Extensions: pattern-based constructs (#78480)

Author: Julien Couvreur

src/Compilers/CSharp/Portable/Binder/Binder_Deconstruct.cs

@@ -683,7 +683,7 @@ private BoundExpression MakeDeconstructInvocationExpression(
                 // This prevents, for example, an unused params parameter after the out parameters.
                 var deconstructMethod = ((BoundCall)result).Method;
                 var parameters = deconstructMethod.Parameters;
-                for (int i = (deconstructMethod.IsExtensionMethod ? 1 : 0); i < parameters.Length; i++) // Tracked by https://github.com/dotnet/roslyn/issues/76130: Test this code path with new extensions
+                for (int i = (deconstructMethod.IsExtensionMethod ? 1 : 0); i < parameters.Length; i++)
                 {
                     if (parameters[i].RefKind != RefKind.Out)
                     {

src/Compilers/CSharp/Portable/Binder/Binder_InterpolatedString.cs

@@ -339,7 +339,7 @@ private BoundInterpolatedString BindUnconvertedInterpolatedExpressionToFactory(
             SyntaxNode syntax = unconvertedSource.Syntax;
             ImmutableArray<BoundExpression> expressions = makeInterpolatedStringFactoryArguments(syntax, parts, diagnostics);
 
-            BoundExpression construction = MakeInvocationExpression(
+            BoundExpression construction = MakeInvocationExpression( // Tracked by https://github.com/dotnet/roslyn/issues/76130 : test this scenario with a delegate-returning property (should be blocked by virtue of allowFieldsAndProperties: false)
                 syntax,
                 new BoundTypeExpression(syntax, null, factoryType) { WasCompilerGenerated = true },
                 factoryMethod,

src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs

@@ -137,11 +137,11 @@ internal BoundExpression MakeInvocationExpression(
             }
 
             BoundExpression result = BindInvocationExpression(
-                node, node, methodName, boundExpression, analyzedArguments, diagnostics, queryClause,
-                ignoreNormalFormIfHasValidParamsParameter: ignoreNormalFormIfHasValidParamsParameter,
+                node, node, methodName, boundExpression, analyzedArguments, diagnostics, acceptOnlyMethods: !allowFieldsAndProperties,
+                queryClause, ignoreNormalFormIfHasValidParamsParameter: ignoreNormalFormIfHasValidParamsParameter,
                 disallowExpandedNonArrayParams: disallowExpandedNonArrayParams);
 
-            // Query operator can't be called dynamically. 
+            // Query operator can't be called dynamically.
             if (queryClause != null && result.Kind == BoundKind.DynamicInvocation)
             {
                 // the error has already been reported by BindInvocationExpression
@@ -245,7 +245,7 @@ BoundExpression bindArgumentsAndInvocation(InvocationExpressionSyntax node, Boun
                 boundExpression = CheckValue(boundExpression, BindValueKind.RValueOrMethodGroup, diagnostics);
                 string name = boundExpression.Kind == BoundKind.MethodGroup ? GetName(node.Expression) : null;
                 BindArgumentsAndNames(node.ArgumentList, diagnostics, analyzedArguments, allowArglist: true);
-                return BindInvocationExpression(node, node.Expression, name, boundExpression, analyzedArguments, diagnostics);
+                return BindInvocationExpression(node, node.Expression, name, boundExpression, analyzedArguments, diagnostics, acceptOnlyMethods: false);
             }
 
             static bool receiverIsInvocation(InvocationExpressionSyntax node, out InvocationExpressionSyntax nested)
@@ -324,6 +324,7 @@ private BoundExpression BindInvocationExpression(
             BoundExpression boundExpression,
             AnalyzedArguments analyzedArguments,
             BindingDiagnosticBag diagnostics,
+            bool acceptOnlyMethods,
             CSharpSyntaxNode queryClause = null,
             bool ignoreNormalFormIfHasValidParamsParameter = false,
             bool disallowExpandedNonArrayParams = false)
@@ -356,7 +357,7 @@ private BoundExpression BindInvocationExpression(
                     ignoreNormalFormIfHasValidParamsParameter: ignoreNormalFormIfHasValidParamsParameter,
                     disallowExpandedNonArrayParams: disallowExpandedNonArrayParams,
                     anyApplicableCandidates: out _,
-                    acceptOnlyMethods: false);
+                    acceptOnlyMethods: acceptOnlyMethods);
             }
             else if ((object)(delegateType = GetDelegateType(boundExpression)) != null)
             {
@@ -727,7 +728,7 @@ private BoundExpression BindMethodGroupInvocation(
                 Debug.Assert(extensionMemberAccess.Kind != BoundKind.MethodGroup);
 
