Simplify most FeatureUnmanagedGenericStructs.CheckFeatureAvailability calls

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

@@ -1141,13 +1141,7 @@ private BoundExpression BindSizeOf(SizeOfExpressionSyntax node, DiagnosticBag di
                 }
                 else if (type.GetArity() != 0)
                 {
-                    var unsupported = Compilation.LanguageVersion < MessageID.IDS_FeatureUnmanagedGenericStructs.RequiredVersion();
-                    if (unsupported)
-                    {
-                        // PROTOTYPE
-                        MessageID.IDS_FeatureUnmanagedGenericStructs.CheckFeatureAvailability(Compilation.LanguageVersion, diagnostics, node.Location);
-                        typeHasErrors = true;
-                    }
+                    MessageID.IDS_FeatureUnmanagedGenericStructs.CheckFeatureAvailability(Compilation.LanguageVersion, diagnostics, node.Location);
                 }
             }
 
@@ -3252,13 +3246,7 @@ private void BindArrayInitializerExpressions(InitializerExpressionSyntax initial
                 }
                 else if (elementType.TypeSymbol.GetArity() != 0)
                 {
-                    var unsupported = Compilation.LanguageVersion < MessageID.IDS_FeatureUnmanagedGenericStructs.RequiredVersion();
-                    if (unsupported)
-                    {
-                        // PROTOTYPE
-                        MessageID.IDS_FeatureUnmanagedGenericStructs.CheckFeatureAvailability(Compilation.LanguageVersion, diagnostics, elementTypeSyntax.Location);
-                        hasErrors = true;
-                    }
+                    MessageID.IDS_FeatureUnmanagedGenericStructs.CheckFeatureAvailability(Compilation.LanguageVersion, diagnostics, elementTypeSyntax.Location);
                 }
             }
 

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

@@ -2140,13 +2140,7 @@ private BoundExpression BindAddressOfExpression(PrefixUnaryExpressionSyntax node
                     }
                     else if (operandType.GetArity() != 0)
                     {
-                        var unsupported = Compilation.LanguageVersion < MessageID.IDS_FeatureUnmanagedGenericStructs.RequiredVersion();
-                        if (unsupported)
-                        {
-                            // PROTOTYPE
-                            MessageID.IDS_FeatureUnmanagedGenericStructs.CheckFeatureAvailability(Compilation.LanguageVersion, diagnostics, node.Location);
-                            hasErrors = true;
-                        }
+                        MessageID.IDS_FeatureUnmanagedGenericStructs.CheckFeatureAvailability(Compilation.LanguageVersion, diagnostics, node.Location);
                     }
                 }