Address some PROTOTYPE markers

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

@@ -7889,7 +7889,6 @@ private BoundExpression BindIndexerOrIndexedPropertyAccess(
             bool allowRefOmittedArguments = receiverOpt.IsExpressionOfComImportType();
             CompoundUseSiteInfo<AssemblySymbol> useSiteInfo = GetNewCompoundUseSiteInfo(diagnostics);
             this.OverloadResolution.PropertyOverloadResolution(propertyGroup, receiverOpt, analyzedArguments, overloadResolutionResult, allowRefOmittedArguments, ref useSiteInfo);
-            diagnostics.Add(syntax, useSiteInfo);
             BoundExpression propertyAccess;
 
             if (analyzedArguments.HasDynamicArgument && overloadResolutionResult.HasAnyApplicableMember)
@@ -7941,6 +7940,8 @@ private BoundExpression BindIndexerOrIndexedPropertyAccess(
                             memberGroup: candidates,
                             typeContainingConstructor: null,
                             delegateTypeBeingInvoked: null);
+
+                        diagnostics.Add(syntax, useSiteInfo);
                     }
                 }
 
@@ -7961,6 +7962,7 @@ private BoundExpression BindIndexerOrIndexedPropertyAccess(
             }
             else
             {
+                diagnostics.Add(syntax, useSiteInfo);
                 MemberResolutionResult<PropertySymbol> resolutionResult = overloadResolutionResult.ValidResult;
                 PropertySymbol property = resolutionResult.Member;
                 RefKind? receiverRefKind = receiverOpt?.GetRefKind();
@@ -8053,9 +8055,8 @@ private bool TryBindIndexOrRangeIndexer(
             }
 
             bool argIsIndex = argIsIndexNotRange.Value();
-            var useSiteInfo = CompoundUseSiteInfo<AssemblySymbol>.Discarded;
-            if (!TryFindIndexOrRangeIndexerPattern(receiverOpt, receiverType, argIsIndex: argIsIndex,
-                out PropertySymbol? lengthOrCountProperty, out Symbol? patternSymbol, diagnostics, ref useSiteInfo))
+            if (!TryFindIndexOrRangeIndexerPattern(syntax, receiverOpt, receiverType, argIsIndex: argIsIndex,
+                out PropertySymbol? lengthOrCountProperty, out Symbol? patternSymbol, diagnostics))
             {
                 return false;
             }
@@ -8068,9 +8069,6 @@ private bool TryBindIndexOrRangeIndexer(
                 BindToNaturalType(argument, diagnostics),
                 patternSymbol.GetTypeOrReturnType().Type);
 
-            ReportDiagnosticsIfObsolete(diagnostics, patternSymbol, syntax, hasBaseReceiver: false);
-            ReportDiagnosticsIfObsolete(diagnostics, lengthOrCountProperty, syntax, hasBaseReceiver: false);
-
             if (!argIsIndex)
             {
                 checkWellKnown(WellKnownMember.System_Range__get_Start);
@@ -8099,14 +8097,13 @@ void checkWellKnown(WellKnownMember member)
         }
 
         private bool TryFindIndexOrRangeIndexerPattern(
+            SyntaxNode syntax,
             BoundExpression? receiverOpt,
             TypeSymbol receiverType,
             bool argIsIndex,
             [NotNullWhen(true)] out PropertySymbol? lengthOrCountProperty,
             [NotNullWhen(true)] out Symbol? patternSymbol,
-            // PROTOTYPE(list-patterns) We should take either of these and adjust the caller.
-            BindingDiagnosticBag diagnostics,
-            ref CompoundUseSiteInfo<AssemblySymbol> useSiteInfo)
+            BindingDiagnosticBag diagnostics)
         {
             // SPEC:
 
@@ -8120,9 +8117,10 @@ private bool TryFindIndexOrRangeIndexerPattern(
 
             var lookupResult = LookupResult.GetInstance();
 
