> Discovered in the logs for #4644:

```
2018-12-17 14:27:44.0304;WARN-2.3.1.4308;Rubberduck.Inspections.Rubberduck.Inspections.Inspector;System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
at Rubberduck.Inspections.Concrete.ProcedureCanBeWrittenAsFunctionInspection.<>c__DisplayClass4_0.<DoGetInspectionResults>b__3(QualifiedContext`1 context) in C:\projects\rubberduck\Rubberduck

> Spotted in the logs presented in #4644. This was originally reported under #4258, but seems to have resurfaced:

```
2018-12-17 14:27:43.7524;WARN-2.3.1.4308;Rubberduck.Inspections.Rubberduck.Inspections.Inspector;System.NullReferenceException: Object reference not set to an instance of an object.
at Rubberduck.Inspections.Concrete.UnreachableCaseInspection.ParseTreeValueVisitor.GetConstantContextValueToken(ParserRuleContext context) in C:\projects\rubberduck\Rubberduck.CodeAnalysis\Ins

> The issue seems to be a COM-Exception that's blowing up when we're inspecting for that.

```
2018-12-17 15:02:01.0154;WARN-2.3.1.4308;Rubberduck.Inspections.Rubberduck.Inspections.Inspector;System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component.
at Microsoft.Vbe.Interop._VBComponent.get_Properties()
at Rubberduck.VBEditor.SafeComWrappers.VBA.VBComponent.get_Properties() in C:\projects\rubberduck\Rubberduck.VBEd

> To enable closing the overarching issue of Code Metrics that originally only intended to deal with an initial implementation, this issue is a follow-up taking one of the proposed inspections and putting it into it's own issue.

The MaintainabilityIndex of a code base is computed by the [magic formula](http://blogs.msdn.com/b/codeanalysis/archive/2007/11/20/maintainability-index-range-and-meaning.aspx "MSDN blog article on maintainability index"):

```
(171 - 5.2 * ln(HV) - 0.23 * CC - 16.

> Currently, it is possible to execute private procedures. Since test modules aren't meant to be run outside well, *tests*, it seems nice to be able to make all procedures as private, as to not pollute the intellisense / global namespace, especially in projects where it's not practical to have a separate test project.

The change would be mainly be in the UI as it currently filters out any private procedures when discovering tests.

> I noticed this while I was meatbagging the Code Explorer. The expression parser in the `UnreachableCaseInspection` apparently has problems with enumerations that use built-in constants. This MCVE...

```
Enum Fubar
Foo = vbObjectError + 1
Bar = vbObjectError + 2
End Enum

Sub Example()
Select Case 42
Case Fubar.Foo
Debug.Print "Foo"
Case Fubar.Bar
Debug.Print "Bar"
End Select
End Sub
```
...results in this error:

```

> We may have a memory leak with some of WPF resources:
https://github.com/rubberduck-vba/Rubberduck/blob/7733e38c57a1d818d507ad374c4d0bab60efcda0/Rubberduck.Core/UI/Inspections/InspectionSeverityImageSourceConverter.cs#L42-L53

and possibly from this:
https://github.com/rubberduck-vba/Rubberduck/blob/7733e38c57a1d818d507ad374c4d0bab60efcda0/Rubberduck.Core/UI/Inspections/InspectionImageSourceConverter.cs#L18-L19

We need to double check that the unmanaged resources are handled appropriate