Merge pull request #50019 from jasonmalinowski/fix-cross-language-generate-constructor-bugs

Fix cross language generate constructor bugs

src/EditorFeatures/VisualBasicTest/GenerateConstructor/GenerateConstructorTests.vb

@@ -1866,6 +1866,83 @@ End Class",
 End Class")
         End Function
 
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateConstructor)>
+        Public Async Function TestDelegateConstructorCrossLanguageCycleAvoidance() As Task
+            Await TestInRegularAndScriptAsync(
+<Workspace>
+    <Project Language="C#" Name="CSharpProject" CommonReferences="true">
+        <Document>
+            public class BaseType
+            {
+                public BaseType(int x, int y) { }
+            }
+        </Document>
+    </Project>
+    <Project Language="Visual Basic" CommonReferences="true">
+        <ProjectReference>CSharpProject</ProjectReference>
+        <Document>
+Public Class B
+    Inherits BaseType
+
+    Public Sub New(a As Integer)
+        [|Me.New(a, 1)|]
+    End Sub
+End Class</Document>
+    </Project>
+</Workspace>.ToString(),
+"
+Public Class B
+    Inherits BaseType
+
+    Public Sub New(a As Integer)
+        Me.New(a, 1)
+    End Sub
+
+    Public Sub New(x As Integer, y As Integer)
+        MyBase.New(x, y)
+    End Sub
+End Class")
+        End Function
+
+        <WorkItem(49850, "https://github.com/dotnet/roslyn/issues/49850")>
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateConstructor)>
+        Public Async Function TestDelegateConstructorCrossLanguage() As Task
+            Await TestInRegularAndScriptAsync(
+<Workspace>
+    <Project Language="C#" Name="CSharpProject" CommonReferences="true">
+        <Document>
+public class BaseType
+{
+    public BaseType(string x) { }
+}</Document>
+    </Project>
+    <Project Language="Visual Basic" CommonReferences="true">
+        <ProjectReference>CSharpProject</ProjectReference>
+        <Document>
+Option Strict On
+
+Public Class B
+    Public Sub M()
+        Dim x = [|New BaseType(42)|]
+    End Sub
+End Class
+        </Document>
+    </Project>
+</Workspace>.ToString(),
+"
+public class BaseType
+{
+    private int v;
+
+    public BaseType(string x) { }
+
+    public BaseType(int v)
+    {
+        this.v = v;
+    }
+}")
+        End Function
+
         <WorkItem(14077, "https://github.com/dotnet/roslyn/issues/14077")>
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateConstructor)>
         Public Async Function CreateFieldDefaultNamingStyle() As Task

src/Features/Core/Portable/GenerateMember/GenerateConstructor/AbstractGenerateConstructorService.cs

@@ -57,6 +57,10 @@ protected bool WillCauseConstructorCycle(State state, SemanticDocument document,
             if (currentConstructor.Equals(delegatedConstructor))
                 return true;
 
+            // Delegating to a constructor in the base type can't cause a cycle
+            if (!delegatedConstructor.ContainingType.Equals(currentConstructor.ContainingType))
+                return false;
+
             // We need ensure that delegating constructor won't cause circular dependency.
             // The chain of dependency can not exceed the number for constructors
             var constructorsCount = delegatedConstructor.ContainingType.InstanceConstructors.Length;

src/Features/Core/Portable/GenerateMember/GenerateConstructor/GenerateConstructorHelpers.cs

@@ -9,6 +9,7 @@
 using System.Linq;
 using Microsoft.CodeAnalysis.LanguageServices;
 using Microsoft.CodeAnalysis.Shared.Extensions;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.GenerateMember.GenerateConstructor
 {
@@ -77,9 +78,17 @@ private static bool IsSymbolAccessible(Compilation compilation, ISymbol symbol)
         {
             Debug.Assert(constructor.Parameters.Length == expressions.Length);
 
-            for (var i = 0; i < constructor.Parameters.Length; i++)
+            // Resolve the constructor into our semantic model's compilation; if the constructor we're looking at is from
+            // another project with a different language.
+            var constructorInCompilation = (IMethodSymbol?)SymbolKey.Create(constructor).Resolve(semanticModel.Compilation).Symbol;
+            Contract.ThrowIfNull(constructorInCompilation);
+
+            for (var i = 0; i < constructorInCompilation.Parameters.Length; i++)
             {
-                var constructorParameter = constructor.Parameters[i];
+                var constructorParameter = constructorInCompilation.Parameters[i];
+                if (constructorParameter == null)
+                    return false;
+
                 var conversion = semanticFacts.ClassifyConversion(semanticModel, expressions[i], constructorParameter.Type);
                 if (!conversion.IsIdentity && !conversion.IsImplicit)
                     return false;