-            if (TryLookupLengthOrCount(receiverType, lookupResult, out lengthOrCountProperty, ref useSiteInfo) &&
-                TryFindIndexOrRangeIndexerPattern(lookupResult, receiverOpt, receiverType, argIsIndex, out patternSymbol, diagnostics, ref useSiteInfo))
+            if (TryLookupLengthOrCount(syntax, receiverType, lookupResult, out lengthOrCountProperty, diagnostics) &&
+                TryFindIndexOrRangeIndexerPattern(syntax, lookupResult, receiverOpt, receiverType, argIsIndex, out patternSymbol, diagnostics))
             {
+                ReportDiagnosticsIfObsolete(diagnostics, patternSymbol, syntax, hasBaseReceiver: false); // TODO2 factor
                 CheckImplicitThisCopyInReadOnlyMember(receiverOpt, lengthOrCountProperty.GetMethod, diagnostics);
                 lookupResult.Free();
                 return true;
@@ -8134,15 +8132,16 @@ private bool TryFindIndexOrRangeIndexerPattern(
         }
 
         private bool TryFindIndexOrRangeIndexerPattern(
+            SyntaxNode syntax,
             LookupResult lookupResult,
             BoundExpression? receiverOpt,
             TypeSymbol receiverType,
             bool argIsIndex,
             [NotNullWhen(true)] out Symbol? patternSymbol,
-            // PROTOTYPE(list-patterns) We should take either of these and adjust the caller.
-            BindingDiagnosticBag diagnostics,
-            ref CompoundUseSiteInfo<AssemblySymbol> useSiteInfo)
+            BindingDiagnosticBag diagnostics)
         {
+            var useSiteInfo = GetNewCompoundUseSiteInfo(diagnostics);
+
             Debug.Assert(lookupResult.IsClear);
             if (argIsIndex)
             {
@@ -8171,6 +8170,9 @@ candidate is PropertySymbol property &&
                         {
                             // note: implicit copy check on the indexer accessor happens in CheckPropertyValueKind
                             patternSymbol = property;
+                            property.AddUseSiteInfo(ref useSiteInfo);
+                            diagnostics.Add(syntax, useSiteInfo);
+
                             return true;
                         }
                     }
@@ -8181,7 +8183,6 @@ candidate is PropertySymbol property &&
                 Debug.Assert(!argIsIndex);
                 // Look for Substring
                 var substring = (MethodSymbol)Compilation.GetSpecialTypeMember(SpecialMember.System_String__Substring);
-                // PROTOTYPE(list-patterns) Consider reporting a missing member for string.Substring
                 if (substring is object)
                 {
                     patternSymbol = substring;
@@ -8218,6 +8219,8 @@ method.OriginalDefinition is var original &&
                             original.Parameters[1] is { Type: { SpecialType: SpecialType.System_Int32 }, RefKind: RefKind.None })
                         {
                             patternSymbol = method;
+                            method.AddUseSiteInfo(ref useSiteInfo);
+                            diagnostics.Add(syntax, useSiteInfo);
                             CheckImplicitThisCopyInReadOnlyMember(receiverOpt, method, diagnostics);
                             return true;
                         }
@@ -8230,18 +8233,26 @@ method.OriginalDefinition is var original &&
         }
 
         private bool TryLookupLengthOrCount(
+            SyntaxNode syntax,
             TypeSymbol receiverType,
             LookupResult lookupResult,
             [NotNullWhen(true)] out PropertySymbol? lengthOrCountProperty,
-            ref CompoundUseSiteInfo<AssemblySymbol> useSiteInfo)
+            BindingDiagnosticBag diagnostics)
         {
             Debug.Assert(lookupResult.IsClear);
-            // PROTOTYPE(list-patterns) Assert about whether diagnostics and dependencies are being accumulated.
-            return tryLookupLengthOrCount(WellKnownMemberNames.LengthPropertyName, out lengthOrCountProperty, ref useSiteInfo) ||
-                   tryLookupLengthOrCount(WellKnownMemberNames.CountPropertyName, out lengthOrCountProperty, ref useSiteInfo);
+            if (tryLookupLengthOrCount(WellKnownMemberNames.LengthPropertyName, out lengthOrCountProperty, diagnostics) ||
+                tryLookupLengthOrCount(WellKnownMemberNames.CountPropertyName, out lengthOrCountProperty, diagnostics))
+            {
+                ReportDiagnosticsIfObsolete(diagnostics, lengthOrCountProperty, syntax, hasBaseReceiver: false);
+                ReportDiagnosticsIfObsolete(diagnostics, lengthOrCountProperty.GetMethod, syntax, hasBaseReceiver: false);
+                return true;
+            }
 
