Fix some issues discovered when running nullability inference on ILSpy.

dgrunwald · dgrunwald · commit 87f1ac3a11bc · 2021-05-12T21:59:24.000+02:00
diff --git a/NullabilityInference/EdgeBuildingOperationVisitor.cs b/NullabilityInference/EdgeBuildingOperationVisitor.cs
@@ -1361,7 +1361,7 @@ private void CreateConversionEdge(TypeWithNode input, TypeWithNode target, Conve
                 if (elementConv.IsNullable)
                     throw new InvalidOperationException("Nullable unwrap failed");
                 CreateConversionEdge(input, target, elementConv, label);
-            } else if (conv.IsNumeric || conv.IsConstantExpression || conv.IsEnumeration) {
+            } else if (conv.IsNumeric || conv.IsConstantExpression || conv.IsEnumeration || conv.IsIntPtr) {
                 // OK, no edge required
                 Debug.Assert(target.Node.NullType == NullType.Oblivious);
             } else if (conv.IsThrow) {
@@ -1789,5 +1789,16 @@ public override TypeWithNode VisitConstantPattern(IConstantPatternOperation oper
         {
             return typeSystem.GetObliviousType(operation.Type);
         }
+
+        public override TypeWithNode VisitAddressOf(IAddressOfOperation operation, EdgeBuildingContext argument)
+        {
+            Visit(operation.Reference, EdgeBuildingContext.LValue);
+            return typeSystem.GetObliviousType(operation.Type);
+        }
+
+        public override TypeWithNode VisitSizeOf(ISizeOfOperation operation, EdgeBuildingContext argument)
+        {
+            return typeSystem.GetObliviousType(operation.Type);
+        }
     }
 }
diff --git a/NullabilityInference/NullabilityNode.cs b/NullabilityInference/NullabilityNode.cs
@@ -89,6 +89,9 @@ public NullabilityNode ReplacedWith {
         /// </summary>
         internal void ReplaceWith(NullabilityNode other)
         {
+            if (this == other) {
+                return;
+            }
             if (this.replacement != null) {
                 this.replacement.ReplaceWith(other);
                 return;
@@ -114,8 +117,7 @@ public SpecialNullabilityNode(NullType nullType)
 
         public override Location? Location => null;
 
-        public override string Name => NullType switch
-        {
+        public override string Name => NullType switch {
             NullType.Nullable => "<nullable>",
             NullType.NonNull => "<nonnull>",
             NullType.Oblivious => "<oblivious>",
@@ -157,7 +159,7 @@ internal sealed class HelperNullabilityNode : NullabilityNode
         private readonly long id = Interlocked.Increment(ref nextId);
 
         public override Location? Location => null;
-        
+
         private string symbolName = "helper";
 
         public override string Name => $"<{symbolName}#{id}>";
