[Version 11.0] Feature support for relaxed shift operator requirements

standard/classes.md

@@ -424,7 +424,7 @@
     : 'where' type_parameter ':' type_parameter_constraints
     ;
 
 type_parameter_constraints
     : primary_constraint (',' secondary_constraints)? (',' constructor_constraint)?
     | secondary_constraints (',' constructor_constraint)?
     | constructor_constraint
@@ -536,15 +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;
@@ -3558,7 +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
@@ -4919,7 +4919,7 @@
     : '!'
     ;
 
 overloadable_unary_operator
     : '+' | '-' | logical_negation_operator | '~' | '++' | '--' | 'true' | 'false'
     ;
 
@@ -5025,7 +5025,7 @@
 The following rules apply to binary operator declarations, where `T` denotes the instance type of the class or struct that contains the operator declaration:
 
 - A binary non-shift operator shall take two parameters, at least one of which shall have type `T` or `T?`, and can return any type.
-- A binary `<<` or `>>` operator ([§12.14](expressions.md#1214-shift-operators)) shall take two parameters, the first of which shall have type `T` or `T?` and the second of which shall have type `int` or `int?`, and can return any type.
+- A binary `<<` or `>>` operator ([§12.14](expressions.md#1214-shift-operators)) shall take two parameters, the first of which shall have type `T` or `T?`, and can return any type.
 
 The signature of a binary operator consists of the operator token (`+`, `-`, `*`, `/`, `%`, `&`, `|`, `^`, `<<`, `>>`, `==`, `!=`, `>`, `<`, `>=`, or `<=`) and the types of the two parameters. The return type and the names of the parameters are not part of a binary operator’s signature.
 
@@ -6212,7 +6212,7 @@
 >     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));
 >     }
@@ -6395,7 +6395,7 @@
 >     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;
 >     }
@@ -6426,11 +6426,11 @@
 >             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;
 >     }

standard/expressions.md

@@ -253,7 +253,7 @@
 
 An operation of the form `x «op» y`, where «op» is an overloadable binary operator, `x` is an expression of type `X`, and `y` is an expression of type `Y`, is processed as follows:
 
-- The set of candidate user-defined operators provided by `X` and `Y` for the operation `operator «op»(x, y)` is determined. The set consists of the union of the candidate operators provided by `X` and the candidate operators provided by `Y`, each determined using the rules of [§12.4.6](expressions.md#1246-candidate-user-defined-operators). For the combined set, candidates are merged as follows:
+- The set of candidate user-defined operators provided by `X` and `Y` for the operation `operator «op»(x, y)` is determined. The set consists of the union of the candidate operators provided by `X` and, unless the operator is a shift operator, the candidate operators provided by `Y`, each determined using the rules of [§12.4.6](expressions.md#1246-candidate-user-defined-operators). For the combined set, candidates are merged as follows:
   - If `X` and `Y` are identity convertible, or if `X` and `Y` are derived from a common base type, then shared candidate operators only occur in the combined set once.
   - If there is an identity conversion between `X` and `Y`, an operator `«op»Y` provided by `Y` has the same return type as an `«op»X` provided by `X` and the operand types of `«op»Y` have an identity conversion to the corresponding operand types of `«op»X` then only `«op»X` occurs in the set.
 - If the set of candidate user-defined operators is not empty, then this becomes the set of candidate operators for the operation. Otherwise, the predefined binary `operator «op»` implementations, including their lifted forms, become the set of candidate operators for the operation. The predefined implementations of a given operator are specified in the description of the operator. For predefined enum and delegate operators, the only operators considered are those provided by an enum or delegate type that is the binding-time type of one of the operands.
@@ -2292,8 +2292,8 @@
 A *null_conditional_invocation_expression* is syntactically either a *null_conditional_member_access* ([§12.8.8](expressions.md#1288-null-conditional-member-access)) or *null_conditional_element_access* ([§12.8.13](expressions.md#12813-null-conditional-element-access)) where the final *dependent_access* is an invocation expression ([§12.8.10](expressions.md#12810-invocation-expressions)).
 
