Partial properties: diagnostics for mismatch between parts (#73250)

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -2210,14 +2210,14 @@ If such a class is used as a base class and if the deriving class defines a dest
   <data name="ERR_InconsistentLambdaParameterUsage" xml:space="preserve">
     <value>Inconsistent lambda parameter usage; parameter types must be all explicit or all implicit</value>
   </data>
-  <data name="ERR_PartialMethodInvalidModifier" xml:space="preserve">
-    <value>A partial method cannot have the 'abstract' modifier</value>
+  <data name="ERR_PartialMemberCannotBeAbstract" xml:space="preserve">
+    <value>A partial member cannot have the 'abstract' modifier</value>
   </data>
-  <data name="ERR_PartialMethodOnlyInPartialClass" xml:space="preserve">
-    <value>A partial method must be declared within a partial type</value>
+  <data name="ERR_PartialMemberOnlyInPartialClass" xml:space="preserve">
+    <value>A partial member must be declared within a partial type</value>
   </data>
-  <data name="ERR_PartialMethodNotExplicit" xml:space="preserve">
-    <value>A partial method may not explicitly implement an interface method</value>
+  <data name="ERR_PartialMemberNotExplicit" xml:space="preserve">
+    <value>A partial member may not explicitly implement an interface member</value>
   </data>
   <data name="ERR_PartialMethodExtensionDifference" xml:space="preserve">
     <value>Both partial method declarations must be extension methods or neither may be an extension method</value>
@@ -2234,20 +2234,20 @@ If such a class is used as a base class and if the deriving class defines a dest
   <data name="ERR_PartialMethodMustHaveLatent" xml:space="preserve">
     <value>No defining declaration found for implementing declaration of partial method '{0}'</value>
   </data>
-  <data name="ERR_PartialMethodInconsistentTupleNames" xml:space="preserve">
-    <value>Both partial method declarations, '{0}' and '{1}', must use the same tuple element names.</value>
+  <data name="ERR_PartialMemberInconsistentTupleNames" xml:space="preserve">
+    <value>Both partial member declarations, '{0}' and '{1}', must use the same tuple element names.</value>
   </data>
   <data name="ERR_PartialMethodInconsistentConstraints" xml:space="preserve">
     <value>Partial method declarations of '{0}' have inconsistent constraints for type parameter '{1}'</value>
   </data>
   <data name="ERR_PartialMethodToDelegate" xml:space="preserve">
     <value>Cannot create delegate from method '{0}' because it is a partial method without an implementing declaration</value>
   </data>
-  <data name="ERR_PartialMethodStaticDifference" xml:space="preserve">
-    <value>Both partial method declarations must be static or neither may be static</value>
+  <data name="ERR_PartialMemberStaticDifference" xml:space="preserve">
+    <value>Both partial member declarations must be static or neither may be static</value>
   </data>
-  <data name="ERR_PartialMethodUnsafeDifference" xml:space="preserve">
-    <value>Both partial method declarations must be unsafe or neither may be unsafe</value>
+  <data name="ERR_PartialMemberUnsafeDifference" xml:space="preserve">
+    <value>Both partial member declarations must be unsafe or neither may be unsafe</value>
   </data>
   <data name="ERR_PartialMethodInExpressionTree" xml:space="preserve">
     <value>Partial methods with only a defining declaration or removed conditional methods cannot be used in expression trees</value>
@@ -5752,8 +5752,8 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="ERR_FieldLikeEventCantBeReadOnly" xml:space="preserve">
