Analyze ref declarations/assignments/foreachs/returns (#33869)

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

@@ -284,23 +284,6 @@ internal static bool IsTypeOrValueExpression(BoundExpression expression)
             }
         }
 
-        private static bool IsLegalSuppressionValueKind(BindValueKind valueKind)
-        {
-            // Need to review allowed uses of the suppression operator
-            // Tracked by https://github.com/dotnet/roslyn/issues/31297
-
-            switch (valueKind)
-            {
-                case BindValueKind.RValue:
-                case BindValueKind.RValueOrMethodGroup:
-                case BindValueKind.RefOrOut:
-                    return true;
-            }
-
-            // all others are illegal
-            return false;
-        }
-
         /// <summary>
         /// The purpose of this method is to determine if the expression satisfies desired capabilities. 
         /// If it is not then this code gives an appropriate error message.
@@ -323,12 +306,6 @@ internal bool CheckValueKind(SyntaxNode node, BoundExpression expr, BindValueKin
                 return false;
             }
 
-            if (expr.IsSuppressed && !IsLegalSuppressionValueKind(valueKind))
-            {
-                Error(diagnostics, ErrorCode.ERR_IllegalSuppression, node);
-                return false;
-            }
-
             switch (expr.Kind)
             {
                 // we need to handle properties and event in a special way even in an RValue case because of getters

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

@@ -238,12 +238,12 @@ private BoundExpression BindArgListOperator(InvocationExpressionSyntax node, Dia
                 // Either we have a dynamic method group invocation "dyn.M(...)" or 
                 // a dynamic delegate invocation "dyn(...)" -- either way, bind it as a dynamic
                 // invocation and let the lowering pass sort it out.
-                reportSuppressionIfPresent();
+                ReportSuppressionIfNeeded(boundExpression, diagnostics);
                 result = BindDynamicInvocation(node, boundExpression, analyzedArguments, ImmutableArray<MethodSymbol>.Empty, diagnostics, queryClause);
             }
             else if (boundExpression.Kind == BoundKind.MethodGroup)
             {
-                reportSuppressionIfPresent();
+                ReportSuppressionIfNeeded(boundExpression, diagnostics);
                 result = BindMethodGroupInvocation(
                     node, expression, methodName, (BoundMethodGroup)boundExpression, analyzedArguments,
                     diagnostics, queryClause, allowUnexpandedForm: allowUnexpandedForm, anyApplicableCandidates: out _);
@@ -270,14 +270,6 @@ private BoundExpression BindArgListOperator(InvocationExpressionSyntax node, Dia
             CheckRestrictedTypeReceiver(result, this.Compilation, diagnostics);
 
             return result;
-
-            void reportSuppressionIfPresent()
-            {
-                if (boundExpression.IsSuppressed)
-                {
-                    Error(diagnostics, ErrorCode.ERR_IllegalSuppression, boundExpression.Syntax);
-                }
-            }
         }
 
         private BoundExpression BindDynamicInvocation(

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

@@ -18,6 +18,7 @@ private BoundExpression BindCompoundAssignment(AssignmentExpressionSyntax node,
             node.Left.CheckDeconstructionCompatibleArgument(diagnostics);
 
             BoundExpression left = BindValue(node.Left, diagnostics, GetBinaryAssignmentKind(node.Kind()));
+            ReportSuppressionIfNeeded(left, diagnostics);
             BoundExpression right = BindValue(node.Right, diagnostics, BindValueKind.RValue);
             BinaryOperatorKind kind = SyntaxKindToBinaryOperatorKind(node.Kind());
 
@@ -2105,6 +2106,7 @@ private static void BindPointerIndirectionExpressionInternal(CSharpSyntaxNode no
         private BoundExpression BindAddressOfExpression(PrefixUnaryExpressionSyntax node, DiagnosticBag diagnostics)
         {
             BoundExpression operand = BindValue(node.Operand, diagnostics, BindValueKind.AddressOf);
+            ReportSuppressionIfNeeded(operand, diagnostics);
 
             bool hasErrors = operand.HasAnyErrors; // This would propagate automatically, but by reading it explicitly we can reduce cascading.
             bool isFixedStatementAddressOfExpression = SyntaxFacts.IsFixedStatementExpression(node);
@@ -2283,6 +2285,14 @@ private BoundExpression BindUnaryOperator(PrefixUnaryExpressionSyntax node, Diag
             return constant ?? BindUnaryOperatorCore(node, node.OperatorToken.Text, operand, diagnostics);
         }
 