-            bool tryLookupLengthOrCount(string propertyName, out PropertySymbol? valid, ref CompoundUseSiteInfo<AssemblySymbol> useSiteInfo)
+            return false;
+
+            bool tryLookupLengthOrCount(string propertyName, [NotNullWhen(true)] out PropertySymbol? valid, BindingDiagnosticBag diagnostics)
             {
+                var useSiteInfo = GetNewCompoundUseSiteInfo(diagnostics);
                 LookupMembersInType(
                     lookupResult,
                     receiverType,
@@ -8263,8 +8274,11 @@ lookupResult.Symbols[0] is PropertySymbol property &&
                 {
                     lookupResult.Clear();
                     valid = property;
+                    property.AddUseSiteInfo(ref useSiteInfo);
+                    diagnostics.Add(syntax, useSiteInfo);
                     return true;
                 }
+
                 lookupResult.Clear();
                 valid = null;
                 return false;

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

@@ -214,7 +214,7 @@ private BoundPattern BindSlicePattern(
                 {
                     sliceType = inputType;
                 }
-                else if (TryPerformPatternIndexerLookup(node, inputType, argIsIndex: false, out indexerAccess, out Symbol? patternSymbol, lengthProperty: out _, diagnostics))
+                else if (TryBindIndexerForPattern(node, inputType, argIsIndex: false, out indexerAccess, out Symbol? patternSymbol, lengthProperty: out _, diagnostics))
                 {
                     if (patternSymbol is MethodSymbol method)
                     {
@@ -280,6 +280,8 @@ private BoundListPattern BindListPattern(
             bool hasErrors,
             BindingDiagnosticBag diagnostics)
         {
+            CheckFeatureAvailability(node, MessageID.IDS_FeatureListPattern, diagnostics);
+
             TypeSymbol elementType;
             BoundIndexerAccess? indexerAccess = null;
             PropertySymbol? indexerSymbol = null;
@@ -295,7 +297,7 @@ private BoundListPattern BindListPattern(
                 elementType = ((ArrayTypeSymbol)inputType).ElementType;
                 hasErrors |= !TryGetSpecialTypeMember(Compilation, SpecialMember.System_Array__Length, node, diagnostics, out lengthProperty);
             }
-            else if (TryPerformPatternIndexerLookup(node, narrowedType, argIsIndex: true, out indexerAccess, out Symbol? patternSymbol, out lengthProperty, diagnostics))
+            else if (TryBindIndexerForPattern(node, narrowedType, argIsIndex: true, out indexerAccess, out Symbol? patternSymbol, out lengthProperty, diagnostics))
             {
                 if (patternSymbol is PropertySymbol indexer)
                 {
@@ -331,7 +333,7 @@ private BoundListPattern BindListPattern(
                 variableAccess: variableAccess, inputType: inputType, narrowedType: narrowedType, hasErrors);
         }
 
-        private bool TryPerformPatternIndexerLookup(
+        private bool TryBindIndexerForPattern(
             SyntaxNode syntax,
             TypeSymbol receiverType,
             bool argIsIndex,
@@ -379,14 +381,14 @@ private bool TryPerformPatternIndexerLookup(
                     switch (boundAccess)
                     {
                         case BoundIndexerAccess boundIndexerAccess:
+                            Debug.Assert(!boundIndexerAccess.Indexer.IsStatic);
+
                             if (boundIndexerAccess.ResultKind == LookupResultKind.Viable &&
                                 boundIndexerAccess.Indexer.GetMethod is { } getMethod &&
                                 IsAccessible(getMethod, ref useSiteInfo) &&
-                                TryLookupLengthOrCount(receiverType, lookupResult, out lengthProperty, ref useSiteInfo))
+                                TryLookupLengthOrCount(syntax, receiverType, lookupResult, out lengthProperty, bindingDiagnostics) &&
+                                !boundIndexerAccess.Indexer.IsStatic)
                             {
-                                // PROTOTYPE(list-patterns) Can this be ever true? If so, move to if above
-                                Debug.Assert(!boundIndexerAccess.Indexer.IsStatic);
-                                ReportDiagnosticsIfObsolete(bindingDiagnostics, lengthProperty, syntax, hasBaseReceiver: false);
                                 GetWellKnownTypeMember(argIsIndex ? WellKnownMember.System_Index__ctor : WellKnownMember.System_Range__ctor, bindingDiagnostics, syntax: syntax);
                                 indexerAccess = BindIndexerDefaultArguments(boundIndexerAccess, BindValueKind.RValue, bindingDiagnostics);
                                 found = true;
@@ -412,8 +414,8 @@ boundIndexerAccess.Indexer.GetMethod is { } getMethod &&
             }
 