     <value>Field-like event '{0}' cannot be 'readonly'.</value>
   </data>
-  <data name="ERR_PartialMethodReadOnlyDifference" xml:space="preserve">
-    <value>Both partial method declarations must be readonly or neither may be readonly</value>
+  <data name="ERR_PartialMemberReadOnlyDifference" xml:space="preserve">
+    <value>Both partial member declarations must be readonly or neither may be readonly</value>
   </data>
   <data name="ERR_ReadOnlyModMissingAccessor" xml:space="preserve">
     <value>'{0}': 'readonly' can only be used on accessors if the property or indexer has both a get and a set accessor</value>
@@ -6536,17 +6536,17 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="ERR_PartialMethodWithExtendedModMustHaveAccessMods" xml:space="preserve">
     <value>Partial method '{0}' must have accessibility modifiers because it has a 'virtual', 'override', 'sealed', 'new', or 'extern' modifier.</value>
   </data>
-  <data name="ERR_PartialMethodAccessibilityDifference" xml:space="preserve">
-    <value>Both partial method declarations must have identical accessibility modifiers.</value>
+  <data name="ERR_PartialMemberAccessibilityDifference" xml:space="preserve">
+    <value>Both partial member declarations must have identical accessibility modifiers.</value>
   </data>
-  <data name="ERR_PartialMethodExtendedModDifference" xml:space="preserve">
-    <value>Both partial method declarations must have identical combinations of 'virtual', 'override', 'sealed', and 'new' modifiers.</value>
+  <data name="ERR_PartialMemberExtendedModDifference" xml:space="preserve">
+    <value>Both partial member declarations must have identical combinations of 'virtual', 'override', 'sealed', and 'new' modifiers.</value>
   </data>
   <data name="ERR_PartialMethodReturnTypeDifference" xml:space="preserve">
     <value>Both partial method declarations must have the same return type.</value>
   </data>
-  <data name="ERR_PartialMethodRefReturnDifference" xml:space="preserve">
-    <value>Partial method declarations must have matching ref return values.</value>
+  <data name="ERR_PartialMemberRefReturnDifference" xml:space="preserve">
+    <value>Partial member declarations must have matching ref return values.</value>
   </data>
   <data name="WRN_PartialMethodTypeDifference" xml:space="preserve">
     <value>Partial method declarations '{0}' and '{1}' have signature differences.</value>
@@ -7947,4 +7947,19 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="ERR_PartialPropertyUnexpectedAccessor" xml:space="preserve">
     <value>Property accessor '{0}' does not implement any accessor declared on the definition part</value>
   </data>
+  <data name="ERR_PartialPropertyInitMismatch" xml:space="preserve">
+    <value>Property accessor '{0}' must be '{1}' to match the definition part</value>
+  </data>
+  <data name="ERR_PartialPropertyTypeDifference" xml:space="preserve">
+    <value>Both partial property declarations must have the same type.</value>
+  </data>
+  <data name="WRN_PartialPropertySignatureDifference" xml:space="preserve">
+    <value>Partial property declarations '{0}' and '{1}' have signature differences.</value>
+  </data>
+  <data name="WRN_PartialPropertySignatureDifference_Title" xml:space="preserve">
+    <value>Partial property declarations have signature differences.</value>
+  </data>
+  <data name="ERR_PartialPropertyRequiredDifference" xml:space="preserve">
+    <value>Both partial property declarations must be required or neither may be required</value>
+  </data>
 </root>