+        private void ReportSuppressionIfNeeded(BoundExpression expr, DiagnosticBag diagnostics)
+        {
+            if (expr.IsSuppressed)
+            {
+                Error(diagnostics, ErrorCode.ERR_IllegalSuppression, expr.Syntax);
+            }
+        }
+
         private BoundExpression BindUnaryOperatorCore(CSharpSyntaxNode node, string operatorText, BoundExpression operand, DiagnosticBag diagnostics)
         {
             UnaryOperatorKind kind = SyntaxKindToUnaryOperatorKind(node.Kind());
@@ -3569,6 +3579,7 @@ private BoundExpression BindNullCoalescingOperator(BinaryExpressionSyntax node,
         private BoundExpression BindNullCoalescingAssignmentOperator(AssignmentExpressionSyntax node, DiagnosticBag diagnostics)
         {
             BoundExpression leftOperand = BindValue(node.Left, diagnostics, BindValueKind.CompoundAssignment);
+            ReportSuppressionIfNeeded(leftOperand, diagnostics);
             BoundExpression rightOperand = BindValue(node.Right, diagnostics, BindValueKind.RValue);
 
             // If either operand is bad, bail out preventing more cascading errors

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

@@ -586,6 +586,7 @@ private BoundExpressionStatement BindExpressionStatement(CSharpSyntaxNode node,
             BoundExpressionStatement expressionStatement;
 
             var expression = BindValue(syntax, diagnostics, BindValueKind.RValue);
+            ReportSuppressionIfNeeded(expression, diagnostics);
             if (!allowsAnyExpression && !IsValidStatementExpression(syntax, expression))
             {
                 if (!node.HasErrors)
@@ -1324,6 +1325,7 @@ private BoundExpression BindAssignment(AssignmentExpressionSyntax node, Diagnost
             }
 
             var op1 = BindValue(node.Left, diagnostics, lhsKind);
+            ReportSuppressionIfNeeded(op1, diagnostics);
 
             var lhsRefKind = RefKind.None;
             // If the LHS is a ref (not ref-readonly), the rhs

src/Compilers/CSharp/Portable/CSharpResources.Designer.cs

@@ -15017,7 +15017,7 @@ internal class CSharpResources {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Argument of type &apos;{0}&apos; cannot be used as an input of type &apos;{1}&apos; for parameter &apos;{2}&apos; in &apos;{3}&apos; due to differences in the nullability of reference types..
+        ///   Looks up a localized string similar to Argument of type &apos;{0}&apos; cannot be used for parameter &apos;{2}&apos; of type &apos;{1}&apos; in &apos;{3}&apos; due to differences in the nullability of reference types..
         /// </summary>
         internal static string WRN_NullabilityMismatchInArgument {
             get {
@@ -15026,7 +15026,7 @@ internal class CSharpResources {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Argument cannot be used as an input for parameter due to differences in the nullability of reference types..
+        ///   Looks up a localized string similar to Argument cannot be used for parameter due to differences in the nullability of reference types..
         /// </summary>
         internal static string WRN_NullabilityMismatchInArgument_Title {
             get {