                 extensionMemberAccess = CheckValue(extensionMemberAccess, BindValueKind.RValue, diagnostics);
-                BoundExpression extensionMemberInvocation = BindInvocationExpression(syntax, expression, methodName: null, extensionMemberAccess, analyzedArguments, diagnostics);
+                BoundExpression extensionMemberInvocation = BindInvocationExpression(syntax, expression, methodName: null, extensionMemberAccess, analyzedArguments, diagnostics, acceptOnlyMethods: false);
                 anyApplicableCandidates = !extensionMemberInvocation.HasAnyErrors;
                 return extensionMemberInvocation;
             }

src/Compilers/CSharp/Portable/Binder/Binder_Patterns.cs

@@ -1058,7 +1058,7 @@ deconstructMethod is null &&
             if (deconstructMethod is null)
                 hasErrors = true;
 
-            int skippedExtensionParameters = deconstructMethod?.IsExtensionMethod == true ? 1 : 0; // Tracked by https://github.com/dotnet/roslyn/issues/76130: Test this code path with new extensions
+            int skippedExtensionParameters = deconstructMethod?.IsExtensionMethod == true ? 1 : 0;
             for (int i = 0; i < node.Subpatterns.Count; i++)
             {
                 var subPattern = node.Subpatterns[i];

src/Compilers/CSharp/Portable/Binder/RefSafetyAnalysis.cs

@@ -627,7 +627,7 @@ static SafeContext getDeclarationValEscape(BoundTypeExpression typeExpression, S
             // and so the ref safety of the pattern is equivalent to a `Deconstruct(out var ...)` invocation
             // where "safe-context inference of declaration expressions" would have the same effect.
             if (node.DeconstructMethod is { } m &&
-                tryGetThisParameter(m)?.EffectiveScope == ScopedKind.None)
+                tryGetReceiverParameter(m)?.EffectiveScope == ScopedKind.None)
             {
                 using (new PatternInput(this, _localScopeDepth))
                 {
@@ -637,12 +637,16 @@ static SafeContext getDeclarationValEscape(BoundTypeExpression typeExpression, S
 
             return base.VisitRecursivePattern(node);
 
-            static ParameterSymbol? tryGetThisParameter(MethodSymbol method)
+            static ParameterSymbol? tryGetReceiverParameter(MethodSymbol method)
             {
-                if (method.IsExtensionMethod) // Tracked by https://github.com/dotnet/roslyn/issues/76130: Test this code path with new extensions
+                if (method.IsExtensionMethod)
                 {
                     return method.Parameters is [{ } firstParameter, ..] ? firstParameter : null;
                 }
+                else if (method.GetIsNewExtensionMember())
+                {
+                    return method.ContainingType.ExtensionParameter;
+                }
 
                 return method.TryGetThisParameter(out var thisParameter) ? thisParameter : null;
             }

src/Compilers/CSharp/Portable/Binder/Semantics/OverloadResolution/MethodTypeInference.cs

@@ -652,7 +652,7 @@ private void MakeExplicitParameterTypeInferences(Binder binder, BoundExpression
                 }
                 else if (IsUnfixedTypeParameter(target) && !target.NullableAnnotation.IsAnnotated() && kind is ExactOrBoundsKind.LowerBound)
                 {
-                    var ordinal = GetOrdinal((TypeParameterSymbol)target.Type); // Tracked by https://github.com/dotnet/roslyn/issues/76130 : test nullability scenario where the override of ordinals matters
+                    var ordinal = GetOrdinal((TypeParameterSymbol)target.Type);
                     _nullableAnnotationLowerBounds[ordinal] = _nullableAnnotationLowerBounds[ordinal].Join(argumentType.NullableAnnotation);
                 }
             }

