Recognize 'allows ref struct' constraint in VB compiler

src/Compilers/CSharp/Portable/SymbolDisplay/SymbolDisplayVisitor.Types.cs

@@ -837,7 +837,7 @@ private static bool TypeParameterHasConstraints(ITypeParameterSymbol typeParam)
         {
             return !typeParam.ConstraintTypes.IsEmpty || typeParam.HasConstructorConstraint ||
                 typeParam.HasReferenceTypeConstraint || typeParam.HasValueTypeConstraint ||
-                typeParam.HasNotNullConstraint;
+                typeParam.HasNotNullConstraint || typeParam.AllowsByRefLike;
         }
 
         private void AddTypeParameterConstraints(ImmutableArray<ITypeSymbol> typeArguments)
@@ -917,7 +917,7 @@ private void AddTypeParameterConstraints(ImmutableArray<ITypeSymbol> typeArgumen
                                 needComma = true;
                             }
 
-                            //ctor constraint must be last
+                            //ctor constraint must be last before 'allows ref struct'
                             if (typeParam.HasConstructorConstraint)
                             {
                                 if (needComma)
@@ -929,6 +929,22 @@ private void AddTypeParameterConstraints(ImmutableArray<ITypeSymbol> typeArgumen
                                 AddKeyword(SyntaxKind.NewKeyword);
                                 AddPunctuation(SyntaxKind.OpenParenToken);
                                 AddPunctuation(SyntaxKind.CloseParenToken);
+                                needComma = true;
+                            }
+
+                            if (typeParam.AllowsByRefLike)
+                            {
+                                if (needComma)
+                                {
+                                    AddPunctuation(SyntaxKind.CommaToken);
+                                    AddSpace();
+                                }
+
+                                AddKeyword(SyntaxKind.AllowsKeyword);
+                                AddSpace();
+                                AddKeyword(SyntaxKind.RefKeyword);
+                                AddSpace();
+                                AddKeyword(SyntaxKind.StructKeyword);
                             }
                         }
                     }

src/Compilers/CSharp/Test/Emit3/RefStructInterfacesTests.cs

@@ -4377,6 +4377,7 @@ void verify(ModuleSymbol m)
                 Assert.False(t.HasNotNullConstraint);
                 Assert.True(t.AllowsByRefLike);
                 Assert.True(t.GetPublicSymbol().AllowsByRefLike);
+                AssertEx.Equal("C<T> where T : allows ref struct", t.ContainingSymbol.ToDisplayString(SymbolDisplayFormat.TestFormatWithConstraints));
             }
 
             comp = CreateCompilation(src, targetFramework: s_targetFrameworkSupportingByRefLikeGenerics, parseOptions: TestOptions.RegularNext).VerifyDiagnostics();
@@ -5085,6 +5086,7 @@ public class C<T>
             Assert.False(t.HasNotNullConstraint);
             Assert.True(t.HasConstructorConstraint);
             Assert.True(t.AllowsByRefLike);
+            AssertEx.Equal("C<T> where T : new(), allows ref struct", t.ContainingSymbol.ToDisplayString(SymbolDisplayFormat.TestFormatWithConstraints));
         }
 
         [Fact]
@@ -5108,6 +5110,7 @@ public class C<T>
             Assert.False(t.HasNotNullConstraint);
             Assert.True(t.HasConstructorConstraint);
             Assert.True(t.AllowsByRefLike);
+            AssertEx.Equal("C<T> where T : new(), allows ref struct", t.ContainingSymbol.ToDisplayString(SymbolDisplayFormat.TestFormatWithConstraints));
         }
 
         [Fact]
@@ -5754,6 +5757,7 @@ void verify(ModuleSymbol m)
                 Assert.False(t.HasNotNullConstraint);
                 Assert.False(t.AllowsByRefLike);
                 Assert.False(t.GetPublicSymbol().AllowsByRefLike);
+                AssertEx.Equal("C<T>", t.ContainingSymbol.ToDisplayString(SymbolDisplayFormat.TestFormatWithConstraints));
             }
         }
 
