Simplify null checks to fix IDE0031 (#119722)

Don't set severity for dotnet_style_null_propagation so the value in eng/CodeAnalysis.src.globalconfig takes precedence

Fixes #119391

Author: akoeplinger

.editorconfig

@@ -99,7 +99,7 @@ dotnet_style_collection_initializer = true:suggestion
 dotnet_style_prefer_collection_expression = when_types_exactly_match
 dotnet_style_explicit_tuple_names = true:suggestion
 dotnet_style_coalesce_expression = true:suggestion
-dotnet_style_null_propagation = true:suggestion
+dotnet_style_null_propagation = true
 dotnet_style_prefer_is_null_check_over_reference_equality_method = true:suggestion
 dotnet_style_prefer_inferred_tuple_names = true:suggestion
 dotnet_style_prefer_inferred_anonymous_type_member_names = true:suggestion

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeConstructorInfo.CoreCLR.cs

@@ -221,8 +221,7 @@ private void InvokeClassConstructor()
         public override MethodBody? GetMethodBody()
         {
             RuntimeMethodBody? mb = RuntimeMethodHandle.GetMethodBody(this, ReflectedTypeInternal);
-            if (mb != null)
-                mb._methodBase = this;
+            mb?._methodBase = this;
             return mb;
         }
 

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeMethodInfo.CoreCLR.cs

@@ -274,8 +274,7 @@ public override MethodImplAttributes GetMethodImplementationFlags()
         public override MethodBody? GetMethodBody()
         {
             RuntimeMethodBody? mb = RuntimeMethodHandle.GetMethodBody(this, ReflectedTypeInternal);
-            if (mb != null)
-                mb._methodBase = this;
+            mb?._methodBase = this;
             return mb;
         }
 

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Threading/Condition.cs

@@ -62,8 +62,7 @@ private unsafe void AddWaiter(Waiter waiter)
             AssertIsNotInList(waiter);
 
             waiter.prev = _waitersTail;
-            if (waiter.prev != null)
-                waiter.prev.next = waiter;
+            waiter.prev?.next = waiter;
 
             _waitersTail = waiter;
 

src/coreclr/nativeaot/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/TypeLoaderEnvironment.ConstructedGenericsRegistration.cs

@@ -102,19 +102,16 @@ internal void RegisterDynamicGenericTypesAndMethods(DynamicGenericsRegistrationD
                             var typeEntry = registeredTypes[i];
                             // There is no Remove feature in the LockFreeReaderHashtable...
                             GenericTypeEntry failedEntry = _dynamicGenericTypes.GetValueIfExists(typeEntry);
-                            if (failedEntry != null)
-                                failedEntry._isRegisteredSuccessfully = false;
+                            failedEntry?._isRegisteredSuccessfully = false;
                         }
                         for (int i = 0; i < registeredMethodsCount; i++)
                         {
                             // There is no Remove feature in the LockFreeReaderHashtable...
                             GenericMethodEntry failedEntry = _dynamicGenericMethods.GetValueIfExists(registeredMethods[i]);
-                            if (failedEntry != null)
-                                failedEntry._isRegisteredSuccessfully = false;
+                            failedEntry?._isRegisteredSuccessfully = false;
 
                             failedEntry = _dynamicGenericMethodComponents.GetValueIfExists(registeredMethods[i]);
-                            if (failedEntry != null)
-                                failedEntry._isRegisteredSuccessfully = false;
+                            failedEntry?._isRegisteredSuccessfully = false;
                         }
                     }
                     catch (Exception e)

src/libraries/Common/src/System/Runtime/InteropServices/ComEventsMethod.cs

@@ -144,10 +144,7 @@ public static ComEventsMethod Add(ComEventsMethod? methods, ComEventsMethod meth
                     current = current._next;
                 }
 
-                if (current != null)
-                {
-                    current._next = method._next;
-                }
+                current?._next = method._next;
 
                 return methods;
             }

src/libraries/Common/src/System/Runtime/InteropServices/ComEventsSink.cs

@@ -73,10 +73,7 @@ public static ComEventsSink Add(ComEventsSink? sinks, ComEventsSink sink)
                     current = current._next;
                 }
 
-                if (current != null)
-                {
-                    current._next = sink._next;
-                }
+                current?._next = sink._next;
             }
 
             sink.Unadvise();

src/libraries/System.Collections/src/System/Collections/Generic/SortedSet.cs

@@ -682,10 +682,7 @@ private void ReplaceNode(Node match, Node parentOfMatch, Node successor, Node pa
                 successor.Left = match.Left;
             }
 
-            if (successor != null)
-            {
-                successor.Color = match.Color;
-            }
+            successor?.Color = match.Color;
 
             ReplaceChildOrRoot(parentOfMatch, match, successor!);
         }

src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/Hosting/AtomicComposition.cs

@@ -137,10 +137,7 @@ protected virtual void Dispose(bool disposing)
             ThrowIfDisposed();
             _isDisposed = true;
 
-            if (_outerAtomicComposition != null)
-            {
-                _outerAtomicComposition.ContainsInnerAtomicComposition = false;
-            }
+            _outerAtomicComposition?.ContainsInnerAtomicComposition = false;
 
             // Revert is always immediate and involves forgetting information and
             // exceuting any appropriate revert actions

src/libraries/System.ComponentModel.Primitives/src/System/ComponentModel/EventHandlerList.cs

@@ -100,10 +100,7 @@ public void AddHandlers(EventHandlerList listToAddFrom)
         public void RemoveHandler(object key, Delegate? value)
         {
             ListEntry? e = Find(key);
-            if (e != null)
-            {
-                e._handler = Delegate.Remove(e._handler, value);
-            }
+            e?._handler = Delegate.Remove(e._handler, value);
         }
 
         private sealed class ListEntry