Public Function DecodeModifiers()

in src/Compilers/VisualBasic/Portable/Binding/Binder_Utils.vb [139:250]
99 lines of code
86 McCabe index (conditional complexity)

        Public Function DecodeModifiers(syntax As SyntaxTokenList,
                                        allowableModifiers As SourceMemberFlags,
                                        errIdBadModifier As ERRID,
                                        defaultAccessibility As Accessibility,
                                        diagBag As DiagnosticBag) As MemberModifiers
            Dim foundModifiers As SourceMemberFlags = Nothing
            Dim privateProtectedToken As SyntaxToken = Nothing
            Dim privateOverridableModifier As SyntaxToken = Nothing
            Dim privateMustOverrideModifier As SyntaxToken = Nothing
            Dim privateNotOverridableModifier As SyntaxToken = Nothing

            
            For Each keywordSyntax In syntax
                Dim currentModifier As SourceMemberFlags = MapKeywordToFlag(keywordSyntax)

                If currentModifier = SourceMemberFlags.None Then
                    Continue For
                End If

                
                If (currentModifier And allowableModifiers) = 0 Then
                    ReportDiagnostic(diagBag, keywordSyntax, errIdBadModifier, keywordSyntax.ToString())
                ElseIf (currentModifier And foundModifiers) <> 0 Then
                    ReportDiagnostic(diagBag, keywordSyntax, ERRID.ERR_DuplicateSpecifier)
                ElseIf (currentModifier And SourceMemberFlags.AllAccessibilityModifiers) <> 0 AndAlso
                       (foundModifiers And SourceMemberFlags.AllAccessibilityModifiers) <> 0 AndAlso
                       Not ((foundModifiers Or currentModifier) And SourceMemberFlags.AllAccessibilityModifiers) = (SourceMemberFlags.Protected Or SourceMemberFlags.Friend) AndAlso
                       Not (((foundModifiers Or currentModifier) And SourceMemberFlags.AllAccessibilityModifiers) = (SourceMemberFlags.Protected Or SourceMemberFlags.Private)) Then
                    ReportDiagnostic(diagBag, keywordSyntax, ERRID.ERR_DuplicateAccessCategoryUsed)
                ElseIf (currentModifier And SourceMemberFlags.AllOverrideModifiers) <> 0 AndAlso
                       (foundModifiers And SourceMemberFlags.AllOverrideModifiers) <> 0 Then
                    ReportDiagnostic(diagBag, keywordSyntax, ERRID.ERR_DuplicateModifierCategoryUsed)
                ElseIf (currentModifier And SourceMemberFlags.AllWriteabilityModifiers) <> 0 AndAlso
                       (foundModifiers And SourceMemberFlags.AllWriteabilityModifiers) <> 0 Then
                    ReportDiagnostic(diagBag, keywordSyntax, ERRID.ERR_DuplicateWriteabilityCategoryUsed)
                ElseIf (currentModifier And SourceMemberFlags.AllConversionModifiers) <> 0 AndAlso
                       (foundModifiers And SourceMemberFlags.AllConversionModifiers) <> 0 Then
                    ReportDiagnostic(diagBag, keywordSyntax, ERRID.ERR_DuplicateConversionCategoryUsed)
                ElseIf (currentModifier And SourceMemberFlags.AllShadowingModifiers) <> 0 AndAlso
                       (foundModifiers And SourceMemberFlags.AllShadowingModifiers) <> 0 Then
                    ReportDiagnostic(diagBag, keywordSyntax, ERRID.ERR_BadSpecifierCombo2, "Overloads", "Shadows")
                ElseIf (currentModifier And (SourceMemberFlags.Overrides Or SourceMemberFlags.Overridable)) <> 0 AndAlso
                       (foundModifiers And (SourceMemberFlags.Overrides Or SourceMemberFlags.Overridable)) <> 0 Then
                    ReportDiagnostic(diagBag, keywordSyntax, ERRID.ERR_OverridesImpliesOverridable)
                ElseIf (currentModifier And SourceMemberFlags.PrivateOverridableModifiers) <> 0 AndAlso
                       (foundModifiers And SourceMemberFlags.PrivateOverridableModifiers) <> 0 Then
                    privateOverridableModifier = keywordSyntax
                    foundModifiers = foundModifiers Or currentModifier
                ElseIf (currentModifier And SourceMemberFlags.ShadowsAndOverrides) <> 0 AndAlso
                    (foundModifiers And SourceMemberFlags.ShadowsAndOverrides) <> 0 Then
                    ReportDiagnostic(diagBag, keywordSyntax, ERRID.ERR_BadSpecifierCombo2, "Overrides", "Shadows")
                ElseIf (currentModifier And SourceMemberFlags.PrivateMustOverrideModifiers) <> 0 AndAlso
                       (foundModifiers And SourceMemberFlags.PrivateMustOverrideModifiers) <> 0 Then
                    privateMustOverrideModifier = keywordSyntax
                    foundModifiers = foundModifiers Or currentModifier
                ElseIf (currentModifier And SourceMemberFlags.PrivateNotOverridableModifiers) <> 0 AndAlso
                       (foundModifiers And SourceMemberFlags.PrivateNotOverridableModifiers) <> 0 Then
                    privateNotOverridableModifier = keywordSyntax
                    foundModifiers = foundModifiers Or currentModifier
                ElseIf (currentModifier And (SourceMemberFlags.Iterator Or SourceMemberFlags.WriteOnly)) <> 0 AndAlso
                       (foundModifiers And (SourceMemberFlags.Iterator Or SourceMemberFlags.WriteOnly)) <> 0 Then
                    ReportDiagnostic(diagBag, keywordSyntax, ERRID.ERR_BadSpecifierCombo2, "Iterator", "WriteOnly")
                ElseIf (currentModifier And SourceMemberFlags.TypeInheritModifiers) <> 0 AndAlso
                       (foundModifiers And SourceMemberFlags.TypeInheritModifiers) <> 0 Then
                    ReportDiagnostic(diagBag, keywordSyntax, ERRID.ERR_BadSpecifierCombo2, "MustInherit", "NotInheritable")
                    
