CSHARP-5155: Avoid unnecessary null checks and null where necessary (Coverity Analysis Issues) (#1360)

Author: adelinowona

src/MongoDB.Driver.Core/Core/Authentication/Oidc/OidcConfiguration.cs

@@ -39,27 +39,24 @@ public OidcConfiguration(
             EndPoints = Ensure.IsNotNullOrEmpty(endPoints, nameof(endPoints));
             Ensure.IsNotNull(authMechanismProperties, nameof(authMechanismProperties));
             PrincipalName = principalName;
-
-            if (authMechanismProperties != null)
+            
+            foreach (var authorizationProperty in authMechanismProperties)
             {
-                foreach (var authorizationProperty in authMechanismProperties)
+                switch (authorizationProperty.Key)
                 {
-                    switch (authorizationProperty.Key)
-                    {
-                        case CallbackMechanismPropertyName:
-                            Callback = GetProperty<IOidcCallback>(authorizationProperty);
-                            break;
-                        case EnvironmentMechanismPropertyName:
-                            Environment = GetProperty<string>(authorizationProperty);
-                            break;
-                        case TokenResourceMechanismPropertyName:
-                            TokenResource = GetProperty<string>(authorizationProperty);
-                            break;
-                        default:
-                            throw new ArgumentException(
-                                $"Unknown OIDC property '{authorizationProperty.Key}'.",
-                                authorizationProperty.Key);
-                    }
+                    case CallbackMechanismPropertyName:
+                        Callback = GetProperty<IOidcCallback>(authorizationProperty);
+                        break;
+                    case EnvironmentMechanismPropertyName:
+                        Environment = GetProperty<string>(authorizationProperty);
+                        break;
+                    case TokenResourceMechanismPropertyName:
+                        TokenResource = GetProperty<string>(authorizationProperty);
+                        break;
+                    default:
+                        throw new ArgumentException(
+                            $"Unknown OIDC property '{authorizationProperty.Key}'.",
+                            authorizationProperty.Key);
                 }
             }
 

src/MongoDB.Driver/Encryption/ExplicitEncryptionLibMongoCryptController.cs

@@ -232,7 +232,7 @@ public BsonValue EncryptField(
                     contentionFactor: encryptOptions.ContentionFactor,
                     encryptOptions.Algorithm,
                     wrappedValueBytes,
-                    ToBsonIfNotNull(encryptOptions?.RangeOptions?.CreateDocument()),
+                    ToBsonIfNotNull(encryptOptions.RangeOptions?.CreateDocument()),
                     isExpressionMode);
 
                 using (context)
@@ -267,7 +267,7 @@ public async Task<BsonValue> EncryptFieldAsync(
                     contentionFactor: encryptOptions.ContentionFactor,
                     encryptOptions.Algorithm,
                     wrappedValueBytes,
-                    ToBsonIfNotNull(encryptOptions?.RangeOptions?.CreateDocument()),
+                    ToBsonIfNotNull(encryptOptions.RangeOptions?.CreateDocument()),
                     isExpressionMode);
 
                 using (context)

src/MongoDB.Driver/Linq/Linq2Implementation/Translators/AggregateLanguageTranslator.cs

@@ -505,7 +505,7 @@ private BsonValue TranslateNewDateTime(NewExpression node)
 
             return new BsonDocument("$dateFromParts", new BsonDocument
             {
-                { "year", year, year != null },
+                { "year", year },
                 { "month", month, month != null },
                 { "day", day, day != null },
                 { "hour", hour, hour != null },