Merge dev16.0-preview2-vs-deps to master-vs-deps

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -2822,10 +2822,16 @@ A catch() block after a catch (System.Exception e) block can catch non-CLS excep
     <value>Unrecognized #pragma directive</value>
   </data>
   <data name="WRN_IllegalPPWarning" xml:space="preserve">
-    <value>Expected disable or restore</value>
+    <value>Expected disable, restore, enable or safeonly</value>
   </data>
   <data name="WRN_IllegalPPWarning_Title" xml:space="preserve">
-    <value>Expected disable or restore after #pragma warning</value>
+    <value>Expected disable, restore, enable or safeonly after #pragma warning</value>
+  </data>
+  <data name="WRN_IllegalPPWarningSafeOnly" xml:space="preserve">
+    <value>Expected nullable</value>
+  </data>
+  <data name="WRN_IllegalPPWarningSafeOnly_Title" xml:space="preserve">
+    <value>Expected nullable after #pragma warning safeonly</value>
   </data>
   <data name="WRN_BadRestoreNumber" xml:space="preserve">
     <value>Cannot restore warning 'CS{0}' because it was disabled globally</value>
@@ -5268,6 +5274,9 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="IDS_FeatureNullableReferenceTypes" xml:space="preserve">
     <value>nullable reference types</value>
   </data>
+  <data name="IDS_FeaturePragmaWarningEnableOrSafeOnly" xml:space="preserve">
+    <value>warning action enable or safeonly</value>
+  </data>
   <data name="WRN_ConvertingNullableToNonNullable" xml:space="preserve">
     <value>Converting null literal or possible null value to non-nullable type.</value>
   </data>

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

@@ -1625,6 +1625,7 @@ internal enum ErrorCode
         ERR_DiscardPatternInSwitchStatement = 8523,
         #endregion diagnostics introduced for recursive patterns
 
+        WRN_IllegalPPWarningSafeOnly = 8599,
         WRN_ConvertingNullableToNonNullable = 8600,
         WRN_NullReferenceAssignment = 8601,
         WRN_NullReferenceReceiver = 8602,

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

@@ -362,6 +362,7 @@ internal static int GetWarningLevel(ErrorCode code)
                 case ErrorCode.WRN_AttributesOnBackingFieldsNotAvailable:
                 case ErrorCode.WRN_TupleBinopLiteralNameMismatch:
                 case ErrorCode.WRN_TypeParameterSameAsOuterMethodTypeParameter:
+                case ErrorCode.WRN_IllegalPPWarningSafeOnly:
                 case ErrorCode.WRN_ConvertingNullableToNonNullable:
                 case ErrorCode.WRN_NullReferenceAssignment:
                 case ErrorCode.WRN_NullReferenceReceiver:

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

@@ -127,7 +127,7 @@ internal enum MessageID
         IDS_FeatureTuples = MessageBase + 12711,
         IDS_FeatureOutVar = MessageBase + 12713,
 
-        // IDS_FeatureIOperation = MessageBase + 12714,
+        IDS_FeaturePragmaWarningEnableOrSafeOnly = MessageBase + 12714,
         IDS_FeatureExpressionBodiedAccessor = MessageBase + 12715,
         IDS_FeatureExpressionBodiedDeOrConstructor = MessageBase + 12716,
         IDS_ThrowExpression = MessageBase + 12717,
@@ -244,6 +244,7 @@ internal static LanguageVersion RequiredVersion(this MessageID feature)
                 case MessageID.IDS_FeatureCoalesceAssignmentExpression:
                 case MessageID.IDS_FeatureUnconstrainedTypeParameterInNullCoalescingOperator:
                 case MessageID.IDS_FeatureNullableReferenceTypes: // syntax and semantic check
+                case MessageID.IDS_FeaturePragmaWarningEnableOrSafeOnly:
                 case MessageID.IDS_FeatureObjectGenericTypeConstraint:   // semantic check
                 case MessageID.IDS_FeatureIndexOperator: // semantic check
                 case MessageID.IDS_FeatureRangeOperator: // semantic check