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -5422,10 +5422,10 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
     <value>A null literal introduces a null value for a type parameter.</value>
   </data>
   <data name="WRN_NullabilityMismatchInArgument" xml:space="preserve">
-    <value>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</value>
+    <value>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</value>
   </data>
   <data name="WRN_NullabilityMismatchInArgument_Title" xml:space="preserve">
-    <value>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</value>
+    <value>Argument cannot be used for parameter due to differences in the nullability of reference types.</value>
   </data>
   <data name="WRN_NullabilityMismatchInArgumentForOutput" xml:space="preserve">
     <value>Argument of type '{0}' cannot be used as an output of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</value>

src/Compilers/CSharp/Portable/FlowAnalysis/NullableWalker.cs

@@ -1169,7 +1169,15 @@ protected override BoundNode VisitReturnStatementNoAdjust(BoundReturnStatement n
             if (_returnTypesOpt == null &&
                 TryGetReturnType(out TypeSymbolWithAnnotations returnType))
             {
-                VisitOptionalImplicitConversion(expr, returnType, useLegacyWarnings: false, AssignmentKind.Return);
+                if (node.RefKind == RefKind.None)
+                {
+                    VisitOptionalImplicitConversion(expr, returnType, useLegacyWarnings: false, AssignmentKind.Return);
+                }
+                else
+                {
+                    // return ref expr;
+                    VisitRefExpression(expr, returnType);
+                }
             }
             else
             {
@@ -1183,6 +1191,28 @@ protected override BoundNode VisitReturnStatementNoAdjust(BoundReturnStatement n
             return null;
         }
 
+        private TypeWithState VisitRefExpression(BoundExpression expr, TypeSymbolWithAnnotations destinationType)
+        {
+            Visit(expr);
+            TypeWithState resultType = ResultType;
+            if (!expr.IsSuppressed && RemoveConversion(expr, includeExplicitConversions: false).expression.Kind != BoundKind.ThrowExpression)
+            {
+                var lvalueResultType = LvalueResultType;
+                if (IsNullabilityMismatch(lvalueResultType, destinationType))
+                {
+                    // declared types must match
+                    ReportNullabilityMismatchInAssignment(expr.Syntax, lvalueResultType, destinationType);
+                }
+                else
+                {
+                    // types match, but state would let a null in
+                    ReportNullableAssignmentIfNecessary(expr, destinationType, resultType, useLegacyWarnings: false);
+                }
+            }
+
+            return resultType;
+        }
+
         private bool TryGetReturnType(out TypeSymbolWithAnnotations type)
         {
             var method = (MethodSymbol)_symbol;
@@ -1238,18 +1268,26 @@ public override BoundNode VisitLocalDeclaration(BoundLocalDeclaration node)
 
             bool inferredType = node.DeclaredType.InferredType;
             TypeSymbolWithAnnotations type = local.Type;
-            TypeWithState valueType = VisitOptionalImplicitConversion(initializer, targetTypeOpt: inferredType ? default : type, useLegacyWarnings: true, AssignmentKind.Assignment);
-
-            if (inferredType)
+            TypeWithState valueType;
+            if (local.IsRef)
+            {
+                valueType = VisitRefExpression(initializer, type);
+            }
+            else
             {
-                if (valueType.HasNullType)
+                valueType = VisitOptionalImplicitConversion(initializer, targetTypeOpt: inferredType ? default : type, useLegacyWarnings: true, AssignmentKind.Assignment);
+
+                if (inferredType)
                 {
-                    Debug.Assert(type.IsErrorType());
-                    valueType = type.ToTypeWithState();
-                }
+                    if (valueType.HasNullType)
+                    {
+                        Debug.Assert(type.IsErrorType());
+                        valueType = type.ToTypeWithState();
+                    }
 
-                type = valueType.ToTypeSymbolWithAnnotations();
-                _variableTypes[local] = type;
+                    type = valueType.ToTypeSymbolWithAnnotations();
+                    _variableTypes[local] = type;
+                }
             }
 
