredVariablesNames).Any())
+                    return true;
+            }
+
+            // If the other section is not a block then we do not need to check as if there were overlapping variables then there would already be a error.
+            if (otherSection.Statements.SingleOrDefault(shouldThrow: false) is not BlockSyntax otherBlock)
                 continue;
 
             foreach (var v in semanticModel.AnalyzeDataFlow(otherBlock)!.VariablesDeclared)
@@ -137,5 +146,4 @@ private static bool LocallyDeclaredVariablesOverlapWithAnyOtherSwitchSections(Sw
         return false;
     }
 
-
 }

src/CSharp/PattenMatchingVariableDeclarationHelper.cs

@@ -0,0 +1,53 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace Roslynator.CSharp.Analysis;
+
+public static class PattenMatchingVariableDeclarationHelper
+{
+    public static IEnumerable<string> GetVariablesDeclared(PatternSyntax patternSyntax)
+    {
+        switch (patternSyntax)
+        {
+            case DeclarationPatternSyntax { Designation: var variableDesignationSyntax}:
+                return GetVariablesDeclared(variableDesignationSyntax);
+            case RecursivePatternSyntax { PositionalPatternClause: var positionalPatternClause, PropertyPatternClause: var propertyPatternClause, Designation: var designation }:
+                 var designationVars = designation != null ? GetVariablesDeclared(designation):Array.Empty<string>();
+                 var propertyVars = propertyPatternClause?.Subpatterns.SelectMany(p=>GetVariablesDeclared(p.Pattern)) ?? Array.Empty<string>();
+                 var positionalVars = positionalPatternClause?.Subpatterns.SelectMany(p => GetVariablesDeclared(p.Pattern)) ?? Array.Empty<string>();
+                 return designationVars.Concat(propertyVars).Concat(positionalVars);
+            case VarPatternSyntax { Designation: var variableDesignationSyntax}:
+                return GetVariablesDeclared(variableDesignationSyntax);
+            case BinaryPatternSyntax binaryPatternSyntax:
+                return GetVariablesDeclared(binaryPatternSyntax.Left)
+                    .Concat(GetVariablesDeclared(binaryPatternSyntax.Right));
+            case ParenthesizedPatternSyntax parenthesizedPatternSyntax:
+                return GetVariablesDeclared(parenthesizedPatternSyntax.Pattern);
+        }
+        return Array.Empty<string>();
+    }
+
+    public static IEnumerable<string> GetVariablesDeclared(VariableDesignationSyntax? designationSyntax)
+    {
+        switch (designationSyntax)
+        {
+            case SingleVariableDesignationSyntax singleVariableDesignationSyntax:
+                yield return singleVariableDesignationSyntax.Identifier.ValueText;
+                break;
+            case ParenthesizedVariableDesignationSyntax parenthesizedVariableDesignationSyntax:
+                foreach (var variable in parenthesizedVariableDesignationSyntax.Variables)
+                {
+                    foreach (var v in GetVariablesDeclared(variable))
+                    {
+                        yield return v;
+                    }
+                }
+                break;
+            case DiscardDesignationSyntax _:
+                yield break;
+        }
+    }
+
+}

src/Common/CSharp/Analysis/ReduceIfNesting/ReduceIfNestingAnalysis.cs

@@ -1,5 +1,8 @@
 // Copyright (c) Josef Pihrt and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
@@ -108,7 +111,16 @@ private static ReduceIfNestingAnalysisResult AnalyzeCore(
                 return Fail(parent);
             }
 
-            if (LocallyDeclaredVariablesOverlapWithOuterScope(ifStatement, parent, semanticModel))
+            var parentBody = parent switch
+            {
+                ForStatementSyntax forStatementSyntax => forStatementSyntax.Statement,
+                ForEachStatementSyntax forEachStatementSyntax => forEachStatementSyntax.Statement,
+                DoStatementSyntax doStatementSyntax => doStatementSyntax.Statement,
+                WhileStatementSyntax whileStatementSyntax => whileStatementSyntax.Statement,
+                _ => throw new ArgumentOutOfRangeException()
+            };
+
+            if (LocallyDeclaredVariablesOverlapWithOuterScope(ifStatement, parentBody, semanticModel))
                 return Fail(parent);
 
             return Success(jumpKind, parent);
@@ -134,19 +146,35 @@ private static ReduceIfNestingAnalysisResult AnalyzeCore(
                         return Fail(parent);
                     }
 
