Add DefaultMemberRequiredInspection

This inspection finds all failed indexed default member resolutions. The non-indexed ones are already covered by the ValueRequiredInspection and the ProcedureRequiredInspection.

Author: MDoerner

Rubberduck.CodeAnalysis/Inspections/Concrete/DefaultMemberRequiredInspection.cs

@@ -0,0 +1,101 @@
+using System.Collections.Generic;
+using System.Linq;
+using Rubberduck.Inspections.Abstract;
+using Rubberduck.Inspections.Inspections.Extensions;
+using Rubberduck.Inspections.Results;
+using Rubberduck.Parsing.Inspections;
+using Rubberduck.Parsing.Inspections.Abstract;
+using Rubberduck.Parsing.Symbols;
+using Rubberduck.Parsing.VBA;
+using Rubberduck.Resources.Inspections;
+
+namespace Rubberduck.CodeAnalysis.Inspections.Concrete
+{
+    /// <summary>
+    /// Locates indexed default member calls for which the corresponding object does not have a suitable suitable default member. 
+    /// </summary>
+    /// <why>
+    /// The VBA compiler does not check whether the necessary default member is present. Instead there is a runtime error whenever the runtime type fails to have the default member.
+    /// </why>
+    /// <example hasResult="true">
+    /// <![CDATA[
+    /// Class1:
+    ///
+    /// Public Function Foo(index As Long) As Long
+    /// 'No default member attribute
+    /// End Function
+    ///
+    /// ------------------------------
+    /// Module1:
+    /// 
+    /// Public Sub DoIt()
+    ///     Dim cls As Class1
+    ///     Dim bar As Variant
+    ///     Set cls = New Class1
+    ///     bar = cls(0) 
+    /// End Sub
+    /// ]]>
+    /// </example>
+    /// <example hasResult="false">
+    /// <![CDATA[
+    /// Class1:
+    ///
+    /// Public Function Foo(index As Long) As Long
+    /// Attribute Foo.UserMemId = 0
+    /// End Function
+    ///
+    /// ------------------------------
+    /// Module1:
+    /// 
+    /// Public Sub DoIt()
+    ///     Dim cls As Class1
+    ///     Dim bar As Variant
+    ///     Set cls = New Class1
+    ///     bar = cls(0) 
+    /// End Sub
+    /// ]]>
+    /// </example>
+    public class DefaultMemberRequiredInspection : InspectionBase
+    {
+        private readonly IDeclarationFinderProvider _declarationFinderProvider;
+
+        public DefaultMemberRequiredInspection(RubberduckParserState state)
+            : base(state)
+        {
+            _declarationFinderProvider = state;
+
+            //This will most likely cause a runtime error. The exceptions are rare and should be refactored or made explicit with an @Ignore annotation.
+            Severity = CodeInspectionSeverity.Error;
+        }
+
+        protected override IEnumerable<IInspectionResult> DoGetInspectionResults()
+        {
+            var finder = _declarationFinderProvider.DeclarationFinder;
+
+            var failedIndexedDefaultMemberAccesses = finder.FailedIndexedDefaultMemberAccesses();
+            return failedIndexedDefaultMemberAccesses
+                .Where(failedIndexedDefaultMemberAccess => !IsIgnored(failedIndexedDefaultMemberAccess))
+                .Select(failedIndexedDefaultMemberAccess => InspectionResult(failedIndexedDefaultMemberAccess, _declarationFinderProvider));
+        }
+
+        private bool IsIgnored(IdentifierReference assignment)
+        {
+            return assignment.IsIgnoringInspectionResultFor(AnnotationName);
+        }
+
+        private IInspectionResult InspectionResult(IdentifierReference failedCoercion, IDeclarationFinderProvider declarationFinderProvider)
+        {
+            return new IdentifierReferenceInspectionResult(this,
+                ResultDescription(failedCoercion),
+                declarationFinderProvider,
+                failedCoercion);
+        }
+
+        private string ResultDescription(IdentifierReference failedIndexedDefaultMemberAccess)
+        {
+            var expression = failedIndexedDefaultMemberAccess.IdentifierName;
+            var typeName = failedIndexedDefaultMemberAccess.Declaration?.FullAsTypeName;
+            return string.Format(InspectionResults.DefaultMemberRequiredInspection, expression, typeName);
+        }
+    }
+}

