diff --git a/pkg/analysis_server/lib/src/services/refactoring/naming_conventions.dart b/pkg/analysis_server/lib/src/services/refactoring/naming_conventions.dart
index 79bf48c..678166f 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/naming_conventions.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/naming_conventions.dart
@@ -19,8 +19,8 @@
 /// - OK if the name is valid;
 /// - WARNING if the name is discouraged;
 /// - FATAL if the name is illegal.
-RefactoringStatus validateConstructorName(String? name) {
-  if (name != null && name.isEmpty) {
+RefactoringStatus validateConstructorName(String name) {
+  if (name.isEmpty) {
     return RefactoringStatus();
   }
   return _validateLowerCamelCase(name, 'Constructor', allowBuiltIn: true);
@@ -46,8 +46,8 @@
 /// - OK if the name is valid;
 /// - WARNING if the name is discouraged;
 /// - FATAL if the name is illegal.
-RefactoringStatus validateImportPrefixName(String? name) {
-  if (name != null && name.isEmpty) {
+RefactoringStatus validateImportPrefixName(String name) {
+  if (name.isEmpty) {
     return RefactoringStatus();
   }
   return _validateLowerCamelCase(name, 'Import prefix');
@@ -65,11 +65,7 @@
 /// - OK if the name is valid;
 /// - WARNING if the name is discouraged;
 /// - FATAL if the name is illegal.
-RefactoringStatus validateLibraryName(String? name) {
-  // null
-  if (name == null) {
-    return RefactoringStatus.fatal('Library name must not be null.');
-  }
+RefactoringStatus validateLibraryName(String name) {
   // blank
   if (isBlank(name)) {
     return RefactoringStatus.fatal('Library name must not be blank.');
@@ -180,14 +176,9 @@
 }
 
 /// Validates [identifier], should be lower camel case.
-RefactoringStatus _validateLowerCamelCase(String? identifier, String desc,
+RefactoringStatus _validateLowerCamelCase(String identifier, String desc,
     {bool allowBuiltIn = false}) {
   desc += ' name';
-  // null
-  if (identifier == null) {
-    var message = '$desc must not be null.';
-    return RefactoringStatus.fatal(message);
-  }
   // is not identifier
   var status = _validateIdentifier(
       identifier, desc, 'a lowercase letter or underscore',
@@ -213,13 +204,8 @@
 }
 
 /// Validate the given identifier, which should be upper camel case.
-RefactoringStatus _validateUpperCamelCase(String? identifier, String desc) {
+RefactoringStatus _validateUpperCamelCase(String identifier, String desc) {
   desc += ' name';
-  // null
-  if (identifier == null) {
-    var message = '$desc must not be null.';
-    return RefactoringStatus.fatal(message);
-  }
   // is not identifier
   var status = _validateIdentifier(
       identifier, desc, 'an uppercase letter or underscore');
diff --git a/pkg/analysis_server/test/services/refactoring/naming_conventions_test.dart b/pkg/analysis_server/test/services/refactoring/naming_conventions_test.dart
index 8441368..50ccb48 100644
--- a/pkg/analysis_server/test/services/refactoring/naming_conventions_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/naming_conventions_test.dart
@@ -111,12 +111,6 @@
             'Constructor name must begin with a lowercase letter or underscore.');
   }
 
-  void test_validateConstructorName_null() {
-    assertRefactoringStatus(
-        validateConstructorName(null), RefactoringProblemSeverity.FATAL,
-        expectedMessage: 'Constructor name must not be null.');
-  }
-
   void test_validateConstructorName_OK() {
     assertRefactoringStatusOK(validateConstructorName('newName'));
   }
@@ -287,12 +281,6 @@
             'Import prefix name must begin with a lowercase letter or underscore.');
   }
 
-  void test_validateImportPrefixName_null() {
-    assertRefactoringStatus(
-        validateImportPrefixName(null), RefactoringProblemSeverity.FATAL,
-        expectedMessage: 'Import prefix name must not be null.');
-  }
-
   void test_validateImportPrefixName_OK() {
     assertRefactoringStatusOK(validateImportPrefixName('newName'));
   }
@@ -433,12 +421,6 @@
             'Library name identifier must begin with a lowercase letter or underscore.');
   }
 
-  void test_validateLibraryName_null() {
-    assertRefactoringStatus(
-        validateLibraryName(null), RefactoringProblemSeverity.FATAL,
-        expectedMessage: 'Library name must not be null.');
-  }
-
   void test_validateLibraryName_OK_oneIdentifier() {
     assertRefactoringStatusOK(validateLibraryName('name'));
   }