             TrackNullableStateForAssignment(initializer, type, slot, valueType, MakeSlot(initializer));
@@ -2836,6 +2874,9 @@ void visitArgumentEvaluateAndUnsplit(int argumentIndex, bool assertsTrue, bool a
             VisitResult result,
             bool extensionMethodThisArgument)
         {
+            // Note: we allow for some variance in `in` and `out` cases. Unlike in binding, we're not
+            // limited by CLR constraints.
+
             var resultType = result.RValueType;
             bool reported = false;
             switch (refKind)
@@ -2861,20 +2902,31 @@ void visitArgumentEvaluateAndUnsplit(int argumentIndex, bool assertsTrue, bool a
                     {
                         if (!argument.IsSuppressed)
                         {
-                            reported = ReportNullableAssignmentIfNecessary(argument, parameterType, resultType,
-                                useLegacyWarnings: false, AssignmentKind.Argument, target: parameter);
-                            if (!reported)
+                            var lvalueResultType = result.LValueType;
+                            if (IsNullabilityMismatch(lvalueResultType, parameterType))
                             {
-                                HashSet<DiagnosticInfo> useSiteDiagnostics = null;
-                                if (!_conversions.HasIdentityOrImplicitReferenceConversion(resultType.Type, parameterType.TypeSymbol, ref useSiteDiagnostics))
-                                {
-                                    ReportNullabilityMismatchInArgument(argument, resultType.Type, parameter, parameterType.TypeSymbol, forOutput: false);
-                                    reported = true;
-                                }
+                                // declared types must match
+                                ReportNullabilityMismatchInRefArgument(argument, argumentType: lvalueResultType, parameter, parameterType);
+                            }
+                            else
+                            {
+                                // types match, but state would let a null in
+                                ReportNullableAssignmentIfNecessary(argument, parameterType, resultType, useLegacyWarnings: false);
                             }
                         }
+
+                        // Check assignment from a fictional value from the parameter to the argument.
+                        var parameterWithState = parameterType.ToTypeWithState();
+                        if (argument.IsSuppressed)
+                        {
+                            parameterWithState = parameterWithState.WithNotNullState();
+                        }
+
+                        var parameterValue = new BoundParameter(argument.Syntax, parameter);
+                        var lValueType = result.LValueType;
+                        TrackNullableStateForAssignment(parameterValue, lValueType, MakeSlot(argument), parameterWithState);
                     }
-                    goto case RefKind.Out;
+                    break;
                 case RefKind.Out:
                     {
                         var parameterWithState = parameterType.ToTypeWithState();
@@ -2884,8 +2936,7 @@ void visitArgumentEvaluateAndUnsplit(int argumentIndex, bool assertsTrue, bool a
                         }
 
                         var lValueType = result.LValueType;
-                        // The argument and the parameter may have different nested or top-level nullabilities,
-                        // so we're going to check assignment from a fictional value from the parameter to the argument.
+                        // Check assignment from a fictional value from the parameter to the argument.
                         var parameterValue = new BoundParameter(argument.Syntax, parameter);
 
                         if (!argument.IsSuppressed && !reported)
@@ -4165,7 +4216,16 @@ public override BoundNode VisitAssignmentOperator(BoundAssignmentOperator node)
             }
             else
             {
-                TypeWithState rightType = VisitOptionalImplicitConversion(right, leftLValueType, UseLegacyWarnings(left), AssignmentKind.Assignment);
+                TypeWithState rightType;
+                if (!node.IsRef)
+                {
+                    rightType = VisitOptionalImplicitConversion(right, leftLValueType, UseLegacyWarnings(left), AssignmentKind.Assignment);
+                }
+                else
+                {
+                    rightType = VisitRefExpression(right, leftLValueType);
+                }
+
                 TrackNullableStateForAssignment(right, leftLValueType, MakeSlot(left), rightType, MakeSlot(right));
                 SetResult(new TypeWithState(leftLValueType.TypeSymbol, rightType.State), leftLValueType);
             }
@@ -4604,6 +4664,14 @@ private void ReportArgumentWarnings(BoundExpression argument, TypeWithState argu
             }
         }
 