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

@@ -529,20 +529,20 @@ internal enum ErrorCode
         ERR_InvalidAnonymousTypeMemberDeclarator = 746,
         ERR_InvalidInitializerElementInitializer = 747,
         ERR_InconsistentLambdaParameterUsage = 748,
-        ERR_PartialMethodInvalidModifier = 750,
-        ERR_PartialMethodOnlyInPartialClass = 751,
+        ERR_PartialMemberCannotBeAbstract = 750,
+        ERR_PartialMemberOnlyInPartialClass = 751,
         // ERR_PartialMethodCannotHaveOutParameters = 752, Removed as part of 'extended partial methods' feature
         // ERR_PartialMethodOnlyMethods = 753, Removed as it is subsumed by ERR_PartialMisplaced
-        ERR_PartialMethodNotExplicit = 754,
+        ERR_PartialMemberNotExplicit = 754,
         ERR_PartialMethodExtensionDifference = 755,
         ERR_PartialMethodOnlyOneLatent = 756,
         ERR_PartialMethodOnlyOneActual = 757,
         ERR_PartialMethodParamsDifference = 758,
         ERR_PartialMethodMustHaveLatent = 759,
         ERR_PartialMethodInconsistentConstraints = 761,
         ERR_PartialMethodToDelegate = 762,
-        ERR_PartialMethodStaticDifference = 763,
-        ERR_PartialMethodUnsafeDifference = 764,
+        ERR_PartialMemberStaticDifference = 763,
+        ERR_PartialMemberUnsafeDifference = 764,
         ERR_PartialMethodInExpressionTree = 765,
         // ERR_PartialMethodMustReturnVoid = 766, Removed as part of 'extended partial methods' feature
         ERR_ExplicitImplCollisionOnRefOut = 767,
@@ -1392,7 +1392,7 @@ internal enum ErrorCode
         ERR_CantChangeTupleNamesOnOverride = 8139,
         ERR_DuplicateInterfaceWithTupleNamesInBaseList = 8140,
         ERR_ImplBadTupleNames = 8141,
-        ERR_PartialMethodInconsistentTupleNames = 8142,
+        ERR_PartialMemberInconsistentTupleNames = 8142,
         ERR_ExpressionTreeContainsTupleLiteral = 8143,
         ERR_ExpressionTreeContainsTupleConversion = 8144,
         #endregion tuple diagnostics introduced in C# 7
@@ -1709,7 +1709,7 @@ internal enum ErrorCode
         ERR_InvalidPropertyReadOnlyMods = 8660,
         ERR_DuplicatePropertyReadOnlyMods = 8661,
         ERR_FieldLikeEventCantBeReadOnly = 8662,
-        ERR_PartialMethodReadOnlyDifference = 8663,
+        ERR_PartialMemberReadOnlyDifference = 8663,
         ERR_ReadOnlyModMissingAccessor = 8664,
         ERR_OverrideRefConstraintNotSatisfied = 8665,
         ERR_OverrideValConstraintNotSatisfied = 8666,
@@ -1809,8 +1809,8 @@ internal enum ErrorCode
         ERR_PartialMethodWithNonVoidReturnMustHaveAccessMods = 8796,
         ERR_PartialMethodWithOutParamMustHaveAccessMods = 8797,
         ERR_PartialMethodWithExtendedModMustHaveAccessMods = 8798,
-        ERR_PartialMethodAccessibilityDifference = 8799,
-        ERR_PartialMethodExtendedModDifference = 8800,
+        ERR_PartialMemberAccessibilityDifference = 8799,
+        ERR_PartialMemberExtendedModDifference = 8800,
 
         ERR_SimpleProgramLocalIsReferencedOutsideOfTopLevelStatement = 8801,
         ERR_SimpleProgramMultipleUnitsWithTopLevelStatements = 8802,
@@ -1832,7 +1832,7 @@ internal enum ErrorCode
         ERR_ModuleInitializerMethodAndContainingTypesMustNotBeGeneric = 8816,
 
         ERR_PartialMethodReturnTypeDifference = 8817,
-        ERR_PartialMethodRefReturnDifference = 8818,
+        ERR_PartialMemberRefReturnDifference = 8818,
         WRN_NullabilityMismatchInReturnTypeOnPartial = 8819,
 
         ERR_StaticAnonymousFunctionCannotCaptureVariable = 8820,
@@ -2317,6 +2317,10 @@ internal enum ErrorCode
         ERR_PartialPropertyDuplicateImplementation = 9303,
         ERR_PartialPropertyMissingAccessor = 9304,
         ERR_PartialPropertyUnexpectedAccessor = 9305,
+        ERR_PartialPropertyInitMismatch = 9306,
+        ERR_PartialPropertyTypeDifference = 9307,
+        WRN_PartialPropertySignatureDifference = 9308,
+        ERR_PartialPropertyRequiredDifference = 9309,
 
         #endregion
 

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

@@ -557,6 +557,7 @@ internal static int GetWarningLevel(ErrorCode code)
                 case ErrorCode.WRN_DynamicDispatchToParamsCollectionMethod:
                 case ErrorCode.WRN_DynamicDispatchToParamsCollectionIndexer:
                 case ErrorCode.WRN_DynamicDispatchToParamsCollectionConstructor:
+                case ErrorCode.WRN_PartialPropertySignatureDifference:
 