 A *null_conditional_invocation_expression* occurs within the context of a *statement_expression* ([§13.7](statements.md#137-expression-statements)), *anonymous_function_body* ([§12.22.1](expressions.md#12221-general)), or *method_body* ([§15.6.1](classes.md#1561-general)).
 
 Unlike the syntactically equivalent *null_conditional_member_access* or *null_conditional_element_access*, a *null_conditional_invocation_expression* may be classified as nothing.
 
 ```ANTLR
 null_conditional_invocation_expression
@@ -2373,7 +2373,7 @@
 - The *primary_expression* has compile-time type `dynamic`.
 - At least one expression of the *argument_list* has compile-time type `dynamic`.
 
 In this case the compile-time type of the *element_access* depends on the compile-time type of its *primary_expression*: if it has an array type then the compile-time type is the element type of that array type; otherwise the compile-time type is `dynamic` and the *element_access* is classified as a value of type `dynamic`. The rules below to determine the meaning of the *element_access* are then applied at run-time, using the run-time type instead of the compile-time type of those of the *primary_expression* and *argument_list* expressions which have the compile-time type `dynamic`. If the *primary_expression* does not have compile-time type `dynamic`, then the element access undergoes a limited compile-time check as described in [§12.6.5](expressions.md#1265-compile-time-checking-of-dynamic-member-invocation).
 
 > *Example*:
 >
@@ -3518,7 +3518,7 @@
 - one of the following value types: `sbyte`, `byte`, `short`, `ushort`, `int`, `uint`, `nint`, `nuint`, `long`, `ulong`, `char`, `float`, `double`, `decimal`, `bool`; or
 - any enumeration type.
 
 ### 12.8.22 Stack allocation
 
 A stack allocation expression allocates a block of memory from the execution stack. The ***execution stack*** is an area of memory where local variables are stored. The execution stack is not part of the managed heap. The memory used for local variable storage is automatically recovered when the current function returns.
 
@@ -3986,8 +3986,8 @@
 All non-positional properties being changed shall have both set and init accessors.
 
 This expression is evaluated as follows:
 
 - For a record class type, the receiver's clone method ([§15.16.3](classes.md#15163-copy-and-clone-members)) is invoked, and its result is converted to the receiver’s type.
 - Each `member_initializer` is processed the same way as an assignment to
 a field or property access of the result of the conversion. Assignments are processed in lexical order. If *member_initializer_list* is omitted, no members are changed.
 
@@ -4512,7 +4512,7 @@
 
 For an operation of the form `x << count` or `x >> count`, binary operator overload resolution ([§12.4.5](expressions.md#1245-binary-operator-overload-resolution)) is applied to select a specific operator implementation. The operands are converted to the parameter types of the selected operator, and the type of the result is the return type of the operator.
 
-When declaring an overloaded shift operator, the type of the first operand shall always be the class or struct containing the operator declaration, and the type of the second operand shall always be `int`.
+When declaring an overloaded shift operator, the type of the first operand shall always be the class or struct containing the operator declaration.
 
 The predefined shift operators are listed below.
 
@@ -5434,7 +5434,7 @@
 An ***anonymous function*** is an expression that represents an “in-line” method definition. An anonymous function does not have a value or type in and of itself, but is convertible to a compatible delegate or expression-tree type. The evaluation of an anonymous-function conversion depends on the target type of the conversion: If it is a delegate type, the conversion evaluates to a delegate value referencing the method that the anonymous function defines. If it is an expression-tree type, the conversion evaluates to an expression tree that represents the structure of the method as an object structure.
 
 > *Note*: For historical reasons, there are two syntactic flavors of anonymous functions, namely *lambda_expression* and *anonymous_method_expression*. For almost all purposes, *lambda_expression* is more concise and expressive than *anonymous_method_expression*s, which remain in the language for backwards compatibility. *end note*
 
 ```ANTLR
 lambda_expression
     : attributes? anonymous_function_modifier?