+        private void ReportNullabilityMismatchInRefArgument(BoundExpression argument, TypeSymbolWithAnnotations argumentType, ParameterSymbol parameter, TypeSymbolWithAnnotations parameterType)
+        {
+            ReportSafetyDiagnostic(ErrorCode.WRN_NullabilityMismatchInArgument,
+                argument.Syntax, argumentType, parameterType,
+                new FormattedSymbol(parameter, SymbolDisplayFormat.ShortFormat),
+                new FormattedSymbol(parameter.ContainingSymbol, SymbolDisplayFormat.MinimallyQualifiedFormat));
+        }
+
         /// <summary>
         /// Report warning passing argument where nested nullability does not match
         /// parameter (e.g.: calling `void F(object[] o)` with `F(new[] { maybeNull })`).
@@ -4762,33 +4830,52 @@ protected override void VisitForEachExpression(BoundForEachStatement node)
         public override void VisitForEachIterationVariables(BoundForEachStatement node)
         {
             // declare and assign all iteration variables
+            TypeSymbolWithAnnotations sourceType = node.EnumeratorInfoOpt?.ElementType ?? default;
+            TypeWithState sourceState = sourceType.ToTypeWithState();
             foreach (var iterationVariable in node.IterationVariables)
             {
-                TypeWithState sourceType = node.EnumeratorInfoOpt?.ElementType.ToTypeWithState() ?? default;
                 var state = NullableFlowState.NotNull;
-                if (!sourceType.HasNullType)
+                if (!sourceState.HasNullType)
                 {
                     TypeSymbolWithAnnotations destinationType = iterationVariable.Type;
-                    HashSet<DiagnosticInfo> useSiteDiagnostics = null;
-                    Conversion conversion = _conversions.ClassifyImplicitConversionFromType(sourceType.Type, destinationType.TypeSymbol, ref useSiteDiagnostics);
-                    TypeWithState result = ApplyConversion(
-                        node.IterationVariableType,
-                        operandOpt: null,
-                        conversion,
-                        destinationType,
-                        sourceType,
-                        checkConversion: false,
-                        fromExplicitCast: false,
-                        useLegacyWarnings: false,
-                        AssignmentKind.Assignment,
-                        reportTopLevelWarnings: false,
-                        reportRemainingWarnings: false);
-                    if (destinationType.IsReferenceType && destinationType.NullableAnnotation.IsAnyNotNullable() && result.MaybeNull)
+
+                    if (iterationVariable.IsRef)
                     {
-                        ReportNonSafetyDiagnostic(node.IterationVariableType.Syntax);
+                        // foreach (ref DestinationType variable in collection)
+                        if (IsNullabilityMismatch(sourceType, destinationType))
+                        {
+                            var foreachSyntax = (ForEachStatementSyntax)node.Syntax;
+                            ReportNullabilityMismatchInAssignment(foreachSyntax.Type, sourceType, destinationType);
+                        }
+                        state = sourceState.State;
                     }
+                    else
+                    {
+                        // foreach (DestinationType variable in collection)
+                        // foreach (var variable in collection)
+                        // foreach (var (..., ...) in collection)
+                        // and asynchronous variants
+                        HashSet<DiagnosticInfo> useSiteDiagnostics = null;
+                        Conversion conversion = _conversions.ClassifyImplicitConversionFromType(sourceType.TypeSymbol, destinationType.TypeSymbol, ref useSiteDiagnostics);
+                        TypeWithState result = ApplyConversion(
+                            node.IterationVariableType,
+                            operandOpt: null,
+                            conversion,
+                            destinationType,
+                            sourceState,
+                            checkConversion: false,
+                            fromExplicitCast: false,
+                            useLegacyWarnings: false,
+                            AssignmentKind.Assignment,
+                            reportTopLevelWarnings: false,
+                            reportRemainingWarnings: false);
+                        if (destinationType.IsReferenceType && destinationType.NullableAnnotation.IsAnyNotNullable() && result.MaybeNull)
+                        {
+                            ReportNonSafetyDiagnostic(node.IterationVariableType.Syntax);
+                        }
 