             // If the argType is missing or the indexer lookup has failed, we will fallback to the implicit indexer support.
-            found = TryLookupLengthOrCount(receiverType, lookupResult, out lengthProperty, ref useSiteInfo) &&
-                    TryFindIndexOrRangeIndexerPattern(lookupResult, receiverOpt: null, receiverType, argIsIndex, out patternSymbol, diagnostics, ref useSiteInfo);
+            found = TryLookupLengthOrCount(syntax, receiverType, lookupResult, out lengthProperty, diagnostics) &&
+                    TryFindIndexOrRangeIndexerPattern(syntax, lookupResult, receiverOpt: null, receiverType, argIsIndex, out patternSymbol, diagnostics);
 
 done:
             if (found)
@@ -1458,7 +1460,7 @@ private ImmutableArray<BoundPropertySubpattern> BindPropertyPatternClause(
                         {
                             isLengthOrCount = receiverType.IsSZArray()
                                 ? ReferenceEquals(memberSymbol, Compilation.GetSpecialTypeMember(SpecialMember.System_Array__Length))
-                                : TryPerformPatternIndexerLookup(node, receiverType, argIsIndex: true, indexerAccess: out _, patternSymbol: out _, lengthProperty: out _, BindingDiagnosticBag.Discarded);
+                                : TryBindIndexerForPattern(node, receiverType, argIsIndex: true, indexerAccess: out _, patternSymbol: out _, lengthProperty: out _, BindingDiagnosticBag.Discarded);
                         }
                     }
                 }

src/Compilers/CSharp/Portable/Errors/ErrorCode.cs

@@ -2000,10 +2000,13 @@ internal enum ErrorCode
         WRN_MethGrpToNonDel = 8974,
         ERR_LambdaExplicitReturnTypeVar = 8975,
 
-        // PROTOTYPE(list-patterns)
-        ERR_UnsupportedTypeForListPattern = 9200,
-        ERR_UnsupportedTypeForSlicePattern,
-        ERR_MisplacedSlicePattern,
+        #endregion
+
+        #region diagnostics introduced for C# 11.0
+
+        ERR_UnsupportedTypeForListPattern = 9000,
+        ERR_UnsupportedTypeForSlicePattern = 9001,
+        ERR_MisplacedSlicePattern = 9002,
 
         #endregion
 

src/Compilers/CSharp/Portable/Errors/MessageID.cs

@@ -224,9 +224,6 @@ internal enum MessageID
         IDS_FeatureInferredDelegateType = MessageBase + 12799,
         IDS_FeatureLambdaAttributes = MessageBase + 12800,
 
-        // PROTOTYPE(list-patterns) To reduce conflicts with upstream. Should be moved/indexed eventually.
-        IDS_FeatureListPattern = MessageBase + 12850,
-
         IDS_FeatureWithOnAnonymousTypes = MessageBase + 12801,
         IDS_FeatureExtendedPropertyPatterns = MessageBase + 12802,
         IDS_FeatureStaticAbstractMembersInInterfaces = MessageBase + 12803,
@@ -238,7 +235,9 @@ internal enum MessageID
         IDS_FeatureFileScopedNamespace = MessageBase + 12809,
         IDS_FeatureParameterlessStructConstructors = MessageBase + 12810,
         IDS_FeatureStructFieldInitializers = MessageBase + 12811,
+
         IDS_FeatureGenericAttributes = MessageBase + 12812,
+        IDS_FeatureListPattern = MessageBase + 12813,
     }
 
