Add IPicture test and fix the failure

src/Microsoft.Windows.CsWin32/Generator.cs

@@ -4021,14 +4021,23 @@ private ISet<string> GetDeclarableProperties(IEnumerable<MethodDefinition> metho
                     badProperty |= !allowNonConsecutiveAccessors && priorPropertyData.Index != rowIndex - 1;
                     if (badProperty)
                     {
-                        badProperties.Add(propertyName.Identifier.ValueText);
-                        goodProperties.Remove(propertyName.Identifier.ValueText);
+                        ReportBadProperty();
                         continue;
                     }
                 }
 
                 goodProperties[propertyName.Identifier.ValueText] = (propertyType, rowIndex);
             }
+            else if (propertyName is not null)
+            {
+                ReportBadProperty();
+            }
+
+            void ReportBadProperty()
+            {
+                badProperties.Add(propertyName.Identifier.ValueText);
+                goodProperties.Remove(propertyName.Identifier.ValueText);
+            }
         }
 
         return goodProperties.Count == 0 ? ImmutableHashSet<string>.Empty : new HashSet<string>(goodProperties.Keys, StringComparer.Ordinal);
@@ -4039,8 +4048,18 @@ private bool TryGetPropertyAccessorInfo(MethodDefinition methodDefinition, [NotN
         propertyName = null;
         accessorKind = null;
         propertyType = null;
+
         if ((methodDefinition.Attributes & MethodAttributes.SpecialName) != MethodAttributes.SpecialName)
         {
+            // Sometimes another method actually *does* qualify as a property accessor, which would have this method as another accessor if it qualified.
+            // But since this doesn't qualify, produce the property name that should be disqualified as a whole since C# doesn't like seeing property X and method set_X as seperate declarations.
+            string disqualifiedMethodName = this.Reader.GetString(methodDefinition.Name);
+            int index = disqualifiedMethodName.IndexOf('_');
+            if (index > 0)
+            {
+                propertyName = IdentifierName(disqualifiedMethodName.Substring(index + 1));
+            }
+
             return false;
         }
 

test/Microsoft.Windows.CsWin32.Tests/GeneratorTests.cs

@@ -632,6 +632,19 @@ public void COMPropertiesAreGeneratedAsStructProperties_NonConsecutiveAccessors(
         Assert.NotEmpty(structSyntax.Members.OfType<MethodDeclarationSyntax>().Where(m => m.Identifier.ValueText == "put_ClassName"));
     }
 
+    /// <summary>
+    /// Verifies that IPicture can be generated.
+    /// It is a special case because of <see href="https://github.com/microsoft/win32metadata/issues/1367">this metadata bug</see>.
+    /// </summary>
+    [Fact]
+    public void COMPropertiesAreGeneratedAsStructProperties_NonConsecutiveAccessors_IPicture()
+    {
+        this.generator = this.CreateGenerator(DefaultTestGeneratorOptions with { AllowMarshaling = false });
+        Assert.True(this.generator.TryGenerate("IPicture", CancellationToken.None));
+        this.CollectGeneratedCode(this.generator);
+        this.AssertNoDiagnostics();
+    }
+
     [Theory, PairwiseData]
     public void COMPropertiesAreGeneratedAsMethodsWhenTheirReturnTypesDiffer([CombinatorialValues(0, 1, 2)] int marshaling)
     {