C#: Use pattern matching

tamasvajk · tamasvajk · commit 28694513a13c · 2020-10-13T14:45:37.000+02:00
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Lambda.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Lambda.cs
@@ -30,10 +30,10 @@ private Lambda(ExpressionNodeInfo info, CSharpSyntaxNode body, IEnumerable<Param
                 foreach (var param in @params)
                     VisitParameter(param);
 
-                if (body is ExpressionSyntax)
-                    Create(cx, (ExpressionSyntax)body, this, 0);
-                else if (body is BlockSyntax)
-                    Statements.Block.Create(cx, (BlockSyntax)body, this, 0);
+                if (body is ExpressionSyntax exprBody)
+                    Create(cx, exprBody, this, 0);
+                else if (body is BlockSyntax blockBody)
+                    Statements.Block.Create(cx, blockBody, this, 0);
                 else
                     cx.ModelError(body, "Unhandled lambda body");
             });
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Types/Type.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Types/Type.cs
@@ -133,18 +133,18 @@ protected void PopulateType(TextWriter trapFile, bool constructUnderlyingTupleTy
                 trapFile.parent_namespace(this, Namespace.Create(Context, symbol.ContainingNamespace));
             }
 
-            if (symbol is IArrayTypeSymbol)
+            if (symbol is IArrayTypeSymbol array)
             {
                 // They are in the namespace of the original object
-                var elementType = ((IArrayTypeSymbol)symbol).ElementType;
+                var elementType = array.ElementType;
                 var ns = elementType.TypeKind == TypeKind.TypeParameter ? Context.Compilation.GlobalNamespace : elementType.ContainingNamespace;
                 if (ns != null)
                     trapFile.parent_namespace(this, Namespace.Create(Context, ns));
             }
 
-            if (symbol is IPointerTypeSymbol)
+            if (symbol is IPointerTypeSymbol pointer)
             {
-                var elementType = ((IPointerTypeSymbol)symbol).PointedAtType;
+                var elementType = pointer.PointedAtType;
                 var ns = elementType.TypeKind == TypeKind.TypeParameter ? Context.Compilation.GlobalNamespace : elementType.ContainingNamespace;
 
                 if (ns != null)
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/SymbolExtensions.cs b/csharp/extractor/Semmle.Extraction.CSharp/SymbolExtensions.cs
@@ -456,11 +456,11 @@ public static bool IsUnboundNullable(this ITypeSymbol type) =>
         /// <returns>The list of parameters, or an empty list.</returns>
         public static IEnumerable<IParameterSymbol> GetParameters(this ISymbol parameterizable)
         {
-            if (parameterizable is IMethodSymbol)
-                return ((IMethodSymbol)parameterizable).Parameters;
+            if (parameterizable is IMethodSymbol meth)
+                return meth.Parameters;
 
-            if (parameterizable is IPropertySymbol)
-                return ((IPropertySymbol)parameterizable).Parameters;
+            if (parameterizable is IPropertySymbol prop)
+                return prop.Parameters;
 
             return Enumerable.Empty<IParameterSymbol>();
         }
diff --git a/csharp/extractor/Semmle.Extraction/Id.cs b/csharp/extractor/Semmle.Extraction/Id.cs
@@ -58,9 +58,9 @@ public Key(params object[] args)
             TrapBuilder = new StringWriter();
             foreach (var arg in args)
             {
-                if (arg is IEntity)
+                if (arg is IEntity entity)
                 {
-                    var key = ((IEntity)arg).Label;
+                    var key = entity.Label;
                     TrapBuilder.Write("{#");
                     TrapBuilder.Write(key.Value.ToString());
                     TrapBuilder.Write("}");

Original file line number	Diff line number	Diff line change
`@@ -133,18 +133,18 @@ protected void PopulateType(TextWriter trapFile, bool constructUnderlyingTupleTy`
`133`	`133`	`trapFile.parent_namespace(this, Namespace.Create(Context, symbol.ContainingNamespace));`
`134`	`134`	`}`
`135`	`135`
`136`		`- if (symbol is IArrayTypeSymbol)`
	`136`	`+ if (symbol is IArrayTypeSymbol array)`
`137`	`137`	`{`
`138`	`138`	`// They are in the namespace of the original object`
`139`		`- var elementType = ((IArrayTypeSymbol)symbol).ElementType;`
	`139`	`+ var elementType = array.ElementType;`
`140`	`140`	`var ns = elementType.TypeKind == TypeKind.TypeParameter ? Context.Compilation.GlobalNamespace : elementType.ContainingNamespace;`
`141`	`141`	`if (ns != null)`
`142`	`142`	`trapFile.parent_namespace(this, Namespace.Create(Context, ns));`
`143`	`143`	`}`
`144`	`144`
`145`		`- if (symbol is IPointerTypeSymbol)`
	`145`	`+ if (symbol is IPointerTypeSymbol pointer)`
`146`	`146`	`{`
`147`		`- var elementType = ((IPointerTypeSymbol)symbol).PointedAtType;`
	`147`	`+ var elementType = pointer.PointedAtType;`
`148`	`148`	`var ns = elementType.TypeKind == TypeKind.TypeParameter ? Context.Compilation.GlobalNamespace : elementType.ContainingNamespace;`
`149`	`149`
`150`	`150`	`if (ns != null)`
Original file line number	Diff line number	Diff line change
`@@ -456,11 +456,11 @@ public static bool IsUnboundNullable(this ITypeSymbol type) =>`
`456`	`456`	`/// <returns>The list of parameters, or an empty list.</returns>`
`457`	`457`	`public static IEnumerable<IParameterSymbol> GetParameters(this ISymbol parameterizable)`
`458`	`458`	`{`
`459`		`- if (parameterizable is IMethodSymbol)`
`460`		`- return ((IMethodSymbol)parameterizable).Parameters;`
	`459`	`+ if (parameterizable is IMethodSymbol meth)`
	`460`	`+ return meth.Parameters;`
`461`	`461`
`462`		`- if (parameterizable is IPropertySymbol)`
`463`		`- return ((IPropertySymbol)parameterizable).Parameters;`
	`462`	`+ if (parameterizable is IPropertySymbol prop)`
	`463`	`+ return prop.Parameters;`
`464`	`464`
`465`	`465`	`return Enumerable.Empty<IParameterSymbol>();`
`466`	`466`	`}`
Original file line number	Diff line number	Diff line change
`@@ -58,9 +58,9 @@ public Key(params object[] args)`
`58`	`58`	`TrapBuilder = new StringWriter();`
`59`	`59`	`foreach (var arg in args)`
`60`	`60`	`{`
`61`		`- if (arg is IEntity)`
	`61`	`+ if (arg is IEntity entity)`
`62`	`62`	`{`
`63`		`- var key = ((IEntity)arg).Label;`
	`63`	`+ var key = entity.Label;`
`64`	`64`	`TrapBuilder.Write("{#");`
`65`	`65`	`TrapBuilder.Write(key.Value.ToString());`
`66`	`66`	`TrapBuilder.Write("}");`