                     return 1;
                 default:
@@ -1069,18 +1070,18 @@ internal static bool IsBuildOnlyDiagnostic(ErrorCode code)
                 case ErrorCode.ERR_InvalidAnonymousTypeMemberDeclarator:
                 case ErrorCode.ERR_InvalidInitializerElementInitializer:
                 case ErrorCode.ERR_InconsistentLambdaParameterUsage:
-                case ErrorCode.ERR_PartialMethodInvalidModifier:
-                case ErrorCode.ERR_PartialMethodOnlyInPartialClass:
-                case ErrorCode.ERR_PartialMethodNotExplicit:
+                case ErrorCode.ERR_PartialMemberCannotBeAbstract:
+                case ErrorCode.ERR_PartialMemberOnlyInPartialClass:
+                case ErrorCode.ERR_PartialMemberNotExplicit:
                 case ErrorCode.ERR_PartialMethodExtensionDifference:
                 case ErrorCode.ERR_PartialMethodOnlyOneLatent:
                 case ErrorCode.ERR_PartialMethodOnlyOneActual:
                 case ErrorCode.ERR_PartialMethodParamsDifference:
                 case ErrorCode.ERR_PartialMethodMustHaveLatent:
                 case ErrorCode.ERR_PartialMethodInconsistentConstraints:
                 case ErrorCode.ERR_PartialMethodToDelegate:
-                case ErrorCode.ERR_PartialMethodStaticDifference:
-                case ErrorCode.ERR_PartialMethodUnsafeDifference:
+                case ErrorCode.ERR_PartialMemberStaticDifference:
+                case ErrorCode.ERR_PartialMemberUnsafeDifference:
                 case ErrorCode.ERR_PartialMethodInExpressionTree:
                 case ErrorCode.ERR_ExplicitImplCollisionOnRefOut:
                 case ErrorCode.ERR_IndirectRecursiveConstructorCall:
@@ -1744,7 +1745,7 @@ internal static bool IsBuildOnlyDiagnostic(ErrorCode code)
                 case ErrorCode.ERR_CantChangeTupleNamesOnOverride:
                 case ErrorCode.ERR_DuplicateInterfaceWithTupleNamesInBaseList:
                 case ErrorCode.ERR_ImplBadTupleNames:
-                case ErrorCode.ERR_PartialMethodInconsistentTupleNames:
+                case ErrorCode.ERR_PartialMemberInconsistentTupleNames:
                 case ErrorCode.ERR_ExpressionTreeContainsTupleLiteral:
                 case ErrorCode.ERR_ExpressionTreeContainsTupleConversion:
                 case ErrorCode.ERR_AutoPropertyCannotBeRefReturning:
@@ -1983,7 +1984,7 @@ internal static bool IsBuildOnlyDiagnostic(ErrorCode code)
                 case ErrorCode.ERR_InvalidPropertyReadOnlyMods:
                 case ErrorCode.ERR_DuplicatePropertyReadOnlyMods:
                 case ErrorCode.ERR_FieldLikeEventCantBeReadOnly:
-                case ErrorCode.ERR_PartialMethodReadOnlyDifference:
+                case ErrorCode.ERR_PartialMemberReadOnlyDifference:
                 case ErrorCode.ERR_ReadOnlyModMissingAccessor:
                 case ErrorCode.ERR_OverrideRefConstraintNotSatisfied:
                 case ErrorCode.ERR_OverrideValConstraintNotSatisfied:
@@ -2053,8 +2054,8 @@ internal static bool IsBuildOnlyDiagnostic(ErrorCode code)
                 case ErrorCode.ERR_PartialMethodWithNonVoidReturnMustHaveAccessMods:
                 case ErrorCode.ERR_PartialMethodWithOutParamMustHaveAccessMods:
                 case ErrorCode.ERR_PartialMethodWithExtendedModMustHaveAccessMods:
-                case ErrorCode.ERR_PartialMethodAccessibilityDifference:
-                case ErrorCode.ERR_PartialMethodExtendedModDifference:
+                case ErrorCode.ERR_PartialMemberAccessibilityDifference:
+                case ErrorCode.ERR_PartialMemberExtendedModDifference:
                 case ErrorCode.ERR_SimpleProgramLocalIsReferencedOutsideOfTopLevelStatement:
                 case ErrorCode.ERR_SimpleProgramMultipleUnitsWithTopLevelStatements:
                 case ErrorCode.ERR_TopLevelStatementAfterNamespaceOrType:
@@ -2072,7 +2073,7 @@ internal static bool IsBuildOnlyDiagnostic(ErrorCode code)
                 case ErrorCode.ERR_ModuleInitializerMethodMustBeStaticParameterlessVoid:
                 case ErrorCode.ERR_ModuleInitializerMethodAndContainingTypesMustNotBeGeneric:
                 case ErrorCode.ERR_PartialMethodReturnTypeDifference:
-                case ErrorCode.ERR_PartialMethodRefReturnDifference:
+                case ErrorCode.ERR_PartialMemberRefReturnDifference:
                 case ErrorCode.WRN_NullabilityMismatchInReturnTypeOnPartial:
                 case ErrorCode.ERR_StaticAnonymousFunctionCannotCaptureVariable:
                 case ErrorCode.ERR_StaticAnonymousFunctionCannotCaptureThis:
@@ -2445,6 +2446,10 @@ internal static bool IsBuildOnlyDiagnostic(ErrorCode code)
                 case ErrorCode.ERR_PartialPropertyDuplicateImplementation:
                 case ErrorCode.ERR_PartialPropertyMissingAccessor:
                 case ErrorCode.ERR_PartialPropertyUnexpectedAccessor:
+                case ErrorCode.ERR_PartialPropertyInitMismatch:
+                case ErrorCode.ERR_PartialPropertyTypeDifference:
+                case ErrorCode.WRN_PartialPropertySignatureDifference:
+                case ErrorCode.ERR_PartialPropertyRequiredDifference:
                     return false;
                 default:
                     // NOTE: All error codes must be explicitly handled in this switch statement

