Allow user to still create a new field/prop when offering to initialize an existing prop

src/EditorFeatures/CSharpTest/CodeActions/InitializeParameter/InitializeMemberFromPrimaryConstructorParameterTests.cs

@@ -1349,6 +1349,50 @@ public partial class Goo
             </Workspace>
             """);
 
+    [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/76565")]
+    public Task TestCouldInitializeThrowingProperty_ButGeneratePropertyInstead()
+        => TestInRegularAndScript1Async(
+            """
+            using System;
+
+            class C([||]string s)
+            {
+                private string S => throw new NotImplementedException();
+            }
+            """,
+            """
+            using System;
+
+            class C(string s)
+            {
+                public string S1 { get; } = s;
+
+                private string S => throw new NotImplementedException();
+            }
+            """, index: 1);
+
+    [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/76565")]
+    public Task TestCouldInitializeThrowingProperty_ButGenerateFieldInstead()
+        => TestInRegularAndScript1Async(
+            """
+            using System;
+
+            class C([||]string s)
+            {
+                private string S => throw new NotImplementedException();
+            }
+            """,
+            """
+            using System;
+
+            class C(string s)
+            {
+                private readonly string s = s;
+
+                private string S => throw new NotImplementedException();
+            }
+            """, index: 2);
+
     [Fact]
     public Task TestUpdateCodeToReferenceExistingField1()
         => TestInRegularAndScript1Async(

src/Features/CSharp/Portable/InitializeParameter/CSharpInitializeMemberFromPrimaryConstructorParameterCodeRefactoringProvider.cs

@@ -20,7 +20,6 @@
 using Microsoft.CodeAnalysis.Editing;
 using Microsoft.CodeAnalysis.Formatting;
 using Microsoft.CodeAnalysis.InitializeParameter;
-using Microsoft.CodeAnalysis.Shared.Collections;
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.CodeAnalysis.Shared.Naming;
 using Roslyn.Utilities;
@@ -73,11 +72,18 @@ public override async Task ComputeRefactoringsAsync(CodeRefactoringContext conte
         var formattingOptions = await document.GetSyntaxFormattingOptionsAsync(cancellationToken).ConfigureAwait(false);
 
         var fieldOrProperty = TryFindMatchingUninitializedFieldOrPropertySymbol();
-        var refactorings = fieldOrProperty == null
-            ? HandleNoExistingFieldOrProperty()
-            : HandleExistingFieldOrProperty();
+        using var refactorings = TemporaryArray<CodeAction>.Empty;
+        if (fieldOrProperty != null)
+        {
+            // Found a field/property that this parameter should be assigned to. Just offer the simple assignment to it.
+            refactorings.Add(CreateCodeAction(
+                string.Format(fieldOrProperty.Kind == SymbolKind.Field ? FeaturesResources.Initialize_field_0 : FeaturesResources.Initialize_property_0, fieldOrProperty.Name),
+                cancellationToken => AddAssignmentForPrimaryConstructorAsync(document, parameter, fieldOrProperty, cancellationToken)));
+        }
+
+        AddCreateFieldOrPropertyCodeActions();
 
-        context.RegisterRefactorings(refactorings.ToImmutableArray(), context.Span);
+        context.RegisterRefactorings(refactorings.ToImmutableAndClear(), context.Span);
         return;
 
         ISymbol? TryFindMatchingUninitializedFieldOrPropertySymbol()
@@ -133,15 +139,7 @@ public override async Task ComputeRefactoringsAsync(CodeRefactoringContext conte
         static CodeAction CreateCodeAction(string title, Func<CancellationToken, Task<Solution>> createSolution)
             => CodeAction.Create(title, createSolution, title);
 
-        IEnumerable<CodeAction> HandleExistingFieldOrProperty()
-        {
-            // Found a field/property that this parameter should be assigned to. Just offer the simple assignment to it.
-            yield return CreateCodeAction(
-                string.Format(fieldOrProperty.Kind == SymbolKind.Field ? FeaturesResources.Initialize_field_0 : FeaturesResources.Initialize_property_0, fieldOrProperty.Name),
-                cancellationToken => AddAssignmentForPrimaryConstructorAsync(document, parameter, fieldOrProperty, cancellationToken));
-        }
-
-        IEnumerable<CodeAction> HandleNoExistingFieldOrProperty()
+        void AddCreateFieldOrPropertyCodeActions()
         {
             // Didn't find a field/prop that this parameter could be assigned to. Offer to create new one and assign to that.
 
@@ -159,8 +157,8 @@ IEnumerable<CodeAction> HandleNoExistingFieldOrProperty()
                 string.Format(FeaturesResources.Create_and_assign_property_0, property.Name),
                 cancellationToken => AddMultipleMembersAsync(document, typeDeclaration, [parameter], [property], cancellationToken));
 
-            yield return siblingFieldOrProperty is IFieldSymbol ? fieldAction : propertyAction;
-            yield return siblingFieldOrProperty is IFieldSymbol ? propertyAction : fieldAction;
+            refactorings.Add(siblingFieldOrProperty is IFieldSymbol ? fieldAction : propertyAction);
+            refactorings.Add(siblingFieldOrProperty is IFieldSymbol ? propertyAction : fieldAction);
 
             var parameters = GetParametersWithoutAssociatedMembers();
             if (parameters.Length >= 2)
@@ -172,8 +170,8 @@ IEnumerable<CodeAction> HandleNoExistingFieldOrProperty()
                     FeaturesResources.Create_and_assign_remaining_as_properties,
                     cancellationToken => AddMultipleMembersAsync(document, typeDeclaration, parameters, parameters.SelectAsArray(CreateProperty), cancellationToken));
 
-                yield return siblingFieldOrProperty is IFieldSymbol ? allFieldsAction : allPropertiesAction;
-                yield return siblingFieldOrProperty is IFieldSymbol ? allPropertiesAction : allFieldsAction;
+                refactorings.Add(siblingFieldOrProperty is IFieldSymbol ? allFieldsAction : allPropertiesAction);
+                refactorings.Add(siblingFieldOrProperty is IFieldSymbol ? allPropertiesAction : allFieldsAction);
             }
         }