Merge pull request #13510 from AlekseyTs/NewScopingRules_10

Disallow declaration of variables within constructor/field initializers.

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

@@ -2044,6 +2044,11 @@ private BoundExpression BindArgumentValue(DiagnosticBag diagnostics, ArgumentSyn
  var declaration = (TypedVariableComponentSyntax)declarationExpression.VariableComponent;
  var typeSyntax = declaration.Type;
 
+ if (InConstructorInitializer || InFieldInitializer)
+ {
+ Error(diagnostics, ErrorCode.ERR_ExpressionVariableInConstructorOrFieldInitializer, declarationExpression);
+ }
+
  bool isConst = false;
  bool isVar;
  AliasSymbol alias;

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

@@ -240,6 +240,12 @@ private BoundPattern BindDeclarationPattern(
  DiagnosticBag diagnostics)
  {
  Debug.Assert(operand != null || operandType != (object)null);
+
+ if (InConstructorInitializer || InFieldInitializer)
+ {
+ Error(diagnostics, ErrorCode.ERR_ExpressionVariableInConstructorOrFieldInitializer, node);
+ }
+
  var typeSyntax = node.Type;
  var identifier = node.Identifier;
 

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -4950,4 +4950,7 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
  <data name="ERR_OutVarDeconstructionIsNotSupported" xml:space="preserve">
  <value>Deconstruction is not supported for an 'out' argument.</value>
  </data>
+ <data name="ERR_ExpressionVariableInConstructorOrFieldInitializer" xml:space="preserve">
+ <value>Out variable or pattern variable declarations are not allowed within constructor/field/auto-implemented property initializers.</value>
+ </data>
 </root>

src/Compilers/CSharp/Portable/Errors/ErrorCode.cs

@@ -1433,6 +1433,7 @@ internal enum ErrorCode
  ERR_TypeInferenceFailedForImplicitlyTypedOutVariable = 8197,
  ERR_ExpressionTreeContainsOutVariable = 8198,
  ERR_OutVarDeconstructionIsNotSupported = 8199,
+ ERR_ExpressionVariableInConstructorOrFieldInitializer = 8200,
  #endregion diagnostics for out var
  }
 }