     // Message IDs may refer to strings that need to be localized.
@@ -345,9 +344,12 @@ internal static LanguageVersion RequiredVersion(this MessageID feature)
             // Checks are in the LanguageParser unless otherwise noted.
             switch (feature)
             {
+                // PREFER reporting diagnostics in binding when diagnostics do not affect the shape of the tree
+
                 // C# preview features.
                 case MessageID.IDS_FeatureStaticAbstractMembersInInterfaces: // semantic check
                 case MessageID.IDS_FeatureGenericAttributes: // semantic check
+                case MessageID.IDS_FeatureListPattern: // semantic check
                     return LanguageVersion.Preview;
 
                 // C# 10.0 features.
@@ -533,10 +535,6 @@ internal static LanguageVersion RequiredVersion(this MessageID feature)
 
                 default:
                     throw ExceptionUtilities.UnexpectedValue(feature);
-
-                // PROTOTYPE(list-patterns)
-                case MessageID.IDS_FeatureListPattern:
-                    return LanguageVersion.Preview;
             }
         }
     }

src/Compilers/CSharp/Portable/FlowAnalysis/NullableWalker_Patterns.cs

@@ -155,16 +155,14 @@ private void LearnFromAnyNullPatterns(
                 case BoundITuplePattern _:
                 case BoundRelationalPattern _:
                 case BoundSlicePattern _:
+                case BoundListPattern lp:
                     break; // nothing to learn
                 case BoundTypePattern tp:
                     if (tp.IsExplicitNotNullTest)
                     {
                         LearnFromNullTest(inputSlot, inputType, ref this.State, markDependentSlotsNotNull: false);
                     }
                     break;
-                case BoundListPattern lp:
-                    // PROTOTYPE(list-patterns)
-                    break;
                 case BoundRecursivePattern rp:
                     {
                         if (rp.IsExplicitNotNullTest)

src/Compilers/CSharp/Portable/Parser/LanguageParser_Patterns.cs

@@ -707,8 +707,7 @@ private PatternSyntax ParseListPattern(bool whenIsKeyword)
                 SyntaxKind.CloseBracketToken,
                 static p => p.ParsePattern(Precedence.Conditional));
             TryParseSimpleDesignation(out VariableDesignationSyntax designation, whenIsKeyword);
-            var result = _syntaxFactory.ListPattern(openBracket, list, closeBracket, designation);
-            return CheckFeatureAvailability(result, MessageID.IDS_FeatureListPattern);
+            return _syntaxFactory.ListPattern(openBracket, list, closeBracket, designation);
         }
     }
 }

src/Compilers/CSharp/Portable/Syntax/SyntaxKind.cs

@@ -829,7 +829,7 @@ public enum SyntaxKind : ushort
         AndPattern = 9032,
         NotPattern = 9033,
 
-        // PROTOTYPE(list-patterns) new patterns added
+        // new patterns added in C# 11.0
         SlicePattern = 9034,
         ListPattern = 9035,
 

src/Compilers/CSharp/Test/Emit/Attributes/AttributeTests_WellKnownAttributes.cs

@@ -13637,11 +13637,16 @@ public void M()
 }
 ";
 
-            // PROTOTYPE missing diagnostics (we're checking the Count property but not the accessor)
             CreateCompilation(code, targetFramework: TargetFramework.NetCoreApp).VerifyDiagnostics(
+                // (23,13): error CS0619: 'C.Count.get' is obsolete: 'error'
+                //         _ = this[^1]; // 1, 2
+                Diagnostic(ErrorCode.ERR_DeprecatedSymbolStr, "this[^1]").WithArguments("C.Count.get", "error").WithLocation(23, 13),
                 // (23,13): error CS0619: 'C.this[int].get' is obsolete: 'error'
                 //         _ = this[^1]; // 1, 2
                 Diagnostic(ErrorCode.ERR_DeprecatedSymbolStr, "this[^1]").WithArguments("C.this[int].get", "error").WithLocation(23, 13),
+                // (24,13): error CS0619: 'C.Count.get' is obsolete: 'error'
+                //         _ = this[..]; // 3, 4
+                Diagnostic(ErrorCode.ERR_DeprecatedSymbolStr, "this[..]").WithArguments("C.Count.get", "error").WithLocation(24, 13),
                 // (24,13): error CS0619: 'C.Slice(int, int)' is obsolete: 'error'
                 //         _ = this[..]; // 3, 4
                 Diagnostic(ErrorCode.ERR_DeprecatedSymbolStr, "this[..]").WithArguments("C.Slice(int, int)", "error").WithLocation(24, 13)