                    foundModifiers = foundModifiers Or currentModifier
                Else
                    If currentModifier = SourceMemberFlags.Private OrElse currentModifier = SourceMemberFlags.Protected Then
                        privateProtectedToken = keywordSyntax
                    End If
                    foundModifiers = foundModifiers Or currentModifier
                End If
            Next

            
            Dim access As Accessibility
            If (foundModifiers And SourceMemberFlags.Public) <> 0 Then
                access = Accessibility.Public
            ElseIf (foundModifiers And (SourceMemberFlags.Friend Or SourceMemberFlags.Protected)) = (SourceMemberFlags.Friend Or SourceMemberFlags.Protected) Then
                access = Accessibility.ProtectedOrFriend
            ElseIf (foundModifiers And (SourceMemberFlags.Private Or SourceMemberFlags.Protected)) = (SourceMemberFlags.Private Or SourceMemberFlags.Protected) Then
                access = Accessibility.ProtectedAndFriend
                InternalSyntax.Parser.CheckFeatureAvailability(
                    diagBag,
                    privateProtectedToken.GetLocation(),
                    DirectCast(privateProtectedToken.SyntaxTree, VisualBasicSyntaxTree).Options.LanguageVersion,
                    InternalSyntax.Feature.PrivateProtected)
            ElseIf (foundModifiers And SourceMemberFlags.Friend) <> 0 Then
                access = Accessibility.Friend
            ElseIf (foundModifiers And SourceMemberFlags.Protected) <> 0 Then
                access = Accessibility.Protected
            ElseIf (foundModifiers And SourceMemberFlags.Private) <> 0 Then
                access = Accessibility.Private
            Else
                access = defaultAccessibility
            End If

            If access = Accessibility.Private Then
                If (foundModifiers And SourceMemberFlags.Overridable) <> 0 Then
                    ReportDiagnostic(diagBag, privateOverridableModifier, ERRID.ERR_BadSpecifierCombo2, "Private", "Overridable")
                ElseIf (foundModifiers And SourceMemberFlags.MustOverride) <> 0 Then
                    ReportDiagnostic(diagBag, privateMustOverrideModifier, ERRID.ERR_BadSpecifierCombo2, "Private", "MustOverride")
                ElseIf (foundModifiers And SourceMemberFlags.NotOverridable) <> 0 Then
                    ReportDiagnostic(diagBag, privateNotOverridableModifier, ERRID.ERR_BadSpecifierCombo2, "Private", "NotOverridable")
                End If
                foundModifiers = foundModifiers And Not (SourceMemberFlags.Overridable Or SourceMemberFlags.MustOverride Or SourceMemberFlags.NotOverridable)
            End If

            
            Return New MemberModifiers(foundModifiers, DirectCast(access, SourceMemberFlags))
        End Function