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -547,7 +547,7 @@
     <value>Inconsistent accessibility: indexer return type '{1}' is less accessible than indexer '{0}'</value>
   </data>
   <data name="ERR_BadVisIndexerParam" xml:space="preserve">
-    <value>Inconsistent accessibility: parameter type '{1}' is less accessible than indexer '{0}'</value>
+    <value>Inconsistent accessibility: parameter type '{1}' is less accessible than indexer or property '{0}'</value>
   </data>
   <data name="ERR_BadVisOpReturn" xml:space="preserve">
     <value>Inconsistent accessibility: return type '{1}' is less accessible than operator '{0}'</value>

src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter.PatternLocalRewriter.cs

@@ -152,6 +152,7 @@ protected BoundExpression LowerEvaluation(BoundDagEvaluation evaluation)
                             PropertySymbol property = p.Property;
                             var outputTemp = new BoundDagTemp(p.Syntax, property.Type, p);
                             BoundExpression output = _tempAllocator.GetTemp(outputTemp);
+                            input = _factory.ConvertReceiverForExtensionMemberIfNeeded(property, input);
                             return _factory.AssignmentExpression(output, _localRewriter.MakePropertyAccess(_factory.Syntax, input, property, LookupResultKind.Viable, property.Type, isLeftOfAssignment: false));
                         }
 
@@ -169,7 +170,7 @@ void addArg(RefKind refKind, BoundExpression expression)
 
                             Debug.Assert(method.Name == WellKnownMemberNames.DeconstructMethodName);
                             int extensionExtra;
-                            if (method.IsStatic) // Tracked by https://github.com/dotnet/roslyn/issues/76130: Test this code path with new extensions
+                            if (method.IsStatic)
                             {
                                 Debug.Assert(method.IsExtensionMethod);
                                 receiver = _factory.Type(method.ContainingType);
@@ -190,6 +191,7 @@ void addArg(RefKind refKind, BoundExpression expression)
                                 addArg(RefKind.Out, _tempAllocator.GetTemp(outputTemp));
                             }
 
+                            receiver = _factory.ConvertReceiverForExtensionMemberIfNeeded(method, receiver);
                             return _factory.Call(receiver, method, refKindBuilder.ToImmutableAndFree(), argBuilder.ToImmutableAndFree());
                         }
 

src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_FixedStatement.cs

@@ -355,6 +355,7 @@ private BoundStatement InitializeFixedStatementGetPinnable(
             }
 
             // .GetPinnable()
+            callReceiver = factory.ConvertReceiverForExtensionMemberIfNeeded(getPinnableMethod, callReceiver);
             var getPinnableCall = getPinnableMethod.IsStatic ?
                 factory.Call(null, getPinnableMethod, callReceiver) :
                 factory.Call(callReceiver, getPinnableMethod);

src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_ObjectOrCollectionInitializerExpression.cs

@@ -698,9 +698,11 @@ private BoundExpression MakeObjectInitializerMemberAccess(
 #if DEBUG
             var discardedUseSiteInfo = CompoundUseSiteInfo<AssemblySymbol>.Discarded;
             Debug.Assert(_compilation.Conversions.ClassifyConversionFromType(rewrittenReceiver.Type, memberSymbol.ContainingType, isChecked: false, ref discardedUseSiteInfo).IsImplicit ||
+                         (memberSymbol.GetIsNewExtensionMember() && !memberSymbol.IsStatic && ConversionsBase.IsValidExtensionMethodThisArgConversion(_compilation.Conversions.ClassifyConversionFromType(rewrittenReceiver.Type, memberSymbol.ContainingType.ExtensionParameter!.Type, isChecked: false, ref discardedUseSiteInfo))) ||
                          _compilation.Conversions.HasImplicitConversionToOrImplementsVarianceCompatibleInterface(rewrittenReceiver.Type, memberSymbol.ContainingType, ref discardedUseSiteInfo, out _));
             // It is possible there are use site diagnostics from the above, but none that we need report as we aren't generating code for the conversion
 #endif
+            rewrittenReceiver = _factory.ConvertReceiverForExtensionMemberIfNeeded(memberSymbol, rewrittenReceiver);
 
             switch (memberSymbol.Kind)
             {