Use pattern switch

src/Workspaces/Core/Portable/Shared/Extensions/ISymbolExtensions.cs

@@ -865,28 +865,17 @@ public static DeclarationModifiers GetSymbolModifiers(this ISymbol symbol)
 
         public static ITypeSymbol GetSymbolType(this ISymbol symbol)
         {
-            if (symbol is ILocalSymbol localSymbol)
+            switch (symbol)
             {
+                case ILocalSymbol localSymbol:
                     return localSymbol.Type;
-            }
-
-            if (symbol is IFieldSymbol fieldSymbol)
-            {
+                case IFieldSymbol fieldSymbol:
                     return fieldSymbol.Type;
-            }
-
-            if (symbol is IPropertySymbol propertySymbol)
-            {
+                case IPropertySymbol propertySymbol:
                     return propertySymbol.Type;
-            }
-
-            if (symbol is IParameterSymbol parameterSymbol)
-            {
+                case IParameterSymbol parameterSymbol:
                     return parameterSymbol.Type;
-            }
-
-            if (symbol is IAliasSymbol aliasSymbol)
-            {
+                case IAliasSymbol aliasSymbol:
                     return aliasSymbol.Target as ITypeSymbol;
             }