Report info diagnostic for field and value in property accessors …

…regardless of language version (#73952)

src/Compilers/CSharp/Portable/Binder/Binder_Expressions.cs

@@ -1750,10 +1750,7 @@ internal void ReportFieldOrValueContextualKeywordConflictIfAny(SyntaxNode syntax
                 case "value" when ContainingMember() is MethodSymbol { MethodKind: MethodKind.PropertySet or MethodKind.EventAdd or MethodKind.EventRemove }:
                     {
                         var requiredVersion = MessageID.IDS_FeatureFieldAndValueKeywords.RequiredVersion();
-                        if (Compilation.LanguageVersion < requiredVersion)
-                        {
-                            diagnostics.Add(ErrorCode.INF_IdentifierConflictWithContextualKeyword, syntax, name, requiredVersion.ToDisplayString());
-                        }
+                        diagnostics.Add(ErrorCode.INF_IdentifierConflictWithContextualKeyword, syntax, name, requiredVersion.ToDisplayString());
                     }
                     break;
             }

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -6866,7 +6866,7 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
     <value>Compiling requires binding the lambda expression many times. Consider declaring the lambda expression with explicit parameter types, or if the containing method call is generic, consider using explicit type arguments.</value>
   </data>
   <data name="INF_IdentifierConflictWithContextualKeyword" xml:space="preserve">
-    <value>'{0}' is a contextual keyword, with a specific meaning, starting in language version {1}. Use '@{0}' to avoid a breaking change when compiling with language version {1} or later.</value>
+    <value>'{0}' is a contextual keyword in property accessors starting in language version {1}. Use '@{0}' instead.</value>
   </data>
   <data name="INF_IdentifierConflictWithContextualKeyword_Title" xml:space="preserve">
     <value>Identifier is a contextual keyword, with a specific meaning, in a later language version.</value>

src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenDeconstructTests.cs

@@ -1906,7 +1906,7 @@ class C
     static int field;
     static long x { set { System.Console.WriteLine($""setX {value}""); } }
     static string y { get; set; }
-    static ref int z { get { return ref field; } }
+    static ref int z { get { return ref @field; } }
 
     static void Main()
     {
@@ -1941,7 +1941,7 @@ class C
     static int field;
     static long x { set { System.Console.WriteLine($""setX {value}""); } }
     static string y { get; set; }
-    static ref int z { get { return ref field; } }
+    static ref int z { get { return ref @field; } }
 
     static void Main()
     {

src/Compilers/CSharp/Test/Emit2/Semantics/RecordTests.cs

@@ -5282,7 +5282,7 @@ record C1(int I1)
     public int this[int i] => 0;
     public int PropertyWithoutGetter { set { } }
     public int P2 { get => 43; }
-    public ref int P3 { get => ref field; }
+    public ref int P3 { get => ref @field; }
     public event System.Action a;
 
     private int field1 = 100;

src/Compilers/CSharp/Test/Semantic/Semantics/BindingAsyncTests.cs

@@ -2313,13 +2313,13 @@ public Task Prop
         get
         {
             Meth(1);
-            return field;
+            return @field;
         }
         set
         {
             Bar();
             Meth("""");
-            field = value;
+            @field = value;
         }
     }
 

src/Compilers/CSharp/Test/Semantic/Semantics/InheritanceBindingTests.cs

@@ -1907,17 +1907,17 @@ class Base
     int field = 0;
 
     public virtual int Proprty1 { get { return 0; } }
-    public virtual ref int Property2 { get { return ref field; } }
-    public virtual ref int Property3 { get { return ref field; } }
+    public virtual ref int Property2 { get { return ref @field; } }
+    public virtual ref int Property3 { get { return ref @field; } }
 }
 
 class Derived : Base
 {
     int field = 0;
 
-    public override ref int Proprty1 { get { return ref field; } }
+    public override ref int Proprty1 { get { return ref @field; } }
     public override int Property2 { get { return 0; } }
-    public override ref int Property3 { get { return ref field; } }
+    public override ref int Property3 { get { return ref @field; } }
 }
 ";
             CreateCompilationWithMscorlib45(text).VerifyDiagnostics(

src/Compilers/CSharp/Test/Semantic/Semantics/LambdaTests.cs

@@ -4742,7 +4742,7 @@ public void NullableTypeArraySwitchPattern()
 class C
 {
     object? field;
-    string Prop => field switch
+    string Prop => @field switch
     {
         string?[] a => ""a""
     };
@@ -4752,9 +4752,9 @@ class C
                 // (4,13): warning CS0649: Field 'C.field' is never assigned to, and will always have its default value null
                 //     object? field;
                 Diagnostic(ErrorCode.WRN_UnassignedInternalField, "field").WithArguments("C.field", "null").WithLocation(4, 13),
-                // (5,26): warning CS8509: The switch expression does not handle all possible values of its input type (it is not exhaustive). For example, the pattern '_' is not covered.
-                //     string Prop => field switch
-                Diagnostic(ErrorCode.WRN_SwitchExpressionNotExhaustive, "switch").WithArguments("_").WithLocation(5, 26));
+                // (5,27): warning CS8509: The switch expression does not handle all possible values of its input type (it is not exhaustive). For example, the pattern '_' is not covered.
+                //     string Prop => @field switch
+                Diagnostic(ErrorCode.WRN_SwitchExpressionNotExhaustive, "switch").WithArguments("_").WithLocation(5, 27));
         }
 
         [Fact, WorkItem(52827, "https://github.com/dotnet/roslyn/issues/52827")]
@@ -7344,7 +7344,7 @@ public void LambdaWithNonConstantDefault()
 class C
 {
     object field;
-    public object Field => field;
+    public object Field => @field;
 
     public C(object f) { field = f; }
 
@@ -7373,7 +7373,7 @@ public void AnonymousMethodWithNonConstantDefault()
 class C
 {
     object field;
-    public object Field => field;
+    public object Field => @field;
 
     public C(object f) { field = f; }
 

src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs

@@ -22615,7 +22615,7 @@ public void MemberNotNull_NotFound_PrivateInBase()
 public class Base
 {
     private string? field;
-    public string? P { get { return field; } set { field = value; } }
+    public string? P { get { return @field; } set { @field = value; } }
 }
 public class C : Base
 {
@@ -156308,7 +156308,7 @@ class C
     public string? field = null;
 
     [MemberNotNullWhen(true, ""field"")]
-    public System.Nullable<bool> Init => field != null;
+    public System.Nullable<bool> Init => @field != null;
 
     public void M()
     {
@@ -156349,7 +156349,7 @@ class C
     public string? field = null;
 
     [MemberNotNullWhen(true, ""field"")]
-    public bool Init => field != null;
+    public bool Init => @field != null;
 
     public void M()
     {
@@ -156387,7 +156387,7 @@ class C
     public string? field = null;
 
     [MemberNotNullWhen(true, ""field"")]
-    public System.Nullable<bool> Init => field != null;
+    public System.Nullable<bool> Init => @field != null;
 
     public void M()
     {