src/Compilers/CSharp/Portable/Symbols/MemberSymbolExtensions.cs

@@ -547,6 +547,7 @@ internal static bool IsExplicitInterfaceImplementation(this Symbol member)
 
         internal static bool IsPartialMember(this Symbol member)
         {
+            Debug.Assert(member.IsDefinition);
             return member
                 is SourceOrdinaryMethodSymbol { IsPartial: true }
                 or SourcePropertySymbol { IsPartial: true }
@@ -555,6 +556,7 @@ internal static bool IsPartialMember(this Symbol member)
 
         internal static bool IsPartialImplementation(this Symbol member)
         {
+            Debug.Assert(member.IsDefinition);
             return member
                 is SourceOrdinaryMethodSymbol { IsPartialImplementation: true }
                 or SourcePropertySymbol { IsPartialImplementation: true }
@@ -563,6 +565,7 @@ internal static bool IsPartialImplementation(this Symbol member)
 
         internal static bool IsPartialDefinition(this Symbol member)
         {
+            Debug.Assert(member.IsDefinition);
             return member
                 is SourceOrdinaryMethodSymbol { IsPartialDefinition: true }
                 or SourcePropertySymbol { IsPartialDefinition: true }

src/Compilers/CSharp/Portable/Symbols/PublicModel/MethodSymbol.cs

@@ -298,7 +298,9 @@ IMethodSymbol IMethodSymbol.PartialDefinitionPart
             }
         }
 
-        bool IMethodSymbol.IsPartialDefinition => _underlying.IsPartialDefinition();
+        // PROTOTYPE(partial-properties): Perhaps this API should be implemented as '_underlying.OriginalDefinition.IsPartialDefinition()' instead.
+        // However, this would be a behavior change. Callers may have been assuming that if the API returned true, then the receiver is an original definition symbol.
+        bool IMethodSymbol.IsPartialDefinition => _underlying.IsDefinition && _underlying.IsPartialDefinition();
 
         INamedTypeSymbol IMethodSymbol.AssociatedAnonymousDelegate
         {

src/Compilers/CSharp/Portable/Symbols/Source/SourceOrdinaryMethodOrUserDefinedOperatorSymbol.cs

@@ -60,12 +60,12 @@ public sealed override bool ReturnsVoid
             {
                 if (MethodKind == MethodKind.ExplicitInterfaceImplementation)
                 {
-                    diagnostics.Add(ErrorCode.ERR_PartialMethodNotExplicit, _location);
+                    diagnostics.Add(ErrorCode.ERR_PartialMemberNotExplicit, _location);
                 }
 
                 if (!ContainingType.IsPartial())
                 {
-                    diagnostics.Add(ErrorCode.ERR_PartialMethodOnlyInPartialClass, _location);
+                    diagnostics.Add(ErrorCode.ERR_PartialMemberOnlyInPartialClass, _location);
                 }
             }