-                    state = result.State;
+                        state = result.State;
+                    }
                 }
 
                 int slot = GetOrCreateSlot(iterationVariable);

src/Compilers/CSharp/Portable/xlf/CSharpResources.cs.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Typ odkazu s možnou hodnotou null v argumentu typu {0} neodpovídá cílovému typu {1} parametru {2} v {3}.</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Typ odkazu s možnou hodnotou null v argumentu neodpovídá cílovému typu.</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.de.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Die NULL-Zulässigkeit von Verweistypen im Argument vom Typ "{0}" entspricht nicht dem Zieltyp "{1}" für den Parameter "{2}" in "{3}".</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Die NULL-Zulässigkeit von Verweistypen im Argument entspricht nicht dem Zieltyp.</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.es.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">La nulabilidad de los tipos de referencia del argumento de tipo "{0}" no coincide con el tipo de destino "{1}" para el parámetro "{2}" en "{3}".</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">La nulabilidad de los tipos de referencia del argumento no coincide con el tipo de destino</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.fr.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">La nullabilité des types référence dans l'argument de type '{0}' ne correspond pas au type cible '{1}' pour le paramètre '{2}' dans '{3}'.</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">La nullabilité des types référence dans l'argument ne correspond pas au type cible.</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.it.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Il supporto dei valori Null dei tipi riferimento nell'argomento di tipo '{0}' non corrisponde al tipo di destinazione '{1}' per il parametro '{2}' in '{3}'.</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Il supporto dei valori Null dei tipi riferimento nell'argomento non corrisponde al tipo di destinazione.</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.ja.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">'{0}' 型の引数における参照型の Null 許容性が、'{3}' 内のパラメーター '{2}' に関する対象の型 '{1}' と一致しません。</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">引数における参照型の Null 許容性が、対象の型と一致しません。</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.ko.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">'{0}' 형식의 인수에 있는 참조 형식 Null 허용 여부가 '{3}'의 매개 변수 '{2}'에 대한 '{1}' 대상 형식과 일치하지 않습니다.</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">인수에 있는 참조 형식 Null 허용 여부가 대상 형식과 일치하지 않습니다.</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.pl.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Obsługa wartości null dla typów referencyjnych w argumencie typu „{0}” jest niezgodna z typem docelowym „{1}” dla parametru „{2}” w „{3}”.</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Obsługa wartości null dla typów referencyjnych w argumencie jest niezgodna z typem docelowym.</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.pt-BR.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">A anulabilidade de tipos de referência em um argumento do tipo '{0}' não coincide com o tipo de destino '{1}' para o parâmetro '{2}' em '{3}'.</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">A anulabilidade de tipos de referência no argumento não corresponde ao tipo de destino.</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.ru.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Допустимость значения NULL для ссылочных типов в аргументе типа "{0}" не соответствует целевому типу "{1}" для параметра "{2}" в "{3}".</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Допустимость значения NULL для ссылочных типов в аргументе не соответствует целевому типу.</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.tr.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">'{0}' türündeki bağımsız değişken için başvuru türlerinin boş değer atanabilirliği, '{3}' içindeki '{2}' parametresi için '{1}' hedef türüyle eşleşmiyor.</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">Bağımsız değişkendeki başvuru türlerinin boş değer atanabilirliği hedef tür ile eşleşmiyor.</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.zh-Hans.xlf

@@ -1048,7 +1048,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">类型“{0}”的实参中引用类型的为 Null 性与“{3}”中形参“{2}”的目标类型“{1}”不匹配。</target>
         <note />
       </trans-unit>
@@ -1063,7 +1063,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">参数中的引用类型的为 Null 性与目标类型不匹配。</target>
         <note />
       </trans-unit>

src/Compilers/CSharp/Portable/xlf/CSharpResources.zh-Hant.xlf

@@ -1343,7 +1343,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument">
-        <source>Argument of type '{0}' cannot be used as an input of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.</source>
+        <source>Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">型別 '{0}' 的引數中參考型別可 Null 性與 '{3}' 中參數 '{2}' 的目標型別 '{1}' 不符合。</target>
         <note />
       </trans-unit>
@@ -1358,7 +1358,7 @@
         <note />
       </trans-unit>
       <trans-unit id="WRN_NullabilityMismatchInArgument_Title">
-        <source>Argument cannot be used as an input for parameter due to differences in the nullability of reference types.</source>
+        <source>Argument cannot be used for parameter due to differences in the nullability of reference types.</source>
         <target state="needs-review-translation">引數中參考型別的可 Null 性與目標型別不符合。</target>
         <note />
       </trans-unit>