-                    if (LocallyDeclaredVariablesOverlapWithOuterScope(ifStatement, parent, semanticModel))
+                    var parentBody = parent switch
+                    {
+                        ConstructorDeclarationSyntax constructorDeclarationSyntax => constructorDeclarationSyntax.Body,
+                        DestructorDeclarationSyntax destructorDeclarationSyntax => destructorDeclarationSyntax.Body,
+                        AccessorDeclarationSyntax accessorDeclarationSyntax => accessorDeclarationSyntax.Body,
+                        _ => throw new NotImplementedException()
+                    };
+
+                    if (LocallyDeclaredVariablesOverlapWithOuterScope(ifStatement, parentBody, semanticModel))
                         return Fail(parent);
 
                     return Success(jumpKind, parent);
                 }
             case SyntaxKind.OperatorDeclaration:
             case SyntaxKind.ConversionOperatorDeclaration:
             case SyntaxKind.GetAccessorDeclaration:
-                {
+            {
                     if (jumpKind == SyntaxKind.None)
                         return Fail(parent);
 
-                    if (LocallyDeclaredVariablesOverlapWithOuterScope(ifStatement, parent, semanticModel))
+                    var parentBody = parent switch
+                    {
+                        OperatorDeclarationSyntax operatorDeclarationSyntax => operatorDeclarationSyntax.Body,
+                        ConversionOperatorDeclarationSyntax conversionOperatorDeclarationSyntax => conversionOperatorDeclarationSyntax.Body,
+                        AccessorDeclarationSyntax accessorDeclarationSyntax=> accessorDeclarationSyntax.Body,
+                        _ => throw new NotImplementedException()
+                    };
+
+                    if (LocallyDeclaredVariablesOverlapWithOuterScope(ifStatement, parentBody, semanticModel))
                         return Fail(parent);
 
                     return Success(jumpKind, parent);
@@ -294,13 +322,31 @@ SemanticModel semanticModel
         if (ifVariablesDeclared.IsEmpty)
             return false;
 
-        var parentStatementDeclared = semanticModel.AnalyzeDataFlow(parent)!
-            .VariablesDeclared;
-
+        IEnumerable<ISymbol> parentVariablesDeclared;
+        if (parent is SwitchSectionSyntax switchSectionSyntax)
+        {
+            var allDeclaredVariables = new List<ISymbol>();
+            foreach (var statement in switchSectionSyntax.Statements)
+            {
+                allDeclaredVariables.AddRange(semanticModel.AnalyzeDataFlow(statement)!.VariablesDeclared);
+            }
+
+            parentVariablesDeclared = allDeclaredVariables;
+        }
+        else
+        {
+            parentVariablesDeclared = semanticModel.AnalyzeDataFlow(parent)!
+                .VariablesDeclared;
+        }
+
         // The parent's declared variables will include those from the if and so we have to check for any symbols occurring twice.
-        return ifVariablesDeclared.Any(variable =>
-            parentStatementDeclared.Count(s => s.Name == variable.Name) > 1
-        );
+        foreach (var variable in ifVariablesDeclared)
+        {
+            if (parentVariablesDeclared.Count(s => s.Name == variable.Name) > 1)
+                return true;
+        }
+
+        return false;
     }
 
     private static bool IsNestedFix(SyntaxNode node, SemanticModel semanticModel, ReduceIfNestingOptions options, CancellationToken cancellationToken)

src/Tests/Analyzers.Tests/RCS1031RemoveUnnecessaryBracesInSwitchSectionTests.cs

@@ -237,7 +237,6 @@ void M()
 }
 ");
     }
-
     [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.RemoveUnnecessaryBracesInSwitchSection)]
     public async Task TestNoDiagnostic_WhenOverlappingLocalVariableDeclaration()
     {
@@ -267,4 +266,66 @@ void M()
 }
 ");
     }
+
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.RemoveUnnecessaryBracesInSwitchSection)]
+    public async Task TestNoDiagnostic_WhenOverlappingLocalVariableWithPatternMatchDeclaration()
+    {
+        await VerifyNoDiagnosticAsync(@"
+using System;
+
+class C
+{
+    void M()
+    {
+        object o = null;
+
+        switch (o)
+        {
+            case string s:
+                var x = 1;
+                break;
+            default:
+                {
+                    var s = 1;
+                    break;
+                }
+        }
+    }
 }
+");
+    }
+
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.RemoveUnnecessaryBracesInSwitchSection)]
+    public async Task TestNoDiagnostic_WhenOverlappingLocalVariableWithRecursivePatternMatchDeclaration()
+    {
+        await VerifyNoDiagnosticAsync(@"
+using System;
+
+class C
+{
+    class Wrapper
+    {
+        public string S;
+    }
+    void M()
+    {
+        object o = null;
+
+        switch (o)
+        {
+            case Wrapper { S: var s }:
+                var x = 1;
+                break;
+            default:
+                {
+                    var s = 1;
+                    break;
+                }
+        }
+    }
+}
+");
+    }
+}
+
+