@@ -23918,5 +23922,67 @@ public class Activator
                 expectedOutput: ExecutionConditionUtil.IsMonoOrCoreClr ? "123 246" : null,
                 verify: ExecutionConditionUtil.IsMonoOrCoreClr ? Verification.Passes : Verification.Skipped).VerifyDiagnostics();
         }
+
+        [Fact]
+        public void NoPiaEmbedding()
+        {
+            string pia = @"
+using System;
+using System.Runtime.InteropServices;
+
+[assembly: ImportedFromTypeLib(""GeneralPIA.dll"")]
+[assembly: Guid(""f9c2d51d-4f44-45f0-9eda-c9d599b58257"")]
+
+[ComImport()]
+[Guid(""f9c2d51d-4f44-45f0-9eda-c9d599b58278"")]
+public interface ITest29
+{
+    void M21<T1>() where T1 : allows ref struct;
+}
+";
+
+            var piaCompilation = CreateCompilation(pia, options: TestOptions.ReleaseDll, assemblyName: "Pia", targetFramework: s_targetFrameworkSupportingByRefLikeGenerics);
+
+            string consumer = @"
+class UsePia
+{
+    public static void Main()
+    {
+    }
+}
+
+interface UsePia5 : ITest29
+{
+}
+";
+
+            var compilation1 = CreateCompilation(consumer, options: TestOptions.ReleaseExe,
+                references: [piaCompilation.ToMetadataReference(embedInteropTypes: true)],
+                targetFramework: s_targetFrameworkSupportingByRefLikeGenerics);
+
+            var compilation2 = CreateCompilation(consumer, options: TestOptions.ReleaseExe,
+                references: [piaCompilation.EmitToImageReference(embedInteropTypes: true)],
+                targetFramework: s_targetFrameworkSupportingByRefLikeGenerics);
+
+            System.Action<ModuleSymbol> metadataValidator =
+                delegate (ModuleSymbol module)
+                {
+                    ((PEModuleSymbol)module).Module.PretendThereArentNoPiaLocalTypes();
+
+                    var itest29 = (PENamedTypeSymbol)module.GlobalNamespace.GetTypeMembers("ITest29").Single();
+                    Assert.Equal(TypeKind.Interface, itest29.TypeKind);
+
+                    var m21 = (PEMethodSymbol)itest29.GetMembers("M21").Single();
+
+                    var t1 = m21.TypeParameters[0];
+                    Assert.Equal("T1", t1.Name);
+                    Assert.True(t1.AllowsByRefLike);
+                    AssertEx.Equal("void ITest29.M21<T1>() where T1 : allows ref struct", m21.ToDisplayString(SymbolDisplayFormat.TestFormatWithConstraints));
+                };
+
+            CompileAndVerify(compilation1, symbolValidator: metadataValidator, verify: Verification.Skipped).VerifyDiagnostics();
+
+            CompileAndVerify(compilation2, symbolValidator: metadataValidator, verify: Verification.Skipped).VerifyDiagnostics();
+        }
     }
 }

src/Compilers/VisualBasic/Portable/Emit/EditAndContinue/VisualBasicSymbolMatcher.vb

@@ -475,6 +475,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Emit
                 ' edit. Furthermore, comparing constraint types might lead to a cycle.
                 Debug.Assert(type.HasConstructorConstraint = other.HasConstructorConstraint)
                 Debug.Assert(type.HasValueTypeConstraint = other.HasValueTypeConstraint)
+                Debug.Assert(type.AllowsByRefLike = other.AllowsByRefLike)
                 Debug.Assert(type.HasReferenceTypeConstraint = other.HasReferenceTypeConstraint)
                 Debug.Assert(type.ConstraintTypesNoUseSiteDiagnostics.Length = other.ConstraintTypesNoUseSiteDiagnostics.Length)
                 Return True

src/Compilers/VisualBasic/Portable/Emit/NoPia/EmbeddedTypeParameter.vb

@@ -37,7 +37,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Emit.NoPia
 
         Protected Overrides ReadOnly Property AllowByRefLike As Boolean
             Get
-                Return False ' PROTOTYPE(RefStructInterfaces): Implement for real
+                Return UnderlyingTypeParameter.AdaptedTypeParameterSymbol.AllowsByRefLike
             End Get
         End Property
 

src/Compilers/VisualBasic/Portable/Emit/TypeParameterSymbolAdapter.vb

@@ -235,7 +235,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
 
         Private ReadOnly Property IGenericParameterAllowByRefLike As Boolean Implements IGenericParameter.AllowByRefLike
             Get
-                Return False ' PROTOTYPE(RefStructInterfaces): Implement for real
+                Return AdaptedTypeParameterSymbol.AllowsByRefLike
             End Get
         End Property
 

src/Compilers/VisualBasic/Portable/Symbols/AnonymousTypes/SynthesizedSymbols/AnonymousTypeOrDelegateTypeParameterSymbol.vb

@@ -93,6 +93,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
                 End Get
             End Property
 
+            Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+                Get
+                    Return False
+                End Get
+            End Property
+
             Public Overrides ReadOnly Property Variance As VarianceKind
                 Get
                     Return VarianceKind.None

src/Compilers/VisualBasic/Portable/Symbols/IndexedTypeParameterSymbol.vb

@@ -116,6 +116,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
             End Get
         End Property
 
+        Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+            Get
+                Return False
+            End Get
+        End Property
+
         Public Overrides ReadOnly Property HasReferenceTypeConstraint As Boolean
             Get
                 Return False

src/Compilers/VisualBasic/Portable/Symbols/InstanceErrorTypeSymbol.vb

@@ -233,6 +233,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
                 End Get
             End Property
 
+            Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+                Get
+                    Return False
+                End Get
+            End Property
+
             Public Overrides ReadOnly Property Locations As ImmutableArray(Of Location)
                 Get
                     Return ImmutableArray(Of Location).Empty

src/Compilers/VisualBasic/Portable/Symbols/Metadata/PE/PETypeParameterSymbol.vb

@@ -245,6 +245,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols.Metadata.PE
             End Get
         End Property
 
