From 36749e8e50e8fc1c6eb686f72e17a7eda543153a Mon Sep 17 00:00:00 2001
From: Cristian Ambrosini <cristian.ambrosini@sonarsource.com>
Date: Thu, 2 Feb 2023 15:15:02 +0100
Subject: [PATCH] Semplifications

---
 .../Rules/UnusedStringBuilder.cs              | 22 +++++++------------
 .../Rules/UnusedStringBuilderBase.cs          |  4 ++--
 .../Rules/UnusedStringBuilder.cs              | 11 ++++------
 3 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/analyzers/src/SonarAnalyzer.CSharp/Rules/UnusedStringBuilder.cs b/analyzers/src/SonarAnalyzer.CSharp/Rules/UnusedStringBuilder.cs
index d6c6203a63d..0bb7c77668e 100644
--- a/analyzers/src/SonarAnalyzer.CSharp/Rules/UnusedStringBuilder.cs
+++ b/analyzers/src/SonarAnalyzer.CSharp/Rules/UnusedStringBuilder.cs
@@ -25,30 +25,20 @@ public sealed class UnusedStringBuilder : UnusedStringBuilderBase<SyntaxKind, Va
 {
     protected override ILanguageFacade<SyntaxKind> Language => CSharpFacade.Instance;
 
-    private const string StringBuilderToString = "System.Text.StringBuilder.ToString()";
-
-    protected override string GetVariableName(VariableDeclaratorSyntax declaration) =>
-        declaration.GetName();
+    protected override string GetVariableName(VariableDeclaratorSyntax declaration) => declaration.GetName();
 
     protected override bool NeedsToTrack(VariableDeclaratorSyntax declaration, SemanticModel semanticModel) =>
         declaration.Initializer is not null
         && declaration.Initializer.Value is { } expression
-        && expression switch
-        {
-            ObjectCreationExpressionSyntax => ObjectCreationFactory.Create(expression).IsKnownType(KnownType.System_Text_StringBuilder, semanticModel),
-            _ when ImplicitObjectCreationExpressionSyntaxWrapper.IsInstance(expression) => ObjectCreationFactory.Create(expression).IsKnownType(KnownType.System_Text_StringBuilder, semanticModel),
-            _ => false
-        };
+        && IsStringBuilderObjectCreation(expression, semanticModel);
 
     protected override SyntaxNode GetAncestorBlock(VariableDeclaratorSyntax declaration) =>
         declaration.Ancestors().OfType<BlockSyntax>().FirstOrDefault();
 
-    protected override bool IsIsStringInvoked(string variableName, IList<InvocationExpressionSyntax> invocations, SemanticModel semanticModel) =>
+    protected override bool IsIsStringInvoked(string variableName, IList<InvocationExpressionSyntax> invocations) =>
         invocations.Any(x => x.Expression is MemberAccessExpressionSyntax { } member
             && IsSameVariable(member.Expression, variableName)
-            && member.NameIs(nameof(ToString))
-            && semanticModel.GetSymbolInfo(x).Symbol is IMethodSymbol symbol
-            && symbol.OriginalDefinition.ToString().Equals(StringBuilderToString));
+            && member.NameIs(nameof(ToString)));
 
     protected override bool IsPassedToMethod(string variableName, IList<InvocationExpressionSyntax> invocations) =>
         invocations.Any(x => x.ArgumentList.Arguments.Any(y => IsSameVariable(y.Expression, variableName)));
@@ -56,6 +46,10 @@ public sealed class UnusedStringBuilder : UnusedStringBuilderBase<SyntaxKind, Va
     protected override bool IsReturned(string variableName, IList<ReturnStatementSyntax> returnStatements) =>
         returnStatements.Any(x => IsSameVariable(x.Expression, variableName));
 
