Changed GetSyntax to use a ImmutableArrayBuilder for RelayCommandGenerator

Author: Avid29

src/CommunityToolkit.Mvvm.SourceGenerators/Input/RelayCommandGenerator.Execute.cs

@@ -207,8 +207,9 @@ public static ImmutableArray<MemberDeclarationSyntax> GetSyntax(CommandInfo comm
                 .Select(static a => AttributeList(SingletonSeparatedList(a.GetSyntax())))
                 .ToArray();
 
+            ImmutableArrayBuilder<MemberDeclarationSyntax> declarations = ImmutableArrayBuilder<MemberDeclarationSyntax>.Rent();
+
             // Declare a backing field if needed
-            FieldDeclarationSyntax? fieldDeclaration = null;
             if (commandInfo.FieldName is not null)
             {
                 // Construct the generated field as follows:
@@ -217,7 +218,7 @@ public static ImmutableArray<MemberDeclarationSyntax> GetSyntax(CommandInfo comm
                 // [global::System.CodeDom.Compiler.GeneratedCode("...", "...")]
                 // <FORWARDED_ATTRIBUTES>
                 // private <COMMAND_TYPE>? <COMMAND_FIELD_NAME>;
-                fieldDeclaration =
+                FieldDeclarationSyntax fieldDeclaration =
                     FieldDeclaration(
                     VariableDeclaration(NullableType(IdentifierName(commandClassTypeName)))
                     .AddVariables(VariableDeclarator(Identifier(commandInfo.FieldName))))
@@ -230,6 +231,8 @@ public static ImmutableArray<MemberDeclarationSyntax> GetSyntax(CommandInfo comm
                                 AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(typeof(RelayCommandGenerator).Assembly.GetName().Version.ToString()))))))
                         .WithOpenBracketToken(Token(TriviaList(Comment($"/// <summary>The backing field for <see cref=\"{commandInfo.PropertyName}\"/>.</summary>")), SyntaxKind.OpenBracketToken, TriviaList())))
                     .AddAttributeLists(forwardedFieldAttributes);
+
+                declarations.Add(fieldDeclaration);
             }
 
             // Prepares the argument to pass the underlying method to invoke
@@ -347,22 +350,25 @@ public static ImmutableArray<MemberDeclarationSyntax> GetSyntax(CommandInfo comm
                             .AddArgumentListArguments(commandCreationArguments.ToArray()))))
                 .WithSemicolonToken(Token(SyntaxKind.SemicolonToken));
 
+            declarations.Add(propertyDeclaration);
+
             // Conditionally declare the additional members for the cancel commands
             if (commandInfo.IncludeCancelCommand)
             {
                 // Prepare all necessary member and type names
                 string? cancelCommandFieldName = commandInfo.FieldName is not null ? $"{commandInfo.FieldName.Substring(0, commandInfo.FieldName.Length - "Command".Length)}CancelCommand" : null;
                 string cancelCommandPropertyName = $"{commandInfo.PropertyName.Substring(0, commandInfo.PropertyName.Length - "Command".Length)}CancelCommand";
 
-                FieldDeclarationSyntax? cancelCommandFieldDeclaration = null;
+                // Declare a backing field for the cancel command if needed.
+                // This is only needed if we can't use the field keyword for the main command, as otherwise the cancel command can just use its own field keyword.
                 if (cancelCommandFieldName is not null)
                 {
                     // Construct the generated field for the cancel command as follows:
                     //
                     // /// <summary>The backing field for <see cref="<COMMAND_PROPERTY_NAME>"/></summary>
                     // [global::System.CodeDom.Compiler.GeneratedCode("...", "...")]
                     // private global::System.Windows.Input.ICommand? <CANCEL_COMMAND_FIELD_NAME>;
-                    cancelCommandFieldDeclaration =
+                    FieldDeclarationSyntax cancelCommandFieldDeclaration =
                         FieldDeclaration(
                         VariableDeclaration(NullableType(IdentifierName("global::System.Windows.Input.ICommand")))
                         .AddVariables(VariableDeclarator(Identifier(cancelCommandFieldName))))
@@ -375,6 +381,7 @@ public static ImmutableArray<MemberDeclarationSyntax> GetSyntax(CommandInfo comm
                                     AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(typeof(RelayCommandGenerator).Assembly.GetName().Version.ToString()))))))
                             .WithOpenBracketToken(Token(TriviaList(Comment($"/// <summary>The backing field for <see cref=\"{cancelCommandPropertyName}\"/>.</summary>")), SyntaxKind.OpenBracketToken, TriviaList())));
 
+                    declarations.Add(cancelCommandFieldDeclaration);
                 }
 
                 // Construct the generated property as follows (the explicit delegate cast is needed to avoid overload resolution conflicts):
@@ -412,20 +419,11 @@ public static ImmutableArray<MemberDeclarationSyntax> GetSyntax(CommandInfo comm
                                 .AddArgumentListArguments(Argument(IdentifierName(commandInfo.PropertyName))))))
                     .WithSemicolonToken(Token(SyntaxKind.SemicolonToken));
 
-                if (fieldDeclaration is not null && cancelCommandFieldDeclaration is not null)
-                {
-                    return ImmutableArray.Create<MemberDeclarationSyntax>(fieldDeclaration, propertyDeclaration, cancelCommandFieldDeclaration, cancelCommandPropertyDeclaration);
-                }
-
-                return ImmutableArray.Create<MemberDeclarationSyntax>(propertyDeclaration, cancelCommandPropertyDeclaration);
-            }
+                declarations.Add(cancelCommandPropertyDeclaration);
 
-            if (fieldDeclaration is not null)
-            {
-                return ImmutableArray.Create<MemberDeclarationSyntax>(fieldDeclaration, propertyDeclaration);
             }
 
-            return ImmutableArray.Create<MemberDeclarationSyntax>(propertyDeclaration);
+            return declarations.ToImmutable();
         }
 
         /// <summary>