diff --git a/pkg/analyzer/lib/src/error/codes.g.dart b/pkg/analyzer/lib/src/error/codes.g.dart
index 3e5d4fd64fea..9fe34ca2b2db 100644
--- a/pkg/analyzer/lib/src/error/codes.g.dart
+++ b/pkg/analyzer/lib/src/error/codes.g.dart
@@ -3818,8 +3818,8 @@ class CompileTimeErrorCode extends AnalyzerErrorCode {
     "Constant values from a deferred library can't be used as a default "
         "parameter value.",
     correctionMessage:
-        "Try leaving the default as null and initializing the parameter inside "
-        "the function body.",
+        "Try leaving the default as 'null' and initializing the parameter "
+        "inside the function body.",
     hasPublishedDocs: true,
   );
 
@@ -4230,7 +4230,7 @@ class CompileTimeErrorCode extends AnalyzerErrorCode {
   static const CompileTimeErrorCode NOT_NULL_AWARE_NULL_SPREAD =
       CompileTimeErrorCode(
     'NOT_NULL_AWARE_NULL_SPREAD',
-    "The Null typed expression can't be used with a non-null-aware spread.",
+    "The Null-typed expression can't be used with a non-null-aware spread.",
   );
 
   ///  No parameters.
@@ -6109,8 +6109,8 @@ class StaticWarningCode extends AnalyzerErrorCode {
   static const StaticWarningCode
       INVALID_NULL_AWARE_OPERATOR_AFTER_SHORT_CIRCUIT = StaticWarningCode(
     'INVALID_NULL_AWARE_OPERATOR',
-    "The receiver can't be null because of short-circuiting, so the null-aware "
-        "operator '{0}' can't be used.",
+    "The receiver can't be 'null' because of short-circuiting, so the "
+        "null-aware operator '{0}' can't be used.",
     correctionMessage: "Try replacing the operator '{0}' with '{1}'.",
     hasPublishedDocs: true,
     uniqueName: 'INVALID_NULL_AWARE_OPERATOR_AFTER_SHORT_CIRCUIT',
@@ -7120,8 +7120,8 @@ class WarningCode extends AnalyzerErrorCode {
   ///  1: the type argument associated with the method
   static const WarningCode NULL_ARGUMENT_TO_NON_NULL_TYPE = WarningCode(
     'NULL_ARGUMENT_TO_NON_NULL_TYPE',
-    "'{0}' shouldn't be called with a null argument for the non-nullable type "
-        "argument '{1}'.",
+    "'{0}' shouldn't be called with a 'null' argument for the non-nullable "
+        "type argument '{1}'.",
     correctionMessage: "Try adding a non-null argument.",
     hasPublishedDocs: true,
   );
@@ -7490,7 +7490,7 @@ class WarningCode extends AnalyzerErrorCode {
   static const WarningCode UNNECESSARY_NULL_COMPARISON_ALWAYS_NULL_FALSE =
       WarningCode(
     'UNNECESSARY_NULL_COMPARISON',
-    "The operand must be null, so the condition is always 'false'.",
+    "The operand must be 'null', so the condition is always 'false'.",
     correctionMessage: "Remove the condition.",
     hasPublishedDocs: true,
     uniqueName: 'UNNECESSARY_NULL_COMPARISON_ALWAYS_NULL_FALSE',
@@ -7500,7 +7500,7 @@ class WarningCode extends AnalyzerErrorCode {
   static const WarningCode UNNECESSARY_NULL_COMPARISON_ALWAYS_NULL_TRUE =
       WarningCode(
     'UNNECESSARY_NULL_COMPARISON',
-    "The operand must be null, so the condition is always 'true'.",
+    "The operand must be 'null', so the condition is always 'true'.",
     correctionMessage: "Remove the condition.",
     hasPublishedDocs: true,
     uniqueName: 'UNNECESSARY_NULL_COMPARISON_ALWAYS_NULL_TRUE',
@@ -7510,7 +7510,7 @@ class WarningCode extends AnalyzerErrorCode {
   static const WarningCode UNNECESSARY_NULL_COMPARISON_NEVER_NULL_FALSE =
       WarningCode(
     'UNNECESSARY_NULL_COMPARISON',
-    "The operand can't be null, so the condition is always 'false'.",
+    "The operand can't be 'null', so the condition is always 'false'.",
     correctionMessage:
         "Try removing the condition, an enclosing condition, or the whole "
         "conditional statement.",
@@ -7522,7 +7522,7 @@ class WarningCode extends AnalyzerErrorCode {
   static const WarningCode UNNECESSARY_NULL_COMPARISON_NEVER_NULL_TRUE =
       WarningCode(
     'UNNECESSARY_NULL_COMPARISON',
-    "The operand can't be null, so the condition is always 'true'.",
+    "The operand can't be 'null', so the condition is always 'true'.",
     correctionMessage: "Remove the condition.",
     hasPublishedDocs: true,
     uniqueName: 'UNNECESSARY_NULL_COMPARISON_NEVER_NULL_TRUE',
diff --git a/pkg/analyzer/messages.yaml b/pkg/analyzer/messages.yaml
index d5ae6d06dfb5..24460a80be0c 100644
--- a/pkg/analyzer/messages.yaml
+++ b/pkg/analyzer/messages.yaml
@@ -11447,7 +11447,7 @@ CompileTimeErrorCode:
       ```
   NON_CONSTANT_DEFAULT_VALUE_FROM_DEFERRED_LIBRARY:
     problemMessage: "Constant values from a deferred library can't be used as a default parameter value."
-    correctionMessage: Try leaving the default as null and initializing the parameter inside the function body.