Rubberduck.Resources/Inspections/InspectionInfo.Designer.cs

@@ -400,4 +400,7 @@ Falls der Parameter 'null' sein kann, bitte dieses Auftreten ignorieren. 'null'
   <data name="ProcedureRequiredInspection" xml:space="preserve">
     <value>Der VBA-Compiler gibt keinen Fehler aus, wenn eine Objektvariable an einer Stelle verwendet wird, die eine Prozedur erfordert, und der deklarierte Type des Objekts keinen passenden Standardmember hat. In fast allen Fällen führt dies zu einem Laufzeitfehler, der schwerer zu entdecken ist und auf einen Programmierfehler hinweist.</value>
   </data>
+  <data name="DefaultMemberRequiredInspection" xml:space="preserve">
+    <value>Der VBA-Compiler gibt keinen Fehler aus, wenn ein Standardmemberzugriff nötig ist, aber der der deklarierte Type des Objekts keinen passenden Standardmember hat. In fast allen Fällen führt dies zu einem Laufzeitfehler, der schwerer zu entdecken ist und auf einen Programmierfehler hinweist.</value>
+  </data>
 </root>

Rubberduck.Resources/Inspections/InspectionInfo.de.resx

@@ -400,4 +400,7 @@ If the parameter can be null, ignore this inspection result; passing a null valu
   <data name="ProcedureRequiredInspection" xml:space="preserve">
     <value>The VBA compiler does not raise an error if an object variable is used in a place that requires a procedure and the object's declared type does not have a suitable default member. Under almost all circumstances, this leads to a run-time error, which is harder to detect and indicates a bug.</value>
   </data>
+  <data name="DefaultMemberRequiredInspection" xml:space="preserve">
+    <value>The VBA compiler does not raise an error if an indexed default member call is required but the object's declared type does not have a suitable default member. Under almost all circumstances, this leads to a run-time error, which is harder to detect and indicates a bug.</value>
+  </data>
 </root>

Rubberduck.Resources/Inspections/InspectionInfo.resx

@@ -384,4 +384,7 @@
   <data name="ProcedureRequiredInspection" xml:space="preserve">
     <value>Objekt statt Prozedur verwendet</value>
   </data>
+  <data name="DefaultMemberRequiredInspection" xml:space="preserve">
+    <value>Standardmemberzugriff ohne Standardmember</value>
+  </data>
 </root>

Rubberduck.Resources/Inspections/InspectionNames.Designer.cs

@@ -404,4 +404,7 @@
   <data name="ProcedureRequiredInspection" xml:space="preserve">
     <value>Object used where a procedure is required</value>
   </data>
+  <data name="DefaultMemberRequiredInspection" xml:space="preserve">
+    <value>Indexed default member access without default member</value>
+  </data>
 </root>

Rubberduck.Resources/Inspections/InspectionNames.de.resx

@@ -425,4 +425,7 @@ In Memoriam, 1972-2018</value>
   <data name="ProcedureRequiredInspection" xml:space="preserve">
     <value>An einer Stelle, die eine Prozedur erfordert, wird der Ausdruck '{0}' vom Objekttyp '{1}'  verwendet, der keinen passendes Standardmember hat.</value>
   </data>
+  <data name="DefaultMemberRequiredInspection" xml:space="preserve">
+    <value>Der Ausdruck '{0}' erfordert einen Standardmemberzugriff, aber der Typ '{1}' hat keinen passenden Standardmember.</value>
+  </data>
 </root>

Rubberduck.Resources/Inspections/InspectionNames.resx

@@ -454,4 +454,8 @@ In memoriam, 1972-2018</value>
     <value>In a context that requires a procedure, the expression '{0}' of object type '{1}' is used that does not have a suitable default member.</value>
     <comment>{0} expression; {1} type</comment>
   </data>
+  <data name="DefaultMemberRequiredInspection" xml:space="preserve">
+    <value>The expression '{0}' requires a default member access, but the type '{0}' does not have a suitable default member.</value>
+    <comment>{0} expression; {1} type</comment>
+  </data>
 </root>