[Version 10.0] Feature support for record class as an alias for record

standard/classes.md

@@ -20,7 +20,7 @@
     ;
 
 class_tag
-    : 'class'
+    : 'record'? 'class'
     | 'record'
     ;
 ```
@@ -33,6 +33,8 @@
 
 If *class_tag* contains `record`, that class is a ***record class***; otherwise, it is a ***non-record class***.
 
+The *class_tag*s `record` and `record class` are equivalent.
+
 For a record class, *class_modifier* shall not be `static`.
 
 *delimited_parameter_list* shall not be present in a non-record class.
@@ -422,7 +424,7 @@
     : 'where' type_parameter ':' type_parameter_constraints
     ;
 
 type_parameter_constraints
     : primary_constraint (',' secondary_constraints)? (',' constructor_constraint)?
     | secondary_constraints (',' constructor_constraint)?
     | constructor_constraint
@@ -534,15 +536,15 @@
 >     static void M()
 >     {
 >         // nonnull constraint allows nonnullable struct type argument
 >         A<int> x1;
 >         // possible warning: nonnull constraint prohibits nullable struct type argument
 >         A<int?> x2;
 >         // nonnull constraint allows nonnullable class type argument
 >         A<C> x3;
 >         // possible warning: nonnull constraint prohibits nullable class type argument
 >         A<C?> x4;
 >         // nonnullable base class requirement allows nonnullable class type argument
 >         B1<C> x5;
 >         // possible warning: nonnullable base class requirement prohibits nullable
 >         // class type argument
 >         B1<C?> x6;
@@ -3556,7 +3558,7 @@
 >     static void Main()
 >     {
 >         field = 10;
 >         Console.WriteLine(Property); // Prints 10
 >         Property = 20;               // This invokes the get accessor, then assigns
 >                                      // via the resulting variable reference
 >         Console.WriteLine(field);    // Prints 20
@@ -4917,7 +4919,7 @@
     : '!'
     ;
 
 overloadable_unary_operator
     : '+' | '-' | logical_negation_operator | '~' | '++' | '--' | 'true' | 'false'
     ;
 
@@ -6134,7 +6136,7 @@
 >     public static bool operator!=(R1? left, R1? right) => !(left == right);
 > 
 >     public override int GetHashCode()
 >     {
 >         return HashCode.Combine(EqualityComparer<Type>.Default.GetHashCode(EqualityContract),
 >             EqualityComparer<T1>.Default.GetHashCode(P1));
 >     }
@@ -6315,7 +6317,7 @@
 >     protected virtual bool PrintMembers(StringBuilder builder)
 >     {
 >         builder.Append(nameof(P1));
 >         builder.Append(" = ");
 >         builder.Append(this.P1); // or builder.Append(this.P1.ToString()); if P1 has a value type
 >         return true;
 >     }
@@ -6346,11 +6348,11 @@
 >             builder.Append(", ");
 >         }
 >         builder.Append(nameof(P2));
 >         builder.Append(" = ");
 >         builder.Append(this.P2); // or builder.Append(this.P2); if P2 has a value type
 >         builder.Append(", ");
 >         builder.Append(nameof(P3));
 >         builder.Append(" = ");
 >         builder.Append(this.P3); // or builder.Append(this.P3); if P3 has a value type
 >         return true;
 >     }
@@ -6484,5 +6486,5 @@
 >
 > *end example*