+    correctionMessage: Try leaving the default as 'null' and initializing the parameter inside the function body.
     hasPublishedDocs: true
     comment: No parameters.
     documentation: |-
@@ -12733,7 +12733,7 @@ CompileTimeErrorCode:
       var m = <int, String>{...l.asMap()};
       ```
   NOT_NULL_AWARE_NULL_SPREAD:
-    problemMessage: "The Null typed expression can't be used with a non-null-aware spread."
+    problemMessage: "The Null-typed expression can't be used with a non-null-aware spread."
     hasPublishedDocs: false
     comment: No parameters.
   NO_ANNOTATION_CONSTRUCTOR_ARGUMENTS:
@@ -22695,7 +22695,7 @@ StaticWarningCode:
       not be appropriate in some cases.)
   INVALID_NULL_AWARE_OPERATOR_AFTER_SHORT_CIRCUIT:
     sharedName: INVALID_NULL_AWARE_OPERATOR
-    problemMessage: "The receiver can't be null because of short-circuiting, so the null-aware operator '{0}' can't be used."
+    problemMessage: "The receiver can't be 'null' because of short-circuiting, so the null-aware operator '{0}' can't be used."
     correctionMessage: "Try replacing the operator '{0}' with '{1}'."
     hasPublishedDocs: true
     comment: |-
@@ -25498,7 +25498,7 @@ WarningCode:
       }
       ```
   NULL_ARGUMENT_TO_NON_NULL_TYPE:
-    problemMessage: "'{0}' shouldn't be called with a null argument for the non-nullable type argument '{1}'."
+    problemMessage: "'{0}' shouldn't be called with a 'null' argument for the non-nullable type argument '{1}'."
     correctionMessage: Try adding a non-null argument.
     hasPublishedDocs: true
     comment: |-
@@ -26984,19 +26984,19 @@ WarningCode:
       ```
   UNNECESSARY_NULL_COMPARISON_ALWAYS_NULL_FALSE:
     sharedName: UNNECESSARY_NULL_COMPARISON
-    problemMessage: "The operand must be null, so the condition is always 'false'."
+    problemMessage: "The operand must be 'null', so the condition is always 'false'."
     correctionMessage: Remove the condition.
     hasPublishedDocs: true
     comment: No parameters.
   UNNECESSARY_NULL_COMPARISON_ALWAYS_NULL_TRUE:
     sharedName: UNNECESSARY_NULL_COMPARISON
-    problemMessage: "The operand must be null, so the condition is always 'true'."
+    problemMessage: "The operand must be 'null', so the condition is always 'true'."
     correctionMessage: Remove the condition.
     hasPublishedDocs: true
     comment: No parameters.
   UNNECESSARY_NULL_COMPARISON_NEVER_NULL_FALSE:
     sharedName: UNNECESSARY_NULL_COMPARISON
-    problemMessage: "The operand can't be null, so the condition is always 'false'."
+    problemMessage: "The operand can't be 'null', so the condition is always 'false'."
     correctionMessage: Try removing the condition, an enclosing condition, or the whole conditional statement.
     hasPublishedDocs: true
     comment: No parameters.
@@ -27054,7 +27054,7 @@ WarningCode:
       ```
   UNNECESSARY_NULL_COMPARISON_NEVER_NULL_TRUE:
     sharedName: UNNECESSARY_NULL_COMPARISON
-    problemMessage: "The operand can't be null, so the condition is always 'true'."
+    problemMessage: "The operand can't be 'null', so the condition is always 'true'."
     correctionMessage: Remove the condition.
     hasPublishedDocs: true
     comment: No parameters.
diff --git a/pkg/analyzer/tool/diagnostics/diagnostics.md b/pkg/analyzer/tool/diagnostics/diagnostics.md
index 063bdde626ef..3eb37202778c 100644
--- a/pkg/analyzer/tool/diagnostics/diagnostics.md
+++ b/pkg/analyzer/tool/diagnostics/diagnostics.md
@@ -10709,7 +10709,7 @@ abstract class C {
 
 ### invalid_null_aware_operator
 
-_The receiver can't be null because of short-circuiting, so the null-aware
+_The receiver can't be 'null' because of short-circuiting, so the null-aware
 operator '{0}' can't be used._
 
 _The receiver can't be null, so the null-aware operator '{0}' is unnecessary._
@@ -16689,7 +16689,7 @@ class C with M {}
 
 ### null_argument_to_non_null_type
 
-_'{0}' shouldn't be called with a null argument for the non-nullable type
+_'{0}' shouldn't be called with a 'null' argument for the non-nullable type
 argument '{1}'._
 
 #### Description
@@ -22799,13 +22799,13 @@ void f(int x) {
 
 ### unnecessary_null_comparison
 
-_The operand can't be null, so the condition is always 'false'._
+_The operand can't be 'null', so the condition is always 'false'._
 
-_The operand can't be null, so the condition is always 'true'._
+_The operand can't be 'null', so the condition is always 'true'._
 
-_The operand must be null, so the condition is always 'false'._
+_The operand must be 'null', so the condition is always 'false'._
 
-_The operand must be null, so the condition is always 'true'._
+_The operand must be 'null', so the condition is always 'true'._
 
 #### Description