+    private static bool IsStringBuilderObjectCreation(ExpressionSyntax expression, SemanticModel semanticModel) =>
+        (expression is ObjectCreationExpressionSyntax || ImplicitObjectCreationExpressionSyntaxWrapper.IsInstance(expression))
+        && ObjectCreationFactory.Create(expression).IsKnownType(KnownType.System_Text_StringBuilder, semanticModel);
+
     private static bool IsSameVariable(ExpressionSyntax expression, string variableName) =>
         expression.DescendantNodesAndSelf().OfType<IdentifierNameSyntax>().Any(p => p.NameIs(variableName));
 }
diff --git a/analyzers/src/SonarAnalyzer.Common/Rules/UnusedStringBuilderBase.cs b/analyzers/src/SonarAnalyzer.Common/Rules/UnusedStringBuilderBase.cs
index 99551cdb288..9572b88fa5e 100644
--- a/analyzers/src/SonarAnalyzer.Common/Rules/UnusedStringBuilderBase.cs
+++ b/analyzers/src/SonarAnalyzer.Common/Rules/UnusedStringBuilderBase.cs
@@ -32,7 +32,7 @@ public abstract class UnusedStringBuilderBase<TSyntaxKind, TVariableDeclarator,
     protected abstract string GetVariableName(TVariableDeclarator declaration);
     protected abstract bool NeedsToTrack(TVariableDeclarator declaration, SemanticModel semanticModel);
     protected abstract SyntaxNode GetAncestorBlock(TVariableDeclarator declaration);
-    protected abstract bool IsIsStringInvoked(string variableName, IList<TInvocationExpression> invocations, SemanticModel semanticModel);
+    protected abstract bool IsIsStringInvoked(string variableName, IList<TInvocationExpression> invocations);
     protected abstract bool IsPassedToMethod(string variableName, IList<TInvocationExpression> invocations);
     protected abstract bool IsReturned(string variableName, IList<TReturnStatement> returnStatements);
 
@@ -53,7 +53,7 @@ public abstract class UnusedStringBuilderBase<TSyntaxKind, TVariableDeclarator,
                 return;
             }
             var invocations = block.DescendantNodes().OfType<TInvocationExpression>().ToList();
-            if (IsIsStringInvoked(variableName, invocations, c.SemanticModel)
+            if (IsIsStringInvoked(variableName, invocations)
                 || IsPassedToMethod(variableName, invocations)
                 || IsReturned(variableName, block.DescendantNodes().OfType<TReturnStatement>().ToList()))
             {
diff --git a/analyzers/src/SonarAnalyzer.VisualBasic/Rules/UnusedStringBuilder.cs b/analyzers/src/SonarAnalyzer.VisualBasic/Rules/UnusedStringBuilder.cs
index ee7f936fa73..19f2be69a72 100644
--- a/analyzers/src/SonarAnalyzer.VisualBasic/Rules/UnusedStringBuilder.cs
+++ b/analyzers/src/SonarAnalyzer.VisualBasic/Rules/UnusedStringBuilder.cs
@@ -27,8 +27,7 @@ public sealed class UnusedStringBuilder : UnusedStringBuilderBase<SyntaxKind, Va
 {
     protected override ILanguageFacade<SyntaxKind> Language => VisualBasicFacade.Instance;
 
-    protected override string GetVariableName(VariableDeclaratorSyntax declaration) =>
-        declaration.Names.FirstOrDefault().ToString();
+    protected override string GetVariableName(VariableDeclaratorSyntax declaration) => declaration.Names.FirstOrDefault().ToString();
 
     protected override bool NeedsToTrack(VariableDeclaratorSyntax expression, SemanticModel semanticModel) =>
         expression.Initializer is not null
@@ -36,14 +35,12 @@ public sealed class UnusedStringBuilder : UnusedStringBuilderBase<SyntaxKind, Va
         && objectCreation.Type.ToString().Equals(nameof(StringBuilder));
 
     protected override SyntaxNode GetAncestorBlock(VariableDeclaratorSyntax declaration) =>
-        declaration.Ancestors().OfType<MethodBlockSyntax>().Any()
-        ? declaration.Ancestors().OfType<MethodBlockSyntax>().First()
-        : declaration.Ancestors().OfType<AccessorBlockSyntax>().FirstOrDefault();
+        declaration.Ancestors().OfType<MethodBlockBaseSyntax>().First();
 
-    protected override bool IsIsStringInvoked(string variableName, IList<InvocationExpressionSyntax> invocations, SemanticModel semanticModel) =>
+    protected override bool IsIsStringInvoked(string variableName, IList<InvocationExpressionSyntax> invocations) =>
         invocations.Any(x => x.Expression is MemberAccessExpressionSyntax { } member
             && IsSameVariable(member.Expression, variableName)
-            && member.IsMemberAccessOnKnownType(nameof(ToString), KnownType.System_Text_StringBuilder, semanticModel));
+            && member.NameIs(nameof(ToString)));
 
     protected override bool IsPassedToMethod(string variableName, IList<InvocationExpressionSyntax> invocations) =>
         invocations.Any(x => x.ArgumentList.Arguments.Any(y => IsSameVariable(y.GetExpression(), variableName)));