+        Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+            Get
+                Return (_flags And MetadataHelpers.GenericParameterAttributesAllowByRefLike) <> 0
+            End Get
+        End Property
+
         Public Overrides ReadOnly Property Variance As VarianceKind
             Get
                 Return CType((_flags And GenericParameterAttributes.VarianceMask), VarianceKind)

src/Compilers/VisualBasic/Portable/Symbols/MethodSignatureComparer.vb

@@ -863,6 +863,7 @@ Done:
             If (typeParameter1.HasConstructorConstraint <> typeParameter2.HasConstructorConstraint) OrElse
                 (typeParameter1.HasReferenceTypeConstraint <> typeParameter2.HasReferenceTypeConstraint) OrElse
                 (typeParameter1.HasValueTypeConstraint <> typeParameter2.HasValueTypeConstraint) OrElse
+                (typeParameter1.AllowsByRefLike <> typeParameter2.AllowsByRefLike) OrElse
                 (typeParameter1.Variance <> typeParameter2.Variance) Then
                 Return False
             End If

src/Compilers/VisualBasic/Portable/Symbols/ReducedExtensionMethodSymbol.vb

@@ -749,6 +749,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
                 End Get
             End Property
 
+            Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+                Get
+                    Return _curriedFromTypeParameter.AllowsByRefLike
+                End Get
+            End Property
+
             Public Overrides ReadOnly Property Locations As ImmutableArray(Of Location)
                 Get
                     Return _curriedFromTypeParameter.Locations

src/Compilers/VisualBasic/Portable/Symbols/Retargeting/RetargetingTypeParameterSymbol.vb

@@ -98,6 +98,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols.Retargeting
             End Get
         End Property
 
+        Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+            Get
+                Return _underlyingTypeParameter.AllowsByRefLike
+            End Get
+        End Property
+
         Public Overrides ReadOnly Property Variance As VarianceKind
             Get
                 Return _underlyingTypeParameter.Variance

src/Compilers/VisualBasic/Portable/Symbols/Source/CrefTypeParameterSymbol.vb

@@ -67,6 +67,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
             End Get
         End Property
 
+        Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+            Get
+                Return False
+            End Get
+        End Property
+
         Friend Overrides ReadOnly Property ConstraintTypesNoUseSiteDiagnostics As ImmutableArray(Of TypeSymbol)
             Get
                 Return ImmutableArray(Of TypeSymbol).Empty

src/Compilers/VisualBasic/Portable/Symbols/Source/SourceTypeParameterSymbol.vb

@@ -77,6 +77,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
             End Get
         End Property
 
+        Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+            Get
+                Return False
+            End Get
+        End Property
+
         Friend Overrides ReadOnly Property ConstraintTypesNoUseSiteDiagnostics As ImmutableArray(Of TypeSymbol)
             Get
                 EnsureAllConstraintsAreResolved()

src/Compilers/VisualBasic/Portable/Symbols/SubstitutedTypeParameterSymbol.vb

@@ -126,6 +126,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
             End Get
         End Property
 
+        Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+            Get
+                Return _originalDefinition.AllowsByRefLike
+            End Get
+        End Property
+
         Public Overrides ReadOnly Property IsImplicitlyDeclared As Boolean
             Get
                 Return _originalDefinition.IsImplicitlyDeclared

src/Compilers/VisualBasic/Portable/Symbols/SynthesizedSymbols/SynthesizedClonedTypeParameterSymbol.vb

@@ -100,6 +100,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
             End Get
         End Property
 
+        Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+            Get
+                Return _correspondingMethodTypeParameter.AllowsByRefLike
+            End Get
+        End Property
+
         Public Overrides ReadOnly Property Locations As ImmutableArray(Of Location)
             Get
                 Return _correspondingMethodTypeParameter.Locations

src/Compilers/VisualBasic/Portable/Symbols/TypeParameterSymbol.vb

@@ -317,11 +317,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
 
         Public MustOverride ReadOnly Property HasValueTypeConstraint As Boolean Implements ITypeParameterSymbol.HasValueTypeConstraint
 
-        Public ReadOnly Property AllowsByRefLike As Boolean Implements ITypeParameterSymbol.AllowsByRefLike
-            Get
-                Return False ' PROTOTYPE(RefStructInterfaces): Implement for real
-            End Get
-        End Property
+        Public MustOverride ReadOnly Property AllowsByRefLike As Boolean Implements ITypeParameterSymbol.AllowsByRefLike
 
         Private ReadOnly Property HasUnmanagedTypeConstraint As Boolean Implements ITypeParameterSymbol.HasUnmanagedTypeConstraint
             Get

src/Compilers/VisualBasic/Portable/Symbols/Wrapped/WrappedTypeParameterSymbol.vb

@@ -61,6 +61,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
             End Get
         End Property
 
+        Public Overrides ReadOnly Property AllowsByRefLike As Boolean
+            Get
+                Return Me._underlyingTypeParameter.AllowsByRefLike
+            End Get
+        End Property
+
         Public Overrides ReadOnly Property Variance As VarianceKind
             Get
                 Return Me